102 reactions | March 17th - on this day in 1958, the U.S. Navy conducted the first successful Vanguard launch, lofting Vanguard 1 to Medium Earth Orbit. The tiny, 1.46 kg Vanguard 1 was the first satellite to have solar electric power. Today, Vanguard 1 and the launch vehicle's upper stage remain the oldest human-made objects still in Earth orbit. | NASASpaceflight.com | Facebook

February 17th - on this day in 1959, the U.S. Navy successfully launched the Vanguard 2 satellite, also known as Vanguard 2E, since four earlier attempts to launch "Vanguard 2" (A-D) had failed. The launcher used was Vanguard SLV-4 which took to the skies from Launch Complex 18A at Cape Canaveral. Vanguard 2 became the first - very basic - weather satellite, using an optical sensor to measure cloud cover distribution. Even though its mission ended after 19 days, as planned, the satellite remains