Cracks discovered in Orion capsule's pressure shell
BY STEPHEN CLARK
Posted: November 23, 2012
Three cracks appeared in NASA's first space-bound Orion crew exploration vehicle during a proof pressure test this month, according to agency officials, but the anomaly and anticipated repairs are not expected to impact the schedule for the capsule's first orbital test flight in late 2014.
"The cracks are in three adjacent, radial ribs of this integrally machined, aluminum bulkhead," Buck said. "The cracks did not penetrate the pressure vessel skin, and the structure was holding pressure after the anomaly occurred."
Engineers will scan the cracks with an electron microscope to investigate the cause, said Bill Gerstenmaier, associate administrator of NASA's human exploration and operations mission directorate, in a presentation to a NASA Advisory Council subcommittee.
According to Buck, "the intent is diagnose root cause and repair the cracks in time to support a second scheduled window for loads testing early next year."
Since the Orion spacecraft's pressure vessel arrived at Kennedy Space Center in late June, technicians have continued assembly of the crew module and finished the first proof pressure test, which was designed to validate engineering models and verify the Orion pressure shell's structural integrity.
Cracks have occurred during pressure tests of other spacecraft, including a Russian Soyuz capsule's descent module, which was damaged in a prelaunch test in January. Russia scrapped the module and delayed the launch of three space station astronauts until a replacement was ready.
The schedule calls for installation of Orion's attitude control thrusters, parachutes, avionics and heat shield in the first half of 2013 before the crew capsule is attached to a mock-up service module.
Lockheed Martin Corp., the Orion capsule's prime contractor, is in charge of the 2014 mission, known as Exploration Flight Test-1. The company will oversee the flight in partnership with NASA, which will receive post-flight data.
A United Launch Alliance Delta 4-Heavy rocket will launch the capsule from Cape Canaveral Air Force Station, Fla., into an elliptical orbit reaching 3,600 miles above Earth. From there, the the Orion will dive back into Earth's atmosphere at more than 20,000 mph, giving engineers key data on how the spacecraft responds to a re-entry at speeds nearly replicating what the capsule will see when returning from deep space missions to the moon, asteroids and other destinations.
After splashdown in the Pacific Ocean, crews will recover the Orion crew vehicle and outfit the capsule for an ascent abort test.
NASA's Space Launch System, a heavy-lift rocket derived from the space shuttle, will launch the second Orion space mission in late 2017 on a flyby around the moon.
The first Orion mission with astronauts is set to fly on the second Space Launch System flight in 2021 to a high-altitude orbit around the moon.