Lunar Orbiter 2

The 1966 Lunar Orbiter 2 robotic spacecraft mission, part of the Lunar Orbiter Program,^[8] 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.

Lunar Orbiter 2

Replica of a Lunar Orbiter spacecraft
Mission type	Lunar orbiter
Operator	NASA
COSPAR ID	1966-100A
SATCAT no.	2534
Website	science.nasa.gov
Mission duration	11 months, 5 days
Spacecraft properties
Manufacturer	Langley Research Center
Launch mass	385.6 kg (850 lb)[1]
Dimensions	3.72 × 1.65 × 1.5 m (12.2 × 5.4 × 4.9 ft)[2]
Power	375 watts[2]
Start of mission
Launch date	November 6, 1966, 23:21:00 (1966-11-06UTC23:21Z) UTC
Rocket	Atlas SLV-3 Agena-D
Launch site	Cape Canaveral LC-13
End of mission
Disposal	Deorbited
Decay date	October 11, 1967, 07:12:54 (1967-10-11UTC07:12:55) UTC
Orbital parameters
Reference system	Selenocentric
Semi-major axis	2,694 km (1,674 mi)
Eccentricity	0.35
Periselene altitude	1,790 km (1,110 mi)
Aposelene altitude	3,598 km (2,236 mi)
Inclination	11.9 degrees
Period	208.07 minutes
Epoch	November 9, 1966, 19:00:00 UTC[2]
Lunar orbiter
Orbital insertion	November 10, 1966
Impact site	3.0°N 119.1°E / 3.0; 119.1
Orbits	2,346
Transponders
Frequency	2295 MHz[2]
Instruments - Cesium Iodide Dosimeters[3] - Lunar Photographic Studies[4] - Meteoroid Detectors[5][6] - Selenodesy[7]
Lunar Orbiter program ← Lunar Orbiter 1 Lunar Orbiter 3 →

Mission summary

The spacecraft was placed in a cislunar trajectory and injected into an elliptical near-equatorial lunar orbit for data acquisition after 92.6 hours' flight time. The initial orbit was 196 by 1,850 kilometres (122 mi × 1,150 mi) at an inclination of 11.8 degrees. The perilune was lowered to 49.7 kilometres (30.9 mi) five days later after 33 orbits. A failure of the amplifier on the final day of readout, December 7, resulted in the loss of six photographs. On December 8, 1966 the inclination was altered to 17.5 degrees to provide new data on lunar gravity.

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

The spacecraft acquired photographic data from November 18 to 25, 1966, and readout occurred through December 7, 1966. A total of 609 high-resolution and 208 medium-resolution frames were returned, most of excellent quality with resolutions down to 1 metre (3 ft 3 in).^[9][10] These included a spectacular oblique picture of Copernicus crater, which was dubbed by the news media as one of the great pictures of the century. The photo was taken on the 23rd November at an altitude of 45km.^[11] Accurate data were acquired from all other experiments throughout the mission. Three micrometeorite impacts were recorded. The spacecraft was used for tracking purposes until it impacted upon the lunar surface on command at 3.0 degrees N latitude, 119.1 degrees E longitude (selenographic coordinates) on October 11, 1967.

In 2011, NASA's Lunar Reconnaissance Orbiter Camera (LROC) was able to locate and image the precise impact point of the spacecraft. The debris from an impact angle of 45 degrees or more spreads out like butterfly wings.^[12]

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

• 
  Near Ariadaeus B crater on November 19, 1966 (4.83°N 15.53°E / 4.83; 15.53)
• 
  Lunar Orbiter 2 about 29 miles (47 km) above the Sea of Tranquility on November 20, 1966
• 
  Centered approximately at one of the satellite craters of Gambart Crater on November 23, 1966 (1.07°N 12.45°W / 1.07; -12.45)
• 
  Mare Insularum as seen by Lunar Orbiter 2 on November 24, 1966 (1.87°N 33.79°W / 1.87; -33.79)

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 3
  • Lunar Orbiter 4
  • Lunar Orbiter 5

References

1. "Lunar Orbiter 2". science.nasa.gov. NASA. Retrieved November 30, 2022.
2. "Lunar Orbiter 2". nssdc.gsfc.nasa.gov. NASA. Retrieved May 2, 2018.
3. "Lunar Orbiter 2: Cesium Iodide Dosimeters". nssdc.gsfc.nasa.gov. NASA. Retrieved August 18, 2024.
4. "Lunar Orbiter 2: Lunar Photographic Studies". nssdc.gsfc.nasa.gov. NASA. Retrieved August 18, 2024.
5. "Lunar Orbiter 2: Meteoroid Detectors". nssdc.gsfc.nasa.gov. NASA. Retrieved August 18, 2024.
6. "Lunar Orbiter 2: Micrometeoroid Detectors". nssdc.gsfc.nasa.gov. NASA. Retrieved August 18, 2024.
7. "Lunar Orbiter 2: Selenodesy". nssdc.gsfc.nasa.gov. NASA. Retrieved August 18, 2024.
8. 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.
9. "Lunar Orbiter Photo Gallery - Mission 2". Lunar and Planetary Institute. Retrieved November 13, 2022.
10. 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.
11. P. Ulivi; D. M. Harland (2004). Lunar Exploration: Human Pioneers and Robot Surveyors. Springer. pp. 75–76. ASIN B01FGPVKN4. ISBN 978-1-852-33746-9.
12. Lester Black (November 2, 2011). "Lunar Lost and Found: Rediscovering Old Wrecks on the Moon". Popular Mechanics. Retrieved November 4, 2011.