Cubesat Missions Detect 360 Gamma-Ray Transients with GRBAlpha & Vzlusat-2

Scientists are pushing the boundaries of gamma-ray burst (GRB) detection with a network of CubeSats, as detailed in new research led by Jakub Ripa and Marianna Dafcikova from Masaryk University, alongside Andras Pal et al from the Konkoly Observatory. Their work summarises results from the GRBAlpha, VZLUSAT-2, and GRBBeta missions, demonstrating the capability of these small satellites , each equipped with CsI(Tl) scintillator gamma-ray detectors , to routinely detect GRBs and other transient events. Having observed approximately 360 transients, including exceptionally bright bursts like GRB 221009A and GRB 230307A, these missions prove that cost-effective nanosatellites can significantly contribute to GRB science and provide valuable data on space radiation effects , paving the way for longer-duration, dedicated GRB monitoring from low Earth orbit.

CubeSat Constellation Detects Intense Gamma-Ray Bursts from distant

Scientists have achieved a significant breakthrough in gamma-ray burst (GRB) detection utilising a constellation of CubeSats, GRBAlpha, VZLUSAT-2, and GRBBeta, demonstrating the feasibility of long-duration, nanosatellite-based astronomical observations. These missions, employing innovative gamma-ray detectors, have collectively observed approximately 360 transient events, including over 170 long and short GRBs, and crucially, captured the data from the exceptionally intense GRB 221009A and the second brightest GRB 230307A. The research team successfully deployed and operated these CubeSats, GRBAlpha, a 1U satellite launched in March 2021, VZLUSAT-2, a 3U satellite launched in January 2022, and the newly launched 2U GRBBeta in July 2024, each equipped with CsI(Tl) scintillator-based gamma-ray detectors read out by silicon photomultipliers (SiPMs). GRBAlpha, operating for over four years until.
Each satellite incorporated a CsI(Tl) scintillator gamma-ray burst (GRB) detector coupled with silicon photomultipliers (SiPMs), sensitive within the approximately 30-900 keV range. These missions collectively detected around 360 gamma-ray transients, including over 170 long and short GRBs, and crucially, captured the exceptionally intense GRB 221009A and GRB 230307A. The study pioneered a command-based clock synchronisation method, utilising an on-ground computer clock rather than GPS, to coordinate time measurements across the CubeSat network. Experiments employed high temporal resolution measurements, approximately 1ms, to enable potential triangulation techniques for pinpointing GRB source locations, a method reliant on precise onboard clock accuracy.

GRBAlpha successfully operated for over four years, de-orbiting in June 2025, while VZLUSAT-2 functioned smoothly for nearly four years before de-orbiting in November 2025; GRBBeta continues to detect GRBs since its launch. The coincident detection of GRB 250313A by both GRBAlpha and GRBBeta exemplifies the potential of multi-satellite GRB observations. Researchers calculated a lower limit on the bolometric peak isotropic-equivalent luminosity for GRB 221009A, the “Brightest Of All Time” GRB, to be ≥8.4+2.5 −1.5 × 1052 erg s−1 over a 4-second timescale, and the isotropic-equivalent released energy to be ≥2.8+0.8 −0.5 × 1054 erg in the 1 −10, 000 keV band. Light curves of GRB 230307A, simultaneously observed by GRBAlpha and VZLUSAT-2, revealed a long prompt emission duration of approximately 35 seconds, associated with a kilonova detection suggesting a compact stellar merger origin. Beyond GRB detection, the team monitored the low Earth orbit (LEO) radiation environment, reconstructing background maps and tracking variations in charged particle backgrounds, particularly in the polar regions and the South Atlantic Anomaly (SAA). The work also investigated SiPM degradation due to radiation exposure and its impact on detector performance.

CubeSat Network Detects Hundreds of Gamma-Ray Bursts, revolutionizing

Scientists have achieved a significant milestone in gamma-ray burst (GRB) detection utilising a network of CubeSats, GRBAlpha, VZLUSAT-2, and GRBBeta. These nanosatellites, equipped with innovative gamma-ray detectors, have collectively observed approximately 360 gamma-ray transients, including over 170 long and short GRBs, demonstrating their capability for routine GRB detection in low Earth orbit. GRBAlpha, a 1U CubeSat launched in March 2021 to a 550km altitude, successfully operated for over four years, monitoring the sky with a detector sensitive to the 30-900 keV range before de-orbiting in June 2025. Experiments with VZLUSAT-2, a 3U CubeSat launched in January 2022 to a 535km altitude, revealed its ability to detect transients with two GRB detectors similar to those on GRBAlpha, operating smoothly for nearly four years until its November 2025 de-orbit.

The team recorded the most intense GRB ever observed, GRB 221009A, and the second brightest, GRB 230307A, with both satellites, confirming the effectiveness of their instrumentation. Each detector utilises a 75×75×5mm CsI(Tl) scintillator read out by eight multi-pixel photon counters (MPPCs) S13360-3050 PE by Hamamatsu Photonics K. K., with two independent readout channels each containing four MPPCs connected in parallel. Measurements from the newly launched GRBBeta, a 2U CubeSat deployed in July 2024 to a 580km altitude, 62-degree inclination orbit, continue to deliver valuable GRB data since its initial activation.

The GRBBeta detector, mirroring the design of GRBAlpha’s, boasts a sensitivity range extending from approximately 50 keV to 2.3 MeV, and is also equipped with a near ultraviolet camera LUVCam sensitive in the 240-310nm range. Results demonstrate the viability of CsI(Tl) scintillator-based detectors read out by silicon photomultipliers (SiPMs) for missions exceeding three years, while simultaneously providing a unique platform to study radiation damage to SiPMs in the low Earth orbit environment and monitor radiation belts. These findings pave the way for future constellations, such as the proposed CAMELOT, dedicated to comprehensive GRB detection and analysis.

CubeSat GRB Detection Over Four Years yielded promising

Scientists have demonstrated the feasibility of utilising CubeSats for long-duration missions in low Earth orbit (LEO) and their capacity to routinely detect gamma-ray bursts (GRBs). The GRBAlpha, VZLUSAT-2, and GRBBeta missions, equipped with compact gamma-ray detectors based on CsI(Tl) scintillators read out by silicon photomultipliers (SiPMs), have collectively observed approximately 360 gamma-ray transients, including over 170 long and short GRBs, and notably captured the exceptionally intense GRB 221009A and the second brightest GRB 230307A. These nanosatellites have successfully operated for over four years, with GRBBeta continuing to detect GRBs since its July 2024 launch. Researchers have also flight-proven the durability of SiPMs in the LEO environment for scientific missions exceeding three years, provided sufficient shielding is implemented.

This work establishes the potential for employing SiPMs in future high-energy astrophysics space missions and opens the possibility of constructing larger constellations of CubeSats for simultaneous GRB detections. The study acknowledges that the gain of the SiPMs is temperature-dependent, varying throughout each orbit, and detailed characterisation of this effect has been undertaken using flight spare GRBBeta detector measurements. Future research may focus on expanding CubeSat constellations to enhance the simultaneous detection capabilities of GRBs, furthering our understanding of these energetic cosmic events. The findings represent a significant advancement in the field of gamma-ray astronomy, demonstrating that cost-effective nanosatellite technology can contribute meaningfully to long-term space-based observations and the study of high-energy phenomena.