- The debris from a large Chinese rocket, the Long March 5B, crashed to earth over the Pacific and Indian oceans, capping off a week of global anxiety and concern. There were fears that the rocket’s 22-tonne core stage would collide with a populated area as it hurtled back to earth. Despite widespread criticism for the rocket re-entry risks it imposes on the world, China has dismissed these concerns.
- The Long March 5B rocket launched on July 24 to deliver a laboratory module to the new Chinese space station in orbit, marking the third flight of China’s most powerful rocket since its maiden launch in 2020.
GS Paper 3: Science Tech: General awareness in the fields of IT, Space
Today, space debris is a major concern for the entire world. Discuss the problem caused by space debris and offer solutions. (150 words)
What is an uncontrolled re-entry?
- The core or first stage of a rocket is typically made up of heavy pieces that do not reach orbit after liftoff, but instead fall back safely along a near-precise projected trajectory.
- If they do enter orbit, a costly de-orbit manoeuvre is required for a controlled, steered return using engine burn. The orbital core stage falls out of control if no de-orbit manoeuvre is performed.
- The core stage of China’s Long March 5B rockets has been known to make such fiery, out-of-control descents back to Earth. The reason for this is a difference in the mission sequence, in which the core stage enters orbit and then crashes back to Earth.
- According to a Guardian report, most nations’ rockets separate the launcher from the payload before leaving the atmosphere. An additional engine then provides a final boost to the payload. According to the report, China’s 5B series, however, does not use a second engine and instead propels itself directly into orbit.
- Long March 5B debris was apparently found in Ivory Coast in May 2020, and a year later, in May 2021, remains of a Chinese rocket were discovered in the Indian Ocean near the Maldives.
Why is it difficult to track uncontrolled descents?
- The variables involved make pinpointing the re-entry time and drop zone of rocket debris in uncontrolled descents difficult. Among the factors that make this prediction extremely difficult are atmospheric drag, variations in solar activity, and the object’s angle and rotational variation.
- A miscalculation of even a minute in re-entry time could result in the debris’s final resting place shifting by hundreds of kilometres.
- “It’s critical for people to understand that, of the ten most difficult things we do in space, debris re-entry is probably one of the most difficult to predict,” Dr. Darren McKnight of satellite tracking company LeoLabs told Cosmos Magazine.
What are the threats posed by space junk?
- Collision of space debris with other satellites or among themselves generates more fragments and exacerbates the problem
- A belt of space junk would render certain low-Earth orbits inaccessible Experts have warned of Kessler syndrome:
- Astronauts in space would be harmed by space debris;
- Old batteries from defunct spacecrafts could explode, causing system leaks; and Space debris is a constant threat to the International Space Station (ISS).
Are there laws regulating space junk?
- The 1972 Space Liability Convention defines responsibility in the event that a space object causes harm. According to the treaty, “a launching State shall be absolutely liable to pay compensation for damage caused by its space objects on the earth’s surface or to aircraft, as well as liable for damage due to its faults in space.” The Convention also includes procedures for resolving damage claims.”
- However, there is no law prohibiting space junk from crashing back to Earth. In April of this year, suspected Chinese rocket debris was discovered in two Maharashtra villages.
- The re-entry of NASA’s 76-ton Skylab in 1979 scattered debris over uninhabited parts of Australia, and the space agency was fined $400 by a local government for littering.
- The only Liability Convention settlement was between the former Soviet Union and Canada over debris from Soviet Cosmos 954 that fell in a barren region.
- An update to the 1967 Outer Space Treaty, which grants countries permanent property rights to their space objects, complicating efforts to clean up debris.
- NASA funding for debris-removal technology research and partnerships with companies;
- US expansion of the Artemis Accords, a framework for space cooperation that includes (so far) 11 other countries