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Many of us who fly regularly have most probably seen a so-called winglet or wingtip device at the end of the wing of an airliner at least once. It is showing up more and more often on more and more types of aircraft, thus we felt it’s time to give an overview to our readers about these sometimes funny, sometimes cool and stylish looking aircraft parts.
History, Reason and Benefits
The initial theoretical concept goes back to times before even the Wright Brothers first took to the skies in 1905, but it was picked up and developed by Richard T. Whitcomb of NASA after the 1973 oil crisis – in order to reduce fuel consumption. The first tests were carried out in 1979/80 in cooperation with the U.S. Air Force. At almost the same time, but independent of any U.S. military organization, a private jet producer, LearJet exhibited a prototype in 1977: the LearJet 28 that featured the first winglets on a jet and a production aircraft. Flight tests made with and without winglets showed that the winglets increased range by about 6.5 percent and also improved directional stability for the LearJet- these two factors are the major reasons behind using this facility at any fixed wing aircraft ever since. A winglet is a (near) vertical extension of the wing tips. The upward angle of the winglet, its inward angle as well as its size and shape are critical for correct performance – this is why they can look quite different. Air rotating around the wing strikes the surface of the winglet that directs it in another direction – thus creating an extra force, basically converting otherwise wasted energy to thrust. This is a small contribution but can save a lot for an operator in an aircraft’s lifetime. Another potential benefit of winglets is that they reduce the strength of wingtip vortices, which trail behind the plane. When other aircraft pass through these vortices, the turbulent air can cause loss of control, possibly resulting in an accident.
Winglet Types
In general any wingtips that not end the wing simply horizontally are considered as some kind of a winglet. Even though in strictly technical terms Wingtip Fences are not real extensions of the wing, and Raked Wingtips do not have a vertical part, they are still widely considered as winglet variants.
WINGTIP FENCES are a special variant of winglets, that extend both upward and downward from the tip of the wing. Preferred by European plane-maker Airbus, it is featured on their full product range (except the A330/340 family and the future A350). The Airbus A300 was actually the first jet airliner to feature this kind of solution by default, but it was a very small version of the tool. Provided that most of the Airbus planes (including all A320 family jets) feature such wingtip fences, this may be the most seen and most produced winglet type. Even the new Airbus A380 double-decker features wingtip fences.
BLENDED WINGLETS (the real “Winglets”) are the most popular winglet type, leveraged by Airbus, Boeing, Embraer, Bombardier but also by Russian Tupolev and Iljushin. Blended winglets were first introduced on the McDonnel Douglas MD-11 aircraft in 1990 with launch customer Finnair (it also features a smaller winglet at the bottom side of the wing). In contrast to Airbus who applies the wingtip fences by default on most of their aircraft (and the winglets on the A330/340 family), blended winglets are considered by Boeing for example as an optional extra feature on their products, except for the Boeing 747-400. For some of the older Boeing jets (737 and 757) such blended winglets have been offered as an aftermarket retrofit, these are the newer, tall designs and do not connect to the tip of the wing with a sharp angle, but with a curve instead. These winglets are popular among airlines that fly these aircraft on medium/long haul routes as most of the real fuel savings materialize while cruising. Longer flights mean longer cruising, thus larger fuel savings. And they also server as marketing surface for airline logos or web addresses usually.
Just recently the Boeing 767-300ER has received 3.4 m high (!) winglets produced by Aviation Partners Inc. with American Airlines as the launch-customer with Air New Zealand and Hawaiian Airlines following with orders of 5 and 8 aircrafts respectively. 141 shipsets have been pre-sold already as the forecasted fuel savings range around 4%-6% for medium/long-range flights. Airbus earlier tested similar blended winglets designed by Winglet Technology for the A320 series, but determined that their benefits did not warrant further development and they stayed with the wingtip fences instead. Aviation Partners Boeing claims that winglets on 737s and 757s have saved a collective 1.2 billion gal. of fuel since they were introduced and 11.5 million tonnes of CO2 while reducing those types’ noise footprint by 6.5%. It has sold winglets to 140 airlines and 95% of all 737NGs are fitted with them. It is working on four winglet concepts for the 777 and hopes to finalize a design for that aircraft type by December, 2008.
G-TCCB - 40067F - Thomas Cook Airlines - Boeing 767-31K (28865)
Infrared converted Sony A6000 with Sony E 16mm F2.8 mounted with the Sony Ultra Wide Converter. HDR AEB +/-2 total of 3 exposures at F8, 16mm, auto focus and processed with Photomatix HDR software. Blue and red color channels swapped.
High Dynamic Range (HDR)
High-dynamic-range imaging (HDRI) is a high dynamic range (HDR) technique used in imaging and photography to reproduce a greater dynamic range of luminosity than is possible with standard digital imaging or photographic techniques. The aim is to present a similar range of luminance to that experienced through the human visual system. The human eye, through adaptation of the iris and other methods, adjusts constantly to adapt to a broad range of luminance present in the environment. The brain continuously interprets this information so that a viewer can see in a wide range of light conditions.
HDR images can represent a greater range of luminance levels than can be achieved using more 'traditional' methods, such as many real-world scenes containing very bright, direct sunlight to extreme shade, or very faint nebulae. This is often achieved by capturing and then combining several different, narrower range, exposures of the same subject matter. Non-HDR cameras take photographs with a limited exposure range, referred to as LDR, resulting in the loss of detail in highlights or shadows.
The two primary types of HDR images are computer renderings and images resulting from merging multiple low-dynamic-range (LDR) or standard-dynamic-range (SDR) photographs. HDR images can also be acquired using special image sensors, such as an oversampled binary image sensor.
Due to the limitations of printing and display contrast, the extended luminosity range of an HDR image has to be compressed to be made visible. The method of rendering an HDR image to a standard monitor or printing device is called tone mapping. This method reduces the overall contrast of an HDR image to facilitate display on devices or printouts with lower dynamic range, and can be applied to produce images with preserved local contrast (or exaggerated for artistic effect).
In photography, dynamic range is measured in exposure value (EV) differences (known as stops). An increase of one EV, or 'one stop', represents a doubling of the amount of light. Conversely, a decrease of one EV represents a halving of the amount of light. Therefore, revealing detail in the darkest of shadows requires high exposures, while preserving detail in very bright situations requires very low exposures. Most cameras cannot provide this range of exposure values within a single exposure, due to their low dynamic range. High-dynamic-range photographs are generally achieved by capturing multiple standard-exposure images, often using exposure bracketing, and then later merging them into a single HDR image, usually within a photo manipulation program). Digital images are often encoded in a camera's raw image format, because 8-bit JPEG encoding does not offer a wide enough range of values to allow fine transitions (and regarding HDR, later introduces undesirable effects due to lossy compression).
Any camera that allows manual exposure control can make images for HDR work, although one equipped with auto exposure bracketing (AEB) is far better suited. Images from film cameras are less suitable as they often must first be digitized, so that they can later be processed using software HDR methods.
In most imaging devices, the degree of exposure to light applied to the active element (be it film or CCD) can be altered in one of two ways: by either increasing/decreasing the size of the aperture or by increasing/decreasing the time of each exposure. Exposure variation in an HDR set is only done by altering the exposure time and not the aperture size; this is because altering the aperture size also affects the depth of field and so the resultant multiple images would be quite different, preventing their final combination into a single HDR image.
An important limitation for HDR photography is that any movement between successive images will impede or prevent success in combining them afterwards. Also, as one must create several images (often three or five and sometimes more) to obtain the desired luminance range, such a full 'set' of images takes extra time. HDR photographers have developed calculation methods and techniques to partially overcome these problems, but the use of a sturdy tripod is, at least, advised.
Some cameras have an auto exposure bracketing (AEB) feature with a far greater dynamic range than others, from the 3 EV of the Canon EOS 40D, to the 18 EV of the Canon EOS-1D Mark II. As the popularity of this imaging method grows, several camera manufactures are now offering built-in HDR features. For example, the Pentax K-7 DSLR has an HDR mode that captures an HDR image and outputs (only) a tone mapped JPEG file. The Canon PowerShot G12, Canon PowerShot S95 and Canon PowerShot S100 offer similar features in a smaller format.. Nikon's approach is called 'Active D-Lighting' which applies exposure compensation and tone mapping to the image as it comes from the sensor, with the accent being on retaing a realistic effect . Some smartphones provide HDR modes, and most mobile platforms have apps that provide HDR picture taking.
Camera characteristics such as gamma curves, sensor resolution, noise, photometric calibration and color calibration affect resulting high-dynamic-range images.
Color film negatives and slides consist of multiple film layers that respond to light differently. As a consequence, transparent originals (especially positive slides) feature a very high dynamic range
Tone mapping
Tone mapping reduces the dynamic range, or contrast ratio, of an entire image while retaining localized contrast. Although it is a distinct operation, tone mapping is often applied to HDRI files by the same software package.
Several software applications are available on the PC, Mac and Linux platforms for producing HDR files and tone mapped images. Notable titles include
Adobe Photoshop
Aurora HDR
Dynamic Photo HDR
HDR Efex Pro
HDR PhotoStudio
Luminance HDR
MagicRaw
Oloneo PhotoEngine
Photomatix Pro
PTGui
Information stored in high-dynamic-range images typically corresponds to the physical values of luminance or radiance that can be observed in the real world. This is different from traditional digital images, which represent colors as they should appear on a monitor or a paper print. Therefore, HDR image formats are often called scene-referred, in contrast to traditional digital images, which are device-referred or output-referred. Furthermore, traditional images are usually encoded for the human visual system (maximizing the visual information stored in the fixed number of bits), which is usually called gamma encoding or gamma correction. The values stored for HDR images are often gamma compressed (power law) or logarithmically encoded, or floating-point linear values, since fixed-point linear encodings are increasingly inefficient over higher dynamic ranges.
HDR images often don't use fixed ranges per color channel—other than traditional images—to represent many more colors over a much wider dynamic range. For that purpose, they don't use integer values to represent the single color channels (e.g., 0-255 in an 8 bit per pixel interval for red, green and blue) but instead use a floating point representation. Common are 16-bit (half precision) or 32-bit floating point numbers to represent HDR pixels. However, when the appropriate transfer function is used, HDR pixels for some applications can be represented with a color depth that has as few as 10–12 bits for luminance and 8 bits for chrominance without introducing any visible quantization artifacts.
History of HDR photography
The idea of using several exposures to adequately reproduce a too-extreme range of luminance was pioneered as early as the 1850s by Gustave Le Gray to render seascapes showing both the sky and the sea. Such rendering was impossible at the time using standard methods, as the luminosity range was too extreme. Le Gray used one negative for the sky, and another one with a longer exposure for the sea, and combined the two into one picture in positive.
Mid 20th century
Manual tone mapping was accomplished by dodging and burning – selectively increasing or decreasing the exposure of regions of the photograph to yield better tonality reproduction. This was effective because the dynamic range of the negative is significantly higher than would be available on the finished positive paper print when that is exposed via the negative in a uniform manner. An excellent example is the photograph Schweitzer at the Lamp by W. Eugene Smith, from his 1954 photo essay A Man of Mercy on Dr. Albert Schweitzer and his humanitarian work in French Equatorial Africa. The image took 5 days to reproduce the tonal range of the scene, which ranges from a bright lamp (relative to the scene) to a dark shadow.
Ansel Adams elevated dodging and burning to an art form. Many of his famous prints were manipulated in the darkroom with these two methods. Adams wrote a comprehensive book on producing prints called The Print, which prominently features dodging and burning, in the context of his Zone System.
With the advent of color photography, tone mapping in the darkroom was no longer possible due to the specific timing needed during the developing process of color film. Photographers looked to film manufacturers to design new film stocks with improved response, or continued to shoot in black and white to use tone mapping methods.
