NASA officials are delaying the launch of space shuttle Discovery after engineers discovered a hydrogen leak.
Officials moved to delay the launch to give engineers time to fix a liquid hydrogen leak in the vent line between the shuttle and its external fuel tank. They say the problem was discovered as the launch team was filling the external tank ahead of the Wednesday evening launch.
The Discovery mission already is running a month late because engineers needed to resolve problems with hydrogen gas valves in the shuttle's main engines. Officials say they replaced the valves, and the new leak is unrelated.
Discovery is set to deliver a solar array and a truss to advance construction work on the International Space Station.
Deputy program manager for the station, Kirk Shireman, says the U.S.-built components are important to expanding the station's capacity.
"We are really looking forward to have that power-generating capability and completing the truss on the ISS [International Space Station]," said Kirk Shireman.
The shuttle's seven-member crew includes two science teachers who have spent the past five years in training for their space flight. The men will take part in multiple space walks to help install the new equipment on the station.
Discovery also will be carrying into space Japanese astronaut Koichi Wakata, who will live aboard the station for several months. He replaces Sandy Magnus who arrived at the station four months ago.