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Delta 2 Rocket Delivers Another GPS Satellite to Orbit

Continuing20 years of building and maintaining the Global Positioning System, theworkhorse Delta 2 rocket this morning successfully launched another satellitefor the navigation network known the world over.

The12-story booster rumbled out of Cape Canaveral's pad 17A at 4:34 a.m. EDT,shaking the sleeping Space Coast and dashing into the predawn skies.

Burning andseparating its nine strap-on solid motors as designed, the kerosene-poweredfirst stage pushed the rocket 60 miles up. The hypergolic second stage thenassumed control, igniting its engine and jettisoning the nose cone shroudingthe GPS 2R-20 satellite payload.

The rocketeased into an initial orbit over the central Atlantic Ocean and began apeaceful coast through space to reach the skies over the western Pacific. Inview of the tracking station on Guam, the second stage fired briefly to raisethe orbit and then released the solid-fuel third stage to propel the new GPSsatellite into its prescribed orbit.

Launchmanagers back at the Cape anxiously waited for the rocket to complete itsprogrammed sequence, finally receiving the news of a successful deployment ofthe GPS 2R-20 spacecraft about 68 minutes after liftoff.

"Congratulationsto the entire team for their hard work and dedication to the mission,"said Brig. Gen. Edward L. Bolton Jr., 45th Space Wing commander at the Cape. "The launch of another GPS satellite provides our warfighters a system on whichthey can depend to complete their missions successfully."

"It'sgreat to see months of hard work by the team pay off in the form of asuccessful launch," added 1st Lt. Jonathan McGuire, the Delta 2 boosteroperations controller. "It's been a long wait, but knowing that thissatellite will be directly supporting the war on terrorism was a reward worthwaiting for."

Out withthe old, in with the new

The GPS2R-20 spacecraft will rejuvenate one of the navigation constellation'spositions, while also conducting critical tests of a new signal to be fieldedby follow-on satellites.

The craftwill replace the aging GPS 2A-27 satellite launched in September 1996. Now wellpast its design life, ground controllers plan to move the old satellite into abackup role.

The new GPS2R-20 spacecraft will take over the Plane B, Slot 2 location of the navigationnetwork, considered one of the primary positions in the constellation that isdivided into six orbital groupings with multiple satellites flying in each.

GPSsatellites fly about 11,000 miles above the planet and emit continuousnavigation signals that allow users to find their precise position in latitude,longitude and altitude and determine time. Originally built for the U.S. military, the GPSservice has spread across the world as an indispensable commercial utility.

"GPScontributes vital capabilities to our nation's military operations, globalinformation infrastructure, emergency response, transportation andtelecommunication industries, the international economy and everyday life. Ourcommitment is to ensure this emerging capability continues to deliver precisepositioning, navigation and timing service to users around the globe,"said Mike Dunn, technical director of the Space and Missile Systems Center's Global Positioning Systems Wing.

Thesatellite is the seventh in a series of eight equipped with modernizedfeatures. The upgraded satellites transmit additional signals and offerimprovements aimed at greater accuracy, tougher resistance to interference andenhanced performance for users around the world.

The newcivilian signal removes navigation errors caused by the Earth's ionosphere. Themilitary advancements will provide a more robust jam-resistant signal andenable better targeting of GPS-guided weapons in hostile environments.

"Everyyear we have made the GPS signal better, every year the accuracy of the systemhas improved," said Gen. Robert Kehler, commander of Air Force SpaceCommand. "And that is what is going to continue to happen."

Thesatellite is the 20th built by Lockheed Martin, but the two-ton craft is uniquebecause it carries a special demonstration package to test a new civil signal,called L5, planned for the aviation community.

"Thisis a demonstration of that signal," said Tom Nagle, program manager ofcivil applications at the Transportation Department. "It is a key part ofall aviation planning for the next generation aviation systems."

Takingadvantage of the satellite's auxiliary payload accommodations and modifyingavailable parts in inventory, Lockheed Martin was able to add the new L5 signalin a straight-forward fashion. Two boxes were put on the spacecraft, increasingits weight by about 40 pounds.

"Justusing the capabilities of the vehicle, some of the spare parts that we had onthe modernization program, we were able to modify them to add thedemonstration," said Dave Podlesney, a GPS executive at Lockheed Martin.