Color film capable of directly recording high-dynamic-range images was developed by Charles Wyckoff and EG&G "in the course of a contract with the Department of the Air Force". This XR film had three emulsion layers, an upper layer having an ASA speed rating of 400, a middle layer with an intermediate rating, and a lower layer with an ASA rating of 0.004. The film was processed in a manner similar to color films, and each layer produced a different color. The dynamic range of this extended range film has been estimated as 1:108. It has been used to photograph nuclear explosions, for astronomical photography, for spectrographic research, and for medical imaging. Wyckoff's detailed pictures of nuclear explosions appeared on the cover of Life magazine in the mid-1950s.
Late 20th century
Georges Cornuéjols and licensees of his patents (Brdi, Hymatom) introduced the principle of HDR video image, in 1986, by interposing a matricial LCD screen in front of the camera's image sensor, increasing the sensors dynamic by five stops. The concept of neighborhood tone mapping was applied to video cameras by a group from the Technion in Israel led by Dr. Oliver Hilsenrath and Prof. Y.Y.Zeevi who filed for a patent on this concept in 1988.
In February and April 1990, Georges Cornuéjols introduced the first real-time HDR camera that combined two images captured by a sensor3435 or simultaneously3637 by two sensors of the camera. This process is known as bracketing used for a video stream.
In 1991, the first commercial video camera was introduced that performed real-time capturing of multiple images with different exposures, and producing an HDR video image, by Hymatom, licensee of Georges Cornuéjols.
Also in 1991, Georges Cornuéjols introduced the HDR+ image principle by non-linear accumulation of images to increase the sensitivity of the camera: for low-light environments, several successive images are accumulated, thus increasing the signal to noise ratio.
In 1993, another commercial medical camera producing an HDR video image, by the Technion.
Modern HDR imaging uses a completely different approach, based on making a high-dynamic-range luminance or light map using only global image operations (across the entire image), and then tone mapping the result. Global HDR was first introduced in 19931 resulting in a mathematical theory of differently exposed pictures of the same subject matter that was published in 1995 by Steve Mann and Rosalind Picard.
On October 28, 1998, Ben Sarao created one of the first nighttime HDR+G (High Dynamic Range + Graphic image)of STS-95 on the launch pad at NASA's Kennedy Space Center. It consisted of four film images of the shuttle at night that were digitally composited with additional digital graphic elements. The image was first exhibited at NASA Headquarters Great Hall, Washington DC in 1999 and then published in Hasselblad Forum, Issue 3 1993, Volume 35 ISSN 0282-5449.
The advent of consumer digital cameras produced a new demand for HDR imaging to improve the light response of digital camera sensors, which had a much smaller dynamic range than film. Steve Mann developed and patented the global-HDR method for producing digital images having extended dynamic range at the MIT Media Laboratory. Mann's method involved a two-step procedure: (1) generate one floating point image array by global-only image operations (operations that affect all pixels identically, without regard to their local neighborhoods); and then (2) convert this image array, using local neighborhood processing (tone-remapping, etc.), into an HDR image. The image array generated by the first step of Mann's process is called a lightspace image, lightspace picture, or radiance map. Another benefit of global-HDR imaging is that it provides access to the intermediate light or radiance map, which has been used for computer vision, and other image processing operations.
21st century
In 2005, Adobe Systems introduced several new features in Photoshop CS2 including Merge to HDR, 32 bit floating point image support, and HDR tone mapping.
On June 30, 2016, Microsoft added support for the digital compositing of HDR images to Windows 10 using the Universal Windows Platform.
HDR sensors
Modern CMOS image sensors can often capture a high dynamic range from a single exposure. The wide dynamic range of the captured image is non-linearly compressed into a smaller dynamic range electronic representation. However, with proper processing, the information from a single exposure can be used to create an HDR image.
Such HDR imaging is used in extreme dynamic range applications like welding or automotive work. Some other cameras designed for use in security applications can automatically provide two or more images for each frame, with changing exposure. For example, a sensor for 30fps video will give out 60fps with the odd frames at a short exposure time and the even frames at a longer exposure time. Some of the sensor may even combine the two images on-chip so that a wider dynamic range without in-pixel compression is directly available to the user for display or processing.
en.wikipedia.org/wiki/High-dynamic-range_imaging
Infrared Photography
In infrared photography, the film or image sensor used is sensitive to infrared light. The part of the spectrum used is referred to as near-infrared to distinguish it from far-infrared, which is the domain of thermal imaging. Wavelengths used for photography range from about 700 nm to about 900 nm. Film is usually sensitive to visible light too, so an infrared-passing filter is used; this lets infrared (IR) light pass through to the camera, but blocks all or most of the visible light spectrum (the filter thus looks black or deep red). ("Infrared filter" may refer either to this type of filter or to one that blocks infrared but passes other wavelengths.)
When these filters are used together with infrared-sensitive film or sensors, "in-camera effects" can be obtained; false-color or black-and-white images with a dreamlike or sometimes lurid appearance known as the "Wood Effect," an effect mainly caused by foliage (such as tree leaves and grass) strongly reflecting in the same way visible light is reflected from snow. There is a small contribution from chlorophyll fluorescence, but this is marginal and is not the real cause of the brightness seen in infrared photographs. The effect is named after the infrared photography pioneer Robert W. Wood, and not after the material wood, which does not strongly reflect infrared.
The other attributes of infrared photographs include very dark skies and penetration of atmospheric haze, caused by reduced Rayleigh scattering and Mie scattering, respectively, compared to visible light. The dark skies, in turn, result in less infrared light in shadows and dark reflections of those skies from water, and clouds will stand out strongly. These wavelengths also penetrate a few millimeters into skin and give a milky look to portraits, although eyes often look black.
Until the early 20th century, infrared photography was not possible because silver halide emulsions are not sensitive to longer wavelengths than that of blue light (and to a lesser extent, green light) without the addition of a dye to act as a color sensitizer. The first infrared photographs (as distinct from spectrographs) to be published appeared in the February 1910 edition of The Century Magazine and in the October 1910 edition of the Royal Photographic Society Journal to illustrate papers by Robert W. Wood, who discovered the unusual effects that now bear his name. The RPS co-ordinated events to celebrate the centenary of this event in 2010. Wood's photographs were taken on experimental film that required very long exposures; thus, most of his work focused on landscapes. A further set of infrared landscapes taken by Wood in Italy in 1911 used plates provided for him by CEK Mees at Wratten & Wainwright. Mees also took a few infrared photographs in Portugal in 1910, which are now in the Kodak archives.
Infrared-sensitive photographic plates were developed in the United States during World War I for spectroscopic analysis, and infrared sensitizing dyes were investigated for improved haze penetration in aerial photography. After 1930, new emulsions from Kodak and other manufacturers became useful to infrared astronomy.
Infrared photography became popular with photography enthusiasts in the 1930s when suitable film was introduced commercially. The Times regularly published landscape and aerial photographs taken by their staff photographers using Ilford infrared film. By 1937 33 kinds of infrared film were available from five manufacturers including Agfa, Kodak and Ilford. Infrared movie film was also available and was used to create day-for-night effects in motion pictures, a notable example being the pseudo-night aerial sequences in the James Cagney/Bette Davis movie The Bride Came COD.
False-color infrared photography became widely practiced with the introduction of Kodak Ektachrome Infrared Aero Film and Ektachrome Infrared EIR. The first version of this, known as Kodacolor Aero-Reversal-Film, was developed by Clark and others at the Kodak for camouflage detection in the 1940s. The film became more widely available in 35mm form in the 1960s but KODAK AEROCHROME III Infrared Film 1443 has been discontinued.
Infrared photography became popular with a number of 1960s recording artists, because of the unusual results; Jimi Hendrix, Donovan, Frank and a slow shutter speed without focus compensation, however wider apertures like f/2.0 can produce sharp photos only if the lens is meticulously refocused to the infrared index mark, and only if this index mark is the correct one for the filter and film in use. However, it should be noted that diffraction effects inside a camera are greater at infrared wavelengths so that stopping down the lens too far may actually reduce sharpness.
Most apochromatic ('APO') lenses do not have an Infrared index mark and do not need to be refocused for the infrared spectrum because they are already optically corrected into the near-infrared spectrum. Catadioptric lenses do not often require this adjustment because their mirror containing elements do not suffer from chromatic aberration and so the overall aberration is comparably less. Catadioptric lenses do, of course, still contain lenses, and these lenses do still have a dispersive property.
Infrared black-and-white films require special development times but development is usually achieved with standard black-and-white film developers and chemicals (like D-76). Kodak HIE film has a polyester film base that is very stable but extremely easy to scratch, therefore special care must be used in the handling of Kodak HIE throughout the development and printing/scanning process to avoid damage to the film. The Kodak HIE film was sensitive to 900 nm.
As of November 2, 2007, "KODAK is preannouncing the discontinuance" of HIE Infrared 35 mm film stating the reasons that, "Demand for these products has been declining significantly in recent years, and it is no longer practical to continue to manufacture given the low volume, the age of the product formulations and the complexity of the processes involved." At the time of this notice, HIE Infrared 135-36 was available at a street price of around $12.00 a roll at US mail order outlets.
Arguably the greatest obstacle to infrared film photography has been the increasing difficulty of obtaining infrared-sensitive film. However, despite the discontinuance of HIE, other newer infrared sensitive emulsions from EFKE, ROLLEI, and ILFORD are still available, but these formulations have differing sensitivity and specifications from the venerable KODAK HIE that has been around for at least two decades. Some of these infrared films are available in 120 and larger formats as well as 35 mm, which adds flexibility to their application. With the discontinuance of Kodak HIE, Efke's IR820 film has become the only IR film on the marketneeds update with good sensitivity beyond 750 nm, the Rollei film does extend beyond 750 nm but IR sensitivity falls off very rapidly.
Color infrared transparency films have three sensitized layers that, because of the way the dyes are coupled to these layers, reproduce infrared as red, red as green, and green as blue. All three layers are sensitive to blue so the film must be used with a yellow filter, since this will block blue light but allow the remaining colors to reach the film. The health of foliage can be determined from the relative strengths of green and infrared light reflected; this shows in color infrared as a shift from red (healthy) towards magenta (unhealthy). Early color infrared films were developed in the older E-4 process, but Kodak later manufactured a color transparency film that could be developed in standard E-6 chemistry, although more accurate results were obtained by developing using the AR-5 process. In general, color infrared does not need to be refocused to the infrared index mark on the lens.
In 2007 Kodak announced that production of the 35 mm version of their color infrared film (Ektachrome Professional Infrared/EIR) would cease as there was insufficient demand. Since 2011, all formats of color infrared film have been discontinued. Specifically, Aerochrome 1443 and SO-734.
There is no currently available digital camera that will produce the same results as Kodak color infrared film although the equivalent images can be produced by taking two exposures, one infrared and the other full-color, and combining in post-production. The color images produced by digital still cameras using infrared-pass filters are not equivalent to those produced on color infrared film. The colors result from varying amounts of infrared passing through the color filters on the photo sites, further amended by the Bayer filtering. While this makes such images unsuitable for the kind of applications for which the film was used, such as remote sensing of plant health, the resulting color tonality has proved popular artistically.
Color digital infrared, as part of full spectrum photography is gaining popularity. The ease of creating a softly colored photo with infrared characteristics has found interest among hobbyists and professionals.
In 2008, Los Angeles photographer, Dean Bennici started cutting and hand rolling Aerochrome color Infrared film. All Aerochrome medium and large format which exists today came directly from his lab. The trend in infrared photography continues to gain momentum with the success of photographer Richard Mosse and multiple users all around the world.
