America's space shuttle fleet has been grounded until engineers can correct a hydrogen leak that has been found on a second spacecraft, officials said today.
The announcement came after engineers conducted a leak check on Atlantis, which is on the launch pad awaiting a planned mid-July launch.
The test, involving pumping up to 200,000 gallons of liquid hydrogen into Atlantis' giant external tank, was intended "to establish confidence in the hardware," NASA spokeswoman Lisa Malone said.
Malone said a concentration of hydrogen was found near a four-inch disconnect valve in the area of a 17-inch-diameter valve, the same type that appeared responsible for the leak that grounded Columbia.
Before the leak was discovered, NASA had hoped to launch Atlantis on a secret military mission in mid-July.