July 21, 2015 – Officials from the 50th Space Wing have completed their operations review of the Defense Meteorological Satellite Program Flight 13 that was permanently shut down February 3, 2015, precipitating a debris-causing event. The review determined there were no actions that could have been taken to prevent the incident. The mission is operated by the National Oceanic and Atmospheric Administration on behalf of the U.S. Air Force.
The review into the unexpected loss of this satellite determined a failure of the battery charger as the likely cause. Analysis indicates one of the wiring harnesses lost functionality due to compression over a long period of time in the battery charge assembly. Once the harness was compromised, the exposed wires potentially caused a short in the battery power, leading to an overcharge situation with eventual rupture of the batteries.
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.”
Currently, the Joint Space Operations Center at Vandenberg Air Force Base, California, is tracking 147 pieces of debris from this incident ranging from baseball to basketball-sized objects, where the original satellite was about the size of a one-car garage. There are approximately 110 payloads in the same orbital regime as DMSP Flight 13 (Perigee height of >300km, < 1200Km). 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.
DMSP Flight 13 was originally launched on March 24, 1995. Despite its original four-year design life, Flight 13 provided service for almost two decades and on August 6, 2014 became the first operational DMSP satellite to reach 100,000 revolutions around the Earth.