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 GPS Block I, Block I GPS satellites to be launched, and the first satellite to receive a List of USA satellites, USA designation.

Background

Global Positioning System (GPS) was developed by the United States Department of Defense, U.S. Department of Defense to provide all-weather round-the-clock navigation capabilities for military ground, sea, and air forces. Since its implementation, GPS has also become an integral asset in numerous civilian applications and industries around the globe, including recreational used (e.g., boating, aircraft, hiking), corporate vehicle fleet tracking, and surveying. GPS employs 24 spacecraft in 20,200 km circular orbits inclined at 55°. These vehicles are placed in 6 orbit planes with four operational satellites in each plane.

Spacecraft

The first eleven spacecraft (GPS Block 1) were used to demonstrate the feasibility of the Global Positioning System, GPS system. They were 3-axis stabilized, nadir pointing using reaction wheels. Dual solar arrays supplied over 400 watts. They had S band, S-band communications for control and telemetry and Ultra high frequency (UHF) cross-link between spacecraft. They were manufactured by Rockwell International, Rockwell Space Systems, were 5.3 meters across with Solar panels on spacecraft, solar panels deployed, and had a design life expectancy of 5 years. Unlike the later operational satellites, GPS Block 1 spacecraft were inclined at 63°.

Launch

USA-1 was launched at 11:37 UTC on 13 June 1984, atop an SM-65E Atlas, Atlas E launch vehicle with an SGS-2 Multistage rocket, upper stage. The Atlas used had the serial number 42E, and was originally built as an Atlas E. The launch took place from Vandenberg Space Launch Complex 3, 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 (MEO) using a Star (rocket stage), Star-27 Apogee kick motor, apogee motor.

Mission

By 19 July 1984, USA-1 had been raised to an orbit with a Apsis, perigee of , an Apsis, apogee of , a Orbital period, period of 718.00 minutes, and 62.80° of Orbital inclination, inclination to the equator. The satellite had a design life of 5 years and a mass of . It broadcast the PRN 13 signal in the GPS demonstration constellation, and was retired from service on 20 June 1994.

References

{{Orbital launches in 1984 1984 in spaceflight GPS satellites USA satellites Spacecraft launched in 1984