While the upper stage of PSLV-C60 (PSLV Orbital Experimental Module or POEM-4) was in orbit, it was continuously tracked by ISRO’s Radar Facilities and United States Space Command (USSPACECOM) facilities as well. Photo: Special Arrangement
The upper stage (PS4) of PSLV-C60 (PSLV Orbital Experimental Module in short POEM-4) which was launched on December 30, 2024, by ISRO re-entered the atmosphere and impacted at 2.33 UTC (8.03 a.m. IST) on April 4, 2025, in the Indian Ocean.
On December 30, ISRO’s PSLV-C60 launched twin SPADEX satellites, and after injecting the satellites at 475 km altitude, the specially configured upper stage (PS4) of PSLV-C60 (called PSLV Orbital Experimental Module in short POEM-4) was also almost in the same orbit.
“Subsequently, POEM-4 was de-orbited by engine restarts to a nearly circular orbit at 350 km altitude with 55.2 inclination. PS4 was then passivated by venting the leftover fuel to minimise any potential risk for accidental break-up. During its mission life, POEM-4 hosted altogether 24 payloads (14 payloads from ISRO and 10 from various NGEs) and all payloads worked as expected yielding valuable science data,” ISRO said.
The space agency added that while the POEM-4 was in orbit, it was continuously tracked by ISRO’s Radar Facilities and United States Space Command (USSPACECOM) facilities as well.
“The tracking data was, in turn, utilised in the re-entry prediction process. It was observed that POEM-4’s orbit had decayed to 174 km x165 km and the platform was predicted to re-enter the Earth’s atmosphere on April 4,” the space agency said.
According to ISRO, the atmospheric re-entry event of POEM-4 was then closely monitored by ISRO System for Safe and Sustainable Space Operations Management (IS4OM) and regular updates in predictions were made. Finally, the POEM-4 module re-entered the atmosphere and impacted at 2.33 UTC (8.03 IST), April 4 in the Indian Ocean.
“The safe re-entry of POEM-4 is yet another accomplishment to ISRO’s commitment to contain the growth of space debris, reaffirming the prominent role of ISRO in the long-term sustainability of the outer space environment and Debris Free Space Mission (DFSM),” the space agency said.
Published – April 05, 2025 12:48 am IST
