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First-of-its-kind satellite for GPS launched into space

Posted: May 28, 2010

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A new era for the Global Positioning System rocketed into orbit Thursday night, beginning a concerted effort to sharpen the precision capabilities beaming from the world's foremost space-based navigation network.

Credit: Stephen Clark/Spaceflight Now
Launch gallery | More pad cameras

"GPS is used by nearly a billion people worldwide for everything from farming and aviation to public safety, disaster relief and recreation, not to mention its military purpose of providing precision navigation and timing to combat forces," said Col. David Madden, the Air Force's GPS Wing commander.

Some 60 satellites have been launched for the system over the past three decades, initially testing the concept and later assembling the operational grid in use today.

And now the Air Force has successfully launched the first spacecraft in the Block 2F series, a new breed of GPS satellite that features even higher accuracy, enhanced internal clocks, longer life and reprogrammable onboard processors to evolve with future needs.

"GPS 2F will increase the signal power, precision and capacity of the system, and form the core of the GPS constellation for years to come," said Madden.

A United Launch Alliance Delta 4 rocket, flying in its Medium+ variant equipped with a pair of solid-fuel strap-on motors, roared into Cape Canaveral's nighttime sky at 11:00 p.m. EDT carrying the GPS 2F-1 satellite nestled in its nose cone.

Unlike GPS launches over the past 20 years that relied on Delta 2 rockets for delivery into orbit, the new-generation 2F satellites also got upgraded to the larger, more capable Delta 4 and Atlas 5 fleets of boosters in the Air Force's Evolved Expendable Launch Vehicle program.

Although the Delta 2 was highly reliable, it wasn't powerful enough to inject the GPS satellites directly into the orbiting constellation. The birds needed their own kick motor and several days to reach the desired destination.

That all changed Thursday night when the Delta 4's upper stage performed three firings that methodically hauled the GPS 2F-1 satellite into a circular orbit 11,000 nautical miles above the planet. In just three-and-a-half hours, the $121 million spacecraft had arrived at the proper altitude and completely bypassed the circuitous route of its predecessors.

An artist's concept shows a GPS 2F satellite in Earth orbit. Credit: Boeing
Boeing is building a dozen Block 2F satellites to replace orbiting GPS spacecraft as they age, keeping the navigation signals going strong for years to come.

"These next-generation satellites provide improved accuracy through advanced atomic clocks; a more jam-resistant military signal and a longer design life than earlier GPS satellites; and a new civil signal that benefits aviation safety and search-and-rescue efforts," said Craig Cooning, vice president and general manager at Boeing Space and Intelligence Systems. "GPS 2F is the culmination of our deep experience with 39 successful satellites from previous missions, representing more than 30 years of teamwork with the Air Force."

"Normally when you are launching the first-of-a-kind satellite you'd be really worried because it's a system that's more complex than the last generation. In this case, we've added capability but it's built on a foundation of success from the 2A program, which was a massively successful program," Madden said.

Today's GPS constellation is comprised of 30 functioning satellites, including 11 Block 2A's made by Boeing, 12 2R's and 7 2R-Modernized spacecraft built by Lockheed Martin. Their ages range from the teens to less than a year old.

"The current GPS constellation has the most satellites and the greatest capability ever. We're committed to maintaining our current level of service, as well as striving to improve service and capability through on-going modernization efforts," Madden said.

"The U.S. Air Force and Air Force Space Command have been diligent stewards of GPS since its conception in the 1970s and continue its commitment to this critical component of our national infrastructure."

GPS satellites emit continuous navigation signals that allow users to find their position in latitude, longitude and altitude and determine time. Originally built as a tool for the U.S. military, the utility has spread across the world as an indispensable commercial service.

One of the GPS 2F satellites is pictured at the manufacturing facility. Credit: Boeing
Ground controllers expect to have the 2F-1 satellite checked out and ready for use in 90 to 120 days, the Air Force says.

The new GPS 2F-1 spacecraft take over the Plane B, Slot 2 location of the network, considered one of the primary positions in the constellation that is divided into six orbital groupings with multiple satellites flying in each.

The craft will take the position presently held by the GPS 2A-27 satellite, which was launched in September 1996 and has exceeded its expected lifetime. It will be relocated as part of the Air Force's efforts to spread out the available satellites and increase coverage.

That particular slot was supposed to be occupied by the GPS 2R-20 satellite after it launched in March 2009. But an interference problem with a test payload aboard the craft prevented it from entering service as scheduled.

Getting to Thursday's launch, which was years in the making, took much longer than planners of the Block 2F program ever imagined.

"We've had some growing pains with the 2F, but our industry and government teams have overcome every obstacle that's been thrown our way as we've maintained our focus on mission assurance," said Madden.

"Over the years, requirements changes, contractor technical challenges, a change in factory location and a increased emphasis on mission assurance have driven changes to the launch schedule. In the end, the changes over the years will give global users better capabilities and improve our confidence in the day-to-day and end-of-life performance," the Global Positioning Systems Wing said.

Since sustaining the constellation is the main purpose for the GPS 2F satellites, the upcoming launches will be scheduled when fresh spacecraft are needed.

"There are too many variables to accurately predict when the entire Block 2F fleet will arrive on-orbit," the Wing says.

The Air Force could launch the GPS 2F-2 satellite in November or December using an Atlas 5 rocket from Cape Canaveral.

"Constellation health and launch vehicle availability will dictate this and the remaining GPS 2F launches," the Wing said.