Proposal Title: A Miniaturized Infrared Atmospheric Spectrometer (MIRAS)
Objectives and relevance: The objective of the effort proposed here is to demonstrate the capabilities of a technology which enables a major reduction in mass, volume, and cost, for EOS-class atmospheric science instruments. The critical aspect of this technology is the High Resolution Linear Variable Etalon (HRLVE) coupled with 2-dimensional detector arrays. This allows for the design of high performance infrared spectrometers with all-solid state wavelength scanning and instantaneous spectral and spatial coverage. To underscore the relevance of this technology to the OES mission we outlined a concept for a HRLVE-based satellite experiment to monitor stratospheric ozone and related chemicals beyond EOS-CHEM. The estimated sensor mass (<50 kg) is up to 10 times less than current generation eos instruments of comparable performance, and the volume (0.5x0.5x0.3m) is as much as 20 times less. such miniaturization enables the use of small satellites and launch vehicles and greatly reduces overall mission cost. this enables frequent, overlapped missions, for long-term monitoring of the recovery of stratospheric ozone in response to reduced cfcs, beyond the year 2000.
approach and methodology>: The key task in bringing the technology to a readiness level for flight instrument development is to demonstrate the required spectral/spatial performance of coupled HRLVE and 2-D arrays at operational wavelengths. We propose to accomplish this by developing 2 HRLVEs designed for the 6-8mm and 10-13mm wavelengths needed for stratospheric monitoring. These etalons with dn=0.5 cm-1 will be first spectrally characterized by an 0.02 cm-1 Fourier transform interferometer. They will then be mounted in a laboratory bread-board simulating the optical configuration of a satellite instrument, and used with a 128x128 HgCdTe array to acquire gas cell and solar absorption spectra of example gases in the short wavelength band (N2O, CH4) and long wave band (CFC12, CO2). We will conclude the 1-year effort by conducting a top-level definition of a flight instrument based on the measured spectral/spatial performance of the HRLVE .
A.E.Roche et al., Distribution and Seasonal Variation of CFCs in the Stratosphere: Comparison of Satellite Global Data and a 2-D model, Advances in Space Research, 21:10, 1998.
A.E.Roche et al., Observations of Lower Stratospheric ClONO2, HNO3, and Aerosol by the UARS CLAES Experi-ment, between January 1992 and April 1993, J. Atm. Sci., 51, 2877, 1994.