Air Force Weather Satellite’s Breakup Blamed on Wiring Harness Compression in Battery Charge Assembly

DMSP Air Force weather satellite is depicted in polar orbit near Alaska. Photo Credit: Lockheed Martin

DMSP Air Force weather satellite is depicted in polar orbit near Alaska. Image Credit: Lockheed Martin

A U.S. Air Force review into the Feb. 3 loss of Defense Meteorological Satellite Program (DMSP) Flight 13 determined a failure of the spacecraft’s battery charger as the likely cause of the satellite’s failure and structural breakup.

Analysis indicates one of the satellite’s wiring harnesses in the battery charge assembly lost functionality due to compression over a long period of time. Once the harness was compromised, exposed wires potentially caused a short in the battery power, leading to an overcharge situation with eventual rupture of the satellite’s two batteries.

The Air Force declined to reveal the breakup until amateur trackers discovered the debris cloud.

This is the second aging DMSP to breakup in orbit. In April 2004, the 13-year-old fully retired DMSP-11 broke into 56 pieces of debris. Investigators believe that breakup was also caused by a battery wiring failure.

The latest failure analysis was conducted by the 50th Space Wing at Schriever AFB, Colo. The 12-foot-long (3.7-m) spacecraft weighed 1,832 lbs (831 kg) and cost $500 million.

DMSP Defense Meteorological Satellite undergoes inspection prior to launch. Photo Credit: Lockheed Martin

DMSP Defense Meteorological Satellite undergoes inspection prior to launch. Photo Credit: Lockheed Martin

The satellite was orbiting near Antarctica when a joint team of ground controllers with the Air Force and National Oceanic and Atmospheric Administration (NOAA) in Suitland, Md., noted a sudden temperature spike in the satellite’s electrical subsystem, followed by an unrecoverable loss of attitude control.

Currently, the Joint Space Operations Center at Vandenberg Air Force Base, Calif., is tracking 147 pieces of debris from this incident, ranging from baseball- to basketball-sized objects. There are approximately 110 payloads in the same orbital regime as DMSP Flight 13 at 515 miles (830 km). The JSpOC has had no reportable conjunctions between the DMSP Flight 13 debris and any of these objects.

“In accordance with our ongoing efforts to protect the space domain, the JSpOC will continue to monitor this debris along with all of the items in the space catalog in order to enhance the long-term sustainability, safety and security of the space environment,” said Col. John Giles, JSpOC director.

The review determined there were no actions that could have been taken to prevent the incident. The mission is operated by NOAA on behalf of the Air Force.

More than two decades ago, the design of the battery charger made it very difficult to assemble, and the entire block of Lockheed Martin 5D-2 Battery Chargers are potentially susceptible to this short circuit failure over time, despite a functional history within the design life.

The assembly is common to nine DMSP satellites, Flight 6 through Flight 14. While only one of these satellites, DMSP Flight 14, remains operational, six remain in orbit and analysis has shown that the risk of potential short circuit remains even after a satellite is permanently shut down.

“While there are no indications of an issue with the battery charge assembly housing on DMSP Flight 14, the results of the DMSP Flight 13 review coupled with ongoing technical analysis will be included in our routine constellation sustainment planning process moving forward,” said Col. Dennis Bythewood, 50th Operations Group commander.

“Our team took quick action to identify the anomaly and to mitigate its impact,” said Bythewood. “Everyone worked well together to address this incident. We are grateful to all of our partners, to include active duty and Reserve Airmen, government civilians, NOAA operators and Lockheed Martin, Aerospace Corp, Harris Corp and Northrop Grumman contractors, in supporting the immediate actions as well as the review that followed this incident.”

The DMSPs are used to cue imaging reconnaissance spacecraft operators to cloud-free areas and to provide units like SEAL teams with critical weather information, even for small landing zones. Along with NOAA polar orbiters, the DMSPs also provide extremely detailed data on hurricane intensity and ground tracks.

DMSP Flight 13 was originally launched from Vandenberg AFB, Calif., into polar orbit on March 24, 1995. Despite its original four-year design life, Flight 13 provided service for almost two decades and on Aug. 6, 2014, became the first operational DMSP satellite to reach 100,000 revolutions around the Earth. The satellite was built by General Electric’s Astro Space Div., later acquired by Lockheed Martin.

“Due to an earlier loss of recording capability and the launch of more modern DMSP satellites, Flight 13 transitioned from a primary mission satellite to a residual satellite in 2006,” said the Air Force. It said that “DMSP Flight 13 provided critical atmospheric data for flight operations in OPERATION ALLIED FORCE, OPERATION ENDURING FREEDOM and OPERATION IRAQI FREEDOM. During its lifetime, DMSP Flight 13 also provided thousands of hours of weather imagery to the Air Force Weather Agency and the U.S. Navy’s Fleet Numerical Meteorology and Oceanography Center.”

 

Be sure to “Like” AmericaSpace on Facebook and follow us on Twitter: @AmericaSpace

2 comments to Air Force Weather Satellite’s Breakup Blamed on Wiring Harness Compression in Battery Charge Assembly