NASA will attempt to launch the Space Shuttle Return to Flight mission (STS-114) no earlier than 2:40 p.m. EDT, Saturday, July 16. Discovery’s liftoff today from NASA’s Kennedy Space Center, Fla. was postponed at 1:30 p.m. EDT. During countdown activities, a low-level fuel cut-off sensor inside the External Tank (ET) failed a routine pre-launch check. The sensor protects a Shuttle’s main engines by triggering their shut down if fuel runs unexpectedly low. The sensor is one of four inside the liquid hydrogen section of the ET. The ET’s liquid oxygen and liquid hydrogen were drained this evening. While the tank was being emptied, engineers monitored and collected data on the failed liquid hydrogen sensor. They will continue to collect and analyze data overnight.

Space Shuttle Program managers plan a series of meetings tomorrow to discuss the problem and determine the steps necessary to get back into the launch countdown. The STS-114 crew will remain at Kennedy while engineers work on the problem. During their 12-day Return to Flight mission to the International Space Station, Discovery’s seven crew members will test new techniques and equipment designed to make Space Shuttles safer. They’ll also deliver supplies and make repairs to the Space Station.

View: Full Article | Source: NASA Press Release

they need to hurry and retire that thing lol

The shuttles are aging, they do need to offer a competition for a new space ride. Perhaps something along the lines of the old Apollo rockets.

If I remember correctly this is a New, Modified Tank put on after the older one's new heating system( to prevent Ice Build up) did not work properly. There is nothing wrong with the shuttle( that we know of). Previous flights had gone up with simular problems, but the powers that be don't want ANY THING to be blamed on them in case of trouble after launch. I don't blame them!

I think they have known that. They said that this is 'The Beggining to the End' of shuttles. I think by 2010 they will have advanced in Space Techonology...I can't recall, probably better space vehicles or space colonization starting with the moon.

My source is CNN when I was watching TV

^Go to SpaceFlightNews.com, that has a massive amount of information on the next geberation space vechiles and the two competing companies hoping to build it for Nasa. It should be around by 2010 as you mentioned!

I have not seen any up dates on the Atlantis Shuttle Preparations. How close is that Shuttle to Launch Ready Status?

I stand corrected. It seems the problem is not the tank sending unit, but more than likely the box that translates the sensor reading to the Ships Computer. That or the wiring of the discovery it's self.

They said in the report they have a replacement box, but it have some voltage problems. Sounds like a Mechanics Nightmare!