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Is China's space laser for real?

 

Full article and graphics: https://www.popsci.com/china-space-laser

It's not a Death Star super laser. It's a space broom.

laser satellite

IT'S NOT THIS.

China's space broom isn't the Death Star super laser. It's an orbiting satellite with a laser only powerful enough to heat up pieces of space junk, so that they change course burn up in the atmosphere.

In a recent article in scientific journal Optik, a faculty member at China's Air Force Engineering University proposed building a laser-armed satellite, a "broom" to do battle with the pernicious problem of space debris.

Laser-armed satellites, naturally, generate a lot of attention, and so the proposal of Quan Wen and his co-authors has made its way into several splashy headlines. But it's more than hype. The concept addresses a real (and growing) problem: there's something like 17,852 artificial objects orbiting earth (PDF), and an estimated 300,000-plus pieces of space debris larger than a marble. At the fast orbital velocities up in space, even large craft like the International Space Station have to maneuver out of the way of small objects to avoid catastrophic damage.

Quan's research looks at the efficacy of a hypothetical laser operating near the infrared spectrum. It would blast away targeted space debris for a couple minutes, at a rate of twenty bursts of laserfire a second. That amount of energy would be sufficient to vaporize part of the object's mass. Contrary to public imagination, space laser brooms like the one proposed don't actually vaporize space debris, but rather "burn off" a chunk. This would create sufficient kinetic force from the chemical combustion to change the object's orbit. With that change in direction, the debris will quickly reenter the atmosphere and burn up. Because of atmospheric distortion, it's much more effective to zap space debris with a satellite than, say, a ground-based laser.