For those who haven't seen the news yet this morning, the shuttle Columbia broke apart on re-entry about an hour and a half before I posted this. At this time, NASA has not declared the shuttle a loss, but from the video on the networks, it's hard to imagine anything less. To the friends and families of the Columbia crew, I wish to extend my deepest sympathies. Yours is a hard loss, expecting the safe return of your loved ones and not having that happen. I grieve with you. To the friends and families of the Challenger crew (who perished 17 years ago), I grieve with them for reliving their loss. I hope they can help provide comfort for the friends and families of the Columbia crew at this time of sorrow.