Here is a link to a very interesting article about one of the oldest and longest running GPS satellites.
http://www.spacedaily.com/reports/GPS_Satellite_Achieves_20_Years_On_Orb... [1]
73/Drew VE3MAF
Links
[1] http://www.spacedaily.com/reports/GPS_Satellite_Achieves_20_Years_On_Orbit_999.html
[2] http://www.ve3nbc.ca/category/newsletter/nbarc-news