Hardware and Embedded Firmware Development of a Gamma-Ray Burst Detector for a 2U CubeSat

Gamma-ray bursts (GRBs) are among the most extreme energetic events in the universe and represent the death knell of massive stars and compact objects. In one scenario, a massive and ancient star has burnt through the fuel reserve resulting in a core collapse event, a supernova. In the other, massive compact binary objects, like black hole - black hole (BH-BH), neutron star - black hole (NS-BH) and NS-NS pairs coalesce through merger events caused by the radiation of gravitational energy. In both cases a GRB may be observed. If the object is orientated just right, a beamed emission directed towards Earth may be detectable as a sudden, intense but brief flash of gamma-ray photons with a later afterglow emission observable in longer wavelengths for days to weeks after the initial event. The advent of gravitational wave astronomy as a multi-messenger for high-energy astrophysical phenomena, along side recent advancements towards the miniaturisation of detector technology, have made it possible for CubeSat missions to perform cost-effective and fruitful science. Furthermore, widely accessible commercial-off-the-shelf hardware allows small non-agency institutions and universities to build robust missions with custom payloads for technology demonstrations and to contribute to the aims of the scientific community alongside traditional flagship missions. The Gamma-Ray Module (GMOD) is a CubeSat compatible, scintillation based gamma-ray detecting instrument, with dimensions <1U (less than 10 cm×10 cm×10 cm). GMOD has been developed primarily for the detection of GRBs and other high-energy electromagnetic phenomena from Earth orbit. This thesis will introduce GMOD through its origin, development and testing, its mission objectives and future outlook, all with respect to the astrophysical context of current high-energy astronomy and instrumentation. During its mission, GMOD will experience the mechanical stresses induced during its launch, deployment and the sustained thermal and radiation effects of the harsh space environment. Furthermore, the instrument firmware will be expected to perform over long durations, often operating continuously for weeks on end. The instrument must be capable of performing effectively and to operate continually without disruption to the handling of science data. To achieve this, several tests have been conducted including a high altitude balloon flight, SiPM irradiation testing, subsystem thermal vacuum and vibration testing and a full benchmarking of the firmware performance and response to simulated GRB events. The GMOD hardware has been fully tested in accordance with European Space Agency standards and the firmware has been rigorously assessed, while the methodology has been subject to peer-review. GMOD has been accepted for flight and will be flown in 2023 onboard EIRSAT-1, Ireland’s first satellite, with an expected detection yield of ∼11–14 GRB triggers at 10σ significance. Once in operation, GMOD will contribute to the high-energy astronomy community and will be a demonstrator for future GRB detecting instruments.