September 27, 2005 The second modernized U.S. Air Force Global Positioning System (GPS) Block IIR satellite has been successfully launched aboard a Delta II rocket on Sept. 25, from Cape Canaveral. Known as GPS IIR-M, the modernized spacecraft are the most technologically advanced GPS satellites ever developed and are designed to significantly improve navigation performance for U.S. military and civilian users worldwide. The satellites orbit the Earth every 12 hours, emitting continuous navigation signals. The signals are so accurate, time can be figured to within one millionth of a second, velocity within a fraction of a mile-per-second and location to within 100 feet.
GPS provides military and civilian users three-dimensional position location data in longitude, latitude and elevation as well as precise time and velocity.
Lockheed Martin Navigation Systems is under contract to modernize eight IIR satellites for its customer, the Global Positioning Systems Wing, Space and Missile Systems Center, Los Angeles Air Force Base, Calif. Designated GPS IIR-15(M), this satellite will join the first modernized IIR spacecraft declared operational last year and 12 other operational Block IIR satellites currently on-orbit within the overall 29-spacecraft constellation. The Air Force is dedicating the mission to honor American POW/MIAs past and present.
The GPS IIR-M series offers a variety of enhanced features for GPS users, such as a modernized antenna panel that provides increased signal power to receivers on the ground, two new military signals for improved accuracy, enhanced encryption and anti-jamming capabilities for the military, and a second civil signal that will provide users with an open access signal on a different frequency.
The Global Positioning System enables properly equipped users to determine precise time and velocity and worldwide latitude, longitude and altitude to within a few meters. Air Force Space Command's 2nd Space Operations Squadron (2SOPS), based at Schriever Air Force Base, Colo., manages and operates the GPS constellation for both civil and military users. GPS IIR-M production takes place at Lockheed Martin facilities in Valley Forge, Pa. The modernized navigation payload is provided by ITT Industries.
The Delta II rocket carrying the GPS IIR-15 (M) spacecraft lifted off from Space Launch Complex 17A at Cape Canaveral Air Force Station, Fla., at 2:50 p.m. EDT, Sept. 24. Following a nominal 68-minute flight, the rocket deployed the satellite to a transfer orbit. The Boeing Delta II 7925-9.5 configuration vehicle used for today's mission featured a Boeing first stage booster powered by a Pratt & Whitney Rocketdyne RS-27A main engine and nine Alliant Techsystems (ATK) solid rocket boosters. An Aerojet AJ10-118K engine powered the storable propellant restartable second stage. A Thiokol Star-48B solid rocket motor propelled the third stage prior to spacecraft deployment. The rocket also flew with a nine-and-a-half-foot-diameter Boeing payload fairing.
A redundant inertial flight control assembly built by L3 Communications Space & Navigation provided guidance and control for the rocket that enabled a precise deployment of the satellite.