Apollo TV camera
Television cameras used on the Apollo Project's missions (and later Apollo-Soyuz Test Project and Skylab missions) varied in design, with image quality improving significantly with each design. A camera was carried in the Apollo Command Module. For each lunar landing mission, a camera was also placed inside the Modularized Equipment Stowage Assembly (MESA) in Quad 4 of the Lunar Module (LM) Descent Stage, so it was capable of broadcasting the first steps of the astronauts as they climbed down the ladder of the LM at the start of the first moonwalk/EVA. Afterwards, the camera would be detached from its mount in the MESA, mounted on a tripod and carried away from the LM to show the progress of the EVA.
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[edit] RCA slow scan TV camera
Apollo 7 and Apollo 8 used an RCA slow scan camera.[1]
- Lines per video frame: 320
- Frame rate: (SSTV) 10 frame/s
- Black and white
[edit] Westinghouse Apollo Lunar Television Camera
In October 1964, NASA awarded Westinghouse the contract for the Lunar TV Camera.[2] Stan Lebar, the Program Manager for the Apollo Lunar TV Camera, headed the team at Westinghouse that developed the camera that brought pictures from the Moon's surface. The camera was first tested in space during the Apollo 9 mission in March 1969.[3] This is the camera that was used on Apollo 11, and captured humanity's first step on another celestial body on 21 July 1969.[3]
- Usage: Apollo 9 (Earth orbit), Apollo 11 (lunar surface), Apollo 13, Apollo 14, Apollo 15, Apollo 16 (back-up to the lunar surface color camera, never used)
- Resolution: 250 TV lines (10 frame/s mode) / 500 TV Line (0.625 frame/s mode) / (SEC sensor - 650 TV Lines)
- Scan rate: (SSTV) 10 frame/s / 320 lines/fr, 0.625 frame/s / 1280 lines/fr (not used)
- Bandwidth: 4 Hz to 500 kHz
- Black and white
- Sensor: 1 Secondary Electron Conduction (SEC) Tube
- Analog FM transmission
The camera was built by Westinghouse, was 11 by 6 by 3 inches (280 mm × 150 mm × 76 mm) in size, and weighed 7.25 pounds (3.29 kg), It consumed 6.25 watts of power. It had four interchangeable lenses: "telephoto", "wide-angle", "lunar day" and "lunar night".
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Photo of the high-quality SSTV image received from Apollo 11 at Honeysuckle Creek Tracking Station
[edit] Westinghouse Lunar Color Camera
- Usage: Apollo 10 (CSM), Apollo 11 (CSM), Apollo 12, Apollo 13, Apollo 14, Apollo 15 (CSM), Apollo 16 (CSM), Apollo 17 (CSM)
- Additional planned usage not implemented: Skylab Orbital Test flights prior to 1980. The ASTP cameras were modified to fly on the shuttle had the STS CCTV system not been available for the hoped 1979 maiden launch. by the time STS-1 flew the RCA CCTV system was already in place. (Crew Station Closed Circuit Television CCTV for Operational Flight Tests 08.06.1976)
- Resolution: more than 200 TV lines (SEC sensor - 350 TV Lines in vertical dimension)
- Scan rate: 59.94+ fields/s monochrome (color filters alternated between each field) / 29.97+ frame/s / 525 lines/fr / 15734.26+ lines/s
- Color: Field-sequential color system camera
- Bandwidth: Real 4.5 MHz / 2 MHz up to 3 MHz (transmitter limitation)
- Sensor: Secondary-Electron-Conduction (SEC) Tube
- Optics: 6x zoom, F/4 to F/44
This camera was based on the TV camera used on previous missions inside the CSM, with modifications to adapt it to the lunar environment.
During the early part of the first Apollo 12 EVA, the camera was inadvertently pointed at the Sun while preparing to mount it on the tripod. This action caused an overload in the secondary electron conduction tube (sensitive for low light conditions), rendering the camera useless for the remainder of the mission. The camera worked properly for about forty-two minutes. On later missions, while modifications were made to prevent such accidents, problems were encountered with image brightness and contrast (and sharpness – due to the camera overheating while stored, and operating in the MESA).
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Edgar Mitchell with the Apollo 14 camera
[edit] RCA J-Series Ground-Commanded Television Assembly (GCTA)
- Usage: Apollo 15 (lunar surface), Apollo 16 (lunar surface) and Apollo 17 (lunar surface)
- Resolution: more than 200 TV lines (SIT sensor - 600 TV Lines)
- Scan rate: 59.94+ fields/s monochrome (color filters alternated between each field) / 29.97+ frame/s / 525 lines/fr / 15734.26+ lines/s
- Color: Field-sequential color system camera
- Spectral response: 350–700 nm
- Gamma: 1.0
- Sensitivity: > 32 dB signal to noise ratio
- Dynamic range: > 32:1
- Bandwidth: up to 5 MHz
- Sensor: Silicon Intensifier Target (SIT) Tube
- Optics: 6x zoom, F/2.2 to F/22
- Automatic light control (ALC): average or peak scene luminance
Because of the failure of the camera on Apollo 12, a new contract was awarded to the RCA Astro division in Hightstown, NJ. The RCA system was a new, more sensitive and durable TV camera tube. The design team was headed by Robert G. Horner. The team used newly developed SIT, and the improved images were obvious to the public.
The system was composed of the Color Television Camera (CTV) and the Television Control Unit (TCU). These were connected to the Lunar Communications Relay Unit (LCRU) when mounted on the Lunar Roving Vehicle (LRV).
Once the LRV was fully deployed, the camera was mounted there and controlled by commands from the ground to tilt, pan, and zoom in and out.
[edit] See also
[edit] Notes
- ^ Apollo TV PDF
- ^ Steven-Boniecki (2010), p. 54
- ^ a b Steven-Bonicki (2010), pp. 80–81
[edit] References
- Apollo TV and Communications Documentation
- Apollo Lunar TV - Its History and Development from Armstrong to Leonov
- Ground-Commanded Television Assembly (GCTA)
- Apollo 10 Television
- Sarkissian, John. Television from the Moon. The Parkes Observatory's Support of the Apollo 11 Mission. Latest Update: 21 October 2005.
- Steven-Boniecki, Dwight (2010). Live TV From the Moon. Burlington, Ontario: Apogee Books. ISBN 9781926592169. http://www.livetvfromthemoon.com/.
[edit] External links
- The Cameras of Apollo - Hosts many pictures and other information on lunar surface cameras
- Honeysuckle Creek discusses some of the Apollo 11 moonwalk video.
- Apollo Talks Episode 8 is about the Apollo TV camera.
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