The great junkyard in outer space

To the naked eye on a clear night, outer space with its bright canopy of stars may look pristine and beautiful, but in fact humankind's 'final frontier' is littered with the debris of human exploration and exploitation. The frenetic pace of pace of activities since the launch of the Soviet Sputnik in 1957 has created a 'space debris belt' around the earth that resembles nothing so much as a garbage dump.

The pollution ring around the earth is made of everything from spent rocket stages and parts and pieces of disintegrated satellites to screwdrivers, empty food cans, and what have you, left in the void by astronauts. Objects in low earth orbit continue to move around till the slow wear of molecular friction and gravity cause them to enter into the earth's atmosphere and burn up into small fragments.

Weapons tests in outer space a major hazard
So far about 10,000 man-made objects that can be tracked have been catalogued orbiting the earth. These objects are larger than 10-12 cm in size, and are being regularly monitored. In addition there are hundreds of thousands of bits of debris which cannot be tracked because of their minuscule size.

Many of these objects, moving at a high velocity, could seriously damage the multi-million dollar satellites in orbit around the earth. There are more than 1000 satellites and spacecraft circling the earth for various purposes. Luckily, so far the only major case of collision in outer space was the one involving the French defense satellite Cerise, which was hit by a fragment of the European Ariane space vehicle.

Another important contributor to the pollution of outer space is the so-called controlled blasting carried out by some nations for reasons ranging from technological experiment to testing a destructive device. For instance, the recent Chinese anti-satellite test led to the creation of hundreds of pieces of space debris.

According to American space agencies, in January 2007 China used a ground-based medium range ballistic missile to hit its ageing FengYun-1C weather watch satellite, orbiting about 800 km above earth. This experiment is seen as a major Chinese step towards creating a 'space war' capability.

Commenting on the Chinese space weapon drive, Indian Space Research Organisation chairman G Madhavan Nair has stated that though it is well within the capability of ISRO to develop and deploy a system capable of knocking down a satellite in orbit, India's concern is to keep outer space a zone of peace and tranquility.

During 1960s and '70s, anti-satellite tests carried out by the erstwhile Soviet Union and the USA are known to have contributed substantially to the growth of the pollution belt in space. In fact, the anti-satellite tests conducted by the Soviets are known to have contributed at least 500 pieces of junk to the pollution ring.

Along with other space agencies including the European Space Agency (ESA) and the US National Aeronautics and Space Administration (NASA), ISRO has been working on devising means to mitigate the problem of space debris and strengthen satellites against the possible threat from the man-made objects in outer space.

The inter-agency space debris coordinating committee (IADC), part of the United Nations committee on the peaceful uses of outer space, has come up with a suggestion to boost the 'dead and inoperative' satellites into the so-called 'graveyard orbit', which would be at least 350 km above the geostationary orbit (GSO) where most communications satellites are located. The GSO is situated about 36,000 km above the equator.

Space debris takes lives on earth
Both, satellites gone out of control and objects moving freely in space, could hit the earth with disastrous consequences. As early as 1961, Cuban Prime Minister Fidel Castro had alleged that a re-entering chunk from a dead American satellite had killed a Cuban cow. Another medium sized metallic piece of an American spacecraft landed on a street junction at Manitowa in Wisconsin in 1962. In early 1970, a German vessel in the Atlantic Ocean was hit by a fragment of the Saturn-V booster used by US Apollo 9 mission to land a man on the moon.

The first case of death or injury due to the impact of descending space debris was reported from China in early 1995. As India was celebrating its Republic Day on January 26, the Chinese Long March-1 vehicle carrying Apstar-2 communications satellites crashed half-way up to its destination, and the rocket stages descending to earth killed a couple and injured several other persons.

In addition, space activities are also being blamed for atmospheric pollution. For instance, environmentalists have for many years now alleged that the exhaust from the American space shuttle has been contributing to ozone depletion.

The hazards involved in space exploration caught the public consciousness in the drama of the uncontrolled descent of NASA's orbiting complex, Skylab in July 1979. But fortunately, the 77-tonne Skylab found a watery grave off the Australian coast. In the first quarter of last year, the US managed to safely de-orbit its partially crippled defense satellite that had created a scare of hitting the earth with serious consequences.

Though far less publicised than the Skylab plunge, the violent crash of the errant Soviet ocean watch satellite Cosmos-954 in January1978 brought home the threat of nuclear radiation from the heavens. Luckily, this spy satellite burnt up over a remote part of Northern Canada, scattering radioactive debris over a wide but unpopulated area. A number of pieces of disintegrated nuclear reactors meant to power satellites on deep space missions remain in various space orbits.

Overcrowding is yet another problem plaguing outer space. The geostationary orbit (GSO), described as the real estate of space, is experiencing near-total congestion. Because a satellite placed in GSO appears stationary in relation to earth, most of the communications satellites are placed in this vital orbital slot. The number of satellites in this orbit has been growing at 10 per cent annually. India's INSAT domestic satellite is located in the GSO belt.

The congestion in this vital belt was highlighted by a big row that broke out in 1994 between China on one side and Japan and America on the other over the positioning of a Chinese spacecraft too close to a Japanese satellite and a privately owned American one. After much wrangling, China shifted the position of its satellite to avoid interference.

International protocols
Significantly, the 1992 convention on international liability with regard to the damage caused by space objects, including space debris, clearly states that in the event of damage or loss caused to space objects (including satellites) of one country by space objects (including pieces of launch vehicles and fragments of satellites) of another country, the liability would be based on fault.

If however, a launching state proves that damage has resulted either wholly or partly from the negligence of the claimant state, then the launching state is exonerated from absolute liability. However, it is yet to be decided whether the compensation for damage caused by a nuclear powered satellite should be different from that for damage caused by a conventionally powered satellite.

The 1967 UN outer space treaty, governing the use of outer space, stresses the peaceful uses of outer space by all nations. In particular, it speaks of "common interests of all mankind in the progress of the exploration and use of outer space for peaceful purposes". By implication, this clearly forbids the placing of nuclear weapons or destructive devices in orbit around the earth or on celestial bodies.

As Space Security 2008, an annual publication brought out by a consortium of government, non-government and academic institutions, says, "Since 1981, the UN General Assembly has passed an annual resolution asking the states to refrain from actions contrary to the peaceful uses of outer space, and calling for negotiations on a multilateral agreement to prevent an arms race in outer space."

However, the USA, keen on maintain its supremacy in space, including its use for defensive and offensive purposes, has turned down all the suggestions for a comprehensive treaty banning the use of outer space for testing destructive devices. In fact, China and Russia had come out with a draft proposal for such a treaty, which USA was not willing to consider.

The US argument is that such an accord would be difficult to verify, and that no additional outer space treaties are needed because there is currently no arms race in outer space. This is specious reasoning, as the time to put such a treaty in place is now - because once an arms race begins, it will be very difficult to retrospectively enforce any agreement.

Clearly, we need to clean up the mess in outer space, just as we need to clean the mess here on earth.