Luna - Exploring the Moon
2016 May 24
Tuesday, Day 145
Selected Luna Missions:
A different view from Ian Ridpath
Summarised by Don P Mitchell
The Mission of Luna 16
Luna 16 was the first automated vehicle to land on the Moon and return a sample of material to Earth. It was not, howeve, the first retrieval of lunar soil sample though. The Apollo 11 and Apollo 12 mission had already taken place by the time Luna 16 reached the Moon.
Luna 16 is shown here sitting on the Moon's surface, having touched down from orbit.
At left, the cone-shaped antenna keeps communication with Earth while the drill arm occupies its rest position on the right. The soil sample was taken by rotating the drill head by one hundred and eighty degrees, lowering the drill arm to the surface and extracting a vertical core. On returning to the rest position, the sample was transferred to the return capsule through a self-sealing hatch and was then sent back to Earth.
Luna 15, an earlier Soviet vehicle had got as far as the Moon, charged with the same mission objective. It crashed on the surface during 1969 July while America's Apollo 11 piloted lunar landing Mission was under way. It was destroyed on impact.
The spacecraft consisted of two separate stages - an ascent stage to propel the sample container back to Earth, and a descent stage to provide course corrections, lunar orbit insertion and the landing manoeuvre. The descent stage had four legs to support the craft on the surface, fuel tanks, a landing radar, and a descent engine which was used for orbital adjustmen while in lunar orbit, and then to slow the craft for landing.
The descent stage also acted as a launch pad for the ascent stage. It was equipped with a television camera covering the drilling area, radiation and temperature monitors, and telecommunications equipment for use in the trans-lunar, lunar orbital and landing phases of the mission.
The ascent stage had a cylindrical housing radio equimpent, etc, with the spherical sample return container on top and a nest of propellant tanks below. In this artist's rendition, the return stage ascends from the lunar surface. A single main engine is assisted by four 'outrigger' engines to steer it. Inside the capsule is a cylindrical, hermetically sealed soil sample container.
The photograph on the right depicts the part of the spacecraft that was heat-shielded to survive re-entry into the Earth's atmosphere in order to parachute down to the ground.
This particular photograph is of a test vehicle lying on its side in open ground after a test drop from an aircraft.
The two cylindrical balloons are a distinctive red colour to aid its visual location by recovery teams. Antennae for its radio beacon sprout from the top of the capsule and wide parachute straps trail across the ground towards the front left of the view.
Luna 16 Statistics:
Launch Vehicle: Proton (four stage version)
Launching Technique: Low orbit around Earth, translunar trajectory, then lunar orbit followed by landing
Mass: 1,880 kilogrammes on lunar surface
Length: 3.1 metres)
Maximum Diameter: 3.3 metres (including landing legs)
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