31st Annual Meeting of the DPS, October 1999
Session 29. Science and Technology of Future Space Missions III
Special Solicited and Contributed Oral Parallel Session, Tuesday, October 12, 1999, 2:00-3:30pm, Sala Kursaal

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[29.08] Spatial Heterodyne Spectrometer: A Compact, Robust Interferometer for Optical Spectroscopic OH Measurements in the Solar System

F.L. Roesler (U Wisc), J. Harlander (St.Cloud SU), R. Conway, M.E. Summers (USNRL)

The predicted importance of the hydroxyl radical, OH, in the chemistry of the atmospheres of Mars and Venus, icy satellites such as Europa, and comets illustrates the broad interest in making definitive OH measurements for a wide array of solar system objects. In particular, hydroxyl is central to the study of the Martian atmosphere, where it is thought to be the primary catalytic agent in the chemical cycles that allow long term stability of the CO2 atmosphere. Observations of OH would thus provide an opportunity to test our understanding of the chemical evolution of the Martian atmosphere. Until now, a compact, highly-sensitive, and robust remote sensing instrument for space deployment capable of making the desired measurements has not been developed.

We have recently completed the testing of laboratory and engineering models of a Spatial Heterodyne Spectrometer (SHS) suitable for making the desired measurements, and meeting the packaging requirements of small spacecraft. SHS is a field-widened Fourier-transform optical spectroscopic technique that requires no moving parts, has relaxed optical tolerances compared to conventional interference spectrometers, and, at a specified resolving power, achieves a throughput higher by four orders of magnitude than conventional grating instruments of similar size (Harlander et al., Ap. J., 396, 730, 1992). We will describe the basic operation of the SHS, illustrate the near-theoretical performance achieved with it in laboratory studies of the OH fluorescence band near 308\,nm, and discuss plans for a monolithic, optically-contacted miniature SHS suitable, for example, for incorporating into a Mars or Europa mission.

Supported in part by NSF grant ATM-9612228 to the University of Wisconsin.

The author(s) of this abstract have provided an email address for comments about the abstract: roesler@wisp.physics.wisc.edu

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