Satellites powered by solid metal could one day use space junk for fuel

Space is getting crowded — humans have now placed over 20,000 satellites into orbit since the start of the space age, and there are plans to launch thousands more over the next few years. Some of those satellites have already burned up in the atmosphere or fallen back to Earth, often into the ocean, but more than 13,000 are still up there. About a fifth are inactive, simply orbiting as as space junk. Over the last couple of decades, hundreds of these dead satellites have collided to create millions of pieces of shrapnel. More

(Source: CNN - Mar 19)