Space Debris

Why in news?

Recently, Surrey Space Centre scheme, “RemoveDebris”, for removing orbiting debris successfully captured experimental test junk. The 100kg RemoveDebris satellite was launched to the station in April as cargo on a supply mission.

What is Space Debris?

• The term ‘space debris’ does not have a unanimously accepted legal definition. It is generally used to describe the collection of unwanted objects in the earth’s orbit which is either man-made or natural
• Natural Debris consists of natural bodies revolving around the sun, like, meteors and asteroids.
• Artificial Debris consists of man-made objects (usually non functional) which revolves around the Earth. (Therefore it is most commonly referred as Orbital Debris)
• According to the Report of Second U.N. Conference on Exploration and Peaceful Uses of Outer Space 1982, space debris consists of dead satellites, spent rocket motors, nuts and bolts etc.

Space Debris-Statistics:

• The U.S Space Surveillance Network is tracking over 13,000 human-made objects larger than 10 cm in diameter orbiting the Earth.
• In addition, there are over 100,000 objects measuring between one and ten cm in diameter and millions smaller than one cm.
• It is estimated that 40 % of the tracked debris is the result of breakups of rockets and space craft bodies.

Examples of space debris

1. Chinese Tiangong-1 which crashed into the South Pacific ocean is the most recent example of space debris
2. China also destroyed its Fengyun-1C weather satellite in January 2007 during a weapons test, creating some 3,300 fragments of debris in what was one of the most classic examples of space pollution.
3. In 2016, Japanese satellite Hitomi “lost” in space
4. ISROs launch vehicle PSLV-C19’s 4th stage (it had launched radar imaging satellite RISAT-1 in 2012) burnt up over the Central Atlantic.

Impact:

1. Spacecraft:

Space debris is a threat to active satellites and spaceships. For example, in 2009, a dead Russian satellite and a functioning US satellite collided and added more than 2,000 pieces of trackable debris into space

2. Kessler Syndrome: The Kessler Effect is a possible effect that if one satellite produces debris that hit another satellite, this will create a chain reaction that will obliterate every orbiting object in the Low Earth Orbit, and thus creating a thick cloud of white dots travelling at high speed. Rockets would no longer be able to reach space since they risk getting hit by these debris. (Watch the movie Gravity!!)
3. On Earth: The possibility of a person being hit and injured by space debris is estimated to be one in million. Till date, there has been only one such incident reported, where a women in Tulsa, Oklahoma was hit by a debris from Delta II stage during its re-entry event in 1997.

Related Laws/ treaties

The major treaties which are dealing with space law along with the provisions of environment safety are:

• Outer Space treaty, 1967
• Moon Treaty, 1979
• The Environment Modification Convention 1977,
• Space Liability Convention 1972,
• The Rescue Agreement 1968
• The Space Registration Convention 1975

Outer Space Treaty:

Key Provisions:

• The exploration and use of outer space shall be carried on for the benefit and in the interests of all mankind
• Outer space and celestial bodies are free for exploration and use by all states
• No Weapons of Mass Destruction are permitted in the outer space.
• States shall be responsible for their national activities in outer space, whether carried on by governmental or non governmental entities;
• States shall be liable for the damage caused by their space objects
• States shall avoid the harmful contamination of outer space

Liability Convention, 1972:

It states that the launching state is absolutely liable for damage caused on Earth’s surface or to aircraft in flight; if the damage is caused elsewhere (e.g., in space), the launching state is liable only if the damage is due to its fault or the fault of persons for whom it is responsible.

Space Debris Mitigation and Removal:

Tracking:

Tracking of Space Debris is very important to have a rough overview of the situation of the problem. It can further help us in avoiding major collisions in future. In the present time, there are some sensors put up for tracking space objects. The United States Space Surveillance Network, track, identify, and catalogue all manmade objects orbiting the earth.

Mitigation:

UN-Space Debris Mitigation Guidelines:

• Limit debris release during nominal operations
• Minimize break-up potential during operations
• Limit accidental in-orbit collision probability
• Avoid intentional destruction & harmful activities
• Limit the probability of post-mission break-up
• Limit the long-term presence of spacecraft and launcher orbital stages in the LEO protected region re-entry objects resulting from this recommendation must not pose an undue risk to the ground population
• Limit the long-term interference of spacecraft and launcher orbital stages with the GEO protected region.

Removal:

• Under this method the space debris is planned to be removed by the human made machines (spacecrafts).
• Recently, a space mission named Remove Debris was launched to demonstrate various space debris removal technologies. It is being led by Surrey Space Centre at the university of Surrey UK and is co funded by European commission and other partners. Recently, Surrey Space Centre scheme for removing orbiting debris successfully captured test junk.
• It showcased 4 methods:

1. Net capture: It involves a net that will be deployed at the target CubeSat.
2. Harpoon Capture: Which will be launched at a target plate made of “representative satellite panel materials”
3. Vision-based navigation: Using cameras and LiDAR (light detection and ranging), the platform will send data about the debris back to the ground for processing.
4. De-orbiting process: As it enters Earth’s atmosphere, the spacecraft will burn up, leaving no debris behind.

Other Measures of removal include:

• Auto Detector Debris Satellites, which can auto-detect the space junk and either destroys it or take it back on Earth.
• Supersonic Laser, which can be use by placing it on Earth only, but it, will burn the space trash. These lasers have been put up in Australia.
• Artificial Robots, which can go to space and there only work will be to destroy orbital debris.
• Space Magnet, which can attract small pieces of debris and throw it out from Earth’s orbit.
• Space Bombs, which can burn the space junk, without harming any other satellites.
• Self De-Orbiting Mechanism, which can allow satellite to automatically go out of Earth’s orbit, after it is of no use.

Space Debris mitigation Measures in India:

• The Indian Space Research Organization (ISRO) recognizes the importance of the current space debris scenario and is committed to effective management of the threats due to space debris.
• ISRO developed its debris environmental models and software to predict the close approach of any of the debris to the functional satellites. The software are regularly used for the debris risk management of the orbiting spacecraft and launch vehicles.
• A multi-object tracking radar (MOTR) developed by the Satish Dhawan Space Centre allows ISRO to track 10 objects simultaneously. It tracks India’s space assets and space debris, for which India was solely dependent on data provide by the US space agency NASA till early 2016.
• ISRO is also part of the Inter-Agency Space Debris Coordination Committee (IADC), an international governmental forum that coordinates global efforts to reduce man-made and natural space debris by sharing research and identifying debris mitigation options.

Steps to be taken:

1. In order to understand and address the threat of space debris there should be  both scientific perspective as well as a legal approach.
2. The future space operations need an active debris removal scientific mechanism thereby ensuring protection and conservation of the space environment.
3. A holistic and a comprehensive policy framework comprising of procedures and guidelines for mitigating the impact of space debris needs to be formulated for implementation of the scientific plan by the international community.