Spacecraft above the Moon.

Artist's concept of Lunar Orbiter at the Moon.

Goals: Following Lunar Orbiter 1's scouting of potential Apollo landing sites in the Moon's southern equatorial region, Lunar Orbiter 2 was to photograph 30 potential landing sites in the northern equatorial area, as well as take various measurements of the Moon and its environment.

Accomplishments: Lunar Orbiter 2 transmitted 211 pictures, covering nearly four million square kilometers of both the near and far sides of the Moon. They included a shot looking across Copernicus crater from an altitude of only 45 km that vividly conveyed the three-dimensional nature of the lunar surface, an image that newspapers hailed as "the picture of the century." Following the main imaging mission, the spacecraft changed its orbital plane to enable scientists to see how its orbit would respond to variations in the Moon's gravitational field over a wider swath.

6 Nov 1966: Launch


Mission Type: Orbiter
Launch Vehicle: Atlas-Agena D (no. 18 / Atlas D no. 5802 / Agena D no. AD122 / 6631)
Launch Site: Eastern Test Range, launch complex 13, Cape Canaveral, USA
NASA Center: Langley Research Center
Spacecraft Mass: 385.6 kg at launch
Spacecraft Instruments: 1) imaging system; 2) micrometeoroid detectors and 3) radiation dosimeters
Spacecraft Dimensions: 2 m high, 5.2 m across with dish and omnidirectional antenna deployed
Spacecraft Power: Four solar panels; nickel-cadmium batteries for use in Moon's shadow
Maximum Power: 375 W
Antenna Diameter: 1 m (high-gain antenna)
Total Cost: $163 million (total for all five spacecraft in Lunar Orbiter program)
References:
Deep Space Chronicle: A Chronology of Deep Space and Planetary Probes 1958-2000, Monographs in Aerospace History No. 24, by Asif A. Siddiqi

National Space Science Data Center, http://nssdc.gsfc.nasa.gov/

Solar System Log by Andrew Wilson, published 1987 by Jane's Publishing Co. Ltd.


Lunar Orbiter 2's mission was to photograph 13 primary and 17 secondary landings sites for the Apollo program in the northern region of the Moon's near-side equatorial area.

On 10 November 1966, the spacecraft entered a 196 x 1,871-km orbit around the Moon. By 6 December, when the probe transmitted back its last photograph, 211 pictures had been taken of both the near side and large areas of the far side. These photos covered nearly four million square km of the lunar surface. The high-gain transmitter failed on the same day, but did not significantly affect the coverage afforded by the photos.

Lunar Orbiter 2 returned perhaps the most memorable photo of any in the series, a spectacular shot looking across the Copernicus crater from an altitude of only 45 km, which vividly emphasized the three-dimensional nature of the lunar surface.

On 8 December, after the main photographic mission was over, Lunar Orbiter 2 fired its main engine to change its orbital plane in order to provide tracking data of the Moon's gravitational field over a wider swath. Finally, on 11 October 1967, when the attitude-control gas was almost depleted, a retro-burn deliberately crashed the spacecraft onto the lunar surface at 4 degrees south latitude and 98 degrees east longitude on the far side to prevent communications interference on future missions.

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