The threat from space debris in low earth orbit: understanding and mitigating the risk

This proposal is effectively about the artificial pollution of the near earth space environment (this area is named in the project call as an acceptable area for applications). We have been launching satellites mostly into low earth (LEO) orbit for 60 years with little regard for the ultimate fate of these vehicles. Consequently, the level of debris has been rapidly rising so that now there is a growing and appreciable risk of collision. Low earth orbits are particularly congested as these are easiest to reach. They are also particularly dangerous as debris in these orbits can be moving at large relative velocities. Given this even small debris (a cm) can disable a spacecraft through collisions. The situation is due to worsen appreciably over the next few years with the launch of so-called "mega" constellations of small satellites. For example, Elon Musk's Starlink constellation is licensed to install 32000 small satellites (16x the number of currently operational satellites) into orbit. Mitigation relies on atmospheric drag supposedly de-orbiting within 25 years. ESA/NASA estimate there are 0.9M- 0.5M pieces of satellite killing debris (1cm or larger in size) in orbit and this is clearly destined to get much worse.

Currently LEO debris are mostly tracked and characterised through radar techniques (RF). Historically these have been military in original (designed for missile early warning systems), but in the last few years a number of smaller scale commercial operators have appeared. Poor orbital parameters derived from sporadic RF measurements means that only 2% of satellite killing debris are currently being tracked. However, optical tracking techniques can offer distinct advantages over the RF: optical observations can give accurate orbits which will lead to a build up of the population catalog. We have been looking at a new methodology/techniques that will be cheaper and more accurate than the RF. While we have a range of difference sensors and optics available to us the prototype will need a high performance telescope mount to be effective and the development of real time analysis software to keep up with the data rate.

Over the grant period we will develop and demonstrate the capability of technique and prototype and with our partners devise the final instrumental configuration to be effective in the field.