Title: A Look at the Indian Space Situational Assessment Report (ISSAR) 2023: Space Debris, Collision Avoidance, and Satellite Re-entry
The Indian Space Situational Assessment Report (ISSAR) for 2023 has highlighted a significant increase in space objects placed in orbit last year compared to 2022. The report, compiled by ISRO System for Safe and Sustainable Space Operations Management (IS4OM), was released in April by ISRO Chairman S. Somanath.
According to the report, the space object population has been growing, indicating better accessibility to space and the increasing applications of space technology in daily life. In 2023, 3,143 space objects were added to the population, compared to 2,533 in 2022. The report attributes five major on-orbit break-up events in 2023, resulting in 69 additional fragments to the space debris population.
In the Indian context, a total of 21 satellites re-entered the atmosphere by the end of 2023. Out of these, eight re-entries occurred in 2023 alone, with Megha-tropiques-1 experiencing a controlled re-entry through a challenging exercise.
Interestingly, 82 rocket bodies from Indian launches were placed in orbit till 2023. Among these, 52 PSLV-C3 debris remained in orbit till 2023-end, following an accidental break-up in 2001. Additionally, 35 rocket bodies from Indian launches re-entered the Earth’s atmosphere by the end of 2023, with five re-entries taking place in 2023.
ISRO regularly conducts analytical assessments using IS4OM-ISTRAC to predict close approaches by other space objects to Indian space assets. In 2023, ISRO received 1,37,565 close approach alerts from USSPACECOM (US Space Command). Out of these, 3,033 alerts represented potential close approaches within a distance of 1 km to ISRO satellites. However, none of them were critical enough to perform a collision avoidance maneuver (CAM).
Overall, 23 CAMs were carried out in 2023, compared to 21 in 2022 and 19 in 2021. This increasing trend in CAMs highlights the growing congestion in outer space. The report further states that no concerning close approaches with other space objects were detected for the Chandrayaan-3 mission or the Aditya-L1 during their respective mission phases.
The ISSAR 2023 underscores the importance of addressing space debris, close approaches, and satellite re-entry to ensure the safety and sustainability of space activities for all stakeholders.