Operation Space Junk

The bits of space debris that orbit our planet unhindered collide with each other in great speeds causing even more junk and new collisions. As nothing can be done about the matter, the problem escalates and creates a situation where no new spacecraft can be launched to space and its research and exploration will wither away for centuries.

This is not a description of the current situation on Earth’s orbits but a summary of the Kessler syndrome dreaded by astronomers all over the world.  The progress of technology and full-scale conquest of space can sound entirely positive, but they do have their down sides. In fact, the Kessler syndrome is no longer just science fiction: space junk is already becoming a problem in low Earth orbit.

– The orbit is starting to fill up with debris at an alarming rate. Some collisions have already happened and their number will probably increase in the future if we cannot find a solution to the problem, says Rami Vainio, Professor of Space Physics and Head of the Space Research Laboratory at the University of Turku.

For instance, the European Space Agency ESA has estimated that approximately 30,000 pieces of debris with a diameter of over 10 centimetres are currently orbiting the Earth. It has also been surmised that there are over 100 million smaller splinters under 1cm in size.

At the moment, Professor Vainio is working in the Academy of Finland’s Centre of Excellence in Research of Sustainable Space, led by Professor of Space Physics Minna Palmroth from the University of Helsinki. The consortium consists of researchers from the Universities of Turku and Helsinki, Aalto University, and the Finnish Meteorological Institute. Their long-term goal is to ensure the sustainable utilisation of space in the future.

– If we act now, we can still manage the problem. We have to remove space debris from orbit and prevent the creation of new junk more effectively than before. Just one piece of debris the size of a pin head can break a functional satellite, says Vainio.

Rami Vainio leads the Space Research Laboratory at the University of Turku. He is holding a copy of the RADMON radiation monitor, which is also part of the Aalto-1 satellite currently orbiting the Earth. Photo: Hanna Oksanen

Living in a New Space Era

The idea for the Centre of Excellence was born when leading Finnish experts participated in the development of the Aalto-1 nanosatellite, which started as student project at Aalto University. Aalto-1 is the first satellite designed and built in Finland, and the researchers from Turku built a radiation monitor called RADMON into the satellite.

In many ways, Aalto-1 is a historic initiative in Finnish space industry and it is an indicator of a new space era in a wider context as well.

– People have started talking about NewSpace, as most of the satellites launched into space after 2012 have been owned by private companies and ventures. The change is partly due to the fact that space technology has become cheaper, lighter and more accessible, says Vainio.

Satellites have become increasingly smaller and it has had a great impact on why the private sector has become such a significant player in space industry in the last few years. Where the launching of satellites used to be a big and expensive project costing millions of euro, now a single rocket can launch even over a hundred of the new, lighter satellites into space.

– As the costs of the launch are divided according to the weight or number of the satellites, the price has dropped to hundreds of thousands, which has created a situation where new initiatives are springing up like mushrooms. You can even talk about a mega constellation orbiting the Earth – an armada of nanosatellites slightly larger than a milk carton, describes Vainio.

When the launch of satellites in itself is no longer so costly, there is no sense in building overly expensive satellites.

– There are devices in orbit that are optimised for a life of two or three years and they are not meant to last any longer than that. This is partly because the payload of satellites improves continuously and, for example, the spectral cameras get better each year.

Cost-effective and Radiation-tolerant Technology

If most of the space debris is created by disintegrating satellites, what turns the expensive devices into worthless junk?

– The single most important factor is radiation and there’s more of it in space than here on Earth, explains Vainio.

The Centre of Excellence focuses on two key factors for the sustainable utilisation of space: radiation-tolerance for satellites and containment of space debris. The consortium studies radiation conditions and develops smart technologies to improve radiation protection.

– The old way of protecting satellites from radiation in space is based on costly special components and armouring the more delicate parts. Based on commercial components, we are developing an active but cost-effective way to protect satellites from radiation.

In the project, the radiation protection is based on software using technologies created for industrial safety and the Internet of Things. In layman’s terms, this means that satellites are built of cheaper parts but their software is so intelligent that it should recognise the damage caused by radiation and steer itself to fix the problem.

– The satellite has to withstand radiation and identify when a part of the system is temporarily or entirely broken. Furthermore, irreplaceable technology has to be multiplied so that one radiation particle does not break the entire satellite. The University’s role in the consortium is to equip satellites with measuring devices that can detect certain things from radiation, such as radiation flux and its types. Developing these kinds of devices is the established area of expertise of the University of Turku, says Vainio.

In addition, a plasma brake developed by Pekka Janhunen from the Finnish Meteorological Institute is also tested in the consortium's satellites. Within the Earth’s magnetosphere, the orbital speed of the satellite can be slowed down with a tether-like plasma brake that functions as a kind of a sail as it harnesses plasma surrounding the planet.
The idea is that the plasma brake could be a future standard equipment in satellites and prevent the creation of new space debris. With the plasma brake, it could be possible to make satellites that have completed their mission to descend into lower orbits, from where they will drop into the atmosphere and be destroyed, describes Professor Vainio.

Space as a Commercial Megatrend

Open satellite data, NewSpace with its nano satellites, and the increasing commercial launches are a sign that the space industry is at a turning-point. According to Vainio, space has become a new megatrend.

– The numbers in the space segment are rather dizzying at the moment, reaching an annual growth of even 10–25 percent depending on the analyst.

The significance of corporate collaboration has also been understood at the Centre of Excellence in Research of Sustainable Space.

– In the consortium, one of the most important matters is the impact of our research. We collaborate with companies and try to conduct open science so that it can also be utilised in the business sector, says Vainio.

Main photo: ESA/AOP, CC BY-SA 3.0 IGO. Most of the known space junk is situated on the low Earth orbit. The photo is an artist’s illustration and the pieces orbiting the Earth are not in the right scale.

The article has been originally published in UTU Life & Science 2018 magazine: www.utu.fi/en/news/UTU-life-science-magazine