Lunar Orbiter 3
OperatorNASA
Cospar id1967-008A
Satcat2666
Websitescience.nasa.gov
ManufacturerLangley Research Center
Launch mass385.6 kg (850 lb)[5]
Dimensions3.72 × 1.65 × 1.5 m (12.2 × 5.4 × 4.9 ft)[6]
Power375 watts[6]
Launch dateFebruary 5, 1967, 01:17:01 UTC[5]
Launch rocketAtlas SLV-3 Agena-D
Launch siteCape Canaveral LC-13
Decay dateOctober 9, 1967, 10:27:11 UTC[6]
Orbit epochFebruary 7, 1967, 19:00:00 UTC[6]
Orbit referenceSelenocentric
Orbit periapsis1,791 km (1,113 mi)
Orbit apoapsis3,598 km (2,236 mi)
Orbit inclination20.9 degrees
Orbit period208.1 minutes
Orbit semimajor2,694 km (1,674 mi)
Orbit eccentricity0.33
Apsisselene
Trans frequency2295 MHz[6]
ProgrammeLunar Orbiter program
Previous missionLunar Orbiter 2
Next missionLunar Orbiter 4
Lunar Orbiter 3
orbiter
ObjectLunar
Orbits1,702
Arrival dateFebruary 8, 1967, 21:54 UTC
Lunar Orbiter 3
Acronym 1-
Name 1Cesium Iodide Dosimeters[1]
Acronym 2-
Name 2Lunar Photographic Studies[2]
Acronym 3-
Name 3Meteoroid Detectors[3]
Acronym 4-
Name 4Selenodesy[4]

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

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 by 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 by 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]

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 (3.3 ft). 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 StudiesEvaluation of Apollo and Surveyor landing sites
Meteoroid DetectorsDetection of micrometeoroids in the lunar environment
Caesium Iodide DosimetersRadiation environment en route to and near the Moon
SelenodesyGravitational field and physical properties of the Moon

See also

References

  1. ^ "Lunar Orbiter 3: Cesium Iodide Dosimeters". nssdc.gsfc.nasa.gov. NASA. Retrieved 19 August 2024.
  2. ^ "Lunar Orbiter 3: Lunar Photographic Studies". nssdc.gsfc.nasa.gov. NASA. Retrieved 19 August 2024.
  3. ^ "Lunar Orbiter 3: Meteoroid Detectors". nssdc.gsfc.nasa.gov. NASA. Retrieved 19 August 2024.
  4. ^ "Lunar Orbiter 3: Selenodesy". nssdc.gsfc.nasa.gov. NASA. Retrieved 19 August 2024.
  5. ^ Asif Siddiqi (2018). Beyond Earth: A Chronicle of Deep Space Exploration, 1958–2016. second ed. NASA. ISBN 978-1-626-83043-1.
  6. ^ "Lunar Orbiter 3". nssdc.gsfc.nasa.gov. NASA. Retrieved 2 May 2018.
  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 12 November 2022.
  8. ^ "Lunar Orbiter 3". science.nasa.gov. NASA. December 8, 2017. Retrieved 19 August 2024.
  9. ^ "Lunar Orbiter Photo Gallery - Mission 3". Lunar and Planetary Institute. Retrieved 13 November 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. ISBN 978-1-499-16108-3. NASA-SP-242. Retrieved 13 November 2022.