Officials say a dozen troubleshooting teams across the country have begun the process of tracking down why a fuel sensor gave controllers false readings just before a scheduled launch Wednesday. The sensor indicates how much liquid hydrogen is inside the shuttle's external fuel tank. Deputy Shuttle Manager Wayne Hale says engineers will first try a low-tech approach. "The repair that might get us to Sunday is if we go in and wiggle some of the wires and find a loose connection. I mean, that's the one that comes to mind," says Hale. "You laugh, that probably is the first first step in any troubleshooting plan is they're going to go in and some technician is going to put his hands on the wires and the connectors that go from the point sensor box out of the orbitor and start wiggling them."
Officials say the fuel gauge now appears to be working after the main fuel tank was drained, which presents an even bigger problem for engineers, who will have to access the situation without the sensor in its faulty mode. Hale expects most of the work to happen on the launch pad, but that could easily change.
Director of Shuttle processing Mike Wetmore says if the troubleshooting process takes more than a few days, the seven astronauts will likely be brought back to Houston while the repairs take place. "Early next week is the breakpoint at which we need to get out of the countdown procedure and get everybody some crew rest and we'll be ready to support the next countdown as soon as the eco-sensor system is ready to go," says Wetmore.
The launch window for Discovery closes at the end of this month, with the next opportunity for a daytime launch sometime in September.