Chances for favorable weather for liftoff were 60 percent Monday morning, reports CBS News Correspondent Peter King.
"The teams are ready. We're certainly very eager. We are anticipating and really look forward to a launch," said NASA Test Director Pete Nickelencko.
If the shuttle Discovery launches as planned today, CBS News will have live television coverage beginning at 10:30 a.m. ET. CBSNews.com will also have a live Webcast of the launch and preparations all morning.
NASA workers rewired some of the sensors and made other electrical repairs after the failure forced the space agency to postpone the shuttle's launch while astronauts were boarding Discovery on July 13.
The space agency's own launch rule — in place since the 1986 Challenger disaster — requires that all four hydrogen fuel gauges in the external tank be working properly, though only two are actually needed.
Engineers still do not fully understand the reason for the failure. But NASA will go ahead with the rescheduled launch at 10:39 a.m. Tuesday if the problem doesn't recur or if it is found only in the two sensors that have been rewired, Wayne Hale, deputy manager of the shuttle program, said Sunday.
"If the problem recurs ... we're going to do some more tests just to make sure we understand what is causing this to happen and if we're comfortable that we have a good understanding, then we can go fly," Hale said.
It will be the first shuttle flight since the Columbia disaster 2½ years ago.
NASA Administrator Michael Griffin said he is comfortable with the decision and even hopes the problem recurs to help pinpoint the source of the trouble. He acknowledged that the public might perceive that the space agency is rushing to launch, but insisted it was the right technical judgment.
"It's not a safety-of-flight issue," Griffin said.
Although the focus of NASA's attention has been on the sensor, rain and clouds may end up causing more concern on launch day. Additionally, the weather at the overseas emergency landing sites is not looking good.
First lady Laura Bush, already in Florida on a previously scheduled trip, planned to watch the shuttle launch Tuesday, reports CBS News Correspondent Mark Knoller.
Best-selling author Mitch Albom on his first nonfiction work since "Tuesdays with Morrie."
