a08_v_c_o_AKP (S-68-55415)
“The Mobile Service Structure (MSS) being pulled back from the Apollo 8 spacecraft.
Also seen at the top of the escape tower is the Q-ball cover. This covers and protects the Q-ball, eight openings at the top of the Launch Escape Tower. These openings lead to air data probes which gauge air pressure and temperature. As well as providing dynamic pressure (known as "Q") information during powered flight, they help determine the angle of attack of the tower during an abort event. The crew can monitor any off-axis pressure on a gauge on panel 1 normally used to monitor combustion pressure in the spacecraft's SPS engine. A switch will be thrown after the tower is jettisoned to effect this change. Dual use of instruments is common in the spacecraft as it saves weight and panel.”
history.nasa.gov/afj/ap08fj/photos/ground/19681217-s68-55...
All above per the Apollo Flight Journey website:
history.nasa.gov/afj/ap08fj/01launch_ascent.html
a08_v_c_o_AKP (S-68-55415)
“The Mobile Service Structure (MSS) being pulled back from the Apollo 8 spacecraft.
Also seen at the top of the escape tower is the Q-ball cover. This covers and protects the Q-ball, eight openings at the top of the Launch Escape Tower. These openings lead to air data probes which gauge air pressure and temperature. As well as providing dynamic pressure (known as "Q") information during powered flight, they help determine the angle of attack of the tower during an abort event. The crew can monitor any off-axis pressure on a gauge on panel 1 normally used to monitor combustion pressure in the spacecraft's SPS engine. A switch will be thrown after the tower is jettisoned to effect this change. Dual use of instruments is common in the spacecraft as it saves weight and panel.”
history.nasa.gov/afj/ap08fj/photos/ground/19681217-s68-55...
All above per the Apollo Flight Journey website:
history.nasa.gov/afj/ap08fj/01launch_ascent.html