Category:Surveyor space probe

NASA mockup of a Surveyor probe, photographed on a beach on Earth [image info]

1971 card showing Surveyor 3, with inspecting astronauts [image info]

Meccano "Surveyor" model in the No.5 1973 "Book of Models" [image info]

Nasa's Surveyor programme (1966-1968) sent a series of unmanned three-legged space probes to the moon, partly to test out the stability and other properties of the surface that the Apollo astronauts would be landing on (from 1969 onwards), and partly to test the ability of the landing systems to operate in the harsh conditions of space.

The pair of large rectangular panels at the top of the central strut, slight reminiscent of the seed-leaves at the top of a newly-sprouting plant, may have helped inspire the expressive angled camera-"eyes" of the robot star of the Disney-Pixar film "Wall-E" (2008).

The programme sent seven craft to the Moon, Surveyor 1 through Surveyor 7. Surveyors 1, 3, and 5-7 had successful missions, while Surveyors 2 and 4 were lost through technical problems.

Missions

While one of Surveyor 1's most important jobs was collecting real (rather than calculated) data on lunar distance and orbital properties, which could be used to fine-tune slight data for further missions, Surveyor 3 was also fitted with an extensible claw and scoop to test the surface properties.

As well as measuring temperature variations and landing site properties, Surveyor 3's video cameras were able to transmit live images of the Moon's surface back to Earth for the first time.

One of the concerns about the lunar surface was the extent to which potentially abrasive lunar dust could be blown off at high speed by the rocket engines. The Surveyors were designed to fire their retro-rockets to slow to a halt 3.4 metres (just over eleven feet) above the lunar surface, and then cut out to let the probe "drop" the remaining distance (the fall being less brutal than it sounds, because of the one-sixth Earth gravity). This was to stop the rocket engine exhaust creating a high-velocity cloud of lunar dust that could "sandblast" the underside and sides of the probe and damage it.

Apollo 12 landed in sight of Surveyor 3 in 1969, and the astronauts trekked over to the probe to examine it, and cut off pieces to be returned to Earth. These let NASA confirm that high-velocity regiolith thrown off by Apollo 12's landing had created measurable sand-blasting effects on Surveyor 3, with the particulates able to travel large distances at high velocity due to the absence of air to slow them down, and the weakness of the Moon's gravity deflecting them into the ground.

1970: Meccano

A Meccano model of a Surveyor probe was featured on the front of a 1970 Meccano catalogue leaflet ("Meccano for the Space-Age"), and also appeared as one of the models on the box of the No.5 set, and in the accompanying Book of Models as a design that owners could build

External links

• NASA Surveyor program (wikipedia.org)