Curious Droid : La lune avant Apollo




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The Apollo landings from 1969 to 1972 marked a high point in lunar exploration but Apollo didn’t just rock up on to the moon out of the blue, it took many, many missions by probes and landers over the preceding years to establish if we could send men to the moon and get them back.
It's quite strange to think that even by the late 1950’s ,just over 10 years before Neil Armstrong set foot on the lunar surface, we knew surprising little about the moon other than what we could observe from the earth and the hypotheses we drew from those observations.
We knew that it had no appreciable atmosphere or large bodies of water but we didn’t know what the surface was like and we didn’t what was on the far side, the side which always faces away from earth.
After the launch of Sputnik on Oct 4th 1957, the Soviets made several attempts at getting a probe to the moon. The first 3 launches in September, October and December of 1958 all failed but the fourth one in January 1959 did work but… they missed the moon and Luna-1 became the first spacecraft escape earth’s gravity to enter orbit around the sun.
After another launch failure in June, in September 1959 Luna-2 became the first man-made object to reach the surface of the moon.
These probes are not like the landers we are used to now, these were impactors, which means that they are designed to crash into the moon surface, taking measurements on the way. During their journey to the moon, Luna-2 took measurements approximately once a minute which was transmitted back to earth up until the time of impact.
Luna 2’s instruments helped prove that the moon had no real magnetic field and also confirmed the exitance of the Van Allen belts which had been discovered by the first US Satellite Explorer 1.
It also released a vapour cloud of bright orange sodium gas that expanded up to 400 miles, 650 km across which could be seen by telescopes on earth.
The US were sceptical of the Soviets and didn’t believe that they had reached the moon. That was until Bernard Lovell at the Jodrell Bank Radio telescope in England, using a Doppler effect method, proved that the signals did indeed come from the moon.
Once again, the US had been caught out by the Soviets who used Luna-2 and Sputnik and as propaganda to show the superiority of the Soviet Space program. The closest the US had come to the moon by then was Pioneer 4 which only got within 37,000 miles, 60,000 Km.
Luna-2 also proved that the impactor method worked and this would also be used later by the US ranger probes.
Then in Oct 1959, the Soviets did it again with Luna-3 when it became the first spacecraft to photograph the far side of the moon. Luna-3 was also the first craft to not only use the gravity assist method to swing it around the moon and back to the earth but also to position itself in space using 3 axis control with thrusters, this was essential to control the spin of the craft and to position the camera towards the lunar surface.
The photographic film used to for the images of the moon was high temperature, radiation hardened film which had been captured from American Genetrix balloons which the US used as high altitude surveillance devices, in effect they were the original spies in the sky, before high altitude planes or satellites. They would float over the Soviet Union taking pictures before being intercepted by the USAF once out of soviet airspace.
However, the Soviets found a way to shoot them down and capture the equipment onboard. Although they soviets didn’t know how to make the film at the time, they found a very good use for it in Luna 3.
The pictures were transferred from the photographic film in the Luna 3 satellite and transmitted back to earth using a method similar to a fax machine. The images were very basic but showed that the far side of the moon was quite different from the side facing earth.
With Kennedys announcement of the Apollo missions and the 8 year deadline to get a man on the moon by the end of the decade meant that the US had their work cut out to find suitable landing sites and working out if the surface was safe to land on as there was speculation by some in NASA that a lander could sink into the lunar dust.
To get close-up images of the lunar surface, the later part of the Ranger program would be used. These probes would use the impactor method that the Soviet Luna-2 pioneered. The program would be done in 3 blocks or phases with the first block of Ranger 1 and 2 testing the systems without trying for the moon, the following Rangers in block 2 and 3 all aimed at the moon.

The Life and Death of a Certain K. Zabriskie, Patriarch by Chris Zabriskie is licensed under a Creative Commons Attribution licence

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