Delta Launches USAF GPS 2R-4 Satellite
A Boeing Delta 2 7925-9.5 rocket
successfully launched NAVSTAR GPS 2R-4 from Cape Canaveral Air
Station, pad 17A, at 6:48 p.m. PDT, May 10 (0148 UTC May 11).
The US$42 million 2032 kg (4479 lbm) satellite was launched into a
12-hour, 20,200 km (10,900 nmi) altitude orbit, inclined at 55°. This is the
fourth Block 2R satellite, of a block order of 21, to be supplied
by Lockheed Martin. The satellite design is based on Lockheed
Martin’s AS-4000 series satellite bus, with a design life of 10
years. This 278th Delta launch cost US$50 million.
Boeing has an additional 16 launches manifested aboard the Delta 2
for the satellite-based navigation system.
GPS 2R-4 is
replacing the failed GPS 2-1 satellite, which suffered a shutdown
of its onboard reaction wheels on March 26. The satellite was
decommissioned on April 14. GPS 2-1 was launched 11 years ago, on
February 14, 1989, as the first spacecraft to form the current
constellation. GPS 2-1 was built by Rockwell International (now
part of Boeing) as part of the Block 2 series, having a 7.5 year
system is separated into six orbital planes, requiring a minimum
of four satellites in each, to operate. Three of the planes
currently have an additional satellite, giving the network a total
of 27 spacecraft. This launch will insert the new satellite into
the E-1 slot of the constellation, previously occupied by the
recently failed GPS 2-1 satellite, and raise the total number of
satellites aloft to 28.
1: GPS Satellite Planes/Slots
on individual cells for more information on the satellite.
Nomenclature used in this table: Block number (2, 2A or
2R), satellite within block. In parentheses, USAF space vehicle
number of GPS satellite. Satellites GPS 2-1
(14), 2-7 (20) and
2A-13 (28) have been retired. GPS 2R-1 (42) was destroyed in a
Delta launch failure on January 17, 1997.
Positioning System (GPS) network is operated by the U.S. Air Force
to provide highly accurate position, speed and timing information
to military forces around the world, and is used by a growing
number of commercial products. The NAVSTAR Global Positioning
System is managed by the NAVSTAR GPS Joint Program Office at the
Space and Missile Systems Center, Los Angeles Air Force Base,
California. The USAF
50th Space Wing located at Falcon Air Force Base, Colorado,
operates and controls the system.
GPS stands for Navigation Signal Timing and Ranging Global
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