Heres the money quote:
"GPS satellites carry a set of nuclear detonation detectors consisting of an optical sensor (Y-sensor), an X-ray sensor, a dosimeter, and an electromagnetic pulse (EMP) sensor (W-sensor), that form a major portion of the United States Nuclear Detonation Detection System.[76][77] General William Shelton has stated that this feature may be dropped from future satellites in order to save money.[78]
back
1 comments
Some also carry bhangmeters - devices for detecting nuclear explosions named after a variety of cannabis!
http://en.wikipedia.org/wiki/Bhangmeter
"the joke being that one would have to be on drugs to believe the bhangmeter detectors would work properly"
Can't believe I've missed the only opportunity to mention bhangmeters - indeed a fun fact.