a06 (AS-502)_v_bw_o_n (Official MSFC-MTF PAO photo, no. '67-566)
“NUMBER TWO COMING IN - - The second flight version of the Saturn V second stage (S-II) is unloaded from the barge “Pearle River” upon its arrival at the National Aeronautics and Space Administration’s Mississippi Test Facility. Weighing 86,000 pounds, the 81 1/2 foot long, 33 feet in diameter stage is shown being towed into the Stage Storage and Servicing Building for checkout and preparations for installation in an S-II stand prior to static firing in March. This is the second flight stage of the S-II to be static fired at MTF. The first S-II test at MTF arrived at the NASA Kennedy Space Center, Fla. last week.”
S-II-2 history:
history.nasa.gov/MHR-5/part-8.htm
More significantly, from the immensely readable & informative article by Andrew LePage:
“The second stage of the Saturn V was designated the S-II stage with North American Aviation as its prime contractor (which merged with Rockwell in March 1967 and subsequently with Boeing 29 years later). Unlike the S-IC and most earlier rockets, the S-II burned the high-energy combination of liquid hydrogen and LOX which yields about half again as much thrust as a like mass of more conventional propellants. With the same ten meter diameter as the S-IC stage, this stage was 24.8 meters long and carried 429 metric tons of cryogenic propellant. Its five Rocketdyne J-2 engines generated a total of about 4,450 kilonewtons of thrust in its initial versions. With a nominal burn time of 367 seconds, the S-II provided most of the energy to drive the rocket and its payload towards Earth orbit during an Apollo lunar mission with burnout occurring at a typical altitude of 185 kilometers and a speed of 6.8 kilometers per second…
…At this point, the delivery of the first two S-II stages from North American was running months behind schedule due to problems encountered during final assembly and testing. In order to keep the processing of the first pair of Saturn V rockets on track, it had been decided that the initial stacking of AS-501 would instead use a substitute – a S-II simulator designated H7-17 which had been originally constructed for handling training and test facility fit checks. The H7-17 test article basically consisted of a small diameter, load-bearing center column with S-II interfaces at either end giving the article a distinct spool-like shape. Modifications would make it suitable for use in the initial stacking and ground testing of the Saturn V…
…After being removed from AS-501 on February 13, 1967, the S-II spacer was added atop of S-IC-2 on March 29 so that stacking of AS-502 could be completed and initial testing of the second Saturn V could proceed. The S-II-2 stage finally arrived at Cape Canaveral on May 24 and, after completing an inspection of its liquid hydrogen tank for cracks on July 6, it was added to the launch vehicle on July 13 to begin the next round of preflight testing during the next six weeks. CSM-020 attached to its SLA with LTA-2R tucked inside was finally added to the stack on December 10…
…After casting off its spent first stage, the five J-2 engines of the S-II stage ignited 149.8 seconds after launch as Apollo 6 continued to accelerate towards orbit. At 184.8 seconds after launch, the LES separated since it was no longer needed to support abort options for the rest of the mission. All was going well until the 319-second mark when the fuel flow rate on engine J-2044 in the #2 position on the S-II stage suddenly increased at the same time its thrust decreased. Following a spike in the engine bay temperature, engine #2 shut down after running for 263.8 seconds out of a planned 368.8-second burn. Although it was showing no signs of trouble, engine J-2508 in the #3 position also shutdown 1.3 seconds later. After the loss of two J-2 engines, the Saturn V guidance system did its best to cope with the situation. While never configured to deal with the loss of two J-2 engines, Apollo 6 continued its ascent. Finally, the remaining three engines of S-II-2 shutdown nine minutes and 36.3 seconds after lift off. With the three remaining engines burning for 58.8 seconds longer than planned, Apollo 6 was travelling 102.3 meters per second slower than expected due to the lower acceleration while being 436.8 kilometer farther downrange and 6.4 kilometers higher because of how the guidance system tried to cope with the unexpected situation.”
The entire article at:
www.drewexmachina.com/2018/04/04/apollo-6-the-saturn-v-th...
