Spacecraft in orbit above the moon.

Artist's concept of a Lunar Orbiter spacecraft at the Moon.

Goals: Lunar Orbiter 1 was designed to photograph the Surveyor 1 landing site and scout potential landing sites for the Apollo program in the Moon's southern equatorial region. It's cameras were to provide the first clear images of the far side of the Moon.

Accomplishments: Lunar Orbiter 1 was the first U.S. spacecraft to orbit the Moon. It took 207 pictures of the lunar surface, covering an area of more than 5 million square kilometers. The high-resolution photos were smeared, but the medium-resolution images were the best lunar-surface images returned to date. Included was the first picture of Earth as seen from the Moon. Tracking of the spacecraft's orbit around the Moon confirmed the Luna 10 finding of strong gravitational variations. The tracking data from Lunar Orbiter 1, combined with the data for the four subsequent Lunar Orbiters, led scientists to conclude that the gravity anomalies were caused by large, dense masses of material ("mascons," for mass concentrations) underlying the Moon's near-side basins.

10 Aug 1966: Launch
18 Aug 1966 - 30 Aug 1966: Moon Imaging

Mission Type: Orbiter
Launch Vehicle: Atlas-Agena D (no. 17 / Atlas D no. 5801 / Agena D no. AD121 / 6630)
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: 375 W
Antenna Diameter: 1 meter (high-gain antenna)
Project Manager: Isidore G. Recant
Total Cost: $163 million (total for all five spacecraft in Lunar Orbiter program)
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,

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

Erik M. Conway, Historian, Jet Propulsion Laboratory

The Lunar Orbiter program originated as a response to the need to obtain 1-meter-resolution photographs of potential Apollo landing sites. NASA planned launches of a series of 3-axis-stabilized spacecraft with 4 solar panels and a main engine (derived from an Apollo attitude-control thruster) for lunar orbit insertion.

The primary instrument on board was a 68-kilogram Eastman-Kodak imaging system (using wide- and narrow-angle lenses) that could develop exposed film, scan the images, and send them back to Earth. The narrow-angle pictures provided resolution of up to 60 to 80 meters, while the wide-angle photos showed resolutions up to 0.5 kilometer.

Lunar Orbiter 1 entered a 191 by 1,854-kilometer orbit around the Moon on 24 August, becoming the first U.S. spacecraft to do so. The spacecraft's primary mission was to photograph 9 potential Apollo landing sites, 7 secondary areas, and the Surveyor 1 landing site.

During its mission, the probe took 207 frames of the lunar surface covering an area of 5.18 million square kilometers. The high-resolution photos were blurred from smearing, but the medium-resolution images were the best lunar surface images returned to date. One of the images returned, taken on 23 August, was the first picture of Earth from the Moon.

Lunar Orbiter 1 returned its last picture on 30 August and was commanded to crash onto the lunar surface on 29 October to prevent its transmissions from interfering with future Lunar Orbiters. Impact coordinates were 6 ° 42' north latitude and 162 ° east longitude (at 13:30 UT).

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