"NASA's new Mars rover is heading for a risky do-or-die touchdown next month to assess conditions for life on the planet, but the U.S. space agency may not know for hours whether it arrived safely, managers said on Monday."
"Those seven minutes are the most challenging part of this entire mission," said Pete Theisinger, JPL's MSL project manager. "For the landing to succeed, hundreds of events will need to go right, many with split-second timing and all controlled autonomously by the spacecraft. We've done all we can think of to succeed. We expect to get Curiosity safely onto the ground, but there is no guarantee. The risks are real."
Keith's note: Funny how NASA never bothers to include minor details in these press releases such as having a satellite failure impede its ability to monitor the landing of Curiosity. So this whole "7 minutes of terror" campaign that NASA has been mounting for the MSL landing is probably inaccurate and may be much longer than "7 minutes".
Three Weeks Before Curiosity Rover Lands on Mars, SpaceRef (With video of the news conference)