Researchers at the University of Surrey are developing a method how to remove obsolete satellites from orbit in a fraction of time needed for natural re-entry.
The work comprising several projects has been introduced during the Space Traffic Management Conference in London on 2 July by professor Vaios Lappas.
The Deorbit sail project, funded by the European Union, is scheduled for launch in 2014 and hopes to become the first European satellite to demonstrate the sail-assisted deorbiting procedure. “We will launch a 3kg cubesat into sun synchronous orbit at the altitude of about 600 km. We will operate it for about 6 months and then deorbit it with the help of the sail,” professor Lappas explained.
The sail technology enables reducing the amount of time needed for a satellite to enter and burn in the Earth’s atmosphere from decades or even hundreds of years to just years or months. “Naturally, a 3kg satellite orbiting at the 600km altitude would require up to 88 years to re-enter. When we deploy a drag sail on it after its mission ends, it would burn up in the atmosphere in 130 days,” Lappas said.
The 25m2 sail would increase the surface area of the spacecraft while not adding to its mass. As a result, the drag the thin atmosphere at such high altitude has on the spacecraft would grow stronger, adding to faster orbital decay.
For Lappas and his team, this is just the first step in the process. “Eventually, we would like to develop a system that would enable attaching such sails to decommissioned satellites that are already in orbit,“ he said, explaining that the sail-assisted re-entry is most suitable for small satellites up to 500kg of weight.
The University of Surrey is also working with Astrium UK on a concept for removing larger satellites. In the past 12 months, the team led by Astrium’s Jamie Reed has performed several tests evaluating the viability of two concepts – using a harpoon and a net to capture decomissioned satellites.
“We have tested the technology in microgravity conditions in a drop tower test and during a parabolic flight and we were pleased with the results,” Reed said. “If everything goes according to the plan, we would like to test a prototype of a debris-chasing satellite in 2017 and commence operations by 2020.”
As the issue of space debris is getting more serious, the pressure on the space community to find solutions is growing. However, there are many issues left to be solved. As Reed said, no-one has been actively removing space debris before and there are many technical challenges, including precise navigation, synchronization and the fact that space debris objects have various shapes and sizes.