The United States launches the first solar-powered satellite, which is also the first satellite to achieve a long-term orbit.

Vanguard 1 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 man-made object still in orbit, together with the upper stage of its launch vehicle.

March 17 is the 76th day of the year in the Gregorian calendar; 289 days remain until the end of the year.