These are incredible, huge, and crystal clear photographs of the May 2009 shuttle mission to repair the Hubble Space Telescope.  The telescope is the greatest astronomical instrument ever devised and this is its last repair.  The mission was very dangerous because the Hubble orbits in an area with a high density of space junk.  A rescue mission was actually waiting on the ground with another shuttle in case the main mission ran into trouble.  These pictures are fantastic.