WEDNESDAY, MARCH 25, 2015
Climbing away from Earth on the power of its liquid hydrogen-fueled main engine and twin solid rockets, a Delta 4 booster launched a new Global Positioning System satellite Wednesday to benefit U.S. military operations and civilian society as a whole.

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2255 GMT (6:55 p.m. EDT)
"I'm elated with today's successful launch, the GPS constellation remains healthy, strong and robust and in over 20 years since initial operational capability, GPS has never failed to deliver on its global positioning, navigation, and timing commitments," said Brig. Gen. Cooley, director of Space and Missile Systems Center's Global Positioning Systems Directorate.

"Each new generation of GPS satellites provides enhanced capability over the prior generations, and has delivered reliable performance demonstrating our commitment that GPS remain the Gold Standard space-based positioning, navigation, and timing service for the future," he said. "Thanks to the men and women of SMC, the 45th, 50th 310th Space Wings, Boeing, United Launch Alliance, the Aerospace Corporation, GPS 2F and Delta 4 launch teams, the GPS 2F program continues to meet GPS enterprise needs."

2220 GMT (6:20 p.m. EDT)
“Congratulations to the Air Force and all of our mission partners on today’s successful launch of GPS 2F-9! The ULA team is privileged to work with this world-class U.S. government and contractor mission team, and we are proud to contribute to the GPS capabilities that were delivered to orbit today,” said Jim Sponnick, ULA vice president, Atlas and Delta Programs.

“This entire team is focused on 100 percent mission success, one launch at a time, and also providing on-time launches to meet our customer’s mission needs.”

2155 GMT (5:55 p.m. EDT)
SPACECRAFT SEPARATION! The GPS satellite has been deployed by the Delta 4 rocket, completing today's launch!

See our photo gallery of the launch.

And you also can watch a video replay.

1900 GMT (3:00 p.m. EDT)
To recap, a United Launch Alliance Delta 4 rocket was launched on-time today at 2:36 p.m. EDT carrying a new Global Positioning System spacecraft to advance the navigation network with every launch.

We will post confirmation of spacecraft separation and mission success when announced.

