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.

Photo of one of three cracks on radial ribs on Orion's aft bulkhead. Credit: NASA
 
The cracks materialized in the aft bulkhead on the lower half of the Orion multipurpose crew vehicle during a proof pressure test at NASA's Kennedy Space Center in mid-November, according to Joshua Buck, a NASA spokesperson.

"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.

The Orion pressure shell enters a chamber for pressure testing at NASA's Kennedy Space Center in Florida. Credit: NASA/Ben Smegelsky
 
During the proof pressure test, engineers pumped air into the crew module to check the structure's ability to hold pressure against the ambient atmosphere at sea level. The test simulates what the spacecraft will see in space, when it must hold pressure against a vacuum.

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.

Artist's concept of the Orion spacecraft and the Delta 4 rocket's upper stage on the EFT-1 flight test. Credit: NASA
 
The uncrewed multi-hour flight is scheduled to launch in September 2014, and Buck said NASA does not expect the crack issue to affect the launch date, which is driven by the availability of Orion's Delta 4 launcher in ULA's manifest, according to NASA officials. NASA and Lockheed Martin aim to have the Orion crew vehicle and a structural mock-up of its service module ready for launch operations by December 2013.

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.