Ranger, Surveyor, Luna, Luna Orbiter, 1960s Missions to Earth's Moon Options

[Bob Shaw]

Have any of the serious experts on this board ever sorted out any 1960s images? I'm thinking of the Surveyor panoramas (in the 60s they did it with photos pasted onto the inside of half-spheres!) and the way that the exposure dropped off toward one corner, making a horrible patchwork effect. Or them lines and spots on the Lunar Orbiter images...

Most of the NASA mission data should be available as digital source material, and thus could be manipulated, though I suspect that getting anything 'real' from Soviet missions would be a bit of a chase!

Any thoughts?

[Guest_BruceMoomaw_*]

Good additional info there.  I'm pretty sure I've heard the bit on the Surveyor 1 descent camera both ways, so I'm not sure of the real story. 

The Shadow Knows! (Pause for deep, chilling laughter.)

Aviation Week, March 28, 1966: "One result of conservative mission planning ws a decision not to use the approach TV camera aboard SC-1 [Surveyor-1]. The camera, built by Hughes around a General Electrodynamics vidicon tube, was to have taken as many as 100 pictures of the Moon'surface from between 1000 to 80 miles above the surfce, just before ignition of the spacecrft's main retrorocket.

"Use of the approach camera was deleted from the first Surveyor mission even before the problems wih the planar array high-gain antenna wer discovered. [This is a reference to the previous section of the article, which refers to a problem discovered with the pointing motors on the solar panel and antenna at low temperatures -- leading to a change in their design starting with Surveyor 2.]

"It was felt that the use of the approach camera would introduce risky complications during the terminal descent phase of the mission, according to S.C. Shallon, chief Surveyor program scientist for Hughes. Transmission of the 600-line frames would have required additional commands -- needed to maneuver the spacecraft, aim the planar array high-gain antenna at Earth and activate the camera.

"Another reason was that the transmission of blocks of pictures would produce blank spots in the spacecraft telemetry record at a critical time.

"Doubts about the ability of the A/SPP polar axis [motor] to position the planar array on command cemented the decision not to use the approach TV. This is because the center of gravity of the spcecraft during the critical main retrorocket firing phase must be determined before launch, based on the planned position of the solar panel and planar array at the time of rocket ignition. This determines the placement of the 8700-pound thrust solid-propellant retromotor within the aluminum frame.

"Failure of the polar axis to orient the planar array to its programmed position could have disastrous effects upon the stability of the spacecraft during retro-firing...

"Hughes is proceeding with S-2, 3 and 4 as if the high-gain antenna will be aimed at the Earth in the pre-terminal phase and approach TV will be used. However, the decision to use the camera will not be made until after SC-1 performance is analyzed. [I never saw anything suggesting that they'd decided to use it on Surveyor 2. By the way, the failure of the attempt to turn it on for a test after landing on Surveyor 1 was due to the fact that they only tried this after Surveyor 1 had survived its first lunar night, during which it underwent serious battery damage from the cold. For the same reason, an attempt to briefly burp its vernier rockets to study the effect on the surface failed; that test had to be delayed until Surveyor 5, since the walls of the crater in which Surveyor 3 landed made it overheat and they had to quickly vent the verniers' helium.]

"Even if the approach TV is not used on later missions, it is possible that the planar array still may be aimed at Earth during the pre-terminal phase and used with the high-power transmitter to increase the telemetry transmission at that time to 4400 bits/second from the 1100 bits/sec. that is possible using one of the two omnidirectional antennas. [They never actually did.]

"However, transmission would still be switched to an omniantenna after main retromotor burnout, because it is expected that during the final vernier engine descent phase, in the last 2-2.5 minutes before landing, the high-gain antenna would probably become pointed away from the Earth."