Tuesday, April 9, 2024

NASA’s BurstCube launches to study universe’s most powerful explosions

ASA has launched its BurstCube, a shoebox-sized satellite designed to study the universe’s most powerful explosions, to the International Space Station. It’s already on its way to the International Space Station aboard SpaceX’s 30th Commercial Resupply Services mission, which lifted off on Thursday, March 21.

After arriving at the station, BurstCube will be unpacked and later released into orbit. Once it’s in orbit, it will be able to detect, locate, and study short gamma-ray bursts.

“BurstCube may be small, but in addition to investigating these extreme events, it’s testing new technology and providing an important experience for early career astronomers and aerospace engineers,” said Jeremy Perkins, BurstCube’s principal investigator at NASA‘s Goddard Space Flight Center in Greenbelt, Maryland.

Short gamma-ray bursts usually occur after the collisions of neutron stars, which are the superdense remnants of massive stars that exploded in supernovae. These neutron star collisions can emit gravitational waves, which are ripples in the fabric of space-time.

The BurstCube satellite sits in its flight configuration in this photo taken in the Goddard CubeSat Lab in 2023.
The BurstCube satellite sits in its flight configuration in this photo taken in the Goddard CubeSat Lab in 2023. Credit: NASA/Sophia Roberts

Astronomers are interested in studying gamma-ray bursts using both light and gravitational waves, as each can teach them about different aspects of the event. The 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, which are essential for life as we know it. The only joint observation of gravitational waves and light from the same event was in 2017. Since then, the scientific community has been hoping and preparing for additional concurrent discoveries.

“BurstCube’s detectors are angled to allow us to detect and localize events over a wide area of the sky,” said Israel Martinez, research scientist and BurstCube team member at the University of Maryland, College Park, and Goddard. “Our current gamma-ray missions can only see about 70% of the sky at any moment because Earth blocks their view. Increasing our coverage with satellites like BurstCube improves the odds we’ll catch more bursts coincident with gravitational wave detections.”

BurstCube’s main instrument can detect gamma rays with energies ranging from 50,000 to 1 million electron volts, which is a lot higher than visible light. 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.

Engineers attach BurstCube to the platform of a thermal vacuum chamber at Goddard ahead of testing.
Engineers attach BurstCube to the platform of a thermal vacuum chamber at Goddard ahead of testing. Credit: NASA/Sophia Roberts

For each gamma ray, the team sees one pulse in the instrument readout that provides the precise arrival time and energy, and 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, which can help facilitate groundbreaking science and test new technologies. Additionally, CubeSats can help educate the next generation of scientists and engineers in mission development, construction, and testing.

“We were able to order many of BurstCube’s parts, like solar panels and other off-the-shelf components, which are becoming standardized for CubeSats,” said Julie Cox, a BurstCube mechanical engineer at Goddard. “That allowed us to focus on the mission’s novel aspects, like the made-in-house components and the instrument, which will demonstrate how a new generation of miniaturized gamma-ray detectors work in space.”