Maybe it hit hard and the panels flew open ?
Did they consider the idea that it did hit hard ( as they suspected ), some of the panels flew open, and the bright spot just North of Beagle 2 is a panel that broke off ?
Anyone who likes the idea of Curiosity driving over to it needs to read this bloody excellent book:
http://www.amazon.co.uk/Martian-Andy-Weir/dp/0091956145
Biting the hand that feeds IT
