Bad Astronomy

Change of address for LCROSS

LCROSSI know I said that NASA’s LCROSS impactor was going to smack into the crater Cabeus-A on October 9th, but NASA changed their minds: the new target is the crater Cabeus proper. New analysis of data from other probes indicates that Cabeus has more hydrogen locked up in the regolith than Cabeus-A, and in fact has the highest hydrogen concentration in the south polar region. As an added bonus, the topography of the crater is such that a valley will let sunlight hit the plume of ejected dust sooner than it would have had they stayed with Cabeus-A as a target. That gives scientists more time to look at the ejecta, and earlier is better because the plume will be denser too.

I hope this is the right choice for NASA, but I have to say I’m impressed they can change their plans this late in the game. Let’s hope they see some water!