The Indian Space Research Organisation (ISRO) announced on Tuesday that the upper stage of the PSLV-C37 rocket has successfully re-entered Earth’s atmosphere after seven years in orbit. This event occurred on October 6 at approximately 9:19 PM IST, as estimated by the US Space Command, with the rocket landing in the North Atlantic Ocean.
The PSLV-C37 mission, launched on February 15, 2017, marked a significant achievement by deploying 104 satellites in a single mission, including the primary payload Cartosat-2D along with 103 others like INS-1A, INS-1B, Al-Farabi 1, BGUSAT, and DIDO-2.
ISRO reported that after deploying the satellites and undergoing passivation, the upper stage PS4 maintained an orbit of roughly 470 x 494 km. The US Space Command monitored the rocket, identified as NORAD ID 42052, tracking its gradual orbital decay primarily due to atmospheric drag.
ISRO’s System for Safe and Sustainable Space Operations Management (IS4OM) had been observing the rocket’s orbital decay since September 2024 and predicted its re-entry during the first week of October.
In line with the Inter-Agency Space Debris Coordination Committee (IADC) guidelines, defunct objects in Low Earth Orbit (LEO) should have a post-mission orbital life of no more than 25 years. The re-entry of the PSLV-C37’s upper stage within eight years of launch adheres to these regulations, achieved by lowering its orbit after satellite deployment.
ISRO is actively working to reduce the residual orbital lifetime of PSLV upper stages to five years or less through controlled de-orbiting strategies, as seen in the PSLV-C38, PSLV-C40, PSLV-C43, PSLV-C56, and PSLV-C58 missions. Future PSLV missions are also being planned with controlled re-entry procedures to ensure the safe disposal of upper stages.
Space debris is an increasing concern, encompassing any non-functional human-made object in space, including defunct satellites, spent rocket stages, collision fragments, and even paint flecks. These debris pose risks to operational satellites. The IADC coordinates global efforts to address the challenges posed by space debris.
