Context

The Indian Space Research Organisation’s PSLV-C58/XPoSat mission has practically left zero debris in earth’s orbit. The last stage of the Polar Satellite Launch vehicle (PSLV) used in the mission was transformed into a kind of orbital station- called the PSLV Orbital Experimental Module-3 (POEM-3), before it was left to re-enter the earth’s atmosphere instead of floating in orbit once its mission was completed.

What is POEM?

• Developed by the Vikram Sarabhai Space Centre (VSSC) as an inexpensive space platform, POEM uses the spent fourth stage of a PSLV rocket as an orbital platform.
• Used for the first time in the PSLV-C53 mission in 2022, ISRO had POEM orbit the earth as a stabilised platform to perform in-orbit scientific experiments with various payloads.
• POEM is powered by solar panels mounted on the fuel tank of the rocket’s fourth stage and a lithium-ion (Li-ion) battery.
• It has a dedicated navigation, guidance, and control (NGC) system to stabilise its altitude along with helium control thrusters.
• The NGC system has four Sun sensors, a magnetometer, and gyroscopes, and talks to ISRO’s NavIC satellite constellation for navigation.
• POEM also has a telecommand system to communicate with the ground station.