Preventative Work

The Air Force is addressing issues that arose this past summer with its two evolved expendable launch vehicles before it will launch them again, Gary Payton, USAF’s deputy under secretary for space programs, said last week. Speaking to reporters at a Space Foundation-sponsored discussion in Washington, D.C., Payton said the Russian-designed RD-180 engine that is used on the Atlas V rocket experienced “an uncommanded actuator anomaly” in one instance, meaning that the actuator moved even though the rocket’s guidance system did not tell it to. “You don’t like that to happen,” he said. In the case of the Delta IV booster, the contractor that has been performing vibration tests on the launch vehicle’s components discovered that its test equipment had not been calibrated correctly for the past several years, Payton said. This means that there are parts in the rocket’s supply chain that may not have been adequately tested. They will be retested “before we launch a rocket with one of those questionable piece parts,” he said. So far, Payton said, these corrective efforts are not affecting the schedules of the next Delta IV and Atlas V launches. The schedule currently calls for a Delta IV heavy rocket to lift a classified intelligence satellite into space at the end of next month and an Atlas V to carry the next Wideband Global Satcom satellite into orbit in November. But the Air Force wants the issues resolved “before we launch anything else,” he said. United Launch Alliance, the Boeing-Lockheed Martin joint venture, supplies these rockets. In the case of the RD-180, the Air Force thinks it has the fix in place, he said.