Digital camera sensors are inherently sensitive to infrared light, which would interfere with the normal photography by confusing the autofocus calculations or softening the image (because infrared light is focused differently from visible light), or oversaturating the red channel. Also, some clothing is transparent in the infrared, leading to unintended (at least to the manufacturer) uses of video cameras. Thus, to improve image quality and protect privacy, many digital cameras employ infrared blockers. Depending on the subject matter, infrared photography may not be practical with these cameras because the exposure times become overly long, often in the range of 30 seconds, creating noise and motion blur in the final image. However, for some subject matter the long exposure does not matter or the motion blur effects actually add to the image. Some lenses will also show a 'hot spot' in the centre of the image as their coatings are optimised for visible light and not for IR.
An alternative method of DSLR infrared photography is to remove the infrared blocker in front of the sensor and replace it with a filter that removes visible light. This filter is behind the mirror, so the camera can be used normally - handheld, normal shutter speeds, normal composition through the viewfinder, and focus, all work like a normal camera. Metering works but is not always accurate because of the difference between visible and infrared refraction. When the IR blocker is removed, many lenses which did display a hotspot cease to do so, and become perfectly usable for infrared photography. Additionally, because the red, green and blue micro-filters remain and have transmissions not only in their respective color but also in the infrared, enhanced infrared color may be recorded.
Since the Bayer filters in most digital cameras absorb a significant fraction of the infrared light, these cameras are sometimes not very sensitive as infrared cameras and can sometimes produce false colors in the images. An alternative approach is to use a Foveon X3 sensor, which does not have absorptive filters on it; the Sigma SD10 DSLR has a removable IR blocking filter and dust protector, which can be simply omitted or replaced by a deep red or complete visible light blocking filter. The Sigma SD14 has an IR/UV blocking filter that can be removed/installed without tools. The result is a very sensitive digital IR camera.
While it is common to use a filter that blocks almost all visible light, the wavelength sensitivity of a digital camera without internal infrared blocking is such that a variety of artistic results can be obtained with more conventional filtration. For example, a very dark neutral density filter can be used (such as the Hoya ND400) which passes a very small amount of visible light compared to the near-infrared it allows through. Wider filtration permits an SLR viewfinder to be used and also passes more varied color information to the sensor without necessarily reducing the Wood effect. Wider filtration is however likely to reduce other infrared artefacts such as haze penetration and darkened skies. This technique mirrors the methods used by infrared film photographers where black-and-white infrared film was often used with a deep red filter rather than a visually opaque one.
Another common technique with near-infrared filters is to swap blue and red channels in software (e.g. photoshop) which retains much of the characteristic 'white foliage' while rendering skies a glorious blue.
Several Sony cameras had the so-called Night Shot facility, which physically moves the blocking filter away from the light path, which makes the cameras very sensitive to infrared light. Soon after its development, this facility was 'restricted' by Sony to make it difficult for people to take photos that saw through clothing. To do this the iris is opened fully and exposure duration is limited to long times of more than 1/30 second or so. It is possible to shoot infrared but neutral density filters must be used to reduce the camera's sensitivity and the long exposure times mean that care must be taken to avoid camera-shake artifacts.
Fuji have produced digital cameras for use in forensic criminology and medicine which have no infrared blocking filter. The first camera, designated the S3 PRO UVIR, also had extended ultraviolet sensitivity (digital sensors are usually less sensitive to UV than to IR). Optimum UV sensitivity requires special lenses, but ordinary lenses usually work well for IR. In 2007, FujiFilm introduced a new version of this camera, based on the Nikon D200/ FujiFilm S5 called the IS Pro, also able to take Nikon lenses. Fuji had earlier introduced a non-SLR infrared camera, the IS-1, a modified version of the FujiFilm FinePix S9100. Unlike the S3 PRO UVIR, the IS-1 does not offer UV sensitivity. FujiFilm restricts the sale of these cameras to professional users with their EULA specifically prohibiting "unethical photographic conduct".
Phase One digital camera backs can be ordered in an infrared modified form.
Remote sensing and thermographic cameras are sensitive to longer wavelengths of infrared (see Infrared spectrum#Commonly used sub-division scheme). They may be multispectral and use a variety of technologies which may not resemble common camera or filter designs. Cameras sensitive to longer infrared wavelengths including those used in infrared astronomy often require cooling to reduce thermally induced dark currents in the sensor (see Dark current (physics)). Lower cost uncooled thermographic digital cameras operate in the Long Wave infrared band (see Thermographic camera#Uncooled infrared detectors). These cameras are generally used for building inspection or preventative maintenance but can be used for artistic pursuits as well.
For my coming Jabba's palace I've built some technical device. I've made an instruction to see how I used some SNOT-techniques.
Nine Inch Nails wallpaper specifically formatted for Apple iPad. Could also work on Android phones and other small devices. For iPhone wallpapers, download the NIN:Access iPhone app at access.nin.com
Spaceflight (or space flight) is ballistic flight into or through outer space. Spaceflight can occur with spacecraft with or without humans on board. Yuri Gagarin of the Soviet Union was the first human to conduct a spaceflight. Examples of human spaceflight include the U.S. Apollo Moon landing and Space Shuttle programs and the Russian Soyuz program, as well as the ongoing International Space Station. Examples of unmanned spaceflight include space probes that leave Earth orbit, as well as satellites in orbit around Earth, such as communications satellites. These operate either by telerobotic control or are fully autonomous.
Spaceflight is used in space exploration, and also in commercial activities like space tourism and satellite telecommunications. Additional non-commercial uses of spaceflight include space observatories, reconnaissance satellites and other Earth observation satellites.
A spaceflight typically begins with a rocket launch, which provides the initial thrust to overcome the force of gravity and propels the spacecraft from the surface of the Earth. Once in space, the motion of a spacecraft – both when unpropelled and when under propulsion – is covered by the area of study called astrodynamics. Some spacecraft remain in space indefinitely, some disintegrate during atmospheric reentry, and others reach a planetary or lunar surface for landing or impact.
History
Main articles: History of spaceflight and Timeline of spaceflight
Tsiolkovsky, early space theorist
The first theoretical proposal of space travel using rockets was published by Scottish astronomer and mathematician William Leitch, in an 1861 essay "A Journey Through Space".[1] More well-known (though not widely outside Russia) is Konstantin Tsiolkovsky's work, "Исследование мировых пространств реактивными приборами" (The Exploration of Cosmic Space by Means of Reaction Devices), published in 1903.
Spaceflight became an engineering possibility with the work of Robert H. Goddard's publication in 1919 of his paper A Method of Reaching Extreme Altitudes. His application of the de Laval nozzle to liquid fuel rockets improved efficiency enough for interplanetary travel to become possible. He also proved in the laboratory that rockets would work in the vacuum of space;[specify] nonetheless, his work was not taken seriously by the public. His attempt to secure an Army contract for a rocket-propelled weapon in the first World War was defeated by the November 11, 1918 armistice with Germany. Working with private financial support, he was the first to launch a liquid-fueled rocket in 1926. Goddard's paper was highly influential on Hermann Oberth, who in turn influenced Wernher von Braun. Von Braun became the first to produce modern rockets as guided weapons, employed by Adolf Hitler. Von Braun's V-2 was the first rocket to reach space, at an altitude of 189 kilometers (102 nautical miles) on a June 1944 test flight.[2]
Tsiolkovsky's rocketry work was not fully appreciated in his lifetime, but he influenced Sergey Korolev, who became the Soviet Union's chief rocket designer under Joseph Stalin, to develop intercontinental ballistic missiles to carry nuclear weapons as a counter measure to United States bomber planes. Derivatives of Korolev's R-7 Semyorka missiles were used to launch the world's first artificial Earth satellite, Sputnik 1, on October 4, 1957, and later the first human to orbit the Earth, Yuri Gagarin in Vostok 1, on April 12, 1961.[3]
At the end of World War II, von Braun and most of his rocket team surrendered to the United States, and were expatriated to work on American missiles at what became the Army Ballistic Missile Agency. This work on missiles such as Juno I and Atlas enabled launch of the first US satellite Explorer 1 on February 1, 1958, and the first American in orbit, John Glenn in Friendship 7 on February 20, 1962. As director of the Marshall Space Flight Center, Von Braun oversaw development of a larger class of rocket called Saturn, which allowed the US to send the first two humans, Neil Armstrong and Buzz Aldrin, to the Moon and back on Apollo 11 in July 1969. Over the same period, the Soviet Union secretly tried but failed to develop the N1 rocket to give them the capability to land one person on the Moon.
Phases
Launch
Main article: Rocket launch
See also: List of space launch system designs
Rockets are the only means currently capable of reaching orbit or beyond. Other non-rocket spacelaunch technologies have yet to be built, or remain short of orbital speeds. A rocket launch for a spaceflight usually starts from a spaceport (cosmodrome), which may be equipped with launch complexes and launch pads for vertical rocket launches, and runways for takeoff and landing of carrier airplanes and winged spacecraft. Spaceports are situated well away from human habitation for noise and safety reasons. ICBMs have various special launching facilities.
A launch is often restricted to certain launch windows. These windows depend upon the position of celestial bodies and orbits relative to the launch site. The biggest influence is often the rotation of the Earth itself. Once launched, orbits are normally located within relatively constant flat planes at a fixed angle to the axis of the Earth, and the Earth rotates within this orbit.
A launch pad is a fixed structure designed to dispatch airborne vehicles. It generally consists of a launch tower and flame trench. It is surrounded by equipment used to erect, fuel, and maintain launch vehicles. Before launch, the rocket can weigh many hundreds of tonnes. The Space Shuttle Columbia, on STS-1, weighed 2,030 tonnes (4,480,000 lb) at take off.
Reaching space
The most commonly used definition of outer space is everything beyond the Kármán line, which is 100 kilometers (62 mi) above the Earth's surface. The United States sometimes defines outer space as everything beyond 50 miles (80 km) in altitude.
Rockets are the only currently practical means of reaching space. Conventional airplane engines cannot reach space due to the lack of oxygen. Rocket engines expel propellant to provide forward thrust that generates enough delta-v (change in velocity) to reach orbit.
For manned launch systems launch escape systems are frequently fitted to allow astronauts to escape in the case of emergency.
Alternatives
Main article: Non-rocket spacelaunch
Many ways to reach space other than rockets have been proposed. Ideas such as the space elevator, and momentum exchange tethers like rotovators or skyhooks require new materials much stronger than any currently known. Electromagnetic launchers such as launch loops might be feasible with current technology. Other ideas include rocket assisted aircraft/spaceplanes such as Reaction Engines Skylon (currently in early stage development), scramjet powered spaceplanes, and RBCC powered spaceplanes. Gun launch has been proposed for cargo.
Leaving orbit
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Main articles: Escape velocity and Parking orbit
Launched in 1959, Luna 1 was the first known man-made object to achieve escape velocity from the Earth.[4] (replica pictured)
Achieving a closed orbit is not essential to lunar and interplanetary voyages. Early Russian space vehicles successfully achieved very high altitudes without going into orbit. NASA considered launching Apollo missions directly into lunar trajectories but adopted the strategy of first entering a temporary parking orbit and then performing a separate burn several orbits later onto a lunar trajectory. This costs additional propellant because the parking orbit perigee must be high enough to prevent reentry while direct injection can have an arbitrarily low perigee because it will never be reached.
However, the parking orbit approach greatly simplified Apollo mission planning in several important ways. It substantially widened the allowable launch windows, increasing the chance of a successful launch despite minor technical problems during the countdown. The parking orbit was a stable "mission plateau" that gave the crew and controllers several hours to thoroughly check out the spacecraft after the stresses of launch before committing it to a long lunar flight; the crew could quickly return to Earth, if necessary, or an alternate Earth-orbital mission could be conducted. The parking orbit also enabled translunar trajectories that avoided the densest parts of the Van Allen radiation belts.
