University of Coimbra leads GLOSS experiment returning from the International Space Station

The GLOSS (Gamma-ray Laue Optics and Solid State Detectors) experiment, led by the Faculty of Sciences and Technology of the University of Coimbra (FCTUC), has returned to Earth aboard SpaceX’s Cargo Dragon C211 capsule, splashing down in the Pacific Ocean off San Diego, California, USA.

The SpX-33 mission was coordinated by Rui Curado Silva, lecturer at FCTUC, and Jorge Maia, from the University of Beira Interior (UBI), both researchers at the Coimbra Laboratory of Instrumentation and Experimental Particle Physics (LIP).

For nearly a year, samples of cadmium zinc telluride (CZT) from the chambers of future gamma-ray telescopes were exposed to the space environment, including orbital radiation, extreme temperature fluctuations, and oxidation. “These sensors degrade in performance and lose sensitivity when operated in space. Until now, the relationship between time spent in the space environment and sensor performance degradation has never been studied in such depth,” explains Rui Curado Silva.

“To observe the Universe in X-ray and gamma-ray bands (high-energy astrophysics), telescopes equipped with sensors capable of imaging these parts of the electromagnetic spectrum must be placed in space, as the Earth’s atmosphere absorbs this radiation before it reaches the surface,” adds Jorge Maia.

The sensors were mounted on the Bartolomeo platform of the International Space Station, constantly exposed to the external space environment, including extreme temperature variations: around –150°C when the Station orbits the night side of Earth, and up to 120°C on the sunlit side.

These sensors will be returned to Coimbra within two months, where they will be tested to assess the level of operational degradation by comparing their performance with identical sensors that remained on Earth.

“From this analysis, we will validate whether these sensors can be integrated into future high-energy astrophysics space telescopes, and explore how even more advanced sensors could be produced. In this way, we aim to contribute to the development of high-energy astrophysics instrumentation and, consequently, to observational sensitivity, which could have important impacts on our understanding of newly discovered gravitational-wave physics,” the researchers conclude.

In addition to the University of Coimbra, the GLOSS experiment involves teams from the Bologna Observatory of Astrophysics and Space Sciences (INAF/OAS-Bologna) and the Institute of Materials for Electronics and Magnetism of the National Research Council in Parma (CNR/IMEM-Parma, Italy). The experiment was funded by the European Space Agency’s PRODEX programme and the Portuguese Space Agency.