Lunar Orbiter 3

NASA orbiter mission to the Moon (1967)

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

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.

• 
  Launch of Lunar Orbiter 3 from an Atlas-Agena rocket on February 5, 1967
• 
  Lunar Orbiter 3 image of the satellite craters of Ariadaeus on February 16, 1967 (4°07′N 19°46′E / 4.12°N 19.77°E / 4.12; 19.77)
• 
  Vallis Schröteri, the planned landing site of the cancelled Apollo 18 mission, on February 18, 1967 (1°25′N 5°59′W / 1.41°N 5.99°W / 1.41; -5.99)
• 
  View inside Hipparchus Crater on February 19, 1967 (4°46′S 4°17′E / 4.77°S 4.28°E / -4.77; 4.28)
• 
  Landing area of Surveyor 1 as seen by Lunar Orbiter 3 on April 28, 1967
• 
  Oblique view of Murchison Crater

See also

• Spaceflight portal

• Lunar Orbiter Image Recovery Project
• Exploration of the Moon
• List of artificial objects on the Moon
• List of missions to the Moon
  • Lunar Orbiter 1
  • Lunar Orbiter 2
  • Lunar Orbiter 4
  • Lunar Orbiter 5

References

1. Asif Siddiqi (2018). Beyond Earth: A Chronicle of Deep Space Exploration, 1958–2016 (PDF) (second ed.). NASA. ISBN 978-1-626-83043-1.
2. "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.