Apollo missions minimized the performance penalty of the parking orbit by keeping its altitude as low as possible. For example, Apollo 15 used an unusually low parking orbit (even for Apollo) of 92.5 nmi by 91.5 nmi (171 km by 169 km) where there was significant atmospheric drag. But it was partially overcome by continuous venting of hydrogen from the third stage of the Saturn V, and was in any event tolerable for the short stay.
Robotic missions do not require an abort capability or radiation minimization, and because modern launchers routinely meet "instantaneous" launch windows, space probes to the Moon and other planets generally use direct injection to maximize performance. Although some might coast briefly during the launch sequence, they do not complete one or more full parking orbits before the burn that injects them onto an Earth escape trajectory.
Note that the escape velocity from a celestial body decreases with altitude above that body. However, it is more fuel-efficient for a craft to burn its fuel as close to the ground as possible; see Oberth effect and reference.[5] This is another way to explain the performance penalty associated with establishing the safe perigee of a parking orbit.
Plans for future crewed interplanetary spaceflight missions often include final vehicle assembly in Earth orbit, such as NASA's Project Orion and Russia's Kliper/Parom tandem.
Astrodynamics
Main article: Orbital mechanics
Astrodynamics is the study of spacecraft trajectories, particularly as they relate to gravitational and propulsion effects. Astrodynamics allows for a spacecraft to arrive at its destination at the correct time without excessive propellant use. An orbital maneuvering system may be needed to maintain or change orbits.
Non-rocket orbital propulsion methods include solar sails, magnetic sails, plasma-bubble magnetic systems, and using gravitational slingshot effects.
Ionized gas trail from Shuttle reentry
Recovery of Discoverer 14 return capsule by a C-119 airplane
Transfer energy
The term "transfer energy" means the total amount of energy imparted by a rocket stage to its payload. This can be the energy imparted by a first stage of a launch vehicle to an upper stage plus payload, or by an upper stage or spacecraft kick motor to a spacecraft.[6][7]
Reentry
Main article: Atmospheric reentry
Vehicles in orbit have large amounts of kinetic energy. This energy must be discarded if the vehicle is to land safely without vaporizing in the atmosphere. Typically this process requires special methods to protect against aerodynamic heating. The theory behind reentry was developed by Harry Julian Allen. Based on this theory, reentry vehicles present blunt shapes to the atmosphere for reentry. Blunt shapes mean that less than 1% of the kinetic energy ends up as heat that reaches the vehicle, and the remainder heats up the atmosphere.
Landing
The Mercury, Gemini, and Apollo capsules all splashed down in the sea. These capsules were designed to land at relatively low speeds with the help of a parachute. Russian capsules for Soyuz make use of a big parachute and braking rockets to touch down on land. The Space Shuttle glided to a touchdown like a plane.
Recovery
After a successful landing the spacecraft, its occupants and cargo can be recovered. In some cases, recovery has occurred before landing: while a spacecraft is still descending on its parachute, it can be snagged by a specially designed aircraft. This mid-air retrieval technique was used to recover the film canisters from the Corona spy satellites.
Types
Uncrewed
See also: Uncrewed spacecraft and robotic spacecraft
Sojourner takes its Alpha particle X-ray spectrometer measurement of Yogi Rock on Mars
The MESSENGER spacecraft at Mercury (artist's interpretation)
Uncrewed spaceflight (or unmanned) is all spaceflight activity without a necessary human presence in space. This includes all space probes, satellites and robotic spacecraft and missions. Uncrewed spaceflight is the opposite of manned spaceflight, which is usually called human spaceflight. Subcategories of uncrewed spaceflight are "robotic spacecraft" (objects) and "robotic space missions" (activities). A robotic spacecraft is an uncrewed spacecraft with no humans on board, that is usually under telerobotic control. A robotic spacecraft designed to make scientific research measurements is often called a space probe.
Uncrewed space missions use remote-controlled spacecraft. The first uncrewed space mission was Sputnik I, launched October 4, 1957 to orbit the Earth. Space missions where other animals but no humans are on-board are considered uncrewed missions.
Benefits
Many space missions are more suited to telerobotic rather than crewed operation, due to lower cost and lower risk factors. In addition, some planetary destinations such as Venus or the vicinity of Jupiter are too hostile for human survival, given current technology. Outer planets such as Saturn, Uranus, and Neptune are too distant to reach with current crewed spaceflight technology, so telerobotic probes are the only way to explore them. Telerobotics also allows exploration of regions that are vulnerable to contamination by Earth micro-organisms since spacecraft can be sterilized. Humans can not be sterilized in the same way as a spaceship, as they coexist with numerous micro-organisms, and these micro-organisms are also hard to contain within a spaceship or spacesuit.
Telepresence
Telerobotics becomes telepresence when the time delay is short enough to permit control of the spacecraft in close to real time by humans. Even the two seconds light speed delay for the Moon is too far away for telepresence exploration from Earth. The L1 and L2 positions permit 400-millisecond round trip delays, which is just close enough for telepresence operation. Telepresence has also been suggested as a way to repair satellites in Earth orbit from Earth. The Exploration Telerobotics Symposium in 2012 explored this and other topics.[8]
Human
Main article: Human spaceflight
ISS crew member stores samples
The first human spaceflight was Vostok 1 on April 12, 1961, on which cosmonaut Yuri Gagarin of the USSR made one orbit around the Earth. In official Soviet documents, there is no mention of the fact that Gagarin parachuted the final seven miles.[9] Currently, the only spacecraft regularly used for human spaceflight are the Russian Soyuz spacecraft and the Chinese Shenzhou spacecraft. The U.S. Space Shuttle fleet operated from April 1981 until July 2011. SpaceShipOne has conducted two human suborbital spaceflights.
Sub-orbital
Main article: Sub-orbital spaceflight
The International Space Station in Earth orbit after a visit from the crew of STS-119
On a sub-orbital spaceflight the spacecraft reaches space and then returns to the atmosphere after following a (primarily) ballistic trajectory. This is usually because of insufficient specific orbital energy, in which case a suborbital flight will last only a few minutes, but it is also possible for an object with enough energy for an orbit to have a trajectory that intersects the Earth's atmosphere, sometimes after many hours. Pioneer 1 was NASA's first space probe intended to reach the Moon. A partial failure caused it to instead follow a suborbital trajectory to an altitude of 113,854 kilometers (70,746 mi) before reentering the Earth's atmosphere 43 hours after launch.
The most generally recognized boundary of space is the Kármán line 100 km above sea level. (NASA alternatively defines an astronaut as someone who has flown more than 50 miles (80 km) above sea level.) It is not generally recognized by the public that the increase in potential energy required to pass the Kármán line is only about 3% of the orbital energy (potential plus kinetic energy) required by the lowest possible Earth orbit (a circular orbit just above the Kármán line.) In other words, it is far easier to reach space than to stay there. On May 17, 2004, Civilian Space eXploration Team launched the GoFast Rocket on a suborbital flight, the first amateur spaceflight. On June 21, 2004, SpaceShipOne was used for the first privately funded human spaceflight.
Point-to-point
Point-to-point is a category of sub-orbital spaceflight in which a spacecraft provides rapid transport between two terrestrial locations. Consider a conventional airline route between London and Sydney, a flight that normally lasts over twenty hours. With point-to-point suborbital travel the same route could be traversed in less than one hour.[10] While no company offers this type of transportation today, SpaceX has revealed plans to do so as early as the 2020s using its BFR vehicle.[11] Suborbital spaceflight over an intercontinental distance requires a vehicle velocity that is only a little lower than the velocity required to reach low Earth orbit.[12] If rockets are used, the size of the rocket relative to the payload is similar to an Intercontinental Ballistic Missile (ICBM). Any intercontinental spaceflight has to surmount problems of heating during atmosphere re-entry that are nearly as large as those faced by orbital spaceflight.
Orbital
Main article: Orbital spaceflight
Apollo 6 heads into orbit
A minimal orbital spaceflight requires much higher velocities than a minimal sub-orbital flight, and so it is technologically much more challenging to achieve. To achieve orbital spaceflight, the tangential velocity around the Earth is as important as altitude. In order to perform a stable and lasting flight in space, the spacecraft must reach the minimal orbital speed required for a closed orbit.
Interplanetary
Main article: Interplanetary spaceflight
Interplanetary travel is travel between planets within a single planetary system. In practice, the use of the term is confined to travel between the planets of our Solar System.
Interstellar
Main article: Interstellar travel
Five spacecraft are currently leaving the Solar System on escape trajectories, Voyager 1, Voyager 2, Pioneer 10, Pioneer 11, and New Horizons. The one farthest from the Sun is Voyager 1, which is more than 100 AU distant and is moving at 3.6 AU per year.[13] In comparison, Proxima Centauri, the closest star other than the Sun, is 267,000 AU distant. It will take Voyager 1 over 74,000 years to reach this distance. Vehicle designs using other techniques, such as nuclear pulse propulsion are likely to be able to reach the nearest star significantly faster. Another possibility that could allow for human interstellar spaceflight is to make use of time dilation, as this would make it possible for passengers in a fast-moving vehicle to travel further into the future while aging very little, in that their great speed slows down the rate of passage of on-board time. However, attaining such high speeds would still require the use of some new, advanced method of propulsion.
Intergalactic
Main article: Intergalactic travel
Intergalactic travel involves spaceflight between galaxies, and is considered much more technologically demanding than even interstellar travel and, by current engineering terms, is considered science fiction.
Spacecraft
Main article: Spacecraft
An Apollo Lunar Module on the lunar surface
Spacecraft are vehicles capable of controlling their trajectory through space.
The first 'true spacecraft' is sometimes said to be Apollo Lunar Module,[14] since this was the only manned vehicle to have been designed for, and operated only in space; and is notable for its non aerodynamic shape.
Propulsion
Main article: Spacecraft propulsion
Spacecraft today predominantly use rockets for propulsion, but other propulsion techniques such as ion drives are becoming more common, particularly for unmanned vehicles, and this can significantly reduce the vehicle's mass and increase its delta-v.
Launch systems
Main article: Launch vehicle
Launch systems are used to carry a payload from Earth's surface into outer space.
Expendable
Main article: Expendable launch system
Most current spaceflight uses multi-stage expendable launch systems to reach space.
Reusable
Main article: Reusable launch system
Ambox current red.svg
This section needs to be updated. Please update this article to reflect recent events or newly available information. (August 2019)
The first reusable spacecraft, the X-15, was air-launched on a suborbital trajectory on July 19, 1963. The first partially reusable orbital spacecraft, the Space Shuttle, was launched by the USA on the 20th anniversary of Yuri Gagarin's flight, on April 12, 1981. During the Shuttle era, six orbiters were built, all of which have flown in the atmosphere and five of which have flown in space. The Enterprise was used only for approach and landing tests, launching from the back of a Boeing 747 and gliding to deadstick landings at Edwards AFB, California. The first Space Shuttle to fly into space was the Columbia, followed by the Challenger, Discovery, Atlantis, and Endeavour. The Endeavour was built to replace the Challenger, which was lost in January 1986. The Columbia broke up during reentry in February 2003.
The Space Shuttle Columbia seconds after engine ignition on mission STS-1
Columbia landing, concluding the STS-1 mission
Columbia launches again on STS-2
The first automatic partially reusable spacecraft was the Buran (Snowstorm), launched by the USSR on November 15, 1988, although it made only one flight. This spaceplane was designed for a crew and strongly resembled the US Space Shuttle, although its drop-off boosters used liquid propellants and its main engines were located at the base of what would be the external tank in the American Shuttle. Lack of funding, complicated by the dissolution of the USSR, prevented any further flights of Buran.
