Monday, November 12, 2012

Global climate change increases the risks associated with space debris: Report

You'd think the International Space Station (ISS) is safe from anything happening in Earth's atmosphere, considering it is orbiting with a minimum mean altitude of 205 miles and a maximum of 255 miles. You'd be wrong.

Climate change from greenhouse gas emissions is causing emissions of carbon dioxide (CO2) that is propagating upward to the highest regions of the atmosphere. Scientists from the Naval Research Laboratory, Old Dominion University, and the University of Waterloo wrote about the issue on Sunday.

In that region, over 50 miles above Earth's surface, carbon emissions cause the opposite effect seen on Earth: cooling rather than warming. That is because carbon dioxide molecules collide with oxygen atoms and release heat into space.

Such cooling causes the planet's atmosphere to contract, which can reduce drag on satellites and debris that orbit the earth, possibly having "adverse consequences for the already unstable orbital debris environment, because it will slow the rate at which debris burn up in the atmosphere," the researchers wrote.

In addition, with less drag being exerted on them, space debris such as old, decrepit satellites other detritus will remain in orbit longer, increasing the chance of collisions.

The scientists added:
Even tiny bits of debris, such as paint chips, can damage satellites and manned spacecraft when they're traveling in low-Earth orbit at about 21,600 mph. An aluminum sphere half an inch in diameter has the potential to do as much damage upon collision as a 400-pound safe traveling at 60 mph. Larger items such as defunct satellites can pulverize the objects they hit in space, generating ever more pieces of dangerous floating trash.
As a prime example, in early October, the ISS was forced to move to avoid space debris.

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