POEM-4 Re-entry: ISRO’s PSLV Orbital Experimental Module-4 (POEM-4) re-entered Earth’s atmosphere and impacted the Indian Ocean on April 4, 2025, at 8:03 am IST.
Mission Overview: POEM-4 was the spent fourth stage (PS4) of PSLV-C60, reconfigured as an orbiting platform for scientific experiments.
Launch Details: Launched on December 30, 2024, alongside twin SPADEX satellites to a 475 km altitude orbit. It was later de-orbited to a 350 km altitude.
Payloads: Hosted 24 payloads (14 from ISRO, 10 from non-government entities). Included the Walking Robotic Arm, Debris Capture Robotic Manipulator, and Gradient Control Reaction Wheel Assembly.
Mission Objectives: Aimed to conduct scientific experiments, including cowpea seed germination in microgravity and operating India’s first space robotic arm.
Tracking: Tracked by ISRO’s Radar Facilities and US Space Command, aiding in re-entry prediction.
Passivation: PS4 was passivated by venting leftover fuel to minimize accidental break-up risks.
Debris Mitigation: Safe re-entry demonstrates ISRO’s commitment to containing space debris and the Debris Free Space Mission (DFSM). This commitment is crucial for the long-term sustainability of space.
Monitoring: The re-entry was closely monitored by ISRO’s System for Safe and Sustainable Space Operations Management (IS4OM).
