The hydrogen vent line attached to the Ground Umbilical Carrier Plate on space shuttle Discovery's fuel tank.

Seen in the photo is the hydrogen vent line attached to the Ground Umbilical Carrier Plate on space shuttle Discovery's external fuel tank. The shuttle is on Launch Pad 39A at NASA's Kennedy Space Center in Florida. A leak of hydrogen at the location during tanking caused the STS-119 mission to be scrubbed at 2:36 p.m. March 11. The vent line is at the intertank and is the overboard vent to the pad and the flare stack where the vented hydrogen is burned off. Mission management teams believe they have sufficient understanding of the repair plan to continue toward a March 15 launch at 7:43 p.m. EDT. Photo courtesy of United Space Alliance