Space Junk is a Problem. Is a Laser Cannon the Solution?

[Ms Jebun Naher Sikta]

There's a general rule in media reporting called Betteridge's Law: Whenever a headline poses a question–especially a sensational one–the answer is "no." I'm going to break the law this time. An orbiting laser cannon is not only an intriguing technology but, yes, it's one of the most promising ways to clean up the ever-thickening cloud of dangerous debris surrounding the Earth.

And just to be clear, space junk is a danger. There are about 25,000 human-made objects larger than your fist flying around in orbit, and about half a million pieces bigger than a dime. If you include millimeter-scale shrapnel, the number of rogue bits reaches deep into the millions. Typical speeds in low-Earth orbit are about 30,000 kilometers per hour (18,000 miles per hour), ten times the velocity of a rifle bullet. You see the problem: A little impact can pack a big wallop.

So far, there have not been any space-junk catastrophes remotely resembling the sensationalized events in the movie Gravity, but the reality is still disconcerting. In 2009, a $50 million Iridium communications satellite was destroyed by a collision with a defunct Russian satellite. Three years later, the Fermi space observatory had a near miss with another Soviet-era satellite. NASA had to clad the International Space Station in shielding to protect it from repeated small impacts, and the agency sometimes moves the whole station to dodge larger pieces of junk. Orbiting debris adds cost and risk to the space business.
The proposed space-station laser cannon (left) would work in conjunction with a telescope called EUSO to track and destroy space debris.