Editing Lunar Orbiter program (section)

==Spacecraft and subsystems==
[[Image:Lunar Orbiter diagram.png|thumb|Lunar Orbiter diagram (NASA)]]
The Boeing-Eastman Kodak proposal was announced by NASA on 20 December 1963. The main bus of the Lunar Orbiter had the general shape of a truncated cone, {{convert|1.65|m|abbr=on}} tall and {{convert|1.5|m|abbr=on}} in diameter at the base. The spacecraft was composed of three decks supported by trusses and an arch. The equipment deck at the base of the craft held the battery, [[transponder]], flight programmer, [[inertial navigation system|inertial reference unit]] (IRU), [[Canopus]] [[star tracker]], command decoder, multiplex encoder, [[traveling-wave tube amplifier]] (TWTA), and the photographic system. Four solar panels were mounted to extend out from this deck with a total span across of {{convert|3.72|m|abbr=on}}. Also extending out from the base of the spacecraft were a high gain antenna on a {{convert|1.32|m|abbr=on}} boom and a low-gain antenna on a {{convert|2.08|m|abbr=on}} boom. Above the equipment deck, the middle deck held the velocity control engine, propellant, oxidizer, and pressurization tanks, Sun sensors, and micrometeoroid detectors. The third deck consisted of a heat shield to protect the spacecraft from the firing of the velocity control engine. The nozzle of the engine protruded through the center of the shield. Mounted on the perimeter of the top deck were four [[Attitude control system|attitude control]] thrusters.

Power of 375 W was provided by the four solar arrays containing 10,856 n/p solar cells which would directly run the spacecraft and also charge the 12 A·h [[nickel-cadmium battery]]. The batteries were used during the brief periods of occultation when no solar power was available. Propulsion for major maneuvers was provided by the gimballed velocity control engine, a [[hypergolic]] {{convert|100|lbf|N|order=flip}} thrust [[Marquardt Corporation|Marquardt Corp.]] rocket motor. Three axis stabilization and attitude control were provided by four {{convert|1|lbf|N|order=flip|sigfig=1}} nitrogen gas jets. Navigational knowledge was provided by five [[Sun sensor]]s, the Canopus star sensor, and the inertial navigation system. Communications were via a 10&nbsp;W transmitter and the directional one-meter diameter high-gain antenna for transmission of photographs, and a 0.5&nbsp;W transmitter and omnidirectional low-gain antenna for other communications. Both transmitters operated in the [[S band]] at about 2295&nbsp;MHz. Thermal control was maintained by a multilayer aluminized [[Mylar]] and [[Dacron]] thermal blanket which enshrouded the main bus, special paint, insulation, and small heaters.

Originally, the Air Force had offered NASA several spare cameras from the [[KH-7 GAMBIT]] program, but then authorities became concerned over security surrounding the classified cameras, including the possibility of images of the Moon giving away their resolution. Some proposals were made that NASA not publish the orbital parameters of the Lunar Orbiter probes so that the resolution of the images could not be calculated through their altitude. In the end, NASA's existing camera systems, while lower resolution, proved to be adequate for the needs of the mission.

=== Photographic subsystem ===
[[File:Lunar_Orbiter_Photographic_Subsystem,_George_Eastman_House,_Rochester,_New_York_02.jpg|alt=Lunar_Orbiter_Photographic_Subsystem,_George_Eastman_House,_Rochester,_New_York_02|thumb|A flight-spare Lunar Orbiter Photographic Subsystem is on display at the [[George Eastman Museum]] in Rochester, N.Y.]]
[[Kodak]] created and constructed built eight photographic subsystems for the Lunar Orbiter program, five of which were used in space missions of 1966 and 1967.<ref name=":0" /> The camera used two lenses to simultaneously expose a wide-angle and a high-resolution image on the same film. The wide-angle, medium resolution mode used an 80&nbsp;mm F 2.8 [[Schneider Kreuznach#Xenotar|Xenotar]] lens manufactured by [[Schneider Kreuznach]] of West Germany. The high-resolution mode used a 610&nbsp;mm F 5.6 Panoramic lens manufactured by the Pacific Optical Company.<ref>{{cite web |last=Byers |first=Bruce K. |date=April 1977 |title=DESTINATION MOON: A History of the Lunar Orbiter Program |url=http://www.hq.nasa.gov/office/pao/History/TM-3487/top.htm |url-status=dead |archive-url=https://web.archive.org/web/20200411153526/http://www.hq.nasa.gov/office/pao/History/TM-3487/top.htm |archive-date=2020-04-11 |access-date=2010-12-18 |publisher=NASA}}</ref> The cameras exposed negatives on [[65 mm film|65 mm]] Kodak Bimat film, which was then developed onboard using a semidry process.<ref name=":1">{{cite web |last=Hall |first=R. Cargill |date=October 2001 |title=SAMOS to the Moon: The Clandestine Transfer of Reconnaissance Technology Between Government Agencies |url=https://www.nro.gov/Portals/65/documents/history/csnr/programs/docs/prog-hist-01.pdf |access-date=November 13, 2022 |publisher=National Reconnaissance Office}}</ref><ref name=":0" /> The subsystem's [[photomultiplier]] then scanned the images by a  for transmission to Earth as [[analog video]].<ref name=":0" /><ref name=":1" /> The receiving stations on Earth then transferred the video images back onto film, which was then shipped to Kodak in [[Rochester, New York|Rochester]] for final processing and printing.<ref name=":0">{{Cite AV media |url=https://www.youtube.com/watch?si=f7TFLqiPwMQ5rbhk&v=7HRF8rQD1Vw&feature=youtu.be |title=The Lunar Orbiter Camera at George Eastman House |date=2007-11-29 |last=George Eastman Museum |access-date=2024-10-22 |via=YouTube}}</ref> This system was adapted under permission of the NRO from the [[Samos (satellite)|SAMOS]] E-1 reconnaissance camera, built by Kodak for a short-lived USAF near-realtime satellite imaging project.<ref name=":1" />

=== Potential backup ===
As a backup for the Lunar Orbiter program, NASA and the NRO cooperated on the [[Lunar Mapping and Survey System]] (LM&SS), based on the [[KH-7]] reconnaissance satellite. Replacing the [[Lunar Module]] in the [[Saturn V]], Apollo astronauts would operate LM&SS remotely in lunar orbit. NASA canceled the project in the summer of 1967 after the complete success of the Lunar Orbiters.<ref name=day20101129>{{cite web |url=http://www.thespacereview.com/article/1734/1 |title=Black Apollo |publisher=www.thespacereview.com |first=Dwayne A. |last=Day |access-date=9 May 2023 |date=29 November 2010}}</ref>

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