Credit: Drew ExMachina/Andrew LePage
a06 (AS-502)_v_bw_o_n (Official MSFC-MTF PAO photo, no. '67-566)
“NUMBER TWO COMING IN - - The second flight version of the Saturn V second stage (S-II) is unloaded from the barge “Pearle River” upon its arrival at the National Aeronautics and Space Administration’s Mississippi Test Facility. Weighing 86,000 pounds, the 81 1/2 foot long, 33 feet in diameter stage is shown being towed into the Stage Storage and Servicing Building for checkout and preparations for installation in an S-II stand prior to static firing in March. This is the second flight stage of the S-II to be static fired at MTF. The first S-II test at MTF arrived at the NASA Kennedy Space Center, Fla. last week.”
S-II-2 history:
history.nasa.gov/MHR-5/part-8.htm
More significantly, from the immensely readable & informative article by Andrew LePage:
“The second stage of the Saturn V was designated the S-II stage with North American Aviation as its prime contractor (which merged with Rockwell in March 1967 and subsequently with Boeing 29 years later). Unlike the S-IC and most earlier rockets, the S-II burned the high-energy combination of liquid hydrogen and LOX which yields about half again as much thrust as a like mass of more conventional propellants. With the same ten meter diameter as the S-IC stage, this stage was 24.8 meters long and carried 429 metric tons of cryogenic propellant. Its five Rocketdyne J-2 engines generated a total of about 4,450 kilonewtons of thrust in its initial versions. With a nominal burn time of 367 seconds, the S-II provided most of the energy to drive the rocket and its payload towards Earth orbit during an Apollo lunar mission with burnout occurring at a typical altitude of 185 kilometers and a speed of 6.8 kilometers per second…
…At this point, the delivery of the first two S-II stages from North American was running months behind schedule due to problems encountered during final assembly and testing. In order to keep the processing of the first pair of Saturn V rockets on track, it had been decided that the initial stacking of AS-501 would instead use a substitute – a S-II simulator designated H7-17 which had been originally constructed for handling training and test facility fit checks. The H7-17 test article basically consisted of a small diameter, load-bearing center column with S-II interfaces at either end giving the article a distinct spool-like shape. Modifications would make it suitable for use in the initial stacking and ground testing of the Saturn V…
…After being removed from AS-501 on February 13, 1967, the S-II spacer was added atop of S-IC-2 on March 29 so that stacking of AS-502 could be completed and initial testing of the second Saturn V could proceed. The S-II-2 stage finally arrived at Cape Canaveral on May 24 and, after completing an inspection of its liquid hydrogen tank for cracks on July 6, it was added to the launch vehicle on July 13 to begin the next round of preflight testing during the next six weeks. CSM-020 attached to its SLA with LTA-2R tucked inside was finally added to the stack on December 10…
…After casting off its spent first stage, the five J-2 engines of the S-II stage ignited 149.8 seconds after launch as Apollo 6 continued to accelerate towards orbit. At 184.8 seconds after launch, the LES separated since it was no longer needed to support abort options for the rest of the mission. All was going well until the 319-second mark when the fuel flow rate on engine J-2044 in the #2 position on the S-II stage suddenly increased at the same time its thrust decreased. Following a spike in the engine bay temperature, engine #2 shut down after running for 263.8 seconds out of a planned 368.8-second burn. Although it was showing no signs of trouble, engine J-2508 in the #3 position also shutdown 1.3 seconds later. After the loss of two J-2 engines, the Saturn V guidance system did its best to cope with the situation. While never configured to deal with the loss of two J-2 engines, Apollo 6 continued its ascent. Finally, the remaining three engines of S-II-2 shutdown nine minutes and 36.3 seconds after lift off. With the three remaining engines burning for 58.8 seconds longer than planned, Apollo 6 was travelling 102.3 meters per second slower than expected due to the lower acceleration while being 436.8 kilometer farther downrange and 6.4 kilometers higher because of how the guidance system tried to cope with the unexpected situation.”
The entire article at:
www.drewexmachina.com/2018/04/04/apollo-6-the-saturn-v-th...
Credit: Drew ExMachina/Andrew LePage