What is PSLV Orbital Experimental Module (POEM)?

• The ISRO has launched three Singaporean satellites in precise orbit through the PSLV Orbital Experimental Module or ‘POEM’.

What is POEM?

• The POEM is a platform that will help perform in-orbit experiments using the final, and otherwise discarded, stage of ISRO’s workhorse rocket, the Polar Satellite Launch Vehicle (PSLV).
• The PSLV is a four-stage rocket where the first three spent stages fall back into the ocean, and the final stage (PS4) — after launching the satellite into orbit — ends up as space junk.
• However, in PSLV-C53 mission, the spent final stage will be utilised as a “stabilised platform” to perform experiments.
• POEM is carrying six payloads, including two from Indian space start-ups Dirgantara and Dhruva Space.

Features of POEM

• POEM has a dedicated Navigation Guidance and Control (NGC) system for attitude stabilization, which stands for controlling the orientation of any aerospace vehicle within permitted limits.
• The NGC will act as the platform’s brain to stabilize it with specified accuracy.
• POEM will derive its power from solar panels mounted around the PS4 tank, and a Li-Ion battery.
• It will navigate using four sun sensors, a magnetometer, gyros & NavIC.
• It carries dedicated control thrusters using Helium gas storage. It is enabled with a telecomm and feature.

Has ISRO repurposed and used PS4 rocket junk earlier?

• The Indian space agency first demonstrated the capability of using PSLV-C44 as an orbital platform in 2019.
• It injected Microsat-R and Kalamsat-V2 satellites into their designated orbits.
• The fourth stage in that mission was kept alive as an orbital platform for space-based experiments.
• While in that mission, the fourth stage had Li-Ion batteries, solar panels are an addition this time.
• The latest repurposing and upgrade of the fourth stage of the PSLV rocket involves the stabilization of the orbital platform.