PW-Sat was the first Polish artificial satellite. Its mission was to test experimental elastic solar cells, as well as an orbital decay technology consisting of a “tail” designed to speed re-entry. It was expected to last for 1 year.
Dream come true
PW-Sat was a type of CubeSat satellite and it was constructed by the Faculty of Power and Aeronautical Engineering of Warsaw University of Technology, in cooperation with the Space Research Centre of the Polish Academy of Sciences.
Members of the Students’ Space Association intended of becoming the first team to design and develop a Polish spacecraft. They were later joined by members of the Student Space Engineering Scientific Group. 70-80 people have worked on this project. In 2011, the team was rearranged and the number of people involved was reduced to 22, with a core of 9 members including prof. Piotr Wolański the laureate of WUT’s Medal for his contribution to education and scientific research in the area of aerospace engineering awarded to him in December 2014 .
The PW-Sat project was created in 2004 when group of students from Warsaw University of Technology decided to build satellite compatible with CubeSat 1U standard. Initially planned for a 2007 launch, delays in the development of the Vega caused the mission to be postponed until 2012. The cost of the project estimated for 200,000 Polish zloty (63,205 USD), with funding coming from the university’s budget, as well as from an agreement between Poland and the European Space Agency.
Before they started building the satellite, the team decided to design it as simply as possible, in order to minimise the chance of failure. Their preliminary work included a wooden model of the CubeSat, which was used to demonstrate the antenna deployment system.
The most important criterion for measuring the success of the project was to prove the ability of the satellite to work in space. However, the team was also motivated to seek a way of mitigating the space debris problem, which is one of the most important problems facing present and future space exploration.
Early ideas about using a balloon and a sail for the deorbit system were eventually dropped, partly because of low reliability. After some organisational problems, the team started to collaborate with the Space Research Centre of the Polish Academy of Sciences. This led to the creation of a new payload, which consists of a deployable drag augmentation device (the tail) covered by a new type of solar cell. The deployment of the tail was to result in a faster deorbitation of PW-Sat (approx. one year as opposed to four years without the tail).
The main aim of this project was to educate engineering students through participation in a real space project. The other objectives of this experiment were: to test the concept of using atmospheric drag to deorbit the satellite (The team was hoping they would be able to remove the satellite from orbit at a predicted time, about one year after launch) and to test the solar cells, which have never before been used in space.
PW-Sat was a 10x10x10 cm cube with a mass of 1 kg. equipped with the following hardware:
• EPS: power module
• ANTS: antenna management system
• COM: communication compartment
• PLD: elastic solar cells management sub-system
• OBC: main computer
• access port
• elastic solar cells (part of primary mission)
• atmospheric drag device (part of primary mission)
• AX.25 transceiver
• CW beacon transmitting on 145.901 MHz for tracking by radio amateurs
PW-Sat lifted off 13 February 2012, 10:00 UTC from ELA-1 at Guiana Space Centre (Kourou, French Guiana) aboard the maiden flight of the Vega rocket, together with LARES and ALMASat-1 satellites and 6 other CubeSats built by various European universities. It was deployed 1 hour 10 minutes into the flight from the P-POD-2 container, along with the ROBUSTA and MaSat-1 CubeSats.
First signals from satellite were received around 12:10 UTC by radio amateurs. The first Polish reception of PW-Sat’s signals came at 12:15 UTC by CAMK in Warsaw.
PW-Sat was supposed to stay in orbit until 2013, when it was going to perform a destructive atmospheric reentry. However, the problems with satellite’s energy balance and changes of orbital conditions (satellite was flying over Poland in shadow) delayed deployment of tail. Commands of tail deployment were sent from Earth on April and May 2012, but PW-Sat did not accept them. Due to hardware issue with communication module (that was discovered on a few other cube sats using the same model) communication with satellite was problematic and tail couldn’t be extended.
Even though the tail did not work as designed, then PW-Sat is the baseline for more advanced studies on a low-cost and effective deorbitation system for small satellites.
PW-Sat is an example of a modern approach to provide hands-on experience to engineering students. After graduation, most of the students working in the PW-Sat project will probably join the emerging Polish aerospace sector. Some of them already started to work in various space projects, including the BRITE-PL scientific satellites.
Development of a successor
A year after the launch of PW Sat – the first Polish satellite – in September 2013 there came a moment when students gathered in Students’ Space Association decided to take another step and build a second satellite – PW Sat2 . A team formed of the students from many different faculties of Warsaw University of Technology started working on a new satellite, twice the size of PW-Sat and much more complex. In PW-Sat2 project education is the first priority. Hands-on experience in real space project is not the only part. Many diploma theses and semester projects are going to be based on the design, construction and tests of the satellite.
“In our new project we would like to develop a deorbitation sail structure based on flat springs. The satellite will be built according to CubeSat standard as 2 unit CubeSat. Space debris problem is also being put into light all around the world so in our opinion it is the best time for such experiment”say members of the PW-Sat Team.
PW-Sat2 is an exceptional project mostly because of the people working on it. Not only there are students from various faculties of Warsaw University of Technology involved, but also many academics offer to help with the project including prof. Piotr Wolański once again.
“Most of the components are our original ideas, in few cases carried out as a bachelor’s or master’s thesis. Thanks to the experience earned in European Space Agency’s educational projects our solutions fulfill strict requirements which are usually imposed on professional space missions. Anticipated duration of the project is 3 years, starting on 4 January 2014. We assume that during this time we will educate over 30 engineers in the field of astronautics and about a dozen students will write their theses or have apprenticeship related to satellite payload and experiments design for PW-Sat2. Poland joined the European Space Agency in 2012 as a full state member, what was a very important step in the state development and started the process of space industry expansion in Poland. Which in turn means that in near future the large group of space engineers will be needed within Poland. We believe that contribution to PW -Sat2 project will allow our members to find engaging jobs in space industry” admit those who are involved in PW-Sat 2 project . This sounds very exciting and promising at the beginning of 2015 – the year when the new satellite will be launched.