Per the Vision for Space Exploration, the Space Shuttle was retired in 2011 due mainly to its old age and high cost of the program reaching over a billion dollars per flight. The Shuttle's human transport role is to be replaced by the partially reusable Crew Exploration Vehicle (CEV) no later than 2021. The Shuttle's heavy cargo transport role is to be replaced by expendable rockets such as the Evolved Expendable Launch Vehicle (EELV) or a Shuttle Derived Launch Vehicle.
Scaled Composites SpaceShipOne was a reusable suborbital spaceplane that carried pilots Mike Melvill and Brian Binnie on consecutive flights in 2004 to win the Ansari X Prize. The Spaceship Company has built its successor SpaceShipTwo. A fleet of SpaceShipTwos operated by Virgin Galactic planned to begin reusable private spaceflight carrying paying passengers (space tourists) in 2008, but this was delayed due to an accident in the propulsion development.[15]
Challenges
Main article: Effect of spaceflight on the human body
Space disasters
Main article: Space accidents and incidents
All launch vehicles contain a huge amount of energy that is needed for some part of it to reach orbit. There is therefore some risk that this energy can be released prematurely and suddenly, with significant effects. When a Delta II rocket exploded 13 seconds after launch on January 17, 1997, there were reports of store windows 10 miles (16 km) away being broken by the blast.[16]
Space is a fairly predictable environment, but there are still risks of accidental depressurization and the potential failure of equipment, some of which may be very newly developed.
In 2004 the International Association for the Advancement of Space Safety was established in the Netherlands to further international cooperation and scientific advancement in space systems safety.[17]
Weightlessness
Main article: Weightlessness
Astronauts on the ISS in weightless conditions. Michael Foale can be seen exercising in the foreground.
In a microgravity environment such as that provided by a spacecraft in orbit around the Earth, humans experience a sense of "weightlessness." Short-term exposure to microgravity causes space adaptation syndrome, a self-limiting nausea caused by derangement of the vestibular system. Long-term exposure causes multiple health issues. The most significant is bone loss, some of which is permanent, but microgravity also leads to significant deconditioning of muscular and cardiovascular tissues.
Radiation
Once above the atmosphere, radiation due to the Van Allen belts, solar radiation and cosmic radiation issues occur and increase. Further away from the Earth, solar flares can give a fatal radiation dose in minutes, and the health threat from cosmic radiation significantly increases the chances of cancer over a decade exposure or more.[18]
Life support
Main article: Life support system
In human spaceflight, the life support system is a group of devices that allow a human being to survive in outer space. NASA often uses the phrase Environmental Control and Life Support System or the acronym ECLSS when describing these systems for its human spaceflight missions.[19] The life support system may supply: air, water and food. It must also maintain the correct body temperature, an acceptable pressure on the body and deal with the body's waste products. Shielding against harmful external influences such as radiation and micro-meteorites may also be necessary. Components of the life support system are life-critical, and are designed and constructed using safety engineering techniques.
Space weather
Main article: Space weather
Aurora australis and Discovery, May 1991.
Space weather is the concept of changing environmental conditions in outer space. It is distinct from the concept of weather within a planetary atmosphere, and deals with phenomena involving ambient plasma, magnetic fields, radiation and other matter in space (generally close to Earth but also in interplanetary, and occasionally interstellar medium). "Space weather describes the conditions in space that affect Earth and its technological systems. Our space weather is a consequence of the behavior of the Sun, the nature of Earth's magnetic field, and our location in the Solar System."[20]
Space weather exerts a profound influence in several areas related to space exploration and development. Changing geomagnetic conditions can induce changes in atmospheric density causing the rapid degradation of spacecraft altitude in Low Earth orbit. Geomagnetic storms due to increased solar activity can potentially blind sensors aboard spacecraft, or interfere with on-board electronics. An understanding of space environmental conditions is also important in designing shielding and life support systems for manned spacecraft.
Environmental considerations
Rockets as a class are not inherently grossly polluting. However, some rockets use toxic propellants, and most vehicles use propellants that are not carbon neutral. Many solid rockets have chlorine in the form of perchlorate or other chemicals, and this can cause temporary local holes in the ozone layer. Re-entering spacecraft generate nitrates which also can temporarily impact the ozone layer. Most rockets are made of metals that can have an environmental impact during their construction.
In addition to the atmospheric effects there are effects on the near-Earth space environment. There is the possibility that orbit could become inaccessible for generations due to exponentially increasing space debris caused by spalling of satellites and vehicles (Kessler syndrome). Many launched vehicles today are therefore designed to be re-entered after use.
The mystery behind the Widget
A widget is a device placed in a container of beer to manage the characteristics of the beer's head. The original widget was patented in Ireland by Guinness. The "floating widget" is found in cans of beer as a hollow plastic sphere, 3 cm in diameter (similar in appearance to a small table tennis ball) with a small hole (about 250 µm) in one side.
en.wikipedia.org/wiki/Widget_(beer)
Courtesy of Mr. FRANCISCO RANGEL , MCTI/INT
Image Details
Instrument used: Quanta SEM
Magnification: 70x
Horizontal Field Width: 4.26 mm
Vacuum: 7.35e-4 Pa
Voltage: 25 kV
Spot: 4.5
Working Distance: 16.2
Detector: MIX: SE plus BSE
A sculpture of a man with an ankle chain which has a mobile phone shaped block attached to it (not visible in this image). The artist's brief: The price of always being connected is -always being connected. All pervasive mobile communication has blurred the boundaries of our work and personal lives; maintaining an online presence cuts into the time we have for people in the real world; and privacy is almost a thing of the past. In the guise of making our lives easier, communications technology has come to control and define our every waking moment and ironically social networking has been shown to make users feel more alienated than ever. Be careful what you wish for!.
David McGuinness
Mixed media, paint, perspex, solar lights. Swell Sculpture festival
Laser Devices DBAL-A2 on a Samson Evolution with Troy Folding Sight, Surefire MB556K, Sabre 14.5'' 5.56mm Barrel and Surefire Scoutlight. LaRue QD Mount.
CSX end of a southbound manifest freight train with small container articulated flat cars bringing up the rear as it enters the yard by-pass track at Erwin, Tennessee, 4-15-2008. You may observe the FRED (Fixed Rear End Device) that is mounted to the rear car that is used to replace the old time caboose. The grade crossing is for 2nd Street. This railroad yard is now out of service, and was the former property of the Clinchfield Railroad. Sure wish that this line and railroad yard were back in full operational service!
Note: John faced some cancer in 2015. Sondra is his wife...
How tardy and bizarrely uncharacteristic of me to "come up short" Carol, on the genealogical history of the deceased equine entity called Tony.
Actually the initial send had more text....in my whimpering inadequacies.... I encountered a road block that was insurmountable for my chemo-laced brain.....I cried until Sondra came to my mewling puddle of shameful "masculine-tech" whining on the floor.....she tried to solve the dilemma .....and had "lift-off" for only a portion of the rocket.....basically it was a cluster fuck, a message that was intended for one planet.....but the message splintered,........you received some of the text, and some of it will arrive on Saturn's second inner ring, around 2525. The video that I tried to include with the text....imploded, folding in-ward unto itself.....consuming its life and frames until it resembled a tiny black jube-jube lying on the sidewalk.........not even the slugs were interested.
Tony was 22 when he died.....born in Saskatchewan......had papers.....not the kind of papers that illegal refugees have....but papers that proved he was pure Percheron. Tony was and is the only papered horse we have ever owned. Both his parents....sire and brood mare were registered Percheron. Percheron is a French heavy horse breed.....that basically opened the west, plowed the soil and pulled the goods.
In my world, being papered and registered means nothing....what does matter .......do I like what I see. And with Tony ....it was all good.
I'n John R's world of horses, registered and papered has meaning.
Sondra and I bought Tony along with another horse named Spider.....they were a team.....had worked as a team, pulling wagons and sleighs and also as a logging team for a teamster/logger/farmer/truck-driver from the 100 Mile House area of BC's Caribou region. Spider was a giant of a horse, also Percheron, not registered and not papered. Spider weighted about a ton, Tony was around 1800 lbs......
Spider was tall, quite a bit taller than Tony, so they looked a bit mis-matched....both horses were black as coal..........Tony had one white sock, rear right, if you are looking up the dirt chute........and both had their tails docked.... I'm not a fan of docked tails, but that's the way they came.
The year was 2004, when we heard about these boys being available.....we already had a team.....two wonderful Belgian/Percheron crosses, both unpapered and un-registered, that were named Pat and Mike, that we bought in 1999.
We were thinking of easing up on using Pat and Mike, as we were logging quite a bit. We wanted a younger team.....and Tony and Spider were around 10 ......a little side bar to horse trading.....a horse trader if he's trying to sell a horse , when confronted with the question .....
"so, how old is this horse"......will almost always tell you, he's 9. (old enough to know better but young enough to be strong and eager)(keep that in mind Carol, when it comes time to trade the old boy in)
To really know how old a horse is.....you look at his teeth, and if you know how to read the markings on their teeth, you can come to within a year or two. Many a 9 year old has turned out to be 17 or even older.
Sondra and I heard about the big blacks being for sale.....made some time to come up from the farm to have a look.
Always an adventure....searching out horses.
So up to the 100 Mile House area.....it was early summer....this area, high in elevation, excels in showing its beauty during the summer. It's sparsely populated.....a few small towns dot the region, to offer commerce and alcohol......the area is home to ranches, lots of large acreages, raising and growing beef..... As well as the ubiquitous logging industry.......give us some trees to exploit.
It's a gorgeous part of the province Carol, a high plateau, spotted with numerous lakes, expansive lodge pole pine forests, and these old, well worn ranch settlements.
It was one of these ranches that Tony and Spider were residing ......log house, log out-buildings, log fences, log barn.........right on the edge of a good sized lake.
Tom the owner was ready for us when we arrived....horses were at the hitching rail....harnessed and ready to perform.
But you never jump right into the task at hand .....you have to have the BC chats first.....sort of like kicking the tires when you are looking to buy a "new to you" truck......so the three of us are walking around the horses, hands running over their bodies, asking questions that don't always pertain to horses, "do you know such and such, he has a logging team near Princeton"......." where did these boys come from"...."when did you last use them"....."any problems"....."how are their feet"........"do these boys come with the harness"..... "how long have you lived up here"......."no kidding, I know Ted Guisbrech, we logged together over near Rock Creek".........and so on.
Then .....you ask if it would be ok to see them walk around.........he may say sure, take the lines, or he may say....sure, let me walk them first and then you can have a go.
All this seemingly unimportant prater......registers...it is all telling us about his relationship with his horses.....does he want to make sure the horses are calmed down when it comes time for us to drive them, .......does he think they might be a bit spooky if we take the lines.....is he setting the standard by showing us how he handles them.....all part of the game.
I want him to walk the horses around, to see what kind of relationship he has with them.....how he holds the lines ......where he stands.....how he gets them to move, does he "kiss them up", or "click" them up .....(two very distinct sounds in the horse world)....or does he remain silent, and communicate through the lines.....do they move on their own, when he grabs the lines......does he say their names to get them to move.......does he hold the lines....firm.......loosely.....does he slap the horses rears with the lines to get them to walk.....all of this shows me how this guy gets along with his horses.....gentle, coarsely, frantic, lazy, attentive, casual, ....and this gives me some incite into what we might be buying.
It's such a dance.....you want it to fall into place....you've invested 6 hours of travel one way......you like the initial viewing.....you need a team .....you want it to work. The foot work, the rhythm, the music, the touch, all these "things" need to be right for the dance to feel good...the flow....and eventually the coupling.
