Evaluation of debris mitigation options for a large constellation

Large constellations of satellites in Low Earth Orbit (LEO) may adversely impact the sustainable use of the space environment over the long-term unless appropriate plans for orbital debris mitigation measures are incorporated into the design and operation. In particular, recent computer modelling studies have shown that comprehensive observance of the Inter-Agency Space Debris Coordination Committee (IADC) guideline on post-mission disposal is a vital element of debris mitigation plans intended for large constellations in LEO. Several operators have proposed that the region of LEO below 600 km altitude could be used to accommodate large numbers of spacecraft without unduly heightening orbital debris concerns. The objective of this study, using the DAMAGE computer model, was to evaluate the implications for the orbital debris population of orbit design options for a large constellation. The build-up, replenishment and disposal of a large, complex constellation comprising 10,440 active spacecraft was simulated. A subset of the constellation, a component comprising 1800 spacecraft in a single band, was deployed at either 1100 km or 550 km altitude. The positioning of this component provided the two fundamental study conditions. The results showed that positioning the 1800-spacecraft component at 550 km altitude reduced the overall impact of the constellation substantially, whilst also reducing the need for a high post-mission disposal success rate