Politecnico di Milano: H.E.R.M.E.S. cubesat constellation launched into orbit

On Saturday, March 15, the Italian Space Agency (ASI) H.E.R.M.E.S. Pathfinder (High Energy Rapid Modular Ensemble of Satellites) satellite constellation was launched; the satellites reached orbit thanks to the Falcon 9 launcher of Space X's Transporter 13 mission, which lifted off from Vandenberg Space Force Base (VSFB) in California.

The six nanosatellites are clustered in a Sun-synchronous orbit at an altitude of about 500-520 km. They will be able to detect and locate random astronomical events such as gamma ray bursts, sending a warning to the scientific community within minutes.

These six CubeSats are designed to be a real breakthrough in the field of multi-messenger high-energy astrophysics and the use of nanosatellites for challenging space missions. The constellation created under the direction of the ASI is able to continuously monitor almost the entire sky, and to transfer the coordinates of cosmic events thanks to its co-pointing capability.

Funding for the mission came mainly from the ASI, with technical and scientific contributions from the National Institute for Astrophysics (INAF), the Politecnico di Milano (POLIMI), and the University of Cagliari (UNICA).

The satellites in the Pathfinder Mission were designed, manufactured and integrated at the facilities of the Department of Aerospace Sciences and Technologies (DAER) of the Politecnico di Milano, while the six X-/gamma-ray monitor payloads were developed, integrated, tested and calibrated at the INAF facilities in Rome and the Fondazione Bruno Kessler in Trento. The on-board software for the payloads was developed by the University of Tübingen. The final environmental tests on the satellites were carried out by the Politecnico di Milano, using the facilities of the Politecnico itself for the mechanical testing and compliance, and those at Thales Alenia Space in Gorgonzola (MI) and INAF Rome for thermal vacuum testing.

"The Politecnico di Milano played a decisive role at various stages of the project: from the design and integration of the satellite system to the final environmental tests, using its own facilities and working with some excellent partners. Fundamental contributions have come from the Advanced Space Technologies for Robotics & Astrodynamics (ASTRA) laboratory of the Department of Aerospace Sciences and Technologies, leader in aerospace research, and from the Department of Electronics, Information and Bioengineering (DEIB), which contributed with the design of the spectrometer integrated circuits and the development of the on-board software. This project once again highlights the University’s ability to be right at the forefront of research and technological innovation, as well as its capacity to collaborate effectively in the face of significant challenges, helping to secure some definite results in this mission." said Donatella Sciuto, Rector of Politecnico di Milano.

The constellation of nanosatellites aims to localize with high precision the X-ray and gamma radiation emitted by high-energy cosmic transients, such as Gamma-Ray Bursts (GRBs) and the electromagnetic counterparts of Gravitational Wave Events (GWEs).

GRBs will be detected and measured by sophisticated X-ray and gamma-ray spectrometers installed on each of the nanosatellites. The HERMES spectrometers, the result of decades of research by a large Italian research collaboration (REDSOX), achieve high energy resolutions thanks to the use of Semiconductor Drift Detectors (SDD), invented in 1982 by Prof. Emilio Gatti of the Department of Electronics, Information and Bioengineering of Politecnico di Milano (DEIB) together with Pavel Rehak (Brookhaven National Laboratory), and to the signal processing microelectronics, conceived, designed and characterized at DEIB in the Semiconductor Devices and Integrated Circuit Laboratory, under the guidance of Prof. Giuseppe Bertuccio, in collaboration with the Integrated Microsystems and Sensors Laboratory of the Department of Industrial and Information Engineering of the University of Pavia, directed by Prof. Piero Malcovati.

At DEIB, the group led by Prof. Fabrizio Ferrandi also contributed to the development of the on-board software in collaboration with the Department of Aerospace Science and Technology (DAER) of Politecnico di Milano. In particular, the DEIB Architectures group was involved in the specification of the requirements and implementation of the on-board computer software of the nanosatellites. For aspects related to the functional verification of the flight software, a DEIB startup “Blue Signals” founded by Prof. William Fornaciari and Davide Zoni was also involved.

The project involved important international contributions and collaborations, mainly as part of the H.E.R.M.E.S.-SP project for the Horizon 2020 program funded by the European Commission. In addition, the ground station at Katherine in Australia is operated by the University of Tasmania under an agreement with INAF, the University of Melbourne and Masaryk University.

The other ground station that will support the project operation was purchased and installed by the Politecnico di Milano group at the university's experimental laboratory, located in Spino D'Adda, Italy.