1856 GMT (2:56 p.m. EDT)
T+plus 20 minutes. The rocket has just entered a three-hour coast period before the final engine burn to deliver GPS 2F-9 into the desired circular orbit to join the navigation network.
1853 GMT (2:53 p.m. EDT)
T+plus 17 minutes. Delta has flown into a good transfer orbit.
1851 GMT (2:51 p.m. EDT)
T+plus 15 minutes, 41 seconds. SECO 1. The upper stage Aerojet Rocketdyne engine has shut down after the first of two planned firings to inject the GPS spacecraft into navigation network today.
1849 GMT (2:49 p.m. EDT)
T+plus 13 minutes, 30 seconds. Second stage performance still looks good.
1847 GMT (2:47 p.m. EDT)
T+plus 11 minutes. Good engine controls and chamber pressure.
1846 GMT (2:46 p.m. EDT)
T+plus 10 minutes. The RL10 engine is burning a mixture of liquid oxygen and liquid hydrogen cryogenic propellants.
1845 GMT (2:45 p.m. EDT)
T+plus 9 minutes. Delta is 149 miles in altitude, 1,078 miles northeast of the launch pad.
1844 GMT (2:44 p.m. EDT)
T+plus 8 minutes. Rock steady controls on the upper stage engine.
1843 GMT (2:43 p.m. EDT)
T+plus 7 minutes. Still looking good as Delta arcs over the Atlantic.
1842 GMT (2:42 p.m. EDT)
T+plus 6 minutes. Delta is 112 miles in altitude, 498 miles northeast of the launch pad.
1840 GMT (2:40 p.m. EDT)
T+plus 4 minutes, 51 seconds. The protective payload fairing enclosing the GPS satellite atop the rocket has separated.
1840 GMT (2:40 p.m. EDT)
T+plus 4 minutes, 34 seconds. The cryogenic RL10B-2 upper stage engine has ignited!
1840 GMT (2:40 p.m. EDT)
T+plus 4 minutes, 19 seconds. The Common Booster Core first stage and the attached interstage have been separated in one piece from the Delta 4's upper stage. The upper stage engine's extendible nozzle is dropping into position.
1840 GMT (2:40 p.m. EDT)
T+plus 4 minutes, 12 seconds. MECO! Main engine cutoff confirmed as the Aerojet Rocketdyne RS-68 powerplant shuts down.
1840 GMT (2:40 p.m. EDT)
T+plus 4 minutes, 5 seconds. The main engine is throttling down to its minimum power setting in preparation for shutdown.
1839 GMT (2:39 p.m. EDT)
T+plus 3 minutes, 5 seconds. Passing Mach 10.
1839 GMT (2:39 p.m. EDT)
T+plus 3 minutes. The main engine continues to perform well, consuming its liquid hydrogen and liquid oxygen propellants.
1838 GMT (2:38 p.m. EDT)
T+plus 2 minutes, 35 seconds. Passing Mach 5.
1838 GMT (2:38 p.m. EDT)
T+plus 2 minutes, 30 seconds. The RS-68 is consuming nearly a ton of propellants per second as the powerplant pushes the Delta 4 rocket closer to the edge of space.
1838 GMT (2:38 p.m. EDT)
T+plus 2 minutes. The vehicle weighs half of what it did at liftoff.
1837 GMT (2:37 p.m. EDT)
T+plus 1 minute, 45 seconds. Solid motor separation! The spent boosters have been shed from the first stage. Delta 4 continues powering its way toward space on the thrust generated by the RS-68 main engine.
1837 GMT (2:37 p.m. EDT)
T+plus 1 minute, 35 seconds. The twin Orbital ATK solid rocket boosters have burned out of their propellant. Standing by for jettison.
1836 GMT (2:36 p.m. EDT)
T+plus 60 seconds. Now passing through the region of maximum aerodynamic pressure as the vehicle accelerates through the lower atmosphere.
1836 GMT (2:36 p.m. EDT)
T+plus 50 seconds. The launcher has broken through the sound barrier.
1836 GMT (2:36 p.m. EDT)
T+plus 30 seconds. The Delta 4 rocket is climbing away from Cape Canaveral with its main engine firing at full throttle and the two strap-on boosters giving a powerful extra kick.
1836 GMT (2:36 p.m. EDT)
LIFTOFF! Liftoff of the Delta 4 rocket with the GPS 2F-9 navigation spacecraft, benefiting U.S. military operations and civilian society as a whole.
1835 GMT (2:35 p.m. EDT)
T-minus 12 seconds. Residual hydrogen burnoff ignitors have been fired beneath the main engine.
1835 GMT (2:35 p.m. EDT)
T-minus 22 seconds. The steering system for the solid rocket motor nozzles has been activated.
1835 GMT (2:35 p.m. EDT)
T-minus 30 seconds. Green board. All systems remain "go" for launch.
1835 GMT (2:35 p.m. EDT)
T-minus 40 seconds. Upper stage liquid hydrogen tank is confirmed at flight level.
1835 GMT (2:35 p.m. EDT)
T-minus 55 seconds. The Air Force-controlled Eastern Range has given its "go" for launch.
1835 GMT (2:35 p.m. EDT)
T-minus 1 minute and counting. The ignition conditions for the RS-68 main engine are "go." Ignition of the RS-68 powerplant will follow at T-minus 5 seconds. The engine powers up to the 102 percent level of thrust for a computer-controlled checkout before liftoff.
1834 GMT (2:34 p.m. EDT)
T-minus 75 seconds. The liquid hydrogen fuel tank on the upper stage is being secured for launch.
1834 GMT (2:34 p.m. EDT)
T-minus 80 seconds. Upper stage liquid oxygen tank has been secured at flight level.
1834 GMT (2:34 p.m. EDT)
T-minus 1 minute, 50 seconds. The first stage liquid hydrogen tank has reached flight level and pressure.
1834 GMT (2:34 p.m. EDT)
T-minus 2 minutes. The rocket's upper stage liquid oxygen tank is being secured.
1833 GMT (2:33 p.m. EDT)
T-minus 2 minutes, 30 seconds. The liquid oxygen tank in the first stage is confirmed at the proper level and pressure for flight.
1833 GMT (2:33 p.m. EDT)
T-minus 3 minutes and counting. Ordnance devices aboard the vehicle are being armed.
1832 GMT (2:32 p.m. EDT)
T-minus 3 minutes, 25 seconds. The systems of the first and second stages of the Delta 4 rocket have switched from ground-fed power to internal batteries for launch.
1832 GMT (2:32 p.m. EDT)
T-minus 3 minutes, 30 seconds. Replenishment of liquid hydrogen and liquid oxygen to the Common Booster Core first stage is being secured in preparation to pressurize the tanks for launch.
1832 GMT (2:32 p.m. EDT)
T-minus 4 minutes and counting! Now into the final phase of the countdown for liftoff at 2:36 p.m. by the Delta 4 rocket carrying the GPS 2F-9 spacecraft from pad 37B at Cape Canaveral Air Force Station.
1830 GMT (2:30 p.m. EDT)
The GPS 2F-9 spacecraft atop the Delta 4 has switched from ground-fed power to its internal batteries for launch.
1830 GMT (2:30 p.m. EDT)
Permission to launch has been granted by the ULA launch director and Air Force mission director.
1829 GMT (2:29 p.m. EDT)
The final readiness polls of the launch team and mission managers have been completed. No technical problems are being worked and all rocket, spacecraft and ground systems are "go" for liftoff at 2:36 p.m.
1828 GMT (2:28 p.m. EDT)
Standing by for the launch team readiness check for continuing the countdown.
1821 GMT (2:21 p.m. EDT)
Now 15 minutes to launch! The launch team will be polled in the next few minutes to confirm all systems are "go" to press onward for 2:36 p.m. liftoff.
1812 GMT (2:12 p.m. EST)
The countdown is entering the final 30 minutes until the Delta 4 rocket launch from Cape Canaveral at 2:36 p.m. EDT. Here's a look at some stats about today's mission. This will be:
1807 GMT (2:07 p.m. EST)
Weather is observed GO and forecast GO for launch.
1802 GMT (2:02 p.m. EST)
T-minus 4 minutes and holding. The countdown has entered the planned 30-minute hold leading toward the 2:36 p.m. EDT liftoff of the Delta 4 rocket.

