I think both the space shuttle program and the International Space Station program have not really lived up to their expectations.

If we're going to complete the space station, we're going to need the shuttle. It's going to take a lot of resources.

When I did my spacewalks, it was during space station construction. So the shuttle was docked to the fledgling ISS at the time. So we would always stay tethered.

Manned spaceflight has lost its glamour - understandably so, because it hardly seems inspiring, 40 years after Apollo, for astronauts merely to circle the Earth in the space shuttle and the International Space Station.

No, I think most astronauts recognize that the space shuttle program is very high-risk, and are prepared for accidents.

CASIS has to succeed because for it not to succeed would be a huge setback for the International Space Station program.