Development of he Nanosat Oxygen A-Band Spatial Heterodyne Interferometer (NOASHIN)

Tuesday, 16 December 2014
Steven R Watchorn, Scientific Solutions, Inc., North Chelmsford, MA, United States, John Noto, Scientific Solutions Inc, North Chelmsford, MA, United States, Richard A. Doe, SRI International Menlo Park, Menlo Park, CA, United States and Chad S Fish, Atmospheric and Space Technology Research Associates LLC, Boulder, CO, United States
The abundance of CO2 in the mesopause region has long been shown to track with mesopause cooling, making mesopause-region temperature measurement a way to track CO2 abundance in this critical region, where climate change indications often manifest early. One of the brightest thermally excited emissions in the mesopause region is the O2 A-band, whose emission peaks are significantly modulated as a function of temperature. Thus, spectroscopic recovery of a set of A-band emission lines between 763 and 765 nm, and a comparison of peak intensities, will provide information about mesopause temperature, and thus CO2 abundance. To get global coverage of this emission with high time resolution ( < 1s) requires a high-etendue spectrometer that can resolve the target lines (resolution ~ .06 nm), preferably aboard an efficient, economical vehicle capable of the global coverage that would be most beneficial to existing mesopause models. Nanosatellites are such a vehicle.

The NOASHIN instrument is a spectrometer very well suited to the low size, weight, and power (SWAP) of the nanosat platform. It is built around a Spatial Heterodyne Spectrometer (SHS), a monolithic Fourier transform spectrometer with no moving parts that shares the high etendue, high resolution advantages of conventional interferometers in a robust package ideal for space-based platforms. The NOASHIN instrument will be developed for, ultimately, a 1-U CubeSat, nadir-viewing nightglow measurement payload, used in a pushbroom imaging configuration from low-Earth orbit (~ 650 km), with an exposure time of < 1 s, leading to a target footprint of 9-km along-track.

The current development project will integrate a prototype NOASHIN SHS monolith into a 1.5-U CubeSat engineering prototype at the design SWAP requirements. The prototype will be detect emissions of the expected intensity (~700 R) from a lab source near the A-band and offload data onto a local computer for analysis.