Title: Small Satellite Passive Microwave Radiometers: MiRaTA and MicroMAS-2A
Presenting Author: Angela Crews
Organization: MIT
Co-Author(s): Cadence Payne, Andrew Kennedy, Greg Allan, Erin Main, Thomas Murphy, Pratik Dave, Bobby Holden, Rebecca Bishop, Bill Blackwell, Vince Leslie, Dan Cousins, Michael Grant, Kerri Cahoy

Abstract:
Miniaturized microwave radiometers deployed on nanosatellites in Low Earth Orbit are now demonstrating cost-effective weather monitoring. A constellation of MicroMAS-2 cubesats would increase temporal and spatial resolution compared to larger weather satellites. The Microwave Radiometer Technology Acceleration (MiRaTA) is a 3U CubeSat launched in November 2017 supported by the NASA Earth Science Technology Office (ESTO). The objectives include demonstration of the performance of a compact three-band microwave radiometer and its calibration using Global Positioning System (GPS) radio occultation (GPSRO) measurements from its second payload, the Compact Total Electron Count (TEC)/Atmosphere GPS Sensor (CTAGS). The MiRaTA radiometer channels include 52-58 GHz (temperature), 175-191 GHz (water vapor), and 206-208 GHz (cloud ice) with the goal of capturing all-weather temperature and humidity for the Earth's atmosphere. We discuss the current status and lessons learned for the MiRaTA mission. The Microsized Microwave Atmospheric Satellite (MicroMAS-2A) is a 3U CubeSat launched in January 2018 with a 1U 10-channel passive microwave radiometer with channels near 90, 118, 183, and 206 GHz for moisture and temperature profiling and precipitation imaging [1]. The MicroMAS-2A objective is to observe weather events such as hurricanes, convective thunderstorms, and tropical cyclones from a low cost, miniaturized microwave radiometer. We present initial diagnostic images and scan-angle average radiances. Radiometric bias validation for MicroMAS-2A is performed using the Community Radiative Transfer Model (CRTM) with Constellation Observing System for Meteorology Ionosphere and Climate (COSMIC) GPSRO and/or radiosonde profiles in order to produce simulated brightness temperatures. We compare the simulated brightness temperatures to MicroMAS-2A measured brightness temperatures and discuss initial bias validation results.