This pause is designed to give the launch team the opportunity to catch up on any work running behind schedule and verify all is in readiness for the final moments of the count. Also, a series of polls will be conducted during the hold to give approval to proceed with the launch.

1751 GMT (1:51 p.m. EDT)
Launch minus 45 minutes! This is the ascent timeline to be followed by the United Launch Alliance Delta 4 rocket in launching the Air Force’s GPS 2F-9 navigation satellite.
1739 GMT (1:39 p.m. EDT)
First stage liquid hydrogen conditioning for flight is complete.
1736 GMT (1:36 p.m. EDT)
One hour till launch! Coming off the pad on the power of the main engine and twin solid rockets, the Delta 4 will be 206 feet tall and generating 1.1 million pounds of thrust.

The vehicle will hit Mach 1 in 48 seconds and surpass the region of maximum air pressure at 61 seconds.

The solids burn out at 95 seconds and jettison five seconds later, leaving the hydrogen-fueled core stage to continue headed to space. Main engine cutoff occurs at 4 minutes, 8 seconds and staging some 7 seconds later.

The upper stage then comes to life four-and-a-half minutes into flight and the protective nose cone enclosing the satellite payload is separated 10 seconds into the burn.

That first burn will last 11 minutes, injecting the rocket into a preliminary, egg-shaped orbit where it will coast for nearly three hours.

A second burn lasting less than two minutes will circularize the orbit and reach the GPS navigation network 11,000 nautical miles in altitude.