Where was I. .....oh yea.... Tom is walking the boys around, they have their harness on, the harness is well worn, with some minor binder-twine fix-it's......binder-twine....the non-natural material they use to tie bales of hay with.....it is ubiquitous with the horse world.....binder-twine is the rural duct-tape....you use it everywhere to tie down, to tie up, to keep apart, to shorten and to lengthen, you use it for clothes lines, and dog leashes, you use it to mark the planting lines for lettuce and carrots.....It almost always comes in the colour orange.....but now they have introduced the colour blue. It the very old days they used wire to wrap bales.
Tom walks the boys around the corral.....whoa-ing them up then asking them to step up(move ahead).....making them "gee" and "haw".....right and left......I watch how his hands work the lines.....lightly.....aggressively.....does he verbally communicate or is it all done with touch (pressure with the lines)......so the lines are long strips of leather or polypropylene that are attached to the bridle, a sort of head set that has the bit, the metal bar that is inserted to the horses mouth, attached to......so every time you pull on the lines it activates the bit......in a good or bad way.....gentle with the lines equates to gentle with the bit......aggressive with the lines, equates to harsh rough bit movement..........I'm certain Carol you've experienced this with the Hun. To get his attention (his noodle buried in a Conan movie) you sometimes have to jerk his bit.
So what you want to see as a perspective buyer, is the owner driving the horses around in a calm atmosphere.....no rodeos.....using "soft" hands........you want the horses displaying a zen.......a zone where they are willing to do what you ask of them.
Think Pointer Sisters......."I want a man with a slow hand....I Want a lover with an easy touch. I want a lover who will take some time. Not come and go in a heated rush"
Now that's what makes a perfect teamster.......Sondra points out that in the equine world, every teamster thinks he has soft hands. Phew, was that air leaving my body!
Then we attach the horses to the double-tree......sometimes made from hard wood and now usually made from metal.....this is the devise that is attached to two big leather straps that are attached to the horses harness.....these straps are called tugs....and then the double tree is attached to the device you want the horses to pull....ie. a wagon, a sleigh, a rake, a mower, or for our purposes a log. The double tree drags on the ground, so sometimes does not drag smoothly, as it gets caught up on debris , small babies, stumps, empty beer cases, that sort of thing......logging horses get acclimatized to this irregular pull and constant clanging, and are not spooked by the sound or pull.....uninitiated horses go ballistic....as they can never run away from the ragged feel, and the scary sound.
Tony and Spider were great.....and after numerous manoeuvres and requests.....lots of backing up, going forward.....asking them to take one step forward and whoa......asking them to stand while putting the lines on the ground......some horses will creep forward....
hooking them up to a big log and pulling it around.....doing the same tasks that we asked of them without the log..... we put them back to the hitching rail......removed their harness.
I ask Tom how "they load"......how easily do they go in a trailer.....a very important feature.....especially for people who move their horses around....like horse loggers.....always going to different sites.......some horses react to trailers like a 9 year old boy going to the dentist.....it can be hell.....and I've participated in many "rodeos" trying to get unwilling horses in a trailer. Both hard on the horse and the handler. Feet stepped on, smashed around by hyper animals, and that's before you get them in the trailer..... Securing them in the trailer is even more ramped up in terms of activity. So having calm, easy going horses to load...can be the deal sealer or breaker.Tom assures me that they "load easy"
We let the horses cool down......and then I picked up every foot......you want a cooperative horse when trimming hooves.....looked in their mouths to check teeth......hands feeling all over their bodies.....feeling and looking for bumps, irregularities, sores.....seeing how the harness fits them, any rubs, buckle wear, .......you try and do a full inspection..........just like the 50 point checkup that your Audi receives every 6 months.
For me it's all fun.....a chance to visit with another teamster.....to check out his stock....see new country.... hear some new lies and stories.
All the while the test drive and chit-chat is happening, Sondra and I are communicating about what we think about the team.....likes and dislikes....this is all done without talking....it's done with eyes, eye brows, facial wrinkles, nostril flares, smiles, hands, and head nods.....we don't want to diss the owner about the abilities of his team, or challenge anything he says about them.....we just register silently the good and bad......we didn't drive 6 hours to tell someone they have a badly mannered team of horses. It's a sort of rural respect and politeness that seems to prevail in rural Canada.
More generalized talk takes place....we find out more about his place.....some of the jobs he did with the team.....his daughter comes out of the house and jumps up on a saddle horse and rides around.....learn that he's bought a truck and car wash in 100 Mile House.....very entrepreneurial ...... He wanders off to feed some animals.... And Sondra and I kick a few horse buns around and decide yes, we want the team......
The negotiations are straight forward....we pay $4000....
In most horse transactions you buy the horse and the seller provides you with a halter and a lead rope......usually the most worn out and manure stained ones he can find in the tack shed.....often repaired with binder-twine, that use to be orange.
We manage, through friendly haggling, to get the harness, a double tree, and some pieces of harness "thrown in" with the 4 grand. We are happy with the deal, he's happy with the deal.
He agrees to feed the horses for a week, and Sondra and I will return the following weekend with our horse trailer, pick them up and bring them to Trinity Valley.
This adventure was wonderful.....a great way to start a new relationship with a new team......we were anxious to play with them, learn more about them.......and see what they could do.
The boys turned out to be all we wished for.....great addition to our already mature and well behaved team of Pat and Mike.....
Spider as he got older developed a rear hip malfunction.....that eventually made it very difficult for him to get up, after he would lie down for a rest and or a roll. At the end I was having to lift him up with the tractor....too complicated to describe, believe me it was as hard on me as it was on Spider.....Spider learned not to lie down too much .....and when he did, he'd try to position himself strategically on a slope so when it was time for lift-off, gravity would help. One time Spider lay down in his corral....winter time....in a hollow and couldn't rise up......thrashed around for awhile, making his bed a skating rink....total ice, caused by his body heat, ..... and even more difficult for him......finally as darkness was settling in I managed to get him up......this was becoming a problem.
In spring time I had a chat with the big boy......I was tiring of the effort it took to get him back up on all "four"...... Eventually the time came and he had his final lie-down.......
After Spider died, Tony was confused and then sad.....no more mate.....these horses when they are teamed up.....often act as one......they eat side by side, they rest side by side......when one heads off in a direction, the other one will follow......when one decides to let it all out and race around the field, full throttle, the other one copies. They are often joined at the hip. So Tony was bummed when Spider passed on, ........and he got little sympathy from the other team......at this point on the calendar, our original team of Pat and Mike, had both died, and we had bought another team, Jackie and Star, younger than both Spider and Tony, and this new team became our "go to team".
Jackie and Star, also Percheron's, also black, but with un-cropped tails, dragging on the ground, beautiful, true warriors......Don Monjoy was so proud of us for staying black, and staying Perch......this team was young, bold, frisky, and dominating. So Tony went to the bottom of the pecking order, and just wasn't too sure where he fit in. Sondra and I continued to show love and attention his way.....and Sondra would harness him and drive him around, but we always felt he was somewhat confused.......and missing his mate. But through that wondering, he was always a treat to be around.....he was extremely handsome.....very curious.....enormously smart.........and we always said he had a great ass.... And we will miss him.
Well now he can rejoin Spider......they can be a team again.
So I got my hands on the prototype Portal gun at the New York Toy Fair this morning. I was told it would be closer to $150, not $120, and it’ll be ready mid to late this year. They’re not sure yet where it will be sold, but Toys R Us was mentioned as a possibility. It’s satisfyingly large, the handle feels good and the thumb toggle to change from orange to blue and back is intuitive, the trigger is a trigger… nothing to get excited or upset over. It feels cheap. It looks cheap. But it also looks easy to dismantle for bulking up and repainting to improve. Honestly, I sort of feel that for the price that shouldn’t be needed, but I can deal with it. This one is not the finished product though, they will at least paint that inner core bit that should be black. Also the orange will be as bright as the blue and the sound effects which were weak should be louder and clearer. I wouldn’t say I’m disappointed, as I expected such flaws, so I’ll still be picking one up. But I can see a lot of unhappy fans that want perfection. Then again, considering the other game replica weapons I’ve seen, and for something this size with lights and sounds, the price is not bad and the cheapness is tolerable to make the price slightly more reasonable.
Tian'anmen Square is huge so to keep it spotless a means of covering the large area efficiently needs a motorized device - this would be one. Do not litter or you will be visited by security.
In preparation for the FAFM photo for "Smoke", I had to make this make-shift 'smoke producing device' to create the smoke for the photo. As always, I have the correct 'supervision' so as to prevent accidents. The string produced a longer trail of smoke so I could take multiple photos and then choose the best one for the FAFM group. While not 'perfect' (and even a two-wick candle didn't suffice with sufficient smoke after extinguishing) this string would smolder for over a minute. The can is a clean tuna can, and the wire is 14-gauge copper wire.
A critical celestial navigational device used inside the Lunar Module bearing traces of lunar dust. This is a post-landing, 8-inch diameter, circular star chart. All major stars and constellations visible from the Taurus-Littrow landing site are plotted underneath a rotating translucent position locator. The locator has six concentric circular plots, sixty degrees apart, that correspond to position locators set for the Alignment Optical Telescope inside the Lunar Module. The Velcro patch on the reverse shows traces of lunar dust.
“In some ways, when we voyaged to the moon, we were not unlike ancient mariners of the past. The stars were not only to light our way, but were used to guide us to our destination. We had onboard a sextant and telescope similar to what has been used for thousands of years but to make them useful we had to know what the heavens looked like, where the stars were, be able to recognize them and tell our computer through the sextant exactly what stars we were tracking. As a quick reference, we took star charts.. and those star charts of particular importance were the ones we carried to the lunar surface. Our first concern after landing would be to prepare for an immediate lift off in case of emergency. In order to assure that our lift off be successful so that we could subsequently rendezvous with our Command Module, we had to be absolutely sure of our Lunar Module’s position and orientation on the Lunar surface.”
— Eugene Cernan, Commander Apollo XVII in accompanying signed letter
When the Star Charts for Apollo were designed, three stars’ names were made up by Gus Ivan Grissom as a tribute to his fellow Apollo 1 crew members. Star number 3 was named “NAVI,” which is Grissom’s middle name spelled backwards. Star number 17 was named “REGOR,” which is Roger (Chaffee) spelled backwards. Star number 20 was named “DNOCES,” which is Second (Ed White II) spelled backwards. After the tragic deaths of the Apollo 1 crew in a training accident, NASA honored the men by maintaining the names on all of the Star Charts.
15x32" in frame (x22" when closed)
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From “Mooncollector” Jim Ruddy lifetime collection, When Jim turned 82 and his health was failing, he wanted to bundle his collection of lunar surface artifacts together in a single sale to someone who would care for them, and so he contacted me. I agreed to procure the collection and spent some time with him discussing each artifact at his home in Palm Springs. He was meticulous and carefully framed each precious treasure. Soon after I added this to the FV space collection in 2015, he passed away.
After toddling around for years with different systems, I finally have a collection of devices that suit my taste;
-Vintage late 70's Akai Direct drive, auto return AP-206C turntable.
-Late 90's Denon AV surround receiver AVR-1801
-Mid 90's Yamaha CDX-480 cd player
-Late 90's Denon DRW-585 double cassette player
- Vintage 70's 484 Philips front speakers
-Vintage mid/late 80's Philips DRC MK2 rear speakers (not on the pic).
Just the stuff I need to annoy the neighbours ;P
The Naked 3D Fitness Tracker goes on pre-request appears to be ready to change your entire body estimation game. It is a beautiful, cutting edge, flawlessly outlined framework saddled with a sketchy name. The apparatus is in general made of an extraordinary mirror glass that outfitted with depth...
LumiSpa device and cleanser on a marble countertop with a textured hand towel, and a chrome soap dispenser.
