In case you haven't seen, NASA just lost contact with the Shuttle Columbia over Texas... it is presumed to have blown up during the mid-stage of re-entry.
A quick note to offer my condolensces to the families of the crew, and the people at Johnson Space Centre. Say a prayer for the crew, if that's what you believe in.
It's a great loss for mankind, not just America. Let's hope this doesn't end our already-fading enthusiasm for space exploration...