Fwd: Air Force: Six More DMSP Satellites Susceptible to Battery Ruptures

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From: "Gary Johnson" <gjohnson144@comcast.net>
Date: July 21, 2015 at 10:06:30 PM CDT
To: "Gary Johnson" <gjohnson144@comcast.net>
Subject: FW: Air Force: Six More DMSP Satellites Susceptible to Battery Ruptures

 

 

Air Force: Six More DMSP Satellites Susceptible to Battery Ruptures

by Brian Berger and Mike Gruss — July 20, 2015

DMSP-F13 was one nine DMSP Block 5D-2 satellites Lockheed Martin built and launched for the U.S. Air Force between 1982 and 1997. Credit: U.S. Air Force/SpaceNews

WASHINGTON — The U.S. Air Force said July 20 it still has six Defense Meteorological Satellite Program spacecraft in orbit that are susceptible to the kind of explosive battery rupture DMSP-F13 experienced in February, producing a large cloud of orbital debris.

Of those six, only one — DMSP-F14 — is still in service. But all six have the same kind of battery charger an Air Force review identified as the likely cause of the DMSP-F13 incident.

"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 Air Force's 50th Space Wing said in a statement. "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."

DMSP-14 launched in April 1997. The satellite's recorder failed in 2008, preventing it from providing global data. Its microwave temperature and humidity sensors are also no longer operational, according to a World Meteorological Organization registry.

"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,"  Col. Dennis Bythewood, commander of the 50th Operations Group, said in a statement

In an interview with SpaceNews, Bythewood said the battery charge assembly used on DMSP-F6 through F14, has "an inherent design flaw."

The failure review, which included input from DMSP prime contractor Lockheed Martin, concluded there were no actions DMSP-F13's operators could have taken to have prevented the incident. Swift action to safe the vehicle after operators noticed spiking battery temperatures, the Air Force said, prevented "what could have been a much greater debris event."

Still, when one of  the batteries ruptured onboard the 20-year-old DMSP-F13 weather satellite, it ruptured with enough force to produce a field of debris analysts say is likely to remain in orbit for decades.

The Air Force's Joint Space Operations Center at Vandenberg Air Force Base, California, is tracking 147 pieces of debris from the DMSP-F13 incident ranging from baseball to basketball-sized objects, according to the service's July 20 statement.

The Air Force said approximately 110 payloads are in the same general vicinity as DMSP-F13, whose elliptical orbit took it as high as 1,200 kilometers and as low as 300 kilometers.

The semi-retired satellite had been providing U.S. Navy ship and shore receivers and other tactical military users with real-time cloud-cover imagery up until the Feb. 3 incident, but the National Weather Service and Air Force and Navy meteorologists had already long since ceased incorporating DMSP-F13 data into weather forecasting models.

So far, the Air Force said, there have been "no reportable conjunctions" between the DMSP-F13 debris and any of its orbital neighbors.

"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," Col. John Giles, JSpOC director, said in the statement.

As for what caused DMSP-F13's battery to overheat and rupture, the Air Force concluded that 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," the Air Force said.

The Air Force detailed the Feb. 3 incident, and its subsequent investigation, in a lightly redacted 12-page report released July 20 but dated March 31.

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