Title: Preliminary performance of the BABAR-ERI instrument from the initial calibration campaign
Presenting Author: Cameron Straatsma
Organization: LASP
Co-Author(s): Odele Coddington, Virginia Drake, Kush Tyagi, Dave Harber, Peter Pilewskie, Sebastian Schmidt, Darren Erickson, Joel Rutkowski, Chip Bollendonk, Paris Buedel, Graham Dean, Adalyn Fyhrie, Marc Miller, David Summers, Weige Wong, Michelle Stephens, Christopher Yung, Nathan Tomlin, and John Lehman

Abstract:
Under the Earth Science Technology Office (ESTO) Instrument Incubator Program (IIP) we have developed a 12U CubeSat instrument to image Earth’s outgoing broadband radiation at 1 km spatial resolution and less than 1% radiometric uncertainty. The Black Array of Broadband Absolute Radiometers (BABAR) Earth Radiation Imager (ERI) is a push-broom imager with a 32 km ground swath that simultaneously measures the total (0.3 to 100 μm) and shortwave (0.3 to 4 μm) broadband radiation from two co-registered telescopes. The core technology development of this IIP is the 1x32 room temperature microbolometer detector array incorporating electrical substitution for absolute radiometry, and a vertically aligned carbon nanotube (VACNT) absorber for >99% absorptance over the full 0.3 to 100 μm spectral range. To calibrate BABAR-ERI we have worked closely with the Libera program to construct the Earth Radiance Facility (ERF) at LASP. This facility incorporates an optical system that creates a stable, uniform source that enables intercomparisons between BABAR-ERI and a primary radiometric standard also developed under the IIP – the Planar Bolometric Radiometer for Radiance (PBR-R). A widely tunable laser with coverage from 0.3 to 16 μm feeds the ERF optical system enabling rapid characterization of the instrument spectral response. Additionally, two blackbody sources have been developed under the IIP to calibrate the far infrared response of the instrument. One blackbody is LN2 cooled and simulates a deep space view whereas the other blackbody is temperature tunable and simulates Earth scenes. We present results from the initial calibration campaign that highlights the baseline performance of the BABAR-ERI instrument. This includes detector performance metrics such as noise floor, uniformity, and fabrication yield, as well as integrated instrument performance metrics such as imaging quality and spectral response.