Artist’s concept of a Defense Meteorological Satellite System (DMSP) military weather spacecraft.
Excerpt from nbcnews.com
The military weather satellite that exploded in orbit last month apparently died of old age, U.S. Air Force officials say. 
While investigators continue to study the dramatic Feb. 3 death of Defense Meteorological Satellite Program Flight 13 (DMSP-F13), the signs currently point not to a collision with a piece of space junk or other external cause but rather to an issue aboard the spacecraft, which launched in 1995. 
“Basically, the spacecraft was 20 years old and experienced what appears to be a catastrophic event associated with a power system failure,” Andy Roake, chief of the Current Operations Division at Air Force Space Command Public Affairs in Colorado Springs, told Space.com. 
 
Investigators think that failure by itself probably blew apart DMSP-F13 — which occupied a sun-synchronous polar orbit about 500 miles (800 kilometers) above Earth — generating the cloud of debris that the Air Force’s Joint Space Operations Center (JSpOC) has detected near the satellite. (To date, 43 pieces of debris have been identified.) 
Indeed, Air Force officials have said that the military weather satellite explosion was preceded by a sudden spike in the power system’s temperature, “followed by an unrecoverable loss of attitude control.” It was first reported by SpaceNews, a Space.com partner, on Feb. 27. 
DMSP-F13 launched in March 1995 and last year surpassed 100,000 orbits around Earth. The satellite contributed key data to a number of U.S. military operations overseas.