The GTOSat CubeSat: scientific objectives and instrumentation
Lauren Blum, L. Kepko, D. L. Turner, Christine Gabrielse, A. N. Jaynes, S. G. Kanekal, Q. Schiller, J. R. Espley, D. Sheppard, Luis Santos, John P. Lucas, Steven West
Abstract
GTOSat is a 6U CubeSat mission that will pave the way for highly reliable, capable CubeSat constellations and missions beyond low Earth orbit (LEO). GTOSat will study Earth’s dynamic radiation belts, acting as a follow-on to NASA’s Van Allen Probe mission and demonstrating the potential utility of SmallSats for both science and space weather monitoring. While a number of previous CubeSats have studied the radiation belts from LEO, GTOSat will launch into a low inclination geosynchronous transfer orbit (GTO) to directly sample the core trapped particle population. From this orbit, it will measure energy spectra and pitch angles of ~hundreds keV - few MeV electrons and ions, with the primary science goal of advancing our quantitative understanding of particle acceleration and loss in the outer radiation belt. High-heritage instrumentation includes the Relativistic Electron Magnetic Spectrometer (REMS), measuring energetic electrons and ions, and a boom-mounted fluxgate magnetometer (MAG) to provide 3-axis knowledge of the local ambient magnetic field. The GTOSat bus consists of a 6U spin-stabilized structure with a Sun-pointing spin axis. Mitigation of radiation effects is accomplished through a multi-pronged systems approach including parts selection and shielding to reduce the total dose for 1 year on orbit to less than ~30 krad. Communication is achieved via an S-band transceiver, enabling high data throughput through the Near-Earth Network (NEN) and low-latency radiation belt monitoring via the Tracking and Data Relay Satellite System (TDRSS).