USA-1 (satellite)

USA-1, also known as Navstar 9, GPS I-9 and GPS SVN-9, was an American navigation satellite launched in 1984 as part of the Global Positioning System development programme. It was the ninth of eleven Block I GPS satellites to be launched, and the first satellite to receive a USA designation.

USA-1 was launched at 11:37 UTC on 13 June 1984, atop an Atlas E/F carrier rocket with an SGS-2 upper stage. The Atlas used had the serial number 42E, and was originally built as an Atlas E. The launch took place from Space Launch Complex 3W at Vandenberg Air Force Base, and placed USA-1 into a transfer orbit. The satellite raised itself into medium Earth orbit using a Star-27 apogee motor.

By 14 July 1984, USA-1 had been raised to an orbit with a perigee of 20009 km, an apogee of 20354 km, a period of 717.94 minutes, and 62.5 degrees of inclination to the equator. The satellite had a design life of 5 years and a mass of 758 kg. It broadcast the PRN 13 signal in the GPS demonstration constellation, and was retired from service on 20 June 1994.