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Lunar Orbiter 3

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Lunar Orbiter 3
Lunar Orbiter 3 image of the far side of the Moon, enhanced by LOIRP
Mission typeLunar orbiter
OperatorNASA
COSPAR ID1967-008A Edit this at Wikidata
SATCAT no.2666
Websitescience.nasa.gov
Mission duration8 months, 4 days
Spacecraft properties
ManufacturerLangley Research Center
Launch mass385.6 kg (850 lb)[1]
Dimensions3.72 × 1.65 × 1.5 m (12.2 × 5.4 × 4.9 ft)[2]
Power375 watts[2]
Start of mission
Launch dateFebruary 5, 1967, 01:17:01 (1967-02-05UTC01:17:01Z) UTC[1]
RocketAtlas SLV-3 Agena-D
Launch siteCape Canaveral LC-13
End of mission
DisposalDeorbited
Decay dateOctober 9, 1967, 10:27:11 (1967-10-09UTC10:27:12) UTC[2]
Orbital parameters
Reference systemSelenocentric
Semi-major axis2,694 km (1,674 mi)
Eccentricity0.33
Periselene altitude1,791 km (1,113 mi)
Aposelene altitude3,598 km (2,236 mi)
Inclination20.9 degrees
Period208.1 minutes
EpochFebruary 7, 1967, 19:00:00 UTC[2]
Lunar orbiter
Orbital insertionFebruary 8, 1967, 21:54 UTC
Impact site14°18′N 97°42′W / 14.3°N 97.7°W / 14.3; -97.7
Orbits1,702
Transponders
Frequency2295 MHz[2]

The Lunar Orbiter 3 was a spacecraft launched by NASA in 1967 as part of the Lunar Orbiter Program.[7] It was designed primarily to photograph areas of the lunar surface for confirmation of safe landing sites for the Surveyor and Apollo missions. It was also equipped to collect selenodetic, radiation intensity, and micrometeoroid impact data.

Mission summary

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Replica of a Lunar Orbiter spacecraft

The spacecraft was placed in a cislunar trajectory and injected into an elliptical near-equatorial lunar orbit on February 8 at 21:54 UT. The orbit was 210.2 by 1,801.9 kilometres (130.6 mi × 1,119.6 mi) with an inclination of 20.9 degrees and a period of 3 hours 25 minutes. After four days (25 orbits) of tracking the orbit was changed to 55 by 1,847 kilometres (34 mi × 1,148 mi). The spacecraft acquired photographic data from February 15 to 23, 1967, and readout occurred through March 2, 1967. The film advance mechanism showed erratic behavior during this period resulting in a decision to begin readout of the frames earlier than planned. The frames were read out successfully until March 4 when the film advance motor burned out, leaving about 25% of the frames on the takeup reel, unable to be read.[8]

Spacecraft orbit and photographic coverage on the near side (left) and far side (right)

A total of 149 medium resolution and 477 high resolution frames were returned.[9] The frames were of excellent quality with resolution down to 1 metre (3 ft 3 in). Included was a frame of the Surveyor 1 landing site, permitting identification of the location of the spacecraft on the surface. The future landing site of Apollo 14 including Cone crater, was photographed by the orbiter.[10] Accurate data were acquired from all other experiments throughout the mission.[11] The spacecraft was used for tracking purposes until it struck the lunar surface on command at 14.3 degrees N latitude, 97.7 degrees W longitude (selenographic coordinates) on October 9, 1967.

Instruments
Lunar Photographic Studies Evaluation of Apollo and Surveyor landing sites
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

See also

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References

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  1. ^ a b Asif Siddiqi (2018). Beyond Earth: A Chronicle of Deep Space Exploration, 1958–2016 (PDF) (second ed.). NASA. ISBN 978-1-626-83043-1.
  2. ^ a b c d e "Lunar Orbiter 3". nssdc.gsfc.nasa.gov. NASA. Retrieved May 2, 2018.
  3. ^ "Lunar Orbiter 3: Cesium Iodide Dosimeters". nssdc.gsfc.nasa.gov. NASA. Retrieved August 19, 2024.
  4. ^ "Lunar Orbiter 3: Lunar Photographic Studies". nssdc.gsfc.nasa.gov. NASA. Retrieved August 19, 2024.
  5. ^ "Lunar Orbiter 3: Meteoroid Detectors". nssdc.gsfc.nasa.gov. NASA. Retrieved August 19, 2024.
  6. ^ "Lunar Orbiter 3: Selenodesy". nssdc.gsfc.nasa.gov. NASA. Retrieved August 19, 2024.
  7. ^ B. A. Byers (1976). Destination Moon: A History of the Lunar Orbiter Program. NASA. ISBN 978-1-495-92029-5. NASA-TM-X-3487. Retrieved November 12, 2022.
  8. ^ "Lunar Orbiter 3". science.nasa.gov. NASA. Retrieved August 19, 2024.
  9. ^ "Lunar Orbiter Photo Gallery - Mission 3". Lunar and Planetary Institute. Retrieved November 13, 2022.
  10. ^ Apollo 14 Preliminary Science Report. NASA. 1971. ISBN 978-1-502-72648-3. NASA-SP-272.
  11. ^ Thomas P. Hansen (1970). Guide to Lunar Orbiter Photographs. NASA. ASIN B003Z5I8CO. ISBN 978-1-499-16108-3. NASA-SP-242. Retrieved November 13, 2022.