Fuel Leak Delays Final Discovery Shuttle Launch, Again

Photo credit: NASA

The final launch of space shuttle Discovery was scrubbed for the fourth time in as many days Friday, raising questions among some space watchers on when old becomes too old.

Two hours into fueling NASA’s longest flying shuttle, engineers found a hydrogen gas leak near an external fuel tank, and opted to postpone the launch to no earlier than Nov. 30. Later in the day, NASA found a crack in the foam of the external tank. Poor weather conditions and problems with a circuit breaker prompted the earlier delays.

“What you worry about in an old system is that these are like cars that have been sitting in a salt-air environment for 20 years, and no one knows what weaknesses might exist in the framework…,” said Howard McCurdy, a space historian and professor at American University. “You can replace a lot of things like brakes, the main engine, the turbine blades, but the air frame itself is old.”

McCurdy is quick to add that he’s never seen any evidence that the shuttle’s problems have increased with age. “It’s just there are too many parts that have to function within tight parameters, and they don’t always do that.”

Allard Beutel, a NASA spokesperson, said that the recent delays were not related to age, but to problems with a fairly new external fuel tank. “Yes, we’re talking about an air frame that is obviously 25-plus years old. And while absolutely you’ve got to pay attention to age, fatigue, and wear and tear, what we’re looking at are not issues of wear and tear. Unfortunately, these were coincidental issues that piled up all on top of us. The hardware wasn’t ready to fly today; the weather wasn’t ready yesterday.”

The leak was found in a fixture connected to a line that carries gaseous hydrogen from the shuttle to a flare stack away from the launch pad, where it then gets burned off. Similar leaks have occurred twice in the last year.

“They’ve got several weeks now to look at the problem and correct it,” said NASA’s Kyle Herring. “The managers determined that the team should take more time, put together a corrective plan and put that into action without trying to rush to get to a Monday launch attempt.”

The 27-year-old orbiter’s age shows in the black stains and rubbed out paint along its frame. The workhorse of the shuttle fleet, Discovery has carried more crew members to orbit and flown more missions than any other shuttle. It has traveled 142 million miles. It launched the Hubble Space Telescope, three communications satellites and former Utah Senator Jake Garn.

And it was the first to return to orbit after both the Challenger and Columbia disasters, inspiring a campaign of support.

“It really looks like a space ship that’s come back and been burned in the process,” McCurdy said. “It looks like it’s been to outer space… it’s scarred.”

Discovery’s next liftoff will mark its 39th and final mission, and will bring NASA’s shuttle fleet closer to its 2011 retirement. For its final mission, Discovery will haul spare parts and a humanoid robot to the International Space Station.