Context

• Recently the Indian Space Research Organization (ISRO) has said that its PSLV-C58/XPoSat mission has left practically zero debris in Earth's orbit.

Key Points

• ISRO said that after completing the primary mission of placing all the satellites in their targeted orbits, the fourth stage of PSLV was converted into PSLV Orbital Experimental Module-3 (POEM-3).
• It was later de-orbited from 650 km to 350 km, making it more vulnerable to being pulled toward Earth and burning up in the atmosphere.
• Additionally it "decommissioned the stage", i.e. dumped its fuel, to avoid an explosion.

About POEM

• Developed by the Vikram Sarabhai Space Center as an inexpensive space platform, POEM uses the spent fourth stage of a PSLV rocket as an orbital platform.
• First used in the PSLV-C53 mission in June 2022, ISRO had placed POEM in Earth orbit to conduct scientific experiments in orbit with various payloads.
• POEM is powered by solar panels and lithium-ion batteries mounted on the rocket's fourth stage fuel tank.
• It has helium control thrusters as well as a navigation, guidance and control (NGC) system to stabilise its altitude.
• The NGC system has four sun sensors, a magnetometer and a gyroscope, and it talks to ISRO's NavIC satellite constellation for navigation.
• POEM also has a telecommunications system to communicate with the ground station.

Importance

• With the increase in the number of satellites orbiting Earth, space debris has become a serious issue. Space debris in low Earth orbit (LEO) consists primarily of spacecraft, rockets and fragments of defunct satellites and fragments of objects that have been explosively detonated as a result of anti-satellite missile tests. It often flies at a high speed of 27,000 km/h.
• Due to their enormous volume and speed, they pose a risk to many space assets.
• In such a situation, the success of ISRO's zero debris based mission is a milestone in the direction of reducing space debris.

Important Facts For Exams

ISRO 

• Founder: Vikram Sarabhai
• Headquarters: Bengaluru, Karnataka
• Current Chairman: Shri S. Somnath