The role of Unipd in space debris mitigation
17.12.2021
Addressing issues related to the increasing amount of orbital debris is critical for the long-term sustainable utilization of circumterrestrial space.
About 35,000 pieces of large debris (defined as 10 cm across or greater) orbit the earth. The US Space Command (formerly known as NORAD) catalogs and tracks about 28,000 of these large pieces daily. Less than 3,500 are functioning satellites, and the rest are untraceable nonfunctioning satellites. All debris, even those only a few centimeters in diameter holds enough kinetic energy to knock out a satellite from an impact. Such an impact could deteriorate the essential functions of satellites such as telecommunications, earth observation, navigation, weather forecasts, and more.
Analytical models show that we must remove and avoid leaving large pieces of debris in orbit for too long, as debris of this size causes the great threat of fragmentation if they experience an orbital impact. Deorbiting a satellite is a problem. The present technology available to deorbit a satellite consumes a considerable amount of chemical propellant, and, as we know, there are no refueling stations in space!
One solution is to create a deorbiting system with an auxiliary energy source that consumes less propellant or, at least very little. Such as system could deorbit a satellite over a relatively short period and drastically reduce the risk of impact with other orbiting objects.
The University of Padua’s role began in the 1970s with the development of a wire cable satellite tethering system thanks to Professor Giuseppe Colombo and Mario Grossi of the Smithsonian Astrophysical Observatory in Cambridge (Massachusetts, USA). The wire cable or tether systemuses electrodynamic propulsion to produce the thrust necessary to modify the orbital height without a chemical propellant.
The University continues its role in this technological growth by participating in two projects funded by the European Commission: the BETs project of the FP7 program and now the ETPACK project of the H2020 FET-OPEN (Future & Emerging Technologies) program. The ETPACK project coordinated by the Universidad Carlos III de Madrid collaborated with the University of Padua, the Technical University of Dresden, the German Fraunhöfer Institute (IKTS), and SENER, a Spanish company the specialized in Aerospace Engineering and Advanced Thermal Devices.
Enrico Lorenzini, Professor in the Industrial Engineering Department of the University of Padua and Research Group Coordinator explains,
“Our project aims to develop and construct an advanced prototype of 12 Units (12U CubeSat) measuring 22cm x 22cm x 34cm and to ground test the program to verify its functionality in orbit. The University of Padua research group role, specifically that of CISAS-UniPD, concerns the most delicate parts of a CubeSat, which is the CubeSat Deployer System, which is designed to deploy 500 meters of a thin conductive ribbon in orbits following a precise velocity profile and without damaging the delicate ribbon itself.”
The research group including Andrea Valmorbida, Giulia Sarego, Alice Brunello, Lorenzo Olivieri, Giacomo Colombatti, Carlo Bettanini and Marco Pertile recently carried out a functional test of the conductor tape successfully. The group presented their results on December 10 to the European Commission, receiving a very positive feedback from experts; the ETPACK project is in first place of "Featured Projects” presented on the European Innovation Council website https://eic.ec.europa.eu/index_en.
The team anticipates further development of projects with new funding, for which the team has already submitted its proposal, from the Horizon Europe program. Projects include a demonstration flight of the deorbiting system (In-Orbit Demonstration) in 2025. After the necessary changes to the current prototype, the updated project brings it to the final qualification for orbital flight, the ETPACK team is eager to see the performance of this very innovative system, first pioneered thanks to Mario Grossi and Giuseppe Colombo.
