Microwave Weather Imaging CubeSat

Space borne microwave radiometer sensors provide critical weather information for numerical weather forecast models. These sensors are able to penetrate clouds; thus, they provide information not only about cloud composition and precipitation, but also about the surface underneath in all weather conditions.

Traditional spaceborne microwave sensors are large, heavy, power hungry and very expensive. For example, the mass of the Advanced Microwave Scanning Radiometer 2 (AMSR2) is 320 kg and it consumes 400 W of power. The Weather System Follow-on program calls for smaller, less expensive sensors capable to operate on small satellites.

There are several Space Based Environmental Monitoring (SBEM) categories that are at risk of having observational gaps. Among them are clouds characterization, theater weather imagery, ocean surface vector winds, snow depth, soil moisture, tropical cyclone density, and sea ice characterization. All of these SBEM potential data gaps can be filled with the data from microwave imaging radiometers.

Boulder Environmental Sciences and Technology is developing a 6U CubeSat mission for weather imaging. The project is funded from the US Air Force SBIR program. The launch is planned for the fourth quarter of 2020. The 6U CubeSat provides limited space, but we were able to fit into it a conically scanning, weather imaging, sensor with two dual polarization radiometers. A parabolic reflector antenna with 175 mm diameter provides a crude footprint, but the goal of the mission is to prove that even in such a small factor, observations can be made. The two MWIC radiometers operate within the vicinity of the 22.235 GHz water vapor absorption line and in the atmospheric window around 150 GHz.

Smaller size, weight, power consumption (SWAP), and costs enable the operation of constellations with improved revisit time. In addition, each constellation satellite is an individually expendable asset and its malfunction doesn’t bring a catastrophic failure of the observational system. Since the expected life time of a small satellite is 2-3 years, the constellation sensors could be constantly improved, incorporating the latest innovations.

We will present the MWIC spacecraft and the microwave sensor design, as well as other technology that enables small satellites to achieve performance parameters close to the current, much larger, satellites and their sensors.