Cemetery, graveyard or burning in the sky: How spacecraft meet their end | science | Hindustan Times
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Cemetery, graveyard or burning in the sky: How spacecraft meet their end

With hundreds of satellites now orbiting the Earth, space debris or ‘junk’ is a real problem.

science Updated: Oct 22, 2017 13:04 IST
HT Correspondent
Satellites that are no longer operational can be ‘hazardous’ to other spacecraft in the orbit.
Satellites that are no longer operational can be ‘hazardous’ to other spacecraft in the orbit.(Representative image )

Retirement may be a kinder way to put it, but spacecraft also die.

Chinese space station Tiangong-1, a 8.5-tonne spacecraft launched in 2011 and called the ‘Heavenly Palace’, is likely to plummet to Earth in the next few months, reported The Guardian earlier this month.

With hundreds of satellites now orbiting the planet, space debris or more commonly known as ‘space junk’ is a real problem. Satellites that are no longer operational can be “hazardous” to other spacecraft in the orbit, according to NASA. Scientists fear a minor collision can trigger a chain reaction of accidents.

There are places on Earth and in space where spacecraft rest after they’ve exhausted their functions, studies, fuel and completed their missions.

The solution was decided in an agreement between space agencies in 1993. The forum Inter-Agency Space Debris Coordinating Committee formalised that to prevent crashes, spacecraft will be disposed by either falling towards Earth or by blasting them further away to a region in space 36,049 km above Earth, according to information by NASA and Phys.org.

Burning in air or resting at Spacecraft Cemetery

Small satellites that are closer to the Earth use their last bit of fuel to fall out of the orbit and burn in the atmosphere. The heat from the friction of entering Earth’s air burns up the satellite as it plunges towards Earth at thousands of miles per hour, NASA Science explained on its website.

It gets complicated for larger satellites or space stations that may not completely burn in Earth’s atmosphere. These objects are directed by ground operators to crash at the ‘spacecraft cemetery’, an area between Australia, New Zealand and South America in the Pacific Ocean. It is one of the farthest points from land with little scope for fishing and crashing spacecraft here ensures there are no accidents or injuries to humans.

The spacecraft cemetery is one of the farthest points from land. (NASA)

An article in BBC said the area where spacecraft are dumped is known as the ‘South Pacific Ocean Uninhabited Area’ and more than 200 decommissioned objects are its occupants. It is also the resting place of the 134-tonne Russian space station Mir that disintegrated over the Pacific Ocean on March 23, 2001 after 15 years in service.

The International Space Station is likely to be part of the debris that will in decades occupy an area spanning across 1,500 sq km.

There are, however, chances that ground controllers can lose touch with the spacecraft on re-entry and it can crash somewhere else, as it happened with the first American space station Skylab; it’s pieces were found in Australia after its descent in 1979.

Skylab space station. (NASA)

‘Graveyard orbits’

Satellites on higher altitudes are simply blasted farther away into stable zones 300 km above the functional geosynchronous orbits where they can remain safely out of the way. Equipments on such satellites are deactivated, their batteries discharged among other measures to make these defunct satellites mostly harmless in case of collisions, reported Slate.