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January 2001
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Boeing Delta II rocket lifts Air Force Navigational Satellite into orbit
 Cape Carniveral, Florida.--Jan. 30, 2001--A Boeing Delta II rocket fired up the night sky to launch a Global Positioning System (GPS) navigational satellite into space. Liftoff occurred at 2:43 a.m. EST. A 28-minute-long launch window was open at 2:43 a.m. EST. Twenty-five minutes later, the satellite was placed into an elliptical orbit almost 11,000 miles above the Earth. The U.S. Air Force has used Boeing Delta rockets to place every GPS satellite into orbit since 1989.
The GPS IIR-7 Mission
 The GPS satellite navigational system operates via a constellation of 28 operational satellites, a ground control system and thousands of terminals to help locate and guide military and civilian users in the air, at sea, on the ground and in space. This was the sixth successful launch of the new-generation spacecraft, designated GPS IIR.
 The satellite launched on Jan 30, designated GPS IIR-7, will join 28 other operational GPS satellites now on orbit. This satellite will improve global coverage and increase the overall performance of the GPS constellation. The Global Positioning System allows any properly equipped user to determine precise time and velocity and worldwide latitude, longitude and altitude to within a few meters. Although originally designed as a guidance and navigational tool for the military, GPS has proven beneficial in the commercial and civil markets for transportation, surveying and rescue operations.
The GPS IIR satellites are compatible with the current system and provide improved navigation accuracy, achieved by using an ITT Industries payload system. Additionally, increased autonomy, on-orbit reprogrammability and longer spacecraft life are inherent in the Lockheed Martin satellite design.
In related GPS IIR news, the Air Force-awarded contract to begin development of modernization changes for up to 12 of the 14 GPS Block IIR satellites that are currently in storage has proceeded through a successful Preliminary Design Review. These satellites will incorporate two new military signals and a second civil signal, thus providing military and civilian users of the navigation system with improved capabilities much sooner than previously envisioned.
In addition, the GPS IIR modifications will include increased signal power and the ability to reprogram signals and power on orbit. These improvements will provide for greater accuracy and better resistance to jamming.
Typical Delta II Mission Profile
Delta II Launch Vehicle Family
Delta II comprises a large and growing family of expendable rockets that can be configured as two- or three-stage vehicles, depending on mission needs. Delta II payload delivery options range from about 1-2 metric tons (1,980 to 4,550 lb) to geosynchronous transfer orbit (GTO) and 2.7 to 5.8 metric tons (6,020 to 12,820 lb) to low-Earth orbit (LEO). Two-stage Delta II rockets typically fly LEO missions, while three-stage Delta II vehicles generally deliver payloads to GTO or are used for deep space explorations such as NASA's recent Mars missions
Delta II Performance
Delta II payload delivery capabilities range from about 1 to 2 metric tons (1,980 to 4,550 lb) to geosynchronous transfer orbit (GTO) and from 2.7 to 5.8 metric tons (6,020 to 12,820 lb) to low-Earth orbit (LEO).
Two-stage Delta II rockets generally fly LEO missions, while three-stage Delta II vehicles typically deliver payloads to GTO or are used for deep-space explorations such as NASA's recent Mars missions.
Boeing is developing a new heavy-lift two-stage Delta II for NASA's Space Infra-red Telescope Facility (SIRTF) mission in 2001. It offers a 13 percent increase in payload capability over the standard 7920 version by using the larger Delta III strap-on graphite-epoxy motors (GEMs) and making structural and acoustic blanket adjustments in the first stage to accommodate the higher aerodynamic loads.
Shown here are Delta II variants with 3-m (10-ft) payload fairings. Also offered is a 2.9-m (9.5-ft) fairing
Mission Accuracy
The Delta II second stage-engine may be restarted in flight and works in conjunction with the Redundant Inertial Flight Control Assembly (RIFCA) that provides vehicle guidance control to achieve highly accurate orbital insertion of Delta II payloads. This conserves satellite fuel and prolongs the spacecraft lifetime
Reliability
Orbital accuracy and reliability
are two of the main reasons NASA selected Delta II for
its critical Mars exploration missions in 1996, 1998,
and 1999. For these missions, both the launch period
(days when the launch may occur) and launch window
(timeframe within a day when the launch may occur) were
extremely short, and missing either would have delayed
these missions by two years. Delta II can support
multiple launch windows in the same day, and on numerous
occasions it has met launch windows as short as one
second, including three of the recent Mars missions
Delta Launch Record
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| Delta | Mission | Vehicle | Results | Launch Date | Range |
| 282 | EO-1/SAC-C | Delta II | Successful | Nov. 21, 2000 | WTR |
| 281 | GPS IIR-6 | Delta II | Successful | Nov. 10, 2000 | ETR |
| 280 | DM-F3 | Delta III | Successful | Aug. 23, 2000 | ETR |
| 279 | GPS IIR-5 | Delta II | Successful | July 16, 2000 | ETR |
| 278 | GPS IIR-4 | Delta II | Successful | May 10, 2000 | ETR |
| 277 | IMAGE | Delta II | Successful | Mar. 25, 2000 | WTR |
| 276 | Globalstar 7 | Delta II | Successful | Feb. 8, 2000 | ETR |
For more information: http://www.lmms.external.imco.com/
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