Lunar Orbiter 4
Encyclopedia : L : LU : LUN : Lunar Orbiter 4
.jpg "Lunar Orbiter 4")
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| Organization: | NASA |
| Major Contractors: | Langley Research Center |
| Mission Type: | Lunar Science |
| Satellite of: | Moon |
| Launch: | May 4, 1967 at 22:25:00 UTC |
| Launch Vehicle: | Atlas-Agena D |
| Decay: | Impacted lunar surface no later than October 31, 1967, near 22--30 degrees W. |
| Mission Duration: | 180 days |
| Mass: | 385.6 kg |
| NSSDC ID: | 1967-041A |
| Webpage: | [NASA NSSDC Master Catalog] |
| Orbital elements | |
|---|---|
| Semimajor Axis: | 6,152.5 km |
| Eccentricity: | .28 |
| Inclination: | 85.5° |
| Orbital Period: | 721 minutes |
| Aposelene: | 6,111 km |
| Periselene: | 2,706 km |
| Orbits: | 360 |
| Instruments | |
| Lunar Photographic Studies : | Evaluation of Apollo and Surveyor landing sites |
| Meteoroid Detectors : | Detection of micrometeoroids in the lunar environment |
| Cesium Iodide Dosimeters : | Radiation environment en route to and near the moon |
| Selenodesy : | Gravitational field and physical properties of the moon |
After initial photography on May 11, 1967 problems started occurring with the camera's thermal door, which was not responding well to commands to open and close. Fear that the door could become stuck in the closed position covering the camera lenses led to a decision to leave the door open. This required extra attitude control maneuvers on each orbit to prevent light leakage into the camera which would ruin the film. On May 13 it was discovered that light leakage was damaging some of the film, and the door was tested and partially closed. Some fogging of the lens was then suspected due to condensation resulting from the lower temperatures. Changes in the attitude raised the temperature of the camera and generally eliminated the fogging. Continuing problems with the readout drive mechanism starting and stopping beginning on May 20 resulted in a decision to terminate the photographic portion of the mission on May 26. Despite problems with the readout drive the entire film was read and transmitted. The spacecraft acquired photographic data from May 11 to 26, 1967, and readout occurred through June 1, 1967. The orbit was then lowered to gather orbital data for the upcoming Lunar Orbiter 5 mission.
A total of 419 high resolution and 127 medium resolution frames were acquired covering 99% of the Moon's near side at resolutions from 58 meters to 134 meters. Accurate data were acquired from all other experiments throughout the mission. Radiation data showed increased dosages due to solar particle events producing low energy protons. The spacecraft was used for tracking purposes until it impacted the lunar surface due to the natural decay of the orbit no later than October 31, 1967, between 22--30 degrees W longitude.
External links
| Lunar Orbiter program |
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| Previous mission: | Lunar Orbiter 3 | Next mission: | Lunar Orbiter 5 | |
| Lunar Orbiter 1 | Lunar Orbiter 2 | Lunar Orbiter 3 | Lunar Orbiter 4 | Lunar Orbiter 5 | ||||
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