about to open the door and walk out on to terra firma and earth for the first time in several days. what's going on inside that shuttle right now? >> well, before they get the hatch open, alisyn, they run through checklists that start to shut down the orbiter's systems. make sure, for example, the rocket powered hydraulic pumps have terminated their operations safely and to be able to power down the vehicle and once that's complete at the same time, they're opening the hatch, medical personnel come on board, two technicians to unstrap you and help the astronauts out of the hatch. about 45 minutes after landing is typically when the first crew member emerges. >> come on, you've been on the space shuttle a couple of times. you know those guys are high fiving each other but at the same time, it's like they're giving each other a bear hug. it's like we did it. it's over. >> there's lots of handshakes and lots of back slapping, you're right. lots of grins inside the cabin and then you try to understand