The AirForce needs the satellite in orbit and the new frequency demonstrated before anInternational Telecommunications Union deadline in late August.

Thein-space testing of the L5 system on this satellite will verify the newfrequency doesn't impact the other signals being broadcast. "So that's animportant way to the pave the path for future use," Dunn said.

The nextgeneration GPS 2F satellites, being built by Boeing, will transmit the new L5signal when they begin launching over the next few years.

"Thesignal has higher power than the other signals that we have, which allows moreprotection from interference sources. Also, the signal is in a band that isprotected by the aviation community," Nagle said.

Delays inthe GPS 2F program prompted the Air Force to have Lockheed Martin add thedemonstration to this satellite to ensure the U.S. government could secure therights to the frequency.

AirForce's use of the Delta 2 nearing end

Flying muchthe same mission as its inaugural flight two decades ago that deployed a GPSsatellite, today's Delta 2 launch occurred just a month after the rocketcelebrated its 20th anniversary. This latest success is the 47th GPS spacecraftput into orbit by the venerable rocket.

"Onethird of the 140 successful Delta 2 launches have been dedicated to GPSsatellites. The ULA Delta team is extremely proud of the role we've played inlaunching this incredible satellite constellation," said Jim Sponnick,United Launch Alliance's vice president of the Delta Product Line.

"Duringthe past two decades, GPS has changed how people navigate around theirneighborhoods and around the globe. GPS has also greatly improved militaryoperations as well as numerous maritime, aircraft and business operationsworldwide."

Born in thelate 1980s during an overhaul of U.S. space policy following the Challengeraccident, the Delta 2 was conceived as part of the nation's desire to shift itsdependence away from the space shuttle.

Newexpendable boosters were ordered to launch satellites, and the Air Force'sGlobal Positioning System would become the anchor customer for the Delta 2.

"TheDelta 2 program was started back in 1987. It was one of the programs that theAir Force started after the Challenger accident, and then the first launch wasin 1989. So this launch vehicle has had a long history of successful launchesand service to the country, both military and civil users," said JohnWagner, technical director of the Launch and Range Systems Wing at the Spaceand Missile Systems Center.

"There'sa lot of us, including myself, that were part of the original Delta 2 program.I had the honor being part of it back in 1989 when I was assigned at thePentagon, and worked it when I was assigned at Vandenberg. There is a lot ofpride that this program has been a huge success for the Air Force. It's doneeverything that we've asked it to do, plus more, and it's helped carry us intothe 21st century."

The AirForce has just one more Delta 2 rocket left to fly. Its stages sit in hangarsat Cape Canaveral awaiting on-pad assembly to begin May 27, said Lt. Col. ErikBowman, commander of the 1st Space Launch Squadron.

Liftoff isplanned for August 21 to loft the final Block 2R satellite in the GPSreplenishment program. It's also the final scheduled use of pad 17A.

The GPS2R-21 satellite was delivered to the launch site in January 2008. The craftwill be brought out of storage and begin its pre-flight processing campaign inJune, said Lt. Col. John Wagner, commander of the 45th Launch Support Squadronat the Cape.

Althoughthe Delta 2 proved to be highly reliable for medium-size satellites, the AirForce is transitioningto newer rockets -- the larger Atlas 5 and Delta 4 vehicles -- that aremeant to be versatile in launching a range of different payloads.

"Whilewe'll be sorry to see it go, obviously, it's been a bridge toward Delta4," Wagner said.

A Delta 4rocket, for instance, is slated to launch first GPS 2F satellite at the end of2009.

UnitedLaunch Alliance has eight other Delta 2 launches for NASA and commercialcustomers planned through 2011. The company also has five rockets available tosell.

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Justin Ray

Justin Ray is the former editor of the space launch and news site Spaceflight Now, where he covered a wide range of missions by NASA, the U.S. military and space agencies around the world. Justin was space reporter for Florida Today and served as a public affairs intern with Space Launch Delta 45 at what is now the Cape Canaveral Space Force Station before joining the Spaceflight Now team. In 2017, Justin joined the United Launch Alliance team, a commercial launch service provider.