Workers removing the Ground Umbilical Carrier Plate on the shuttle external fuel tank. Image credit: NASA/Jack Pfaller

The hydrogen leak keeping the shuttle Endeavour  and STS-127  on the ground was determined to be a misalignment in a couple of plates on the External tank.  On June 24, the plates were removed and the problems were thought to be corrected.  The only way to be sure is to refill the External tank.  I had a couple of comments a while back wondering why the leaks could not be found before, and the answer has to do with the fact the tank has to be nearly full inorder for the vent valve to cycle.

This morning the “fix” was put to the test and by all accounts everything looks good.  While more details will be forthcoming the early press release is very positive.  Looks like STS-127 is ready to fly!

Here’s the press release:

Space shuttle Endeavour’s tanking test officially began at 6:52 a.m. EDT at NASA’s Kennedy Space Center in Florida. No abnormal gaseous hydrogen leaks were detected during the test, which involved filling Endeavour’s external fuel tank with liquid hydrogen and liquid oxygen just as it is on launch day.

At about 9 a.m., the liquid hydrogen tank was 98 percent full and the “topping” mode began. A vent valve at the top of the hydrogen tank began cycling, as planned, to disperse excess gaseous Hydrogen through a vent system that carries it safely away from the launch pad. At that point during two June launch attempts, a gaseous hydrogen leak was detected outside the Ground Umbilical Carrier Plate, or GUCP, where the vent line is attached.

NASA Television will air a news conference at 1 p.m. with Space Shuttle Program Launch Integration Manager Mike Moses and STS-127 Launch Director Pete Nickolenko. Watch it live at http://www.nasa.gov/ntv