Interesting fact of the day(GPS)
 

Unlike Galileo satellites GPS satellites have "anti-radiation shielding to protect against nuclear attacks in space, as well as other military requirements such as the ability to immediately detect, pinpoint and report atomic weapons test explosions anywhere on earth." Because of this extra weight, four of Galileo's satellites can be launched in a single rocket compared to a single GPS space vehicle."

And the source of this piece of.... interesting information is?

Aviation International News. November 2006. Page 98. They are online at www.ainonline.com

Here is the article. Magazine subscription is free.

http://www.ainonline.com/Issues/11_06/11_06_GPS_98.htm