A look at BurstCube after its first burst is confirmed
NASA’s shoebox-sized CubeSat BurstCube satellite, which was launched to the ISS on March 21st 2024 and later deployed into an orbit on April 18th 2024 on a mission to study gamma-ray bursts that last less than 2 seconds (This usually will occur after neutron star collisions) with energies from 50,000 to 1,000,000 electron volts (Visible light has about 2-3 electron volts).
In reaction to the small satellite observing its first gamma-ray burst, Sean Semper, BurstCube’s lead engineer at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, said “We’re excited to collect science data…It’s an important milestone for the team and for the many early career engineers and scientists that have been part of the mission.” The event it noticed was “GRB 240629A” and occurred on the 29th of June 2024 in the southern constellation Microscopium.
When a gamma ray enters one of the instrument’s four detectors, it encounters a caesium iodide layer called a scintillator, which converts it into visible light. The light then enters another layer, an array of 116 silicon photomultipliers, that converts it into a pulse of electrons, which is what BurstCube measures. For each gamma ray detected, the team will see one pulse in the instrument readout that provides the precise arrival time and energy. The four detectors are angled to give BurstCube a wide view of the sky. Together, they can inform scientists of the general direction of the event.
However, the mission has not been without problems, after it was deployed from the ISS, one of the two solar panels did not fully extend which obscured the mission’s star tracker, meaning the team could not properly orientate the satellite in a way that minimises drag. Due to this BurstCube could be looking to re-enter the atmosphere at some point this month, abandoning its planned 12-18 month mission.
It is the first CubeSat to use NASA’s TDRS (Tracking and Data Relay Satellite) system - which is a specialised communications satellite constellation which helps coordinate rapid follow-up measurements from other observatories both in space and on the ground through NASA’s GCN - General Coordinates Network. It also utilises the Direct to Earth system which both it and TDRS make up part of NASA’s Near Space Network -which provides missions within one million miles of Earth with robust communications services. It uses a blend of government and commercial assets to support science, human spaceflight, and technology demonstration missions exploring our planet and the solar system and it collects data gathered through global direct-to-Earth antenna systems and a fleet of relay satellites.
But why are Astrophysicists interested in this? It is because neutron stars are the superdense remnants of huge stars that have exploded in a supernova. These stars are also important to research because they produce gravitational waves and by studying both light and gravitational waves – an approach called multimessenger astronomy – they can learn more about different aspects of the event. Jeremy Perkins, BurstCube’s principal investigator at Goddard said, “Small missions like BurstCube not only provide an opportunity to do great science and test new technologies, like our mission’s gamma-ray detector, but also important learning opportunities for the up-and-coming members of the astrophysics community.”