Separation of the GPS 2F-9 satellite to complete the launch sequence happens at T+plus 3 hours and 14 minutes, or 5:50 p.m. EDT given an on-time liftoff.

1730 GMT (1:30 p.m. EDT)
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1720 GMT (1:20 p.m. EDT)
The flight slews and commanding tests for the vehicle steering systems are being performed. The first stage Common Booster Core, the strap-on solid rocket motors and upper stage engine steering checks were run through a pre-launch test pattern.
1717 GMT (1:17 p.m. EDT)
Upper stage fuel and oxidizer conditioning for flight iscomplete.
1716 GMT (1:16 p.m. EDT)
The flight hazard area has been established.
1710 GMT (1:10 p.m. EDT)
The first stage liquid oxygen tank is conditioned for flight.
1706 GMT (1:06 p.m. EDT)
Now entering into the final 90 minutes of the countdown to launch of Delta 371 and the ninth Block 2F satellite for the GPS constellation.

The rocket stands fueled and ready for launch at 2:36 p.m. EDT today. The launch team is not reporting any significant issues, weather conditions are green and the countdown remains on schedule.

1655 GMT (12:55 p.m. EDT)
Engineers are conducting the standard evaluation of the Delta 4 rocket's thermal insulation following the loading of supercold propellants into the vehicle.
1636 GMT (12:36 p.m. EDT)
Two hours and counting! If you are need tips on picking a good viewing spot, check out this authoritative guide on where to go.
1621 GMT (12:21 p.m. EDT)
The vehicle is fully fueled! Loading of the upper stage liquid oxygen tank has been accomplished.
1605 GMT (12:05 p.m. EDT)
The first stage liquid oxygen loading just finished. The tank has been loaded with its supercold oxidizer that is chilled to Minus-298 degrees F. Topping will be completed as the count rolls on.
1557 GMT (11:57 a.m. EDT)
Loading of the upper stage liquid hydrogen tank has been accomplished as fueling proceeds today at Complex 37.
1545 GMT (11:45 a.m. EDT)
Fast-filling of the first stage liquid hydrogen tank is complete. After post-filling checks and valve tests, the tank will be placed in topping mode. The launch team will confirm the propellant is conditioned for flight.
1535 GMT (11:35 a.m. EDT)
Chilldown of the upper stage liquid oxygen system is complete for loading the rocket's tank. This is the last of the rocket's four cryogenic supplies to be filled in today's countdown to launch.
1530 GMT (11:30 a.m. EDT)
The Delta 4 rocket's Common Booster Core first stage and upper stage are being loaded with supercold liquid oxygen and liquid hydrogen.

Complex 37 has two giant sphere-shaped fuel tanks to store the cryogenic liquid oxygen and liquid hydrogen. The LOX tank holds 250,000 gallons and LH2 sphere about 850,000 gallons.

The cryogenics are fed from the storage tanks through pipelines to the pad. For the Common Booster Core, the propellants are routed up to the launch table upon which the rocket sits. Tail service masts, the large box-like structures at the base of the vehicle, feed the oxygen and hydrogen to the booster via separate umbilicals.

The upper stage receives its cryos from the middle swing arm that extends from the Fixed Umbilical Tower to the front-side of the rocket.

