Vanguard I celebrates 50 years in space from PhysOrg.com
The Vanguard I satellite celebrates its 50th birthday this year. Its launch on March 17, 1958 from Cape Canaveral, Florida, culminated the efforts of America’s first official space satellite program begun in September 1955. The first solar-powered satellite, Vanguard I has the distinction of being the oldest artificial satellite orbiting the earth. Its predecessors, Sputniks I and II and Explorer I, have since fallen out of orbit.