Apollo TV camera

TV cameras used on the Apollo 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.

RCA slow scan TV camera

Apollo 7 and Apollo 8 used an RCA slow scan camera. [http://www.hq.nasa.gov/alsj/ApolloTV-Acrobat7.pdf Apollo TV]
*Lines per video frame: 320
*Frame rate: (SSTV) 10 frame/s
*Black and white

Westinghouse Apollo Lunar Television Camera

*Usage: Apollo 9 (Earth orbit), Apollo 11 (lunar surface), Apollo 13 and Apollo 14 (back-up to the lunar surface color camera, never used)
*Optical resolution: ~220x~220
*Lines per video frame: 320, 1280 (not used)
*Frame rate: (SSTV) 10 frame/s, 0.65 frame/s (not used)
*Bandwidth: 409.6 kHz
*Black and white
*Sensor: 1" vidicon
*Analog FM transmission

The camera was built by Westinghouse, was 11" x 6" x 3" in size, and weighed 7.25 pounds, It consumed 6.25 watts of power. It had four interchangeable lenses: "telephoto", "wide-angle", "lunar day" and "lunar night".

Westinghouse Lunar Color Camera

*Usage: Apollo 10 (lunar orbit), Apollo 11 (lunar orbit), Apollo 12, Apollo 13 and Apollo 14
*Resolution: ~175x~175
*Lines per frame: 262
*Frame rate: 60 frame/s BW / 20 frame/s color (color filters alternated between each field)
*Color: Field-sequential color system camera
*Bandwidth: 2 MHz
*Sensor: Secondary-Electron-Conduction (SEC) Tube

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 vidicon tube, rendering the camera useless for the remainder of the mission. The camera worked properly for about forty-two minutes. On later missions problems were encountered with image brightness and contrast.

RCA J-Series Ground-Commanded Television Assembly (GCTA)

*Usage: Apollo 15, Apollo 16 and Apollo 17
*Resolution: ~ 200 lines
*Frame rate: 60 frame/s BW / 20 frame/s color (color filters alternated between each field)
*Color: Field-sequential color system camera
*Spectral response: 3500–7000 angstroms (350–700 nm)
*Gamma: 1.0
*Sensitivity: > 32 dB signal to noise ratio
*Dynamic range: > 32:1
*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.

ee also

*Apollo program missing tapes

Notes

References

* [http://www.hq.nasa.gov/alsj/alsj-TVDocs.html Apollo TV and Communications Documentation]
* [http://klabs.org/mapld06/abstracts/126_lebar_a.html Apollo Lunar TV - Its History and Development from Armstrong to Leonov]
* [http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19730010465_1973010465.pdf Ground-Commanded Television Assembly (GCTA)]
* [http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19790073158_1979073158.pdf Apollo 10 Television]
*Sarkissian, John. [http://www.parkes.atnf.csiro.au/apollo11/tv_from_moon.html Television from the Moon] . The Parkes Observatory's Support of the Apollo 11 Mission. Latest Update: 21 October 2005.
* [http://www.myspacemuseum.com/apollocams.htm The Cameras of Apollo] - Hosts many pictures and other information on lunar surface cameras

External links

* [http://www.honeysucklecreek.net/dvds/dvd2_discussion.html Honeysuckle Creek] discusses some of the Apollo 11 moonwalk video.
* [http://apollotalks.com/ Apollo Talks] Episode 8 is about the Apollo TV camera.