Vanguard 1 (Harvard designation: 1958-Beta 2, COSPAR ID: 1958-005B) is an American satellite that was the fourth artificial Earth-orbiting satellite to be successfully launched (following Sputnik 1, Sputnik 2, and Explorer 1); it was launched 17 March 1958. Vanguard 1 was the first satellite to have solar electric power. Although communications with the satellite were lost in 1964, it remains the oldest human-made object still in orbit, together with the upper stage of its launch vehicle.Vanguard 1 was designed to test the launch capabilities of a three-stage launch vehicle as a part of Project Vanguard, and the effects of the space environment on a satellite and its systems in Earth orbit. It also was used to obtain geodetic measurements through orbit analysis. Vanguard 1 was described by the Soviet Premier, Nikita Khrushchev, as "the grapefruit satellite".