CHIME Satellite Design for Disposal minimising Casualty Risk upon re-entry

Paper number

IAC-24,A6,5,7,x84833

Author

Ms. Puloma Chatterjee, Thales Alenia Space, France

Coauthor

Ms. Anca-Maria Stan, Elecnor Deimos, Romania

Year

2024

Abstract

Low Earth Orbit earth observation satellites with large optical payloads have a high casualty risk at disposal in an uncontrolled re-entry scenario. In the case of CHIME, the casualty risk would have been higher than the European Space Agency’s Space Debris Mitigation Policy requirement of a risk level less than 1 in 10000 for any re-entry event.  The CHIME satellite is therefore designed with dual disposal technology: it is sized to perform a controlled re-entry into the earth’s atmosphere at end of life, in addition to being compatible with ESA’s Active Debris Removal concept.

This paper provides a concrete example of how a satellite and its AOCS and Propulsion sub-systems are designed to perform the re-entry manoeuvres, as well as the operational concept for the controlled re-entry, which is the nominal disposal strategy for the CHIME mission. The paper also describes the implementation of “Design for Removal” on the CHIME satellite, providing the navigation aids and mechanical interfaces enabling a "removal vehicle" to perform a rendezvous and capture of the satellite in case of double failures leading to the loss of the propulsion sub-system, or a chain of other platform failures leading to loss of control of the satellite itself.

The reliability analysis shows a reliability of over 90\% of the systems needed to perform the controlled re-entry at the end of its nominal lifetime of 7.5 years operation in orbit, in compliance with ESA requirements. In this baseline scenario, the casualty risk is shown to be zero. 
Further analysis demonstrates that in spite of many double failures, the controlled re-entry may be performed either in the nominal planned way, or with a modified approach depending on the type and combination of failures.
Both single and double failures involving critical elements leading to impossibility of performing a successful controlled re-entry were also identified, justifying the implementation of Design for Removal for compatibility with ESA's Active Debris Removal programme.

Thanks to the baseline strategy of controlled re-entry as well as the implementation of Design for Removal, the casualty risk of the disposal of a LEO satellite is minimised, reducing the overall risk level to well below the current requirements of 1/10000.

Abstract document

IAC-24,A6,5,7,x84833.brief.pdf

Manuscript document

IAC-24,A6,5,7,x84833.pdf (🔒 authorized access only).

To get the manuscript, please contact IAF Secretariat.