The consensus was we have a pristine box, so let?s buy down the risk even further by changing out the box.

That's due to the amount of fuel the 747 can take on due to the heavy orbiter on its back.

It was a fairly long and tedious process.

Even with the devastation to their lives, it's been kind of remarkable that they have stepped up and are back at work and are trying to balance that with their own personal issues,

Doing a late inspection is one of the ways that you increase the likelihood that you have a clean vehicle. It's the length of time in space that drives up the risk of impacts.

It's like your car. If you open up your engine to try to find a small problem, you might create some others.

It's a problem that has been around for years.

It's a problem that has been around for years. It's probably of greater interest now because we're getting ready to fly.

They had a valve misconfigured between the air lock and space station.

The teams are now looking at all the data to determine what may have caused the inadvertent alarms that woke up the crew.