Luna - Exploring the Moon
2015 Dec 1
Tuesday, Day 335
Selected Luna Missions:
A different view from Ian Ridpath
Summarised by Don P Mitchell
The Mission of Luna 3
Luna 3 was designed to operate more than the few hours of its predecessors, so a new design was needed involving solar cells to re-charge its chemical batteries during its flight around the Earth-Moon system.
Luna 3 was also equipped with a camera that pointed through an aperture at one end of the body. The design included protection for the lens in the form of a light baffle formed by the camera recess. A pair of hinged doors open for the photographic session.
In order to prevent it going into orbit around the Sun, it was launched with a lower velocity than Luna 1, hence its three-day, rather than two-day, journey to the Moon.
Luna 3's images were far from clear so, although they covered much of the 'back' of the Moon, their interpretation was difficult. Luna 3 produced this view of the Moon during a photographic session 1959 October 7 - three days after launch.
The large, nearly circular object at middle left is the Mare Crisium, which is visible from Earth. Another notable feature is the crater Tsiolkovsky towards the bottom right. Tsiolkovsky has a very dark floor but its central mountain is light in colour, making it stand out.
Clearer views might have been obtained when Luna 3 was scheduled to transmit its images a second time from closer to the Earth. However, no transmission was received. It seem that Luna 3 had died.
Luna 3's photographic system used standard 35mm film onto which calibration marks had been printed prior to the mission. The marks helped scientists in interpreting the photo transmissions.
The photographic system used two lenses, with focal lengths of 200mm and 500mm. The shorter focal length was capable of fitting an image of the Moon onto a single 35mm frame of film. The photo above is a mosaic of pictures from the 500mm lens.
The film itself was specially formulated so that it could be processed in a high-temperature environment and so that the temperature itself was not important. After the film was dried, it passed in front of a television scanning system for images to be converted to a form in which could be transmitted by radio. At all times, the film was shielded from radiation in order to prevent it becoming fogged.
After its mission was finished, Luna 3 continued to orbit the Earth-Moon system under the combined gravitational influences of both bodies until 1960 March 29. On that day, its trajectory actually took it into the Earth's atmosphere at high speed, where it burned up as a result of friction with the air.
Luna 3 Statistics:
Launch Vehicle: Vostok
Launching Technique: Direct ascent
Mass: 278 kilogrammes
Length: 1.3 metres
Maximum Diameter: 1.2 metres
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