Lockheed Examining Sats For Contamination

SUNNYVALE, Calif. — Lockheed Martin officials are confident the suspected cause of a liquid apogee engine failure on the first Advanced Extremely High Frequency (AEHF) satellite — the introduction of foreign object debris (FOD) in the manufacturing process — will not pose a problem for other satellites built on the A2100 bus.

The company has been conducting “exoneration” exercises for other A2100-based satellites in various stages of manufacturing, including the U.S. Navy’s Mobile User Objective System, the Space-Based Infrared System (Sbirs) series, other AEHF spacecraft, and the Japanese Broadcasting Satellite Corporation System series, says Kevin Bilger, vice president of global communications for Lockheed Martin Space Systems here. These satellites are worth billions of dollars and took years to build.

The exoneration exercises are required to ensure that FOD was not introduced into the fuel or oxidizer lines for the propulsion systems of these satellites during manufacturing.

FOD in the oxidizer line is thought to have caused the failure of the liquid apogee engine (LAE), made by IHI Aerospace, on the first AEHF satellite shortly after launch Aug. 14, according to Bilger. “We have most probable cause as FOD,” he says. “In our business, you never have a smoking gun, but we have been able to replicate what we think the most probable cause is in the laboratory.”

AEHF is estimated to have cost the government more than $2 billion. Though the LAE failed, operators are using two of four onboard Hall Current Thrusters to slowly raise the perigee of the satellite. It is slated to reach orbit in the summer, months later than planned (Aerospace DAILY, Aug. 31, 2010).

The propulsion system for AEHF-1 was built at Lockheed Martin’s facility at the John C. Stennis Space Center in Mississippi in 2006. “During the manufacturing process, somehow [FOD] was introduced,” Bilger says. “The only known enemy to satellites is man. So, the longer you have them on the ground, the more opportunities there are for errors.” AEHF had a long buildup time owing to development issues and delayed delivery of encryption equipment from the National Security Agency.

Though the various A2100-based satellites share a similar core propulsion system, they do not all have the electric Hall Current Thrusters that are now raising AEHF-1’s orbit. This underscores the need to eliminate the risk of an FOD problem because not all models have other onboard resources for propulsion.

First to go through the exercise was the initial Sbirs satellite, GEO-1, which is slated for launch April 30. Lockheed Martin officials are now focusing on AEHF-2.

In each case, officials examine X-ray films taken of the propulsion system, including fuel lines, and all of the paperwork generated in the satellite manufacturing process. “As a result of our review, we made changes in our process,” Bilger says.

In the summer, Lockheed Martin will pressurize and test the fuel and oxidizer lines on AEHF-2 to validate their confidence that FOD is not present. “The actual test is not that long,” Bilger says. “But it is the test setup, it is the monitoring — getting all of the equipment and the electronics in place — and then looking at that data itself” that will require some time. AEHF-2 is slated for launch Jan. 30, 2012.