The problem of space junk has proven increasingly vexing to both national space agencies, such as NASA, and commercial space companies. Millions of pieces of debris, ranging from nuts and bolts to spent satellites, orbit the Earth at thousands of miles an hour, providing a navigational hazard to both crewed spacecraft and active satellites. Periodically the International Space Station is obliged to maneuver to avoid a collision with a piece of space junk that might otherwise severely damage it.
According to MIT Technology Review, a group of engineers at Tsinghua University in Beijing, China have proposed an innovative solution to the problem. The idea is to launch a satellite with a source of power, solar or nuclear and have it swallow space junk, grind it up into powder, superheat it into plasma, and use the plasma to maneuver about. In theory, such a vehicle could move about in orbit around the Earth indefinitely, swallowing up debris and using it as fuel.
To be sure, the debris-eating spacecraft would only work with space junk less than 10 centimeters in diameter. Larger pieces of space junk would be heated by a laser to cause them to crash into the Earth’s atmosphere and burn up. Also, some have expressed concern about using nuclear power in low Earth orbit.
Still, the Chinese engineers may be onto something. Previous ideas of dealing with space junk were limited by the problem of fuel. Once the fuel runs out for a space junk collection vehicle, it becomes space junk itself. But the use of space junk as fuel seems to be an elegant solution to that problem.