Space Debris

IN NEWS:

• The Union Minister of State (Independent Charge) for Science and Technology recently announced that there are 111 payloads and 105 space debris identified as Indian Objects orbiting the Earth. 

WHAT IS SPACE DEBRIS?

• According to NASA, space debris encompasses both natural meteoroid and artificial (human-made) orbital debris.
• Meteoroids are in orbit about the sun, while most artificial debris is in orbit about the Earth (hence the term “orbital” debris).
• Orbital debris is any human-made object in orbit about the Earth that no longer serves useful function.
• So, space debris (orbital debris) refers to all the human-made objects such as whole and abandoned satellites, pieces of broken satellites, spent rocket stages, fragments after anti-satellite weapon strikes (ASAT) and other random objects such as tiny flecks of paint from spacecraft and even tools left behind by astronauts during space walks.
• The majority of them orbit the Earth, and some even go beyond it. Some of them have made it to Venus and Mars. Twenty tonnes of them have been found on the moon, according to NASA.

STATISTICS:

• Based on statistical models produced by European Space Agency (ESA)'s space debris office, it is estimated that there are 36,500 objects larger than 10cm, 1 million objects between 1-10cm, and an extraordinary 130 million objects between 1mm to 1cm.
• At present, NASA is officially tracking more than 26,000 pieces of orbital debris (the U.S. and Russia/USSR are responsible for over 70% of this) that are endangering astronauts and space missions.
• According to NASA, debris in orbits below 600 kilometres will fall back to Earth within several years, but above 1,000 kilometres it will continue circling the Earth for a century or more.

HAZARDS AND CHALLENGES ASSOCIATED WITH SPACE DEBRIS:

• Risk posed to space exploration:
  • Debris in Low Earth Orbit (LEO) travels at speeds of up to 10 km/s, fast enough to cause significant damage to satellites, spacecraft, or spacewalking astronauts.
  • The rising number of pieces of space debris increases the potential danger to all space vehicles, especially those with humans aboard, like the International Space Station (ISS). 
  • For instance, in 2006, the International Space Station’s (ISS) fused-silica and borosilicate-glass fortified window suffered a 7-mm chip due to an impact from a piece of space debris no larger than thousandths of a millimetre across.
  • Also, since its launch in 1999, the ISS has performed 29 debris avoidance manoeuvres up to May 2021.

• Increases the cost of operation:
  • Space debris is not only a hazard; it also raises the cost of satellite operators.
  • Satellite operators in geostationary orbit have estimated that protective and mitigation measures account for about 5–10% of mission costs, and for lower-Earth orbits the cost is higher, according to an OECD study.
• Potential impact on ability of satellite technology:
  • The density of the space debris may become so great that it could hinder the ability to use weather satellites and, hence, monitor weather changes.
• Impact on environment and human life:
  • Hazards associated with space debris do not just exist in space; they can also endanger the environment.
  •  A proportion of the space junk in low Earth orbit will gradually lose altitude and burn up in Earth’s atmosphere; larger debris, however, can occasionally impact the Earth and have detrimental effects on the environment.
  • For instance, debris from Russian Proton rockets, launched from the Baikonur cosmodrome in Kazakhstan, litters the Altai region of eastern Siberia. This includes debris from old fuel tanks containing highly toxic fuel residue, unsymmetrical dimethylhydrazine (UDMH), a carcinogen that is harmful to plants and animals.
  • Also, space debris impacts earth’s environment and atmosphere by releasing compositional chemicals into the atmosphere when they burn up upon re-entry. These chemicals can deplete ozone and also pose a threat to future launches and space exploration.
• Threat to human life:
  • Larger debris poses a danger to human life and property.
  • For instance, the debris from a large Chinese rocket, the Long March 5B, crashed to earth over the Pacific and Indian oceans. As the 22-tonne core stage of the rocket hurtled uncontrollably back to earth, there were fears that it might hit a populated area.

INITIATIVES TO TACKLE THE ISSUE:

NATIONAL:

• ISRO System for Safe and Sustainable Operations Management (IS 4 OM)
  • In 2022, ISRO System for Safe and Sustainable Operations Management (IS 4 OM) has been established towards more focused efforts to continually monitor the objects posing collision threat, improve prediction of evolution of space debris environment and concerted activities to mitigate the risk posed by space debris.
• Project NETRA:
  • The Indian Space Research Organisation (ISRO) has initiated ‘Project NETRA’ to monitor space debris.
  • The domestic surveillance system would provide first-hand information on the status of debris, which would aid further planning on protecting space assets.
•  India - U.S. pact:
  • In April 2022, India and the U.S. signed a new pact for monitoring space objects at the 2+2 dialogue.
• ‘SPADEX’:
  • To provide in-orbit servicing, ISRO is developing a docking experiment called ‘SPADEX’.
  • It looks at docking a satellite on an existing satellite, offering support in re-fuelling and other in-orbit services while enhancing the capability of a satellite.
  • This would not only ensure the longevity of a mission but would also provide a futuristic option to combine missions or experiments, thereby promoting reuse and efficient use of satellites.
• Collision Avoidance Manoeuvres:
  • ISRO has carried out 21 collision avoidance manoeuvres of Indian Operational Space assets in 2022 to avoid collision threats from other space objects.
  • To deal with the threat of very small debris objects which are too small to be tracked, spacecraft needs to shielded against the impact risk. Spacecraft shielding related studies and development are under progress in ISRO to improve the protection for the upcoming missions.

INTERNATIONAL:

• Space Debris Mitigation Guidelines:
  • In 2007, the United Nations General Assembly adopted the Space Debris Mitigation Guidelines drafted by the Committee on the Peaceful Uses of Outer Space (COPUOS).
  • The guidelines specify, among other things, that rockets and satellites should be designed to produce no debris, and that satellites in low Earth orbit should re-enter the atmosphere within 25 years of ending their mission.

• RemoveDebris Mission:
  • RemoveDebris is an EU (European Union) research project to develop and fly a low cost in-orbit demonstrator mission that aims to de-risk and verify technologies needed for future ADR (Active Debris Removal) missions.
• e.Deorbit mission:
  • ESA’s proposed e.Deorbit mission aims to capture and safely deorbit a derelict ESA-owned satellite in a highly trafficked low-Earth orbit.

WAY FORWARD:

• Reuse and recycling:
  • For the long-term sustainability of outer space, support space research and the development of technology to ensure the reuse and recycling of satellites at every stage.
  • Allow the private sector to develop models that improve operational safety and reduce debris footprint. 
  • Also, more focus should be placed on developing reusable launch vehicles.
  • For instance, the SpaceX Falcon 9 is a two-stage rocket that is partially reusable.
• Self-destruction of satellites:
  • Satellites should be programmed to leave their orbit at the end of their useful lives and be eliminated when they come into contact with the atmosphere.
  • Also, many modern satellites are launched into elliptical orbits with perigees within the Earth's atmosphere, which causes them to break up eventually.
• Passivation:
  • During passivation, all latent energy reservoirs of a satellite or orbital stage are depleted to prevent an accidental post-mission explosion.
  • Such passivation measures may include depletion burns, fuel and/or pressurant venting, the discharging of batteries, and the inhibiting of pyro devices.
• Cooperation at the international level:
  • At the international level, countries with the largest footprint in space must come together to agree on some basic standards, such as limiting the number of satellites in a given orbital shell.
  • Also, countries need to detach sustainability from national security concerns; countries should be able to share information about the location of their satellites without revealing their purpose.

PRACTICE QUESTION:

Q. What constitutes space debris? Also, explain why space debris is a serious problem.