Satellite deorbitation is an increasingly popular topic these days. It is related to the growing amount of space debris in low earth orbits. These objects include multi-stage rocket modules, inactive satellites, and small components that have been generated by satellite collisions.

Consequently, a multitude of small elements are created, which orbit endangering active satellites. This leads to an increased risk of the so-called “Kessler syndrome”. It is a scenario proposed by NASA employee Donald J. Kessler, according to which space debris will continuously increase – and exponentially, due to secondary collisions. Without proven ways to avoid collisions or deorbit, spaceflight could become just history.

If all devices sent into space had deorbitation systems, these unfortunate events could be avoided. Students at Warsaw University of Technology were thinking about solving this problem in the early 2000s.

Our story begins in 2004 at the Warsaw University of Technology when members of the Student Astronautical Circle decided to build the PW-Sat – a CubeSat type 1U, which became the first Polish satellite. Best of all, it was an educational satellite, built at the university.

We were very lucky when ESA offered us a chance to launch our satellite during the virgin flight of the Vega rocket. This was happening as part of an educational project at the ESA Education Office. The chance turned into a real mission, which was finally realized in cooperation with the Space Research Center of the Polish Academy of Sciences. The PW-Sat satellite was launched into orbit on February 13, 2012. Thus, we joined the satellite community in the year when Poland also joined the European Space Agency as a rightful member.

Two main goals were achieved – the launch of the first Polish satellite and the education of young engineers in the field of space engineering.

After the end of the PW-Sat project, it was logical to start building its successor: the PW-Sat2, whose main technological goal was to construct and test an innovative deorbitation system in the form of a 4 sq. m. deployable deorbitation sail. PW-Sat2 was a 2U-type CubeSat ( thus twice the size of its precursor) and successfully tested the main experiment during its mission. A solar sensor and an openable solar panel system were also tested. The satellite was launched on December 3, 2018, by a Falcon 9 rocket, and burned up in the atmosphere on February 23, 2021 – many years earlier than if no sail had been used.

Since 2018, PW-Sat3 has been under development, with the main goal of testing a custom warm-gas propulsion system. The team is once again focusing on solving the problem of space debris. However, before deorbitation, other orbital maneuvers will also be performed, and the AOCS (satellite orientation control system) designed by us will be tested together with horizon sensors.

The PW-Sata3 launch is planned for the last quarter of 2023.