The BurstCube Gamma-Ray Instrument: Hunting for the Largest Cosmic Explosions

The joint detection of gravitational waves (GWs) and their electromagnetic counterparts offers critical insight into the extreme physics of binary neutron star and neutron star-black hole mergers. BurstCube was a 6U (10 x 20 x 30 cm) astrophysics CubeSat built in-house at NASA’s Goddard Space Flight Center to enhance the search for GW counterparts by increasing coverage of the transient gamma-ray sky. Operating in Low Earth Orbit in 2024, the spacecraft was sensitive to the 50 keV – 1 MeV energy range and searched for short gamma-ray bursts (sGRBs) using four cesium-iodide crystal scintillators coupled to arrays of silicon photomultipliers. As the first CubeSat to utilize NASA’s Tracking and Data Relay Satellite System (TDRSS), BurstCube was also capable of autonomously transmitting science alerts to the ground for rapid, multi-wavelength follow-up by other astronomical observatories, though this feature was not ultimately enabled in flight. Here, we present a high-level overview of BurstCube’s science instrument, including its science goals, on-orbit operations, results, closeout, and lessons learned for future gamma-ray small satellite payloads.