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Lunar Orbiter Program

a series of probes launched to the Moon by the United States in 1966 and 1967 for the purpose of "scouting" potential manned landing sites

model of a Lunar Orbiter
Lunar Orbiter

A total of five Lunar Oribters were launched, and all five were successful. The first three were dedicated to photographing potential landing sites, while the fourth and fifth were devoted primarily to scientific objectives. By the time the last mission ended the entire "nearside" and 95 per cent of the "farside" of the Moon had been imaged.

Lunar Orbiter I was launched on August 10, 1966, reached the Moon on August 18, and completed its mission on August 29. A total of 413 photographs were taken, including the first view of the Earth from the distance of the Moon (below).

Earth as seen from the Moon
Earth as seen from the Moon

Lunar Orbiter II was launched on November 6, 1966, reached the Moon on November 18, and completed its mission on November 25. A total of 211 photographs were taken, but some were not transmitted to Earth due to an equipment failure. One of the received photos showed the Sea of Tranquility, where Neil Armstrong became the very first man to walk on the Moon. The second photo shown below was taken on November 23 and transmitted five days later. In the foreground is the crater Fauth, about 13 miles across and 4,500 feet deep. Above the center of the picture is the crater Copernicus, which is 60 miles in diameter and 2 miles deep. Mountains rise about 1,000 feet from the floor of Copernicus. The last picture shows domes that are 2 to 10 miles across and 1,000 to 1,500 feet high. Those domes indicate a history of volcanic activity.

Sea of Tranquility as seen by Lunar Orbiter 2
Sea of Tranquility as seen by Lunar Orbiter 2

the Moon as seen by Lunar Orbiter 2 on November 23, 1966
the Moon as seen by Lunar Orbiter 2 on November 23, 1966

domes on the Moon
domes on the Moon

Lunar Orbiter III was launched on February 5, 1967, reached the Moon on February 15, and ended its mission on February 23. While the first two orbiters "scouted" potential landing sites, Orbiter III was tasked with "confirming" potential landing sites. A total of 211 pictures were taken, but only about 75 per cent of them were successfully transmitted to Earth before an equipment failure prevented reception.

Lunar Orbiter III view of the Moon
Lunar Orbiter III view of the Moon

Lunar Orbiter IV was launched on May 4, 1967, reached the Moon on May 11, and completed its mission on May 26. The primary objective of this mission was to obtain as much information about the lunar surface and its geological processes as possible. A total of 199 pictures were taken and transmitted, covering almost all of the nearside and a fair amount of the farside.

the Mare Orientale Basin
the Mare Orientale Basin

Lunar Orbiter V was launched on August 1, 1967, reached the Moon on August 6, and ended its mission on August 18. A total of 174 pictures were taken, with a significant number being from the farside.

Tycho Crater
Tycho Crater

SOURCES
Lunar and Planetary Institute http://www.lpi.usra.edu/lunar/missions/orbiter/
National Space Science Data Center http://nssdc.gsfc.nasa.gov/planetary/lunar/lunarorb.html

SEE ALSO
Neil Armstrong

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The Robinson Library >> Technology >> Astronautics >> Unmanned Programs and Missions

This page was last updated on 04/12/2017.