Disposal of high inclination geosynchronous spacecraft and orbital stages

At the end of its 35th meeting in Darmstadt, in 2017, the WG4 proposed - at the request of CNES - a new AI on Disposal of High Inclination Geosynchronous Spacecraft and Orbital Stages. The SG discussed the proposal at the intermediate meeting held in Adelaide during the IAC-2017 conference. There, several delegations asked for changes and further clarifications. At the 36th IADC plenary meeting, held in Tsukuba in 2018, ASI made two technical presentations addressing the class of objects in geosynchronous orbits for which the IADC re-orbiting formula is not able to prevent the later crossing of the GEO protected region. After the meeting, the WG4 modified the wording and resubmitted the AI to the SG on 13 September 2018. It was discussed at the SG intermediate meeting held in Bremen during the IAC-2018 conference (3 October 2018), but no decision was taken. On 10 December 2018, the SG approved the proposal as AI 36.3, stressing that «updating guidelines should not be a direct output of the action item». As part of the wrap-up work on AI 32.1 Update of the IADC Space Debris Mitigation Guidelines and of the Support Document (On-ground Casualty Expectation and Max Long Term Presence in GEO) during 2020 and early 2021, it was noted that there are similarities between the long-term presence of spacecraft and upper stages on orbits crossing the GEO protected region. Such crossing orbits include (super-)GTO's as well as highly eccentric orbits. Noting that also AI 22.2 failed to find consensus on the topic of limiting the long-term presence in GEO, the lessons learned are put in context in this report as well.