NASA Scrubs Shuttle Mission

After 2 1/2 years of waiting, a faulty fuel tank sensor scrubbed today's space shuttle mission. All seven astronauts were already on board Discovery when the launch was called off, less than three hours before liftoff.

NASA says it will take some time to figure out the exact problem, but it has something to do with the engines four cutoff sensors, which are responsible for making sure the engines shut down at the exact right time during its ascent.

No new launch date has been set, but NASA only has until the end of July. After that, they'd have to wait until September. The schedule is driven by many things, including the position of the International Space Station.

Today's launch was to be the first since the deadly breakup of the Columbia in February of 2003. NASA scientists were on pins and needles trying to make sure everything was perfect.

Chuck Watson, a local NASA consultant, spoke with us about what it's like at NASA in the final hours before liftoff. According to Watson, it's extremely nerve wracking, because when something goes wrong, years of preparation can be scrubbed within a matter of seconds.

"You have a 227-page checklist, very fine print front and back," he said.

But through all the checking and rechecking, Watson feels this latest launch attempt is weighing heavily on the collective minds of the space community.

"We need to be up there and there's a lot riding on it, because human space exploration is vitally important in my view," he said.

If the weather didn't pose a big enough threat, a sensor problem in the main fuel tank was the culprit that forced NASA to pull the plug before the scheduled liftoff.

"This could have caused a premature shutdown of the engines, the shuttle would not have made it into orbit," explained Watson. "If in fact there was a leak somewhere, it could have even caused an explosion."

A shuttle designed more than 30 years ago was destroyed 2 1/2 years ago on reentry, and while Watson remains an advocate for human space exploration, another disaster is something NASA simply cannot afford.

"We're sweating it," he said. "Everybody in the community knows how much is riding on this flight. If there's another accident, God forbid, it's going to be causing a lot of thinking, do we need to be doing this?"

You might not know this, but once the Discovery launches, if it's unable to land back in Florida because of bad weather--like a hurricane--Hunter Army Airfield is a prime alternative for an emergency landing.

Reported by: Nicole Teigen,