Limited space in outer space, ISRO dodges 23 collisions

BENGALURU: With the growing demand in the space sector, last year, the Indian Space Research Organisation (ISRO) witnessed over 1,37,565 close approach alerts for its space assets on the US Space Command (USSPACECOM). The space agency was able to carry out successful collision avoidance manoeuvres (CAMs) for the satellites after re-assessing these threats and saving them from crashing into space debris or other space objects.

The data was revealed in the annual report released by S Somanath, Secretary, Department of Space and Chairman, ISRO, titled Indian Space Situational Assessment Report (ISSAR) for 2023 and has been compiled by ISRO System for Safe and Sustainable Space Operations Management (IS4OM).

According to ISSAR, a total of 3,033 alerts for close approaches within a distance of 1 km were detected for ISRO satellites and 2,700 close approaches were found with other operational satellites within 5 km.

ISRO said 23 CAMs were used to protect the Low Earth Orbit (LEO) and Geo-synchronous Earth Orbit (GEO), the highest till date. This can be attributed to the increasing space debris and frequent launches globally leading to congestion in outer space. In 2022, the space agency performed 22 CAMs.

On certain occasions, scientists carried out coordination with other international agencies like SpaceX, EUMETSAT and more. However, none of the close approaches were critical enough to warrant a CAM.

Data on Collision Avoidance Analysis (COLA) for Launch Vehicles revealed that there was a necessary four-second delay in Chandrayaan-3’s launch or it would have been hit by debris and India would have missed the iconic feet.

Similar was the case for DS-SAR (developed under a partnership with the Government of Singapore and ST Engineering). The lift-off had to be delayed by one minute to avoid close approaches between Starlink satellites and the injected satellites due to overlapping operations.

ISSAR emphasised that the increasing population of active satellites require Space Traffic Management (STM). “Unlike air and marine traffic, no universally accepted framework for STM exists at present, hence the resolution of an on-orbit close approach between two active satellites is carried out on case-by-case by inter-operator coordination” warned the report.

The experts also believe that space activities need to be made sustainable. It must be recognised by all space actors that, unlike terrestrial activities, any activity in space has potentially global and far-reaching implications, and near-Earth space is a finite resource that must be utilized responsibly to harness it for societal benefits, said the report.