MiniCarb: A Passive, Occultation-Viewing, 6U CubeSat for Observations of CO2, CH4, and H2O

Abstract We present the final design, environmental testing, and launch history of MiniCarb, a 6U CubeSat developed through a partnership between NASA Goddard Space Flight Center and Lawrence Livermore National Laboratory. MiniCarb’s science payload, developed at Goddard, was an occultation-viewing, passive laser heterodyne radiometer for observing methane, carbon dioxide, and water vapor in Earth’s atmosphere at ~1.6 microns. MiniCarb’s satellite, developed at Livermore, implemented their CubeSat Next Generation Bus plug-and-play architecture to produce a modular platform that could be tailored to a range of science payloads. Following the launch on December 5, 2019, MiniCarb traveled to the International Space Station and was set into orbit on February 1, 2020 via Northrop Grumman’s (NG) Cygnus capsule which deployed MiniCarb with tipoff rotation of about 20 deg/sec (significantly higher than the typical rate of 3 deg/sec from prior CubeSats), from which the attitude control system was unable to recover resulting in a loss of power. In spite of this early failure, MiniCarb had many successes including rigorous environmental testing, successful deployment of its solar panels, and a successful test of the radio and communication through the Iridium network. This prior work and enticing cost (approximately $2M for the satellite and $250K for the payload) makes MiniCarb an ideal candidate for a low-cost and rapid rebuild as a single orbiter or constellation to globally observe key greenhouse gases.