NASA’s BurstCube Mission
NASA’s BurstCube, a shoebox-sized satellite designed to study the universe’s most powerful explosions, is on its way to the International Space Station.
Short gamma-ray bursts usually occur after the collisions of neutron stars, the superdense remnants of massive stars that exploded in supernovae. The neutron stars can also emit gravitational waves, ripples in the fabric of space-time, as they spiral together.
Astronomers are interested in studying gamma-ray bursts using both light and gravitational waves because each can teach them about different aspects of the event. This approach is part of a new way of understanding the cosmos called multimessenger astronomy.
The collisions that create short gamma-ray bursts also produce heavy elements like gold and iodine, an essential ingredient for life as we know it.
Currently, the only joint observation of gravitational waves and light from the same event – called GW170817 – was in 2017. It was a watershed moment in multimessenger astronomy, and the scientific community has been hoping and preparing for additional concurrent discoveries since.
BurstCube’s main instrument detects gamma rays with energies ranging from 50,000 to 1 million electron volts. (For comparison, visible light ranges between 2 and 3 electron volts.)
When a gamma ray enters one of BurstCube’s four detectors, it encounters a cesium 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, the team sees one pulse in the instrument readout that provides the precise arrival time and energy. The angled detectors inform the team of the general direction of the event.
BurstCube belongs to a class of spacecraft called CubeSats. These small satellites come in a range of standard sizes based on a cube measuring 10 centimeters (3.9 inches) across. CubeSats provide cost-effective access to space to facilitate groundbreaking science, test new technologies, and help educate the next generation of scientists and engineers in mission development, construction, and testing.
Comments