Science News

The US space shuttle Endeavour has apparently cleared a test for potentially harmful hydrogen gas leaks that had twice delayed its high-profile launch, NASA said Wednesday.

The massive tank was filled with 526,000 gallons (two million liters) of liquid hydrogen (80 percent) and liquid oxygen (20 percent), as takes place on the launch day.

Engineers from the US space agency seemed to have successfully repaired the external fuel tank of the shuttle, which is waiting to embark on its final mission to the International Space Station with a seven-member crew.

NASA officials were set to provide details on the new launch date and the test results later Wednesday.

During the test, which began shortly before 7:00 am (1100 GMT) “no abnormal gaseous hydrogen leaks were detected,” NASA said, which increases chances that Endeavour will be set for a launch on July 11 at 2339 GMT.

NASA has said a misaligned plate linking the hydrogen gas vent line with the external fuel tank had caused the leak, which was first detected during fueling.

After the tank was 98 percent full, it successfully began its “topping” mode, during which the June 13 and June 17 leaks had occurred, where a valve at the top of the tank cycled to disperse excess gaseous hydrogen through a vent system that carries it safely away from the launch pad.

It is the last of three missions to assemble the Japanese Kibo laboratory aboard the orbiting space station.

Endeavour is set to travel on a 16-day voyage to install a platform on the ISS, allowing astronauts to conduct experiments in the vacuum of space, 350 kilometers (220 miles) above Earths surface.

The race is on to finish construction before NASA ends its shuttle missions in September 2010.