NAVSTAR 66, a US Air Force satellite, was launched from Cape Canaveral on 2011 July 16 at 06:41 UT by a Delta 4 rocket. The satellite is part of the GPS constellation which is comprised of 31 operational satellites. The GPS constellation satellites orbit about 11,000 nautical miles above the planet and emit continuous navigation signals that allow users to find their location in latitude, longitude, and altitude and determine time. The constellation features six orbital planes with multiple satellites flying in each. NAVSTAR 66 will occupy the Plane D, Slot 2A location of the network and entered service approximately 30 days after launch. It replaced the NAVSTAR 39 satellite.
The initial orbital parameters were period = 729.19 minutes, apogee = 20,463.8 km, perigee = 20,452.3 km, inclination = 55.0 degrees on 2011 Aug 4 at 03:04:46 UTC.
The Global Positioning System (GPS) was developed by the US 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 degrees. These vehicles are placed in 6 orbit planes with four operational satellites in each plane. There are also four additional satellites orbiting as reserves.
GPS Block 2 was the operational system, following the demonstration system comprised of Block 1 (Navstar 1 - 11) spacecraft. These spacecraft are 3-axis stabilized, nadir pointing using reaction wheels. Dual solar arrays supplied 710 watts of power. They used S-band (SGLS) communications for control and telemetry and UHF cross-link between spacecraft. The payload consisted of two L-band navigation signals at 1575.42 MHz (L1) and 1227.60 MHz (L2). Each spacecraft carried 2 rubidium and 2 cesium clocks and nuclear detonation detection sensors. Built by Rockwell Space Systems for the US Air Force, the spacecraft measured 5.3 m across with solar panels deployed and had a design life of 7.5 years.
GPS navigational location had originally been at 100-meter accuracy for civilian use signals, and at 20-meter accuracy for military use signals. As of 2000 May 01, the DOD voided the intentional degradation of the accuracy for civilian use, and made it on a par with the military accuracy. But it retained the prerogative to degrade the accuracy at selected locations when necessary.
Alternate Names
Navstar 66
GPS 2F-2
USA 232
Facts in Brief
Launch Date: 2011-07-16
Launch Vehicle: Delta IV
Launch Site: Cape Canaveral, United States
Mass: 1542.0 kg