Engineering back-up of Surveyor lunar lander in the Space Hall at the Smithsonian Air and Space Museum in Washington, D.C.
Mapping of the Moon began with the Ranger spacecraft. They were followed up by the Surveyor program, which actually landed spacecraft on the Moon. The Lunar Orbiter craft did the high-resolution mapping just before the Apollo Moon landings.
The Surveyor program lasted from 1966 through 1968. There were seven Surveyors, whose goal was to prove it was possible to land on the Moon.
The Surveyors also tested a host of spacecraft abilities — all of them brand new. The spacecraft had to make midcourse corrections, successfully use a closed-loop terminal descent guidance and control system (which meant it had to use doppler radar to measure how have it was from the lunar surface, and how fast it was moving toward it), successfully demonstrate throttleable engines (instead of "on/off"), and have an on-board computer successfully calculate altitude, velocity, and attitude almost instantaneously. It all had to be done in a high-radiation environment where temperatures could be 250 degrees F i the sun or 300 degrees below in the shade.
Once on the Moon, the Surveyor craft were to determine what the lunar surface was like. Many scientists seriously believed the Moon was covered with dust so thick that any lunar lander would sink hundreds of feet! If the lander managed to hit solid rock, then it needed to evaluate that site for a manned landing.
Surveyor 1 carried instruments designed to tell how hard it landed on the Moon. This engineering data helped eningeers design landing gear for Apollo. Its TV camera sent medium-resolution images back to Earth which helped scientists identify the soil mechanics of the lunar surface. (These images were used in developing other Surveyor experiments.)
Surveyor 2 crashed on the Moon. During its mid-course correction, one of its engines failed to ignite and the spacecraft tumbled. Contact with it was never restored. It crashed near Sinus Medii on September 22, 1966. Surveyor 2 carried a TV camera, and was designed to lift off briefly again after landing ("bounce" on the lunar surface). It also carried sophisticated radar to determine how reflective the lunar surface was (if it absorbed radar, how could a manned craft know how fast it was moving and how high it was?), had special landing gear to determing how much weight the lunar surface could hold, and temperature gauges.
Surveyor 3 was the first spacecraft to actually leave another planet. As it was landing, highly reflective rocks confused its radar. The cut off too early, causing the lander to bounce 35 feet into the air. It landed and bounced again, this time to a height of 11 feet. It landed on the third try. Surveyor 3 carried a soil sampling-scoop, The soil in the scoop was then photographed. The camera of Surveyor 3 was returned to Earth by the crew of Apollo 12.
Surveyor 4 also carried a soil scoop-sampling arm. It was designed to look for iron in the lunar surface by using a magnet. But all contact was lost with the spacecraft 2.5 minutes before it landed. NASA believes its solid fuel rockets exploded.
Surveyor 5 carried a TV camera as well as a chemical analysis lab. Soil was scooped from the lunar surface, then irradiated using curium 242. The energy released by the lunar soil (in the form of alpha particles and of protons) was interpreted. Surveyor 5 was able to tell how much of each major element was in the soil except for hydrogen, helium, and lithium. It proved the Moon was made largely of basaltic rock.
Surveyor 5 almost didn’t make it! Half its rocket motors failed due to a helium leak. NASA allowed the craft to get half again as close to the surface as intended, and then turned on the rockets. By keeping the rockets on full blast (rather than throttling them up and down), NASA was able to soft-land Surveyor 5 after all.
Surveyor 6 was the first spacecraft to launch via rocket from the Moon’s surface. When it landed, it lifted itself back up into the sky, and then landed again 10 feet away. Surveyor 6 carried a TV camera, a chemical analysis lab (just like Surveyor 5), temperature equipment, and special radar to determine reflectivity. It also analyzed its lift-off sit to determine how much dust the engines kicked up during lift-off. Its soil sampling-scoop also contained a magnet to look for iron.
Surveyor 7 was purposefully schedule to land in a rocky, hazardous area. The idea was that if it landed successfully, it would send back data on types of soil and rock never yet analyzed. It carried the same instrument package as Surveyor 6. However, its TV camera had polarizing filters, which allowed for improved photographic soil mechanical studies. It also had mirror which it could use to look beneath the spacecraft, to analyze the effect of the landing thrusters on the lunar surface. Its carried the traditional bar magnets in its scoop, but it also had horseshoe magnets.
Surveyor 7’s chemical analysis package failed to deploy properly, so mission controller pushed it into place using the soil sampling claw.
While on the Moon, Surveyor 7 clearly saw two laser beams aimed at it from the Earth (one from Kitt Peak Observatory and the other from Table Mountain, California). Surveyor 7 was also the first spacecraft to detect "moonglow" — the faint glow on the lunar horizon after dark that is caused by light reflected from moon dust in the lunar atmosphere.
Posted by Tim Evanson on 2012-05-22 02:23:09
Tagged: , Smithsonian Institution , Smithsonian Air and Space Museum , Washington D.C. , Space Hall , satellite , Surveyor , lunar lander