Lunar Orbiter 4 was a robotic U.S. spacecraft, part of the Lunar Orbiter Program, designed to orbit the Moon, after the three previous orbiters had completed the required needs for Apollo mapping and site selection. It was given a more general objective, to "perform a broad systematic photographic survey of lunar surface features in order to increase the scientific knowledge of their nature, origin, and processes, and to serve as a basis for selecting sites for more detailed scientific study by subsequent orbital and landing missions". It was also equipped to collect selenodetic, radiation intensity, and micrometeoroid impact data. The spacecraft was placed in a cislunar trajectory and injected into an elliptical near polar high lunar orbit for data acquisition. The orbit was 2,706 by 6,111 kilometres (1,681 mi × 3,797 mi) with an inclination of 85.5 degrees and a period of 12 hours.
![]() Image taken by Lunar Orbiter 4, showing the Moon with a crescent Earth in the background. Enhanced by LOIRP. | |
Mission type | Lunar orbiter |
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Operator | NASA |
COSPAR ID | 1967-041A ![]() |
SATCAT no. | 2772 |
Mission duration | 180 days |
Spacecraft properties | |
Manufacturer | Langley Research Center |
Launch mass | 385.6 kilograms (850 lb) |
Start of mission | |
Launch date | May 4, 1967, 22:25:00 (1967-05-04UTC22:25Z) UTC[1] |
Rocket | Atlas SLV-3 Agena-D |
Launch site | Cape Canaveral LC-13 |
End of mission | |
Last contact | July 17, 1967 (1967-07-18)[2] |
Decay date | October 6, 1967[3] |
Orbital parameters | |
Reference system | Selenocentric |
Semi-major axis | 6,152.5 kilometers (3,823.0 mi) |
Eccentricity | 0.28 |
Periselene altitude | 4,449 kilometers (2,764 mi) |
Aposelene altitude | 7,856 kilometers (4,881 mi) |
Inclination | 85.5 degrees |
Period | 721 minutes |
Epoch | March 7, 1967, 20:00:00 UTC[4] |
Lunar orbiter | |
Orbital insertion | May 8, 1967, 21:54 UTC |
Orbits | 360 |
Lunar Orbiter program |
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 to 134 metres (190 to 440 ft). Accurate data was 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 until it struck the lunar surface due to the natural decay of the orbit no later than October 31, 1967, between 22–30 degrees W longitude.
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 |
Lunar Orbiter program | ||
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See also |
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← 1966 · Orbital launches in 1967 · 1968 → | |
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Intelsat II F-2 | OPS 1664 | IDCSP 9 · IDCSP 10 · IDCSP 11 · IDCSP 12 · IDCSP 13 · IDCSP 14 · IDCSP 15 · IDCSP 16 | Kosmos 138 | Kosmos 139 | ESSA-4 | OV3-5 | OPS 4399 | Lunar Orbiter 3 | Kosmos 140 | OPS 6073 | Diadème 1 | Kosmos 141 | Kosmos 142 | Diadème 2 | OPS 4750 | OPS 4204 | Kosmos 143 | Kosmos 144 | Kosmos 145 | OSO 3 | Kosmos 146 | Kosmos 147 | Kosmos 148 | Kosmos 149 | Kosmos 150 · OGCh No.8 | Intelsat II F-3 | Kosmos 151 | Kosmos 152 | OPS 4779 | Kosmos 153 | ATS-2 · RPM-481 | Kosmos 154 | Kosmos 155 | Unnamed | OPS 0100 | Surveyor 3 | ESSA-5 | Soyuz 1 | San Marco 2 | OPS 4243 | Kosmos 156 | OPS 6638 · OPS 6679 · ERS-18 · ERS-20 · ERS-27 | Lunar Orbiter 4 | Ariel 3 | OPS 4696 · OPS 1967 | Kosmos 157 | Kosmos 158 | Kosmos 159 | Kosmos 160 | OPS 7218 | Kosmos 161 | OPS 4321 · OPS 5557 | Explorer 34 | Molniya-1 No.8 | ESRO-2A | NRL PL-151 · NRL PL-152 · NRL PL-153 · NRL PL-154 · NRL-PL 159 · Timation 1 · Calsphere 3 · Calsphere 4 · OPS 5712 | Kosmos 162 | OPS 4360 | Kosmos 163 | Kosmos 164 | Venera 4 | Kosmos 165 | Mariner 5 | Kosmos 166 | OPS 3559 · OPS 1873 | Kosmos 167 | Zenit-4 No.32 | OPS 4286 | Unnamed | SECOR-9 · Aurora | IDCSP 16 · IDCSP 17 · IDCSP 18 · IDCSP 19 · LES-5 · DODGE | Kosmos 168 | Surveyor 4 | Kosmos 169 | Explorer 35 | Zenit-4 No.33 | OPS 1879 | OV1-11 · OV1-12 · OV1-86 | OGO-4 | Kosmos 170 | Lunar Orbiter 5 | OPS 4827 | Kosmos 171 | Kosmos 172 | OPS 4886 | OPS 7202 | Kosmos 173 | Kosmos 174 | Zenit-2 No.51 | Biosatellite 2 | Surveyor 5 | Kosmos 175 | Kosmos 176 | OPS 5089 | Kosmos 177 | Kosmos 178 | OPS 4941 | Kosmos 179 | OPS 4947 | Kosmos 180 | Unnamed | 7K-L1 No.4L | Intelsat II F-4 | Molniya-1 No.9 | OPS 1264 | Kosmos 181 | Kosmos 182 | Kosmos 183 | OSO 4 | Molniya-1 No.12 | Kosmos 184 | OPS 4995 | Kosmos 185 | Kosmos 186 | Kosmos 187 | Kosmos 188 | Kosmos 189 | OPS 0562 · OPS 1587 | Kosmos 190 | ATS-3 | Surveyor 6 | Apollo 4 | ESSA-6 | Kosmos 191 | 7K-L1 No.5L | Kosmos 192 | Kosmos 193 | WRESAT | Kosmos 194 | OV3-6 | OPS 5000 | OPS 1001 | Pioneer 8 · ERS-30 | Kosmos 195 | Kosmos 196 | Kosmos 197 | Kosmos 198 | |
Payloads are separated by bullets ( · ), launches by pipes ( | ). Crewed flights are indicated in underline. Uncatalogued launch failures are listed in italics. Payloads deployed from other spacecraft are denoted in brackets. |
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