Two-car Class 156 'Super Sprinter' DMU 156 480 rumbles through Kirkby-in-Furness station, a deserted request stop, whilst forming Northern Rail's 07.41 (SaO) Barrow-Sellafield service. @07.52
Spaceflight (or space flight) is ballistic flight into or through outer space. Spaceflight can occur with spacecraft with or without humans on board. Yuri Gagarin of the Soviet Union was the first human to conduct a spaceflight. Examples of human spaceflight include the U.S. Apollo Moon landing and Space Shuttle programs and the Russian Soyuz program, as well as the ongoing International Space Station. Examples of unmanned spaceflight include space probes that leave Earth orbit, as well as satellites in orbit around Earth, such as communications satellites. These operate either by telerobotic control or are fully autonomous.
Spaceflight is used in space exploration, and also in commercial activities like space tourism and satellite telecommunications. Additional non-commercial uses of spaceflight include space observatories, reconnaissance satellites and other Earth observation satellites.
A spaceflight typically begins with a rocket launch, which provides the initial thrust to overcome the force of gravity and propels the spacecraft from the surface of the Earth. Once in space, the motion of a spacecraft – both when unpropelled and when under propulsion – is covered by the area of study called astrodynamics. Some spacecraft remain in space indefinitely, some disintegrate during atmospheric reentry, and others reach a planetary or lunar surface for landing or impact.
History
Main articles: History of spaceflight and Timeline of spaceflight
Tsiolkovsky, early space theorist
The first theoretical proposal of space travel using rockets was published by Scottish astronomer and mathematician William Leitch, in an 1861 essay "A Journey Through Space".[1] More well-known (though not widely outside Russia) is Konstantin Tsiolkovsky's work, "Исследование мировых пространств реактивными приборами" (The Exploration of Cosmic Space by Means of Reaction Devices), published in 1903.
Spaceflight became an engineering possibility with the work of Robert H. Goddard's publication in 1919 of his paper A Method of Reaching Extreme Altitudes. His application of the de Laval nozzle to liquid fuel rockets improved efficiency enough for interplanetary travel to become possible. He also proved in the laboratory that rockets would work in the vacuum of space;[specify] nonetheless, his work was not taken seriously by the public. His attempt to secure an Army contract for a rocket-propelled weapon in the first World War was defeated by the November 11, 1918 armistice with Germany. Working with private financial support, he was the first to launch a liquid-fueled rocket in 1926. Goddard's paper was highly influential on Hermann Oberth, who in turn influenced Wernher von Braun. Von Braun became the first to produce modern rockets as guided weapons, employed by Adolf Hitler. Von Braun's V-2 was the first rocket to reach space, at an altitude of 189 kilometers (102 nautical miles) on a June 1944 test flight.[2]
Tsiolkovsky's rocketry work was not fully appreciated in his lifetime, but he influenced Sergey Korolev, who became the Soviet Union's chief rocket designer under Joseph Stalin, to develop intercontinental ballistic missiles to carry nuclear weapons as a counter measure to United States bomber planes. Derivatives of Korolev's R-7 Semyorka missiles were used to launch the world's first artificial Earth satellite, Sputnik 1, on October 4, 1957, and later the first human to orbit the Earth, Yuri Gagarin in Vostok 1, on April 12, 1961.[3]
At the end of World War II, von Braun and most of his rocket team surrendered to the United States, and were expatriated to work on American missiles at what became the Army Ballistic Missile Agency. This work on missiles such as Juno I and Atlas enabled launch of the first US satellite Explorer 1 on February 1, 1958, and the first American in orbit, John Glenn in Friendship 7 on February 20, 1962. As director of the Marshall Space Flight Center, Von Braun oversaw development of a larger class of rocket called Saturn, which allowed the US to send the first two humans, Neil Armstrong and Buzz Aldrin, to the Moon and back on Apollo 11 in July 1969. Over the same period, the Soviet Union secretly tried but failed to develop the N1 rocket to give them the capability to land one person on the Moon.
Phases
Launch
Main article: Rocket launch
See also: List of space launch system designs
Rockets are the only means currently capable of reaching orbit or beyond. Other non-rocket spacelaunch technologies have yet to be built, or remain short of orbital speeds. A rocket launch for a spaceflight usually starts from a spaceport (cosmodrome), which may be equipped with launch complexes and launch pads for vertical rocket launches, and runways for takeoff and landing of carrier airplanes and winged spacecraft. Spaceports are situated well away from human habitation for noise and safety reasons. ICBMs have various special launching facilities.
A launch is often restricted to certain launch windows. These windows depend upon the position of celestial bodies and orbits relative to the launch site. The biggest influence is often the rotation of the Earth itself. Once launched, orbits are normally located within relatively constant flat planes at a fixed angle to the axis of the Earth, and the Earth rotates within this orbit.
A launch pad is a fixed structure designed to dispatch airborne vehicles. It generally consists of a launch tower and flame trench. It is surrounded by equipment used to erect, fuel, and maintain launch vehicles. Before launch, the rocket can weigh many hundreds of tonnes. The Space Shuttle Columbia, on STS-1, weighed 2,030 tonnes (4,480,000 lb) at take off.
Reaching space
The most commonly used definition of outer space is everything beyond the Kármán line, which is 100 kilometers (62 mi) above the Earth's surface. The United States sometimes defines outer space as everything beyond 50 miles (80 km) in altitude.
Rockets are the only currently practical means of reaching space. Conventional airplane engines cannot reach space due to the lack of oxygen. Rocket engines expel propellant to provide forward thrust that generates enough delta-v (change in velocity) to reach orbit.
For manned launch systems launch escape systems are frequently fitted to allow astronauts to escape in the case of emergency.
Alternatives
Main article: Non-rocket spacelaunch
Many ways to reach space other than rockets have been proposed. Ideas such as the space elevator, and momentum exchange tethers like rotovators or skyhooks require new materials much stronger than any currently known. Electromagnetic launchers such as launch loops might be feasible with current technology. Other ideas include rocket assisted aircraft/spaceplanes such as Reaction Engines Skylon (currently in early stage development), scramjet powered spaceplanes, and RBCC powered spaceplanes. Gun launch has been proposed for cargo.
Leaving orbit
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Main articles: Escape velocity and Parking orbit
Launched in 1959, Luna 1 was the first known man-made object to achieve escape velocity from the Earth.[4] (replica pictured)
Achieving a closed orbit is not essential to lunar and interplanetary voyages. Early Russian space vehicles successfully achieved very high altitudes without going into orbit. NASA considered launching Apollo missions directly into lunar trajectories but adopted the strategy of first entering a temporary parking orbit and then performing a separate burn several orbits later onto a lunar trajectory. This costs additional propellant because the parking orbit perigee must be high enough to prevent reentry while direct injection can have an arbitrarily low perigee because it will never be reached.
However, the parking orbit approach greatly simplified Apollo mission planning in several important ways. It substantially widened the allowable launch windows, increasing the chance of a successful launch despite minor technical problems during the countdown. The parking orbit was a stable "mission plateau" that gave the crew and controllers several hours to thoroughly check out the spacecraft after the stresses of launch before committing it to a long lunar flight; the crew could quickly return to Earth, if necessary, or an alternate Earth-orbital mission could be conducted. The parking orbit also enabled translunar trajectories that avoided the densest parts of the Van Allen radiation belts.
Apollo missions minimized the performance penalty of the parking orbit by keeping its altitude as low as possible. For example, Apollo 15 used an unusually low parking orbit (even for Apollo) of 92.5 nmi by 91.5 nmi (171 km by 169 km) where there was significant atmospheric drag. But it was partially overcome by continuous venting of hydrogen from the third stage of the Saturn V, and was in any event tolerable for the short stay.
Robotic missions do not require an abort capability or radiation minimization, and because modern launchers routinely meet "instantaneous" launch windows, space probes to the Moon and other planets generally use direct injection to maximize performance. Although some might coast briefly during the launch sequence, they do not complete one or more full parking orbits before the burn that injects them onto an Earth escape trajectory.
Note that the escape velocity from a celestial body decreases with altitude above that body. However, it is more fuel-efficient for a craft to burn its fuel as close to the ground as possible; see Oberth effect and reference.[5] This is another way to explain the performance penalty associated with establishing the safe perigee of a parking orbit.
Plans for future crewed interplanetary spaceflight missions often include final vehicle assembly in Earth orbit, such as NASA's Project Orion and Russia's Kliper/Parom tandem.
Astrodynamics
Main article: Orbital mechanics
Astrodynamics is the study of spacecraft trajectories, particularly as they relate to gravitational and propulsion effects. Astrodynamics allows for a spacecraft to arrive at its destination at the correct time without excessive propellant use. An orbital maneuvering system may be needed to maintain or change orbits.
Non-rocket orbital propulsion methods include solar sails, magnetic sails, plasma-bubble magnetic systems, and using gravitational slingshot effects.
Ionized gas trail from Shuttle reentry
Recovery of Discoverer 14 return capsule by a C-119 airplane
Transfer energy
The term "transfer energy" means the total amount of energy imparted by a rocket stage to its payload. This can be the energy imparted by a first stage of a launch vehicle to an upper stage plus payload, or by an upper stage or spacecraft kick motor to a spacecraft.[6][7]
Reentry
Main article: Atmospheric reentry
Vehicles in orbit have large amounts of kinetic energy. This energy must be discarded if the vehicle is to land safely without vaporizing in the atmosphere. Typically this process requires special methods to protect against aerodynamic heating. The theory behind reentry was developed by Harry Julian Allen. Based on this theory, reentry vehicles present blunt shapes to the atmosphere for reentry. Blunt shapes mean that less than 1% of the kinetic energy ends up as heat that reaches the vehicle, and the remainder heats up the atmosphere.
Landing
The Mercury, Gemini, and Apollo capsules all splashed down in the sea. These capsules were designed to land at relatively low speeds with the help of a parachute. Russian capsules for Soyuz make use of a big parachute and braking rockets to touch down on land. The Space Shuttle glided to a touchdown like a plane.
Recovery
After a successful landing the spacecraft, its occupants and cargo can be recovered. In some cases, recovery has occurred before landing: while a spacecraft is still descending on its parachute, it can be snagged by a specially designed aircraft. This mid-air retrieval technique was used to recover the film canisters from the Corona spy satellites.
Types
Uncrewed
See also: Uncrewed spacecraft and robotic spacecraft
Sojourner takes its Alpha particle X-ray spectrometer measurement of Yogi Rock on Mars
The MESSENGER spacecraft at Mercury (artist's interpretation)
Uncrewed spaceflight (or unmanned) is all spaceflight activity without a necessary human presence in space. This includes all space probes, satellites and robotic spacecraft and missions. Uncrewed spaceflight is the opposite of manned spaceflight, which is usually called human spaceflight. Subcategories of uncrewed spaceflight are "robotic spacecraft" (objects) and "robotic space missions" (activities). A robotic spacecraft is an uncrewed spacecraft with no humans on board, that is usually under telerobotic control. A robotic spacecraft designed to make scientific research measurements is often called a space probe.
Uncrewed space missions use remote-controlled spacecraft. The first uncrewed space mission was Sputnik I, launched October 4, 1957 to orbit the Earth. Space missions where other animals but no humans are on-board are considered uncrewed missions.
Benefits
Many space missions are more suited to telerobotic rather than crewed operation, due to lower cost and lower risk factors. In addition, some planetary destinations such as Venus or the vicinity of Jupiter are too hostile for human survival, given current technology. Outer planets such as Saturn, Uranus, and Neptune are too distant to reach with current crewed spaceflight technology, so telerobotic probes are the only way to explore them. Telerobotics also allows exploration of regions that are vulnerable to contamination by Earth micro-organisms since spacecraft can be sterilized. Humans can not be sterilized in the same way as a spaceship, as they coexist with numerous micro-organisms, and these micro-organisms are also hard to contain within a spaceship or spacesuit.
