There’s a lot going on above our heads as things are getting more and more crowded in space. Decommissioned satellites, upper stages of launch vehicles and other objects are out there in orbit. Space debris is increasingly becoming a challenge for the industry. With this in mind, OHB subsidiary LuxSpace is working on a product for microsatellites, known as the “DoWn!” drag sail, which is designed to lower satellites into the Earth’s atmosphere more quickly at the end of their mission so that they can burn up there. In an interview, Florio Dalla Vedova, Head of Technology Development at LuxSpace, talks about this innovation “Made in Luxembourg”.
Space debris is becoming an ever greater problem. And now LuxSpace has arrived on the scene with a solution ...?
Florio Dalla Vedova: It would appear so! Obviously, we generally advise our customers to keep space debris avoidance in mind when they make their technical and economic decisions. For example, you can choose a material that combusts more readily. But we also offer an instant solution: We have developed a drag sail called “DoWn!”.DoWn! stands for “Deorbit Wing” and makes it possible for a correspondingly equipped satellite to “sail” more quickly back into the Earth’s atmosphere at the end of its life cycle. In this way, it doesn’t need its own propulsion. We have already developed a small DoWn! drag sail with an area measuring half a square meter, bringing it to Technology Readiness Level 7. Right now, we’re planning a big brother with a sizeable sail measuring one and a half square meters.
Interesting ... and what does a drag sail do?
A drag sail is a kind of sail that is mounted to the satellite and used in orbit during phase F, i.e. the disposal/de-orbiting phase at the end of the mission. The thin drag sail can unfold and stretch out at lightning speed on command. Whereas the satellite was previously traveling in its planned orbit, the air resistance rises when the sail opens, causing the satellite to crash and combust in less than 25 years. The 25-year deadline is also specified in ISO 24113 for the prevention of space debris. DoWn! has a triangular surface when it is unfolded. We turned to nature for our inspiration: when unfolded, butterfly wings also have a “triangular” shape. And best of all, a DoWn! drag sail can be stored on a very small surface, namely in a tube measuring 5x5x30 centimeters.
What is space debris?
Space debris refers to all space vehicles or objects that are in orbit around the Earth but have reached the end of their life cycles, i.e. they have fulfilled their mission. This includes ejected upper stages and defective, deactivated satellites. In addition, numerous very small parts, which have arisen from explosions or collisions in space, are increasingly creating problems for the space industry. Scientists estimate that a total of about 150 million parts larger than one millimeter are orbiting the Earth. In addition there are 750,000 objects a little over a centimeter in size. In view of the high speed with which these miniature objects travel in their orbits, they can yield a very strong destructive force and pose a threat to astronauts, satellites and other spacecraft.
Explain this to us again in greater detail ...
Drag sails use atmospheric air resistance to slow down the microsatellite and to reduce its orbit until re-entry. Like a parachute, a large exposed drag sail can intensify the braking process and in this way shorten the time to re-entry. Depending on requirements, several DoWn! drag sails can be installed simply on the microsatellite to provide the greatest possible area. After the drag sail has deployed, the decommissioned microsatellite no longer needs to be controlled from the ground and can be deactivated completely.
Not bad! But who is paying for the project?
DoWn! was developed by our Research, Technology Development & Innovation (RTDI) department at LuxSpace. Various partners have been supporting us since 2008. Thus, we have received funding from the ESA programs “Sails Made in Luxembourg” and “Solar Sails Materials”, the EU “Hollistic Approach to De-orbiting/Re-entry” program, the ESA and LuxImpulse “Large Deployable Antenna Systems” program, the ESA “DragCOL” program and the ESA “Drag Sails Guidance, Navigation and Control" program. We are very grateful for this assistance. However, the cost of procuring and installing one or more DoWn! drag sails will subsequently be paid by the respective customer.
Is it realistic to assume that we will soon be able to avoid space debris?
In the interests of sustainable development in space, it is important for us to plan end-of-life solutions for space vehicles during the engineering phase. Drag sails like DoWn! are an easy and cost-saving way of achieving this.
In this documentation about space debris Markus Katzkowski, CFO of LuxSpace, among others, talks about space.