Imagine being trapped on a space station orbiting Earth with no available ride home. Three Chinese astronauts, or taikonauts, are facing that very scenario. Since Friday, the trio has been stranded on board the Tiangong space station without a viable return craft. The only craft available to them was hit by space junk in early November, cracking the craft's viewing port. The cause of the collision was a "tiny piece of space debris," the China Manned Space Agency (CMSA) said in a statement at