NASA is planning an emergency repair of the damaged solar panel astronauts discovered recently outside the International Space Station. Set to take place on Saturday, just a few days before the shuttle returns home, the plan will require two spacewalking astronauts, and it's risky but necessary.

If NASA does nothing, the tear could worsen and the entire panel might have to be jettisoned. Yes, the ISS does have a few more at its disposal, but this panel provides 15% of the station's electricity, and the ISS needs every bit of that to incorporate the planned new modules. The fix will require some ingenuity, as the ripped panel is far from an anchoring point for the spacewalking repairman. But NASA has pulled off plenty of feats like this before.—Gregory Mone