New Delhi: Eight years after its launch from India, carrying a record-breaking 104 satellites, the upper stage of the Polar Satellite Launch Vehicle has safely descended over the Atlantic Ocean.
On October 6, 2024, the upper stage of India’s PSLV-C37 re-entered the Earth’s atmosphere, concluding its nearly eight-year odyssey in space. This occurrence underscores India’s dedication to responsible space conduct and the reduction of debris.
Launched on February 15, 2017, PSLV-C37 went down in history for deploying 104 satellites in a single mission. The main payload, Cartosat-2D, was accompanied by 103 co-passenger satellites, which included two Indian nanosatellites and a variety of international small satellites.
Following the successful delivery of all satellites into their intended orbits, the rocket’s upper stage, known as PS4, remained in an orbit with an apogee and perigee of approximately 470 km and 494 km, respectively.
The altitude of PS4 gradually diminished over the years due to atmospheric drag, a phenomenon meticulously tracked by the Indian Space Research Organisation (ISRO) via its IS4OM (ISRO System for Safe and Sustainable Space Operations Management) facility.
The re-entry took place on October 6, 2024, as forecasted by both the US Space Command and IS4OM, with the debris landing in the North Atlantic Ocean.
This re-entry, occurring within eight years of the launch, adheres to international debris mitigation guidelines that advise limiting the post-mission orbital lifetime of objects in Low-Earth Orbit to 25 years.
The agency is proactively working to shorten the orbital lifetime of PSLV upper stages to five years or fewer using controlled de-orbiting maneuvers. Missions such as PSLV-C38, PSLV-C40, PSLV-C43, PSLV-C56, and PSLV-C58 have already adopted these measures.
Looking to the future, ISRO is planning to implement controlled re-entry of upper stages in upcoming PSLV missions, which will further reduce space debris. These initiatives are in line with ISRO’s Debris Free Space Mission (DFSM) goals, which are set for realization by 2030.
