Cape Canaveral - Nasa is delaying next week's planned launch of space shuttle Discovery on a cargo delivery run to the International Space Station until at least mid-December, officials said on Wednesday.
The extra time is needed for engineers to understand why two metal support structures on the shuttle's fuel tank cracked while Discovery was being filled with liquid oxygen and liquid hydrogen for a launch attempt, since scrapped, on November 5.
“This is turning out to be a little more complicated from an analysis standpoint,” Nasa's associate administrator Bill Gerstenmaier told reporters. Engineers are trying to figure out if a manufacturing flaw or some other problem is behind the defective equipment or if there are other unknown hazards.
The fissures in Discovery's tank led to a 20-inch crack in the tank's foam insulation, which could have posed a debris hazard during launch.
The shuttle Columbia was destroyed in 2003 due to damage from a piece of foam insulation that fell off during launch. Seven astronauts were killed when the ship broke apart as it attempted to return to Earth for landing.
Nasa called off its November 5 launch attempt of Discovery due to a hydrogen fuel leak, but it would not have flown in any case once engineers spotted the foam crack, said shuttle programme manager John Shannon.
The cracks and hydrogen leak have been repaired, but Nasa will not fly until managers better understand the risks.
“We have an unknown here: How did something get through our processes and get to the launch pad and do you have the susceptibility to have another one appear?” Shannon said.
The next opportunity to fly would be December 17, but “a lot of data has to come together to support that,” Shannon said.
The shuttle is carrying a storage room, a prototype robot and spare parts needed to fix the space station's water recycling system and other equipment.
The mission, slated to last 11 days, is among the final flights of the space shuttle fleet, which is being retired next year due to high operating costs and a shift in the US human space programme to develop vehicles capable of flying astronauts into deep space.
The station, a $100-billion project of 16 nations, has been under construction 350km above Earth since 1998.
The delay in the shuttle launch clears Space Exploration Technologies to move ahead with a test flight of a commercially developed station cargo capsule.
Launch of the company's Falcon 9 rocket with a Dragon capsule is targeted for December 7 from Cape Canaveral Air Force Station, adjacent to Nasa’s Kennedy Space Centre. - Reuters