1528 GMT (11:28 a.m. EDT)
After chilldown of the upper stage liquid hydrogen system, the was clear for loading the rocket's tank. The launch team is actively filling the upper stage's liquid hydrogen tank with propellant for the RL10 engine.
1523 GMT (11:23 a.m. EDT)
The "go" has been given for the upper stage liquid oxygen chilldown in advance of filling that tank.
1521 GMT (11:21 a.m. EDT)
First stage liquid oxygen tanking operation is switching from "slow-fill" to "fast-fill" mode. The rocket will be loaded with 40,000 gallons of supercold LOX.
1504 GMT (11:04 a.m. EDT)
The first stage liquid oxygen chilldown is complete. "Slow-fill" mode is beginning to load a small percentage of the tank. The process then speeds up to the "fast-fill" mode until the tank is nearly full.
1501 GMT (11:01 a.m. EDT)
With today's countdown going very smoothly, the launch team is preparing to start fueling the Delta 4 rocket's upper stage. The "go" has been given to start the chilldown conditioning of the upper stage liquid hydrogen system.
1455 GMT (10:55 a.m. EDT)
First stage liquid hydrogen tanking operation is switching from "slow-fill" to "fast-fill" mode.
1445 GMT (10:45 a.m. EDT)
And now the chilldown of Delta's first stage liquid oxygen system is starting. This preps the tank and pumping to guard against shock when the supercold oxidizer begins flowing into the rocket a short time from now.
1442 GMT (10:42 a.m. EDT)
Liquid hydrogen flow to the first stage is confirmed. Some 110,000 gallons of LH2 will fill the rocket's tank.
1439 GMT (10:39 a.m. EDT)
The cold gas chilldown conditioning of the liquid hydrogen system has been accomplished. Liquid hydrogen propellant will begin to flow into the first stage in "slow-fill" mode. That is sped up to "fast-fill" after a small portion of the tank is loaded.

Chilled to Minus-423 degrees Fahrenheit, the liquid hydrogen will be consumed by the RS-68 main engine along with liquid oxygen during the first four minutes of the launch.

1415 GMT (10:15 a.m. EDT)
A "go" has been given to start the cold gas chilldown conditioning of the first stage liquid hydrogen system. This is the precursor to filling the vehicle with propellant.
1351 GMT (9:51 a.m. EDT)
T-minus 4 hours, 15 minutes and counting! The team is ready for cryogenic fueling as the countdown is underway for today's opportunity to launch the Delta 4 rocket with the GPS 2F-9 navigation satellite at 2:36 p.m. EDT.
1342 GMT (9:42 a.m. EDT)
The launch team is manning stations for the start of fueling operations.
1321 GMT (9:21 a.m. EDT)
T-minus 4 hours, 15 minutes and holding. The countdown has entered a 30-minute built-in hold, a pre-planned pause designed to give the team time to catch up on any work that could be running behind schedule. Once the clocks resume ticking, the main countdown for today's launch operation will begin.
1310 GMT (9:10 a.m. EDT)
A check of the current weather shows everything is green and the odds of acceptable of conditions has improved to 90 percent today.

The specifics include scattered clouds at 3,000 feet, a broken deck at 27,000 feet, good visibility, easterly winds of 12 gusting to 17 knots and a temperature of 77 degrees F.

1145 GMT (7:45 a.m. EDT)
The 330-foot tall mobile service tower has been retracted from the Delta 4 rocket at Cape Canaveral's pad 37B for today's launch that will place the GPS 2F-9 satellite into Earth orbit.

The wheeled structure moved along rail tracks to its launch position about the length of a football field away from the rocket. The 9-million pound tower shielded the Delta from the elements during the its stay on the pad, provided workers 360-degree access to the various areas on the vehicle and was used to attach the strap-on solid motors and the payload during the launch campaign. The tower is 90-feet wide and 40-feet deep.

Crews will spend the next couple of hours securing the complex for launch before leaving the danger area around the pad. All workers must be clear of the area for the start of hazardous operations in the countdown, which include fueling the Delta 4's Common Booster Core first stage and the second stage with supercold liquid oxygen and liquid hydrogen propellants.

Testing of communications links between the rocket and Air Force Eastern Range will occur after fueling is accomplished. Steering checks of the first stage RS-68 engine and second stage RL10 powerplant are on tap in the last hour of the count.

A build-in hold is slated for T-minus 4 minutes, during which time teams will go through final polling to grant clearance to launch. The Delta 4 will transition to internal power as the count resumes, ordnance will be armed and the propellant tanks pressurized as clocks target the main engine ignition time at T-minus 5 seconds.

Liftoff remains scheduled for 2:36 p.m. EDT, the opening of an 18-minute window that extends to 2:54 p.m