The WIRE Mishap Investigation Board found that the design of the instrument's electronics box did not take into account subtle, but known, start-up characteristics of one component within the box. Electrical power created at the start-up of this component reached explosive devices, called pyrotechnics, meant to eject the telescope's cover later in the mission. The power reached the pyrotechnics within a fraction of a second after the box was turned on, and the cover was ejected.

With the premature loss of the telescope's cover, the frozen hydrogen used to cool the telescope's sensitive infrared detectors was exposed to the Sun. As the telescope warmed, the hydrogen converted into a gas and vented entirely into space within 48 hours of launch. Without the frozen hydrogen, the instrument could not conduct its scientific mission.

"There was no component failure," said Darrell Branscome, chairman of the eight-member WIRE Mishap Board and Deputy Associate Administrator (Enterprise Development) for NASA's Office of Space Flight, Washington, DC. "This was simply a case of a design error that allowed power to get to the explosive charges before it should have. The system operated the way it was designed. Unfortunately, the design was flawed."

The report added that simulators and other support equipment used for design and verification tests lacked the fidelity required to detect this potential failure.

"A significant contributing cause of the anomaly was the failure to identify, understand, and correct the electronic design of the pyro electronics box," the report said. "Design errors in the circuitry, which controlled pyro functions, were not identified. The pyro electronics box design was not peer reviewed, and other system reviews conducted by the instrument design team did not focus on the electronics box."

WIRE was launched from Vandenberg Air Force Base, CA, March 4 aboard a Pegasus XL launch vehicle. WIRE's mission was to detect infrared light in the background cosmos to learn more about the formation of stars, galaxies and the current state of the universe.

NASA has already taken additional steps to ensure that design engineers are aware of this condition. A NASA Parts Advisory was issued on May 27 at the request of the Mishap Board informing design engineers of the need to consider the startup behavior of electronic devices to prevent unwanted or unexpected power discharges.

The team's report also included recommendations for future spacecraft designers. These include the use of independent, separate inhibiting devices for pyrotechnics for mission-critical or irreversible events; additional testing for anomalous start-up behavior; detailed, independent reviews to assess the system design; and consideration of the design, location and mounting of external vent hardware in the event of a worst-case venting scenario.

The WIRE spacecraft is now in a stable orbit with its other systems and electronics in good working order. Ground controllers will proceed with tests on new flight-control technology aboard the spacecraft.

The WIRE mission was the latest in a series of Small Explorers, a project under the Explorers Program managed by NASA's Goddard Space Flight Center, Greenbelt, MD. Goddard also built the WIRE spacecraft. The Jet Propulsion Laboratory, Pasadena, CA, managed development of the WIRE instrument, which was constructed by the Space Dynamics Laboratory at Utah State University, North Logan, Utah.

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