PSLV-C37 Upper Stage Re-entry Marks ISRO's Commitment to Debris-Free Space by 2030

What’s in today’s article?

• Why in News?
• Space Debris
• PSLV- C37 upper stage re-enters Earth orbit

Why in News?

ISRO announced the successful re-entry of the Polar Satellite Launch Vehicle-C37 (PSLV-C37) upper stage into Earth's atmosphere on October 6. This achievement aligns with global efforts to reduce space debris, supporting ISRO's goal of achieving debris-free space missions by 2030.

Space Debris

• About
  • Space debris refers to defunct, human-made objects in Earth's orbit, such as non-functional satellites, spent rocket stages, and fragments from satellite collisions.
  • These debris pose a growing threat to operational spacecraft, satellites, and the International Space Station (ISS).
• Challenges
  • Collisions: Even tiny debris can cause severe damage to satellites and space stations due to their high velocities.
  • Chain Reaction (Kessler Syndrome): Increasing debris can lead to more collisions, creating even more debris and increasing the risk of cascading damage.
  • Cost of Mitigation: Tracking and removing debris require advanced technology and substantial financial investment.
• Increasing space debris
  • With the rise in the number of satellites in orbit around the earth, space debris has become a pressing issue.
  • According to ISRO’s Space Situational Assessment report 2022, the world placed 2,533 objects in space in 179 launches in 2022.
  • The number of space objects greater than 10 cm in size in LEO is expected to be about 60,000 by 2030.
• Legal provisions
  • Currently, there are no international space laws pertaining to LEO debris.
  • However, most space-exploring nations abide by the Space Debris Mitigation Guidelines 2002 specified by the IADC. This was endorsed by the U.N. in 2007.
  • The guidelines outline methods to limit accidental collisions in orbit, break-ups during operations, intentional destruction, and post-mission break-ups.
• International Institutions
  • Inter-Agency Space Debris Coordination Committee (IADC): A global forum that coordinates efforts to mitigate space debris.
  • United Nations Committee on the Peaceful Uses of Outer Space (COPUOS): Sets space debris mitigation guidelines.
  • International Telecommunication Union (ITU): Regulates satellite orbital slots to prevent overcrowding.
• Steps taken by India
  • Debris Free Space Mission (DFSM): ISRO is committed to achieving a debris-free space environment by 2030 through passivation, active de-orbiting, and controlled re-entry of spent rocket stages.
  • The implementation of this DFSM initiative will start by the beginning of 2025.
  • This includes selecting clean orbits, budgeting fuel for post-mission disposal, and precisely controlling re-entry trajectories.
  • ISRO’s Debris Mitigation Strategy: India’s space agency, ISRO, follows international guidelines, including the IADC's recommendation to limit post-mission orbital life to 25 years.
  • IS4OM (ISRO System for Safe and Sustainable Space Operations Management): Monitors space debris and orbital decay, ensuring compliance with mitigation guidelines.

PSLV- C37 upper stage re-enters Earth orbit

• Re-entry of PSLV- C37 upper stage
  • On October 6, 2024, the upper stage of ISRO's PSLV-C37 mission, launched in February 2017, re-entered Earth's atmosphere.
• The PSLV-C37 carried 104 satellites, including Cartosat-2D as the primary payload.
  • After the mission, the upper stage (PS4) remained in orbit at approximately 470x494 km.
  • Over time, its orbit decayed due to atmospheric drag and was closely monitored by ISRO and US Space Command (USSPACECOM).
• Re-entry followed international debris mitigation guidelines
  • This re-entry followed international debris mitigation guidelines, specifically the IADC recommendation to limit the post-mission orbital life to 25 years.
  • ISRO's passivation sequence successfully lowered PS4’s orbit, ensuring re-entry within eight years.
  • ISRO is now working to further reduce the orbital lifetime of rocket stages to five years through active de-orbiting, with future missions focusing on controlled re-entry.
• ISRO also aims to achieve a Debris Free Space Mission (DFSM) by 2030.

Q.1. What is space debris and why is it a concern?

Space debris consists of defunct objects in orbit, posing risks of collisions and cascading damage, impacting space operations and safety.

Q.2. How is ISRO addressing the space debris issue?

ISRO is implementing strategies like active de-orbiting and controlled re-entry to reduce space debris, with a goal of achieving debris-free space missions by 2030.

Source: Upper stage of historic PSLV-37 mission re-enters Earth’s atmosphere eight years after launch: ISRO | ISRO | Indian Express