As expected by the team, the PW-Sat2 satellite completed its mission after 813 days in orbit and as of February 23, 2021, it is considered to be deorbited. The satellite completely burned up in the Earth’s atmosphere. The last signal was received 14 minutes after midnight CET.
PW-Sat2 is a student educational project carried out at the Warsaw University of Technology in the Students’ Space Association. Its main technological goal was to develop and test an innovative deorbit system in the form of a 4 m² sail. The satellite was launched into orbit on December 3, 2018 on board the Falcon 9 launcher.
During the main phase of the mission, which lasted until December 29, 2018, all subsystems of the satellite were successfully tested: the electrical power system EPS, communication system, on-board computer OBC, cameras, and the sun and radiation sensor. At that time, the PW-Sat2 made the first Polish photo from the onboard of the satellite.
The deorbit sail had been deployed on December 29, 2018, when the PW-Sat2 satellite received a telecommand sent by a ground station. The deorbit sail, which was rolled up in the container has been released and obtained the target shape by increasing its area to 4 m2.
On the same day, the first shots from the on-board cameras were collected. Unfortunately, after about 3 days, tears appeared on the sail, which over time covered about 30-35% of the sail surface. This reduced the effectiveness of its operation and extended the estimated time of decaying from 12-15 months to about 2.5 years.
With the sail deployment, the team moved to the next phase of the project. Since then, satellite communications have been established regularly: more than 5,000 communication sessions were made and almost 1,500 images captured by on-board cameras were received. During this time, the on-board computer software was updated twice, which allowed for energy saving by reducing power consumption when the solar panels were shaded by the deployed sail.
Over the past few weeks, the Operations Team has been monitoring the condition of the deorbit sail on a daily basis, taking and downloading photos and downlinking the telemetry data. The final series of photos was taken on Saturday, February 20, 2021, when the satellite was at an altitude of approx. 312 km. The sail remained in good condition.
At the end of the mission, the photos showed the rotation of the sail relative to the satellite and the gradual increase in the rotation of the entire satellite, reaching an angular velocity of about 80 degrees per second.
The satellite remained fully operational until the end of the mission. Due to the rapid degradation of the orbit and the satellite’s unpredictable position, it was a challenge to conduct the last few sessions. The last communication session took place on the night of February 22/23, when the satellite was below 275 km. Exactly at 12:14:14 the ground station in Gliwice received the last radio frame from PW-Sat2, which contained the message:
Goodbye PW-Sat2 and youtu.be/dQw4w9WgXcQ
The deorbitation probably took place in the morning of February 23, 2021. The deorbit sail lowered the satellite’s orbit from the original height of 590 km in 2 years, 1 month and 24 days. Without the use of any deorbit system, the PW-Sat2 satellite would remain in orbit around the Earth for about 15 years.
Most of the project’s output has been made public, incl. in the form of technical documentation, publications or conference presentations. In our opinion, the project is a huge educational and technological success.
You can follow the deorbitation process on sail.pw-sat.pl and radio.pw-sat.pl.
We would like to thank all radio amateurs who provided us with the telemetry data of the PW-Sat2 satellite they collected! Many thanks also go to the ground station team (OPER) in Warsaw and KP Labs in Gliwice, which have been communicating with the satellite every day for the last 2 years – congratulations and thank you!
The PW-Sat2 satellite project started in 2013 at the Students’ Space Association at the Warsaw University of Technology. Since then, over 100 people have worked on this project, and several dozen of whom have found employment in the Polish and European space industry.
Members of the Students’ Space Association at the Faculty of Power and Aeronautical Engineering worked on the satellite in the cleanroom of the Space Research Center of the Polish Academy of Sciences and, thanks to the Rector of the Warsaw University of Technology, in the Center for Advanced Materials and Technologies CEZAMAT. Previously, for many months, they designed and developed their solutions at the Center for Innovation Management and Technology Transfer CZIiTT of the Warsaw University of Technology.
The strategic partners for the PW-Sat2 project are Future Processing and FP Instruments companies from Gliwice. Both companies provided substantive support to students, and in the spring of 2016 they funded and created software for the on-board computer, the PW-Sat2 “brain”. This software is available open-source on GitHub PW-Sat2. In recent months, support has also been provided by KP Labs.
Together with SoftwareMill we created a tool for the analysis and presentation of data received from the satellite, which is available to Internet users and radio amateurs – radio.pw-sat.pl.
In 2016, the project received financial support in the amount of 180 thousand euro from the Ministry of Science and Higher Education to cover the launch of PW-Sat2. Co-financing was transferred in the form of an increased contribution to the European Space Agency, which was paid by the Ministry of Development.
WUT students collaborated with companies such as OMAX Polska, EC Test Systems and Astronika. During their work, they received invaluable help from PGNiG S.A., the Institute of Aviation, the Industrial Development Agency ARP and SSW Pragmatic Solutions. Companies such as Polska Grupa Zbrojeniowa PGZ, ABM Space, the Students’ Self-Government of the Warsaw University of Technology, Piasecka & Żylewicz, Weil, Komes, Spacive, Rapid Crafting and Ltt provided their support during the development of the project.
The author of the title graphics is Maciej Rębisz. The satellite visualization was prepared by Marcin Świetlik. Krzysztof Karaś is the author of the project logo.
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