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

Lead Research Organisation: University of Warwick
Department Name: Physics


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.


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Description Dstl collaboration 
Organisation Defence Science & Technology Laboratory (DSTL)
Country United Kingdom 
Sector Public 
PI Contribution Dstl have recognized the skills we have developed in GEO observation and data reduction through this project and have been keen to develop collaboration in this project and in future projects. Our expertise and analysis is clear and we have developed much software in the course of this project which is attractive to Dstl. In addition our ability to apply and win large telescope time has been paramount.
Collaborator Contribution On my invitation Dstl staff joined our collaboration to make best use of the INT observations we were obtaining. Their main contributions at this time were some aspects that impact the observations that we had less experience of (eg accurate earth shadow calculation). More recently we have begun discussions with Dstl orbital dynamics and modelling staff. Dstl have recently placed a 5-year fellowship at Warwick to fully exploit the collaboration. In addition Dstl are in the process of buying significant telescope time in Australia to repeat the original experiment at a different longitude.
Impact There are some but they are in AMOS currently, next years reporting will have journal references.
Start Year 2019
Description PLATO Selection Outreach 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Press release over the selection of PLATO as ESA M3 mission. Picked up by many organisations. Here is one from the telegraph.
Year(s) Of Engagement Activity 2014
Description University Christmas Lecture to the Public 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Christmas lecture to a full Butterworth Hall at the Warwick Arts Centre holding around 1000 people (probably around 600 children and the rest public)
Year(s) Of Engagement Activity 2021