Space Shuttle managers now say the launch of NASA's Space Shuttle Return to Flight mission, STS-114, will take place no earlier than late next week. At 1 p.m. EDT today, managers officially stopped the current launch countdown for Space Shuttle Discovery at Kennedy Space Center, Fla. Space Shuttle managers are optimistic that Discovery can lift off by July 31, the end of this launch window.

This weekend, managers and engineers will continue troubleshooting the problem with a liquid hydrogen low-level fuel sensor inside the External Tank. The sensor failed a routine prelaunch check during the launch countdown Wednesday, causing mission managers to postpone Discovery's first launch attempt. A dozen teams, with hundreds of engineers across the country, are working on the issue.

Once the problem is resolved and the countdown can be restarted, it will take about four days to launch. A countdown from this point will be a complete start over at T-43 (time minus 43) hours. Currently, there are no plans to roll Discovery back from the launch pad.

For now, Commander Eileen Collins and her six Discovery crew mates will stay at Kennedy Space Center while engineers work on the solution.

The next media update from Space Shuttle managers is planned for Monday. For any developments over the weekend, media can call for a recorded message at 321/867-2525.

For the latest information about the STS-114 mission, visit:

http://www.nasa.gov/returntoflight