Viability of a circular economy for space debris.

The orbital debris population is rapidly growing, increasing the chance of a Kessler-style collision event. We report a novel method for the production of estimates for the total monetary value of all debris objects and total mass of all objects currently in orbit. The method was devised using debris object data from the European Space Agency's DISCOS dataset, classified via a decision tree. 'Reuse' and 'scrap material' scenarios were developed. A high-end estimate for reuse shows a net value of $1.2 trillion. Median and low-end net value estimates of $600 billion and $570 billion, respectively, are probably judicious. A scrap material scenario produced a high mass estimate of 19,124 tonnes, a median of 6,978 tonnes and a low estimate of 5,312 tonnes. Development of in-orbit services will be crucial to solve the orbital debris problem. A future circular economy for space may be financially viable, with potentially beneficial consequences for risk reduction; resource efficiency; additional high-value employment; and climate-change knowledge, science, monitoring and early warning data.