The UVC was one of the experiments deployed on the lunar surface by the Apollo 16 astronauts. It consisted of a telescope and camera that obtained astronomical images and spectra in the far ultraviolet region of the electromagnetic spectrum.
The Far Ultraviolet Camera/Spectrograph was a tripod mounted, f/1.0, 75 mm electronographic Schmidt camera weighing 22 kg. It had a 20° field of view in the imaging mode, and 0.5×20° field in the spectrographic mode.[1] Spectroscopic data were provided from 300 to 1350 Ångström, with 30 Å resolution, and images were provided in two passbands ranges, 1050-1260 Å and 1200-1550 Å.[2] There were two corrector plates made of lithium fluoride (LiF) or calcium fluoride (CaF2), which could be selected for different bands of UV.[1] The camera contained a cesium iodide (CsI) photocathode and used a film cartridge[2] which was recovered and returned to earth for processing.
The experiment was placed on the Descartes Highlands region of lunar surface where Apollo 16 astronauts John Young and Charles Duke landed in April 1972. To keep it cool and eliminate solar glare, it was placed in the shadow of the lunar module. It was manually aimed by the astronauts, who would re-point the telescope at targets throughout the lunar stay (Experiment Operations During Apollo EVAs”. Archived from the original on 20 February 2013. Retrieved 1 May 2013).
Built
Apollo 16 astronauts placed the observatory on the moon in April 1972, where it sits today on the moon’s Descartes highland region, in the shadow of the lunar module Orion. Asked to explain highlights of the instrument’s findings for a general audience, Dr. Carruthers said “the most immediately obvious and spectacular results were really for the Earth observations, because this was the first time that the Earth had been photographed from a distance in ultraviolet light, so that you could see the full extent of the hydrogen atmosphere, the polar auroris and what we call the tropical airglow belt.”
Dr. Carruthers made the first detection of molecular hydrogen in space, in 1970, using a sounding rocket. He developed a rocket instrument that obtained an ultraviolet image of Comet Halley, and an instrument with two cameras, with different far-UV wavelength sensitivities, used on the STS-39 space shuttle mission in 1991. He has worked on UV imaging of Earth’s polar auroras and of the faint photochemical luminescence found in the upper atmosphere, with an instrument, Global Imaging Monitor of the Ionosphere (GIMI), on a Department of Defense satellite, the Advanced Research and Global Observation Satellite (ARGOS), launched in 1999. In 2012, he was awarded the National Medal of Technology and Innovation, the nation’s highest honor for technology achievement. ( Reference https://www.nasa.gov/image-feature/looking-back-dr-george-carruthers-and-apollo-16-far-ultraviolet-cameraspectrograph)
Purpose/ Goal
A miniature observatory that acquired imagery and spectra in the far- UV range ( below 1600 angstrom). The Goal of the experiment were to
1) determine composition and structure of the upper atmosphere of Earth from its spectra
2) determine the structure of the geocorona and study day and night airglow and polar aurorae
3) obtain direct evidence of intergalactic hydrogen in distant galaxy clusters
4) obtain spectra and imagery of the solar wind and other gas clouds in the solar system
5) detect gasses in the lunar atmosphere, including volcanic gasses, if any
6) obtain spectra and colors of external galaxies in the far UV 7) obtain spectra and colors of stars and nebulae in the Milky Way
8) evaluate the lunar surface as a site for future astronomical observatories.
Hazards in the experiment?
There was no explosive, radioactive, toxic or high voltages in the object. There was a strong magnet in the camera which was shown not to affect the worn by the crew.
Was the experiment successful? Yes.
Were there related experiments on other flights?
UV telescopes have flown in Earth orbit. One example was the OAO. Hand-held photography of the Earth and Moon was performed during many of the Apollo flights. On A-17 a far UV spectrometer in the SIM Bay of the SM, which was primarily used to study lunar atmospheric density and composition while in lunar orbit, was also used during TEC to observe Earth’s atmosphere, zodiacal light, and galactic and extragalactic sources. As mentioned under “design changes,” above, the back-up unit to A-16 was flown on Skylab 4. An extreme ultraviolet survey experiment flew on the Apollo-Soyuz test flight.
Where was it stored during flight? Quad III of the LM, scientific equipment bay.
Were there any problems photographing the experiment?
No. Photos clearly show the unit deployed on the surface. Some scattering of far UV light in the photos of the Magellanic cloud was attributed to lunar dust electrostatically suspended above the surface. See also Lunar Dust Detector – DTREM.
What pre-launch and cruise request were there?
power, thermal, late access, early recovery?
A major requirement was to avoid gas contamination of the photocathode. The unit was placed into a bag. The bag was then purged with dry nitrogen continuously until 72 h before launch to keep out moisture while on the launch pad. The bag must have vented upon launch. The mass of this bag is included in the 22 kg.
What was different between training and actual EVA?
The sun angle was different than planned and trained under.
What problems were due to the suit rather than the experiment? None.
Any experiences inside the LM of interest from the experiment/operations viewpoint? No.
References
A-16 Preliminary Science Report, NASA SP-315, 1972
A-16 Mission Report
Apollo Scientific Experiments Data Handbook, JSC-09166, NASA TM X-58131, August, 1974, In JSC History Office.
Page, T. and G. R. Carruthers, S201 Far Ultraviolet Atlas of the Large Magellanic Cloud, NRL Report 8206, 1978.
George R. Carruthers, “Apollo 16 Far-Ultraviolet Camera/Spectrograph: Instrument and Operations, Applied Optics”, Vol. 12, p. 2501 – 2508, Oct., 1973.
Thornton Page, personal communication with Thomas Sullivan
Thornton Page, “S201 Far-Ultraviolet Photographs of Comet Kohoutek From Skylab 4 (SL4), Preliminary Report”, in Comet Kohoutek, Proceedings of a Workshop held at MSFC, June 13-14, 1974, pp. 37-75.
Apollo 16 Final Lunar Surface Procedures, March 16, 1972, MSC
Apollo Program Summary Report, section 3.2.31 Far-Ultraviolet Camera/Spectrograph, JCS-09423, April, 1975.
Apollo 16 Technical Crew Debriefing, 5 May 1972, in JSC History Office.
ALL INFORMATION HAS BEEN COLLECTED FROM THE WEBSITES AND ARTICLES MENTIONED ABOVE. NO WORK OR INFORMATION HAS BEEN MY OWN OR DO I SUGGEST THAT ANYWHERE IN THIS WORDPRESS.
Astronomy 