SRO’s ‘zero orbital debris’ milestone & the space debris crisis

SRO’s ‘zero orbital debris’ milestone & the space debris crisis

Subject: Science and tech

Section: Space

Context:

• The Indian Space Research Organisation (ISRO) has successfully minimized space debris from its PSLV-C58/XPoSat mission.

Details:

• After the mission’s primary goal of satellite deployment was achieved, ISRO converted the PSLV’s fourth stage into the PSLV Orbital Experimental Module-3 (POEM-3).
• This module was then intentionally lowered in orbit from 650 kilometers to 350 kilometers to facilitate its re-entry and disintegration in the Earth’s atmosphere.
• Additionally, ISRO took measures to “passivate” the stage by draining its fuel to prevent any risk of explosion and the resultant debris scattering in orbit. This approach ensured that the mission produced negligible debris.

What is POEM (Polar Satellite Launch Vehicle Orbital Experimental Module)?

• POEM is a cost-effective orbital platform developed by the Vikram Sarabhai Space Centre (VSSC).
• It repurposes the spent fourth stage of a PSLV rocket, utilizing it as a stable platform for conducting scientific experiments in orbit.
• First used during the PSLV-C53 mission in June 2022, POEM is equipped with solar panels and a lithium-ion battery for power.
• It features a dedicated navigation, guidance, and control (NGC) system with helium control thrusters to maintain its altitude.
• This system includes Sun sensors, a magnetometer, gyroscopes, and communication with ISRO’s NavIC satellite constellation for precise navigation. Additionally, POEM can communicate with ground stations via a telecommand system.
• The concept of reusing the rocket’s fourth stage was first demonstrated by ISRO in the PSLV C-44 mission in 2019, where the stage, carrying a student payload, was relocated to a higher orbit for extended observational activities.

What has POEM-3 achieved?

• The POEM-3, a component of ISRO’s PSLV C-58 mission launched on January 1, 2024, successfully achieved its mission objectives before reentering the Earth’s atmosphere on March 21, 2024.
• After deploying the XpoSat satellite into a 650 km orbit, POEM-3 was subsequently lowered to a 350 km orbit. This lower orbit increases atmospheric drag, requiring more energy to maintain position.
• Notable achievements include the completion of experiments like ARKA200, RUDRA, and LEAP-TD, with other experiments collecting data for ground analysis. 
• Two fuel cells demonstrated power generation capability.

Why is it significant?

• The increasing number of satellites and consequent space debris in Low Earth Orbit (LEO) poses significant risks due to high-speed collisions that can damage active satellites and other space assets.
• LEO, ranging from 100 km to 2000 km above Earth, is crowded with operational satellites and millions of debris pieces, including those from spacecraft, rockets, and defunct satellites.
• The Space Situational Assessment report by ISRO in 2022 noted a sharp increase in objects placed in space, rising from 1,860 in 2021 to 2,533 in 2022.
• Additionally, incidents such as the intentional destruction of satellites and accidental explosions have contributed significantly to debris accumulation.
• This issue is not only a risk in space but also on Earth, as demonstrated by an incident where a piece of space debris damaged a house in Florida.
• The rapid expansion of satellite constellations, notably SpaceX’s Starlink project planning 42,000 satellites, further underscores the urgent need for effective debris management and mitigation strategies to safeguard space infrastructure and ensure long-term sustainability in space operations.

How are space agencies dealing with debris?

• Space agencies globally are addressing the problem of space debris through various initiatives, despite the absence of specific international laws governing debris in Low Earth Orbit (LEO).
• Agencies adhere to the Space Debris Mitigation Guidelines endorsed by the U.N. in 2007, which aim to reduce risks associated with debris in space, including preventing long-term presence in LEO and limiting interference in Geosynchronous Earth Orbit (GEO).
• NASA, which started its Orbital Debris Program in 1979, focuses on tracking and studying space debris, though it has yet to implement debris removal technologies. The U.S. Space Force actively monitors space debris to prevent collisions.
• The European Space Agency (ESA) has pledged to achieve zero space debris by 2030 through its ‘Zero Debris charter’ and encourages other agencies to adopt similar policies.
• China recently launched a spacecraft with a solar sail designed to accelerate the de-orbiting of defunct spacecraft by utilizing solar radiation pressure.
• Japan’s Aerospace Exploration Agency (JAXA), in partnership with Astroscale, is advancing the Commercial Removal of Debris Demonstration (CRD2) project, which involves capturing and removing space debris.
• Private companies are contributing too, with ventures like Astroscale in Japan working on technologies to refuel and repair satellites to extend their operational life and enhance debris removal efficiency. China’s Origin Space has developed a prototype for capturing debris with a large net.
• In India, ISRO is actively working on debris mitigation with initiatives like the POEM missions and the establishment of the Space Situational Awareness Control Centre to safeguard satellites against potential collisions. 
• ‘Project NETRA’ of ISRO is also an early warning system in space to detect debris and other hazards to Indian satellites.
• Indian startups like Manastu Space are developing technologies for in-space refueling, satellite life extension, and de-orbiting strategies.

Source: TH