Global Observations from a Science-Quality Passive Millimeter-wave Atmospheric Sounder on a CubeSat: Temporal Experiment for Storms and Tropical Systems Demonstration (TEMPEST-D)

Steven C. Reising ¹ Todd C. Gaier ³ Shannon T. Brown ³ Sharmila Padmanabhan ³ Christian D. Kummerow ² V. Chandrasekar ¹ Wesley Berg ² Boon H. Lim ³ Cate Heneghan ³ Richard Schulte ² Yuriy Goncharenko ¹ Matthew Pallas ⁴ Doug Laczkowski ⁴ Austin Bullard ⁴

¹Electrical and Computer Engineering, Colorado State University, Fort Collins, CO, USA
²Atmospheric Science, Colorado State University, Fort Collins, CO, USA
³Jet Propulsion Laboratory, NASA/Caltech, Pasadena, CA, USA
⁴Blue Canyon Technologies, Inc., Boulder, CO, USA

Global observations of clouds and precipitation processes are essential to improve prediction of tropical cyclones and severe storms with substantial impacts on human life and property. To improve understanding of convective processes, global observations with rapid revisit times are necessary. Geostationary satellites provide visible and infrared measurements every few minutes. However, passive microwave measurements provide greater contributions to forecast skill, since they penetrate inside the storm where processes leading to precipitation occur.

To address this critical observational need, the Temporal Experiment for Storms and Tropical Systems (TEMPEST) mission deploys a closely-spaced train of 6U CubeSats with identical low-mass, low-power millimeter-wave radiometers. The TEMPEST train samples rapid changes in convection and water vapor by observing every 3-4 minutes for up to 30 minutes. TEMPEST millimeter-wave radiometers at 87 to 181 GHz provide soundings of mid-tropospheric water vapor to improve understanding of its role in convection. TEMPEST fills a critical observational gap and complements existing and future satellite missions, e.g. TROPICS and GPM.

The TEMPEST Demonstration (TEMPEST-D) mission is a partnership among Colorado State University, NASA/Caltech Jet Propulsion Laboratory and Blue Canyon Technologies. The TEMPEST-D 6U CubeSat was launched to the ISS on May 21, 2018 and deployed on July 13, 2018, into a 400-km orbit with 51.6° inclination. The TEMPEST-D mission met its mission success criteria in the first 90 days. Global brightness temperature measurements by TEMPEST-D have been compared to well-calibrated, on-orbit reference sensors, demonstrating that TEMPEST-D is well-calibrated and highly stable, compared to much larger, more expensive operational instruments.