The 1966 Lunar Orbiter 1 robotic spacecraft mission, part of NASA's Lunar Orbiter program, was the first American spacecraft to orbit the Moon. It was designed primarily to photograph smooth areas of the lunar surface for selection and verification of safe landing sites for the Surveyor and Apollo missions. It was also equipped to collect selenodetic, radiation intensity, and micrometeoroid impact data.
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Mission type | Lunar orbiter |
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Operator | NASA |
COSPAR ID | 1966-073A ![]() |
SATCAT no. | 2394 |
Mission duration | 80 days |
Spacecraft properties | |
Manufacturer | The Boeing Co. |
Launch mass | 385.6 kg (850 lb) |
Start of mission | |
Launch date | August 10, 1966, 19:31 (1966-08-10UTC19:31) UTC[1] |
Rocket | Atlas SLV-3 Agena-D |
Launch site | Cape Canaveral LC-13 |
End of mission | |
Disposal | Deorbited |
Decay date | October 29, 1966 (1966-10-30) "about 13:29 GMT"[2] |
Orbital parameters | |
Reference system | Selenocentric |
Semi-major axis | 2,694 km (1,674 mi) |
Eccentricity | 0.33 |
Periselene altitude | 189.1 to 40.5 km (117.5 to 25.2 mi) |
Aposelene altitude | 1,866.8 km (1,160.0 mi) |
Inclination | 12 degrees |
Period | 208.1 minutes |
Lunar orbiter | |
Orbital insertion | August 14, 1966 |
Impact site | 6.35°N 160.72°E / 6.35; 160.72 |
Orbits | 577 |
Lunar Orbiter program ← None |
Mission controllers injected the spacecraft into a parking orbit around Earth on August 10, 1966, at 19:31 UTC. The trans-lunar injection burn occurred at 20:04 UTC. The spacecraft experienced a temporary failure of the Canopus star tracker (probably due to stray sunlight) and overheating during its cruise to the Moon. The star tracker problem was resolved by navigating using the Moon as a reference, and the overheating was abated by orienting the spacecraft 36 degrees off-Sun to lower the temperature.
Lunar Orbiter 1 was injected into an elliptical near-equatorial lunar orbit 92.1 hours after launch. The initial orbit was 189.1 by 1,866.8 kilometers (117.5 mi × 1,160.0 mi) and had a period of 3 hours 37 minutes and an inclination of 12.2 degrees. On August 21, perilune was dropped to 58 km (36 mi) and on August 25 to 40.5 km (25.2 mi). The spacecraft acquired photographic data from August 18 to 29, 1966, and readout occurred through September 14, 1966.
A total of 42 high-resolution and 187 medium-resolution frames were taken and transmitted to Earth covering more than 5 million square kilometers of the Moon's surface, accomplishing about 75% of the intended mission, although a number of the early high-resolution photos showed severe smearing. It also took the first two pictures of Earth from the Moon. Accurate data were acquired from all other experiments throughout the mission.
Orbit tracking showed a slight "pear-shape" of the Moon based on the gravity field, and no micrometeorite impacts were detected. The spacecraft was tracked until it impacted the lunar surface on command at 7 degrees north latitude, 161 degrees east longitude (selenographic coordinates) on the Moon's far side on October 29, 1966, on its 577th orbit. The early end of the nominal one-year mission resulted from a shortage of remaining attitude control gas and other deteriorating conditions and was planned to avoid transmission interference with Lunar Orbiter 2.
Lunar Photographic Studies | Evaluation of Apollo and Surveyor landing sites |
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Meteoroid Detectors | Detection of micrometeoroids in the lunar environment |
Caesium Iodide Dosimeters | Radiation environment en route to and near the Moon |
Selenodesy | Gravitational field and physical properties of the Moon |
Lunar Orbiter program | ||
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← 1965 · Orbital launches in 1966 · 1967 → | |
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Kosmos 104 | OPS 2394 | OPS 7253 · OPS 3179 | Kosmos 105 | Kosmos 106 | OPS 1593 | Luna 9 | OPS 7291 | ESSA-1 | OPS 1439 | Kosmos 107 | Kosmos 108 | OPS 1184 · OPS 3011 · OPS 3031 | Dipason | Kosmos 109 | DS-K-40 No.2 | Kosmos 110 | ESSA-2 | Kosmos 111 | OPS 3488 | GATV-5003 | Gemini VIII | Kosmos 112 | OPS 0879 · OPS 0974 | Kosmos 113 | N-4 No.3 | OPS 1117 | Molniya-1 No.5 | OV1-4 · OV1-5 | OPS 0340 | Luna 10 | Kosmos 114 | OPS 1612 | Surveyor SD-3 | OAO-1 | OPS 0910 | Kosmos 115 | OV3-1 | Molniya 1-03 | Kosmos 116 | OPS 1508 | Kosmos 117 | Kosmos 118 | OPS 1950 · OPS 6785 | Nimbus 2 | Zenit-4 | GATV-5004 | OPS 0082 | OPS 1788 | Kosmos 119 | Explorer 32 | Surveyor 1 | ATDA | Gemini IX-A | OPS 1577 · OPS 1856 | OGO-3 | Kosmos 120 | OV3-4 | FTV-1351 · Secor 6 · ERS-16 | OPS 9311 · OPS 9312 · OPS 9313 · OPS 9314 · OPS 9315 · OPS 9316 · OPS 9317 · GGTS | Kosmos 121 | OPS 1599 | PAGEOS | Kosmos 122 | Explorer 33 | AS-203 | Proton 3 | Kosmos 123 | OPS 1850 | OV1-7 · OV1-8 | Kosmos 124 | GATV-5005 | Gemini X | Kosmos 125 | Kosmos 126 | OPS 3014 | OV3-3 | Kosmos 127 | OPS 1545 | Lunar Orbiter 1 | OPS 1832 · OPS 6810 | Pioneer 7 | OPS 2366 | FTV-1352 · Secor 7 · ERS-15 | Luna 11 | IDSCP 1 · IDSCP 2 · IDSCP 3 · IDSCP 4 · IDSCP 5 · IDSCP 6 · IDSCP 7 · GGTS | Kosmos 128 | GATV-5006 | Gemini XI | OPS 6026 | OPS 1686 · OPS 6874 | Zenit-2 No.40 | OPS 6026 | OPS 1686 · OPS 6874 | OGCh No.05L | Surveyor 2 | OPS 1703 | Ōsumi 1 | OPS 4096 | ESSA-3 | FTV-1583 · Secor 8 | OPS 2055 · OPS 5345 | Kosmos 129 | Molniya 1-04 | Kosmos 130 | Luna 12 | Surveyor SM-3 | Intelsat II F-1 | OV3-2 | OGCh No.06L | OPS 2070 · OPS 5424 | OPS 0855 · OV4-1R · OV4-1T · OV1-6 | Lunar Orbiter 2 | OPS 1866 | GATV-5001A | Gemini XII | Kosmos 131 | Strela-2 No.1 | Kosmos 132 | Kosmos 133 | Kosmos 134 | OPS 1890 | ATS-1 | OV1-9 · OV1-10 | Kosmos 135 | Soyuz 7K-OK No.1 | OPS 8968 | Biosatellite 1 | Kosmos 136 | Ōsumi 2 | Kosmos 137 | Luna 13 | OPS 1584 | |
Payloads are separated by bullets ( · ), launches by pipes ( | ). Crewed flights are indicated in underline. Uncatalogued launch failures are listed in italics. Payloads deployed from other spacecraft are denoted in brackets. |
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