The Lunar Transit Telescope (LTT): An Early Lunar-Based Science and Engineering Missionby John T. McGraw, Univ of Arizona, Tucson, United States,
Abstract: The moon is an excellent spacecraft, with mass, rotational, thermal and orbital properties which make its utilization as a base for astronomical observations superbly reasonable. The Lunar Transit Telescope (LTT) Project is being planned as the first astronomical mission on our imminent return to the moon precisely because it utilizes these properties to enable a mission with an immense scientific benefit-to-cost ratio and at the same time provides an engineering platform for future lunar missions of all kinds. In effect, the 'Sentinel,' the soft-landed lunar telescope of the LTT Project, in addition to being a superb scientific instrument, represents a well-instrumented 'Lunar LDEF.' This paper describes the Sentinel, a unique two meter telescope with virtually no moving parts, which accomplishes an imaging survey of the sky over almost five octaves of the electromagnetic spectrum from the ultraviolet into the near infrared, and with angular resolution better than 0.1 arcsecond/pixel. While the Sentinel can be built with existing and emerging technology, the engineering challenge is great. Because of the scientific necessity for continuously monitoring the mechanical, optical and thermal properties of the telescope in order to assess data quality and provide instrumental signature removal and calibration, the telescope itself must be highly instrumented. This instrumentation, coupled with knowledge of the (wavelength dependent) optical throughput, detector response, electronics performance and pointing, all derived from analysis of the images, provides an excellent long duration exposure facility on the lunar surface. The Sentinel will incorporate innovative techniques of significance for future lunar-based telescopes and will return significant engineering data which can be incorporated into future lunar missions.
Subject Headings: Moon | Telescopes | Thermal properties | Space colonies | Engineering profession | Imaging techniques | Space exploration
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