Telepresence
Telerobotics becomes telepresence when the time delay is short enough to permit control of the spacecraft in close to real time by humans. Even the two seconds light speed delay for the Moon is too far away for telepresence exploration from Earth. The L1 and L2 positions permit 400-millisecond round trip delays, which is just close enough for telepresence operation. Telepresence has also been suggested as a way to repair satellites in Earth orbit from Earth. The Exploration Telerobotics Symposium in 2012 explored this and other topics.[8]
Human
Main article: Human spaceflight
ISS crew member stores samples
The first human spaceflight was Vostok 1 on April 12, 1961, on which cosmonaut Yuri Gagarin of the USSR made one orbit around the Earth. In official Soviet documents, there is no mention of the fact that Gagarin parachuted the final seven miles.[9] Currently, the only spacecraft regularly used for human spaceflight are the Russian Soyuz spacecraft and the Chinese Shenzhou spacecraft. The U.S. Space Shuttle fleet operated from April 1981 until July 2011. SpaceShipOne has conducted two human suborbital spaceflights.
Sub-orbital
Main article: Sub-orbital spaceflight
The International Space Station in Earth orbit after a visit from the crew of STS-119
On a sub-orbital spaceflight the spacecraft reaches space and then returns to the atmosphere after following a (primarily) ballistic trajectory. This is usually because of insufficient specific orbital energy, in which case a suborbital flight will last only a few minutes, but it is also possible for an object with enough energy for an orbit to have a trajectory that intersects the Earth's atmosphere, sometimes after many hours. Pioneer 1 was NASA's first space probe intended to reach the Moon. A partial failure caused it to instead follow a suborbital trajectory to an altitude of 113,854 kilometers (70,746 mi) before reentering the Earth's atmosphere 43 hours after launch.
The most generally recognized boundary of space is the Kármán line 100 km above sea level. (NASA alternatively defines an astronaut as someone who has flown more than 50 miles (80 km) above sea level.) It is not generally recognized by the public that the increase in potential energy required to pass the Kármán line is only about 3% of the orbital energy (potential plus kinetic energy) required by the lowest possible Earth orbit (a circular orbit just above the Kármán line.) In other words, it is far easier to reach space than to stay there. On May 17, 2004, Civilian Space eXploration Team launched the GoFast Rocket on a suborbital flight, the first amateur spaceflight. On June 21, 2004, SpaceShipOne was used for the first privately funded human spaceflight.
Point-to-point
Point-to-point is a category of sub-orbital spaceflight in which a spacecraft provides rapid transport between two terrestrial locations. Consider a conventional airline route between London and Sydney, a flight that normally lasts over twenty hours. With point-to-point suborbital travel the same route could be traversed in less than one hour.[10] While no company offers this type of transportation today, SpaceX has revealed plans to do so as early as the 2020s using its BFR vehicle.[11] Suborbital spaceflight over an intercontinental distance requires a vehicle velocity that is only a little lower than the velocity required to reach low Earth orbit.[12] If rockets are used, the size of the rocket relative to the payload is similar to an Intercontinental Ballistic Missile (ICBM). Any intercontinental spaceflight has to surmount problems of heating during atmosphere re-entry that are nearly as large as those faced by orbital spaceflight.
Orbital
Main article: Orbital spaceflight
Apollo 6 heads into orbit
A minimal orbital spaceflight requires much higher velocities than a minimal sub-orbital flight, and so it is technologically much more challenging to achieve. To achieve orbital spaceflight, the tangential velocity around the Earth is as important as altitude. In order to perform a stable and lasting flight in space, the spacecraft must reach the minimal orbital speed required for a closed orbit.
Interplanetary
Main article: Interplanetary spaceflight
Interplanetary travel is travel between planets within a single planetary system. In practice, the use of the term is confined to travel between the planets of our Solar System.
Interstellar
Main article: Interstellar travel
Five spacecraft are currently leaving the Solar System on escape trajectories, Voyager 1, Voyager 2, Pioneer 10, Pioneer 11, and New Horizons. The one farthest from the Sun is Voyager 1, which is more than 100 AU distant and is moving at 3.6 AU per year.[13] In comparison, Proxima Centauri, the closest star other than the Sun, is 267,000 AU distant. It will take Voyager 1 over 74,000 years to reach this distance. Vehicle designs using other techniques, such as nuclear pulse propulsion are likely to be able to reach the nearest star significantly faster. Another possibility that could allow for human interstellar spaceflight is to make use of time dilation, as this would make it possible for passengers in a fast-moving vehicle to travel further into the future while aging very little, in that their great speed slows down the rate of passage of on-board time. However, attaining such high speeds would still require the use of some new, advanced method of propulsion.
Intergalactic
Main article: Intergalactic travel
Intergalactic travel involves spaceflight between galaxies, and is considered much more technologically demanding than even interstellar travel and, by current engineering terms, is considered science fiction.
Spacecraft
Main article: Spacecraft
An Apollo Lunar Module on the lunar surface
Spacecraft are vehicles capable of controlling their trajectory through space.
The first 'true spacecraft' is sometimes said to be Apollo Lunar Module,[14] since this was the only manned vehicle to have been designed for, and operated only in space; and is notable for its non aerodynamic shape.
Propulsion
Main article: Spacecraft propulsion
Spacecraft today predominantly use rockets for propulsion, but other propulsion techniques such as ion drives are becoming more common, particularly for unmanned vehicles, and this can significantly reduce the vehicle's mass and increase its delta-v.
Launch systems
Main article: Launch vehicle
Launch systems are used to carry a payload from Earth's surface into outer space.
Expendable
Main article: Expendable launch system
Most current spaceflight uses multi-stage expendable launch systems to reach space.
Reusable
Main article: Reusable launch system
Ambox current red.svg
This section needs to be updated. Please update this article to reflect recent events or newly available information. (August 2019)
The first reusable spacecraft, the X-15, was air-launched on a suborbital trajectory on July 19, 1963. The first partially reusable orbital spacecraft, the Space Shuttle, was launched by the USA on the 20th anniversary of Yuri Gagarin's flight, on April 12, 1981. During the Shuttle era, six orbiters were built, all of which have flown in the atmosphere and five of which have flown in space. The Enterprise was used only for approach and landing tests, launching from the back of a Boeing 747 and gliding to deadstick landings at Edwards AFB, California. The first Space Shuttle to fly into space was the Columbia, followed by the Challenger, Discovery, Atlantis, and Endeavour. The Endeavour was built to replace the Challenger, which was lost in January 1986. The Columbia broke up during reentry in February 2003.
The Space Shuttle Columbia seconds after engine ignition on mission STS-1
Columbia landing, concluding the STS-1 mission
Columbia launches again on STS-2
The first automatic partially reusable spacecraft was the Buran (Snowstorm), launched by the USSR on November 15, 1988, although it made only one flight. This spaceplane was designed for a crew and strongly resembled the US Space Shuttle, although its drop-off boosters used liquid propellants and its main engines were located at the base of what would be the external tank in the American Shuttle. Lack of funding, complicated by the dissolution of the USSR, prevented any further flights of Buran.
Per the Vision for Space Exploration, the Space Shuttle was retired in 2011 due mainly to its old age and high cost of the program reaching over a billion dollars per flight. The Shuttle's human transport role is to be replaced by the partially reusable Crew Exploration Vehicle (CEV) no later than 2021. The Shuttle's heavy cargo transport role is to be replaced by expendable rockets such as the Evolved Expendable Launch Vehicle (EELV) or a Shuttle Derived Launch Vehicle.
Scaled Composites SpaceShipOne was a reusable suborbital spaceplane that carried pilots Mike Melvill and Brian Binnie on consecutive flights in 2004 to win the Ansari X Prize. The Spaceship Company has built its successor SpaceShipTwo. A fleet of SpaceShipTwos operated by Virgin Galactic planned to begin reusable private spaceflight carrying paying passengers (space tourists) in 2008, but this was delayed due to an accident in the propulsion development.[15]
Challenges
Main article: Effect of spaceflight on the human body
Space disasters
Main article: Space accidents and incidents
All launch vehicles contain a huge amount of energy that is needed for some part of it to reach orbit. There is therefore some risk that this energy can be released prematurely and suddenly, with significant effects. When a Delta II rocket exploded 13 seconds after launch on January 17, 1997, there were reports of store windows 10 miles (16 km) away being broken by the blast.[16]
Space is a fairly predictable environment, but there are still risks of accidental depressurization and the potential failure of equipment, some of which may be very newly developed.
In 2004 the International Association for the Advancement of Space Safety was established in the Netherlands to further international cooperation and scientific advancement in space systems safety.[17]
Weightlessness
Main article: Weightlessness
Astronauts on the ISS in weightless conditions. Michael Foale can be seen exercising in the foreground.
In a microgravity environment such as that provided by a spacecraft in orbit around the Earth, humans experience a sense of "weightlessness." Short-term exposure to microgravity causes space adaptation syndrome, a self-limiting nausea caused by derangement of the vestibular system. Long-term exposure causes multiple health issues. The most significant is bone loss, some of which is permanent, but microgravity also leads to significant deconditioning of muscular and cardiovascular tissues.
Radiation
Once above the atmosphere, radiation due to the Van Allen belts, solar radiation and cosmic radiation issues occur and increase. Further away from the Earth, solar flares can give a fatal radiation dose in minutes, and the health threat from cosmic radiation significantly increases the chances of cancer over a decade exposure or more.[18]
Life support
Main article: Life support system
In human spaceflight, the life support system is a group of devices that allow a human being to survive in outer space. NASA often uses the phrase Environmental Control and Life Support System or the acronym ECLSS when describing these systems for its human spaceflight missions.[19] The life support system may supply: air, water and food. It must also maintain the correct body temperature, an acceptable pressure on the body and deal with the body's waste products. Shielding against harmful external influences such as radiation and micro-meteorites may also be necessary. Components of the life support system are life-critical, and are designed and constructed using safety engineering techniques.
Space weather
Main article: Space weather
Aurora australis and Discovery, May 1991.
Space weather is the concept of changing environmental conditions in outer space. It is distinct from the concept of weather within a planetary atmosphere, and deals with phenomena involving ambient plasma, magnetic fields, radiation and other matter in space (generally close to Earth but also in interplanetary, and occasionally interstellar medium). "Space weather describes the conditions in space that affect Earth and its technological systems. Our space weather is a consequence of the behavior of the Sun, the nature of Earth's magnetic field, and our location in the Solar System."[20]
Space weather exerts a profound influence in several areas related to space exploration and development. Changing geomagnetic conditions can induce changes in atmospheric density causing the rapid degradation of spacecraft altitude in Low Earth orbit. Geomagnetic storms due to increased solar activity can potentially blind sensors aboard spacecraft, or interfere with on-board electronics. An understanding of space environmental conditions is also important in designing shielding and life support systems for manned spacecraft.
Environmental considerations
Rockets as a class are not inherently grossly polluting. However, some rockets use toxic propellants, and most vehicles use propellants that are not carbon neutral. Many solid rockets have chlorine in the form of perchlorate or other chemicals, and this can cause temporary local holes in the ozone layer. Re-entering spacecraft generate nitrates which also can temporarily impact the ozone layer. Most rockets are made of metals that can have an environmental impact during their construction.
In addition to the atmospheric effects there are effects on the near-Earth space environment. There is the possibility that orbit could become inaccessible for generations due to exponentially increasing space debris caused by spalling of satellites and vehicles (Kessler syndrome). Many launched vehicles today are therefore designed to be re-entered after use.