The Proposed NASA Lunar-Based Astronomical Observatories

Swanson, Paul N.; ,

The Proposed NASA Lunar-Based Astronomical Observatories

by Paul N. Swanson, California Inst of Technology, Pasadena, United States,

Document Type: Proceeding Paper

Part of: Engineering, Construction, and Operations in Space III

Abstract:

The goals of the Space Exploration Initiative are a manned return to the Moon, a permanent lunar outpost and then a manned expedition to Mars. This presents an opportunity to construct astronomical telescopes on the Moon using the infrastructure provided by the lunar outpost. The Moon provides several unique advantages for astronomical telescopes. Among these are a lack of obscuring atmosphere or ionosphere, a large stable base, very low night time temperatures and a slow rotation rate providing long integration times. The large areas of highly stable lunar surface are ideal for interferometric type instruments whose elements may be separated by several kilometers and require extreme positional accuracy. The first astronomical telescopes on the Moon may be implemented very early in the program, perhaps even before the manned landings. Small automatically deployed telescopes can be carried on the survey missions, be deployed on the lunar surface and be operated remotely from the Earth. Possibilities for early, small optical telescopes are a zenith pointed, wide angle, transit telescope; a student telescope, operated from any secondary school with a computer and modem; and a 0.5 to 1 meter automatic, fully steerable telescope. After the lunar outpost is established the lunar interferometers will be constructed in an evolutionary fashion. That is, the initial configuration may have only two elements with additional elements being added with each additional cargo flight. There are three lunar interferometers which have been studied. The most ambitious is the optical interferometer with a 1 km baseline and twelve 1.5 m aperture elements arranged in a 'Y' configuration with a central beam combiner. The Submillimeter interferometer would use twelve, 5 m reflectors in a 'Y' or circular configuration with a 1 km baseline. The Very Low Frequency (VLF) array would operate below 30 mHz with as many as 100 elements and a 200 km baseline. In addition to the lunar interferometers, a large optical telescope has been proposed. This telescope would be approximately 8 m in diameter (scaled down from the original 16 m). Lunar siting for the astronomical telescopes has been studied in a series of workshops at the Johnson Space Flight Center. A site near the equator and either of the lunar limbs satisfies most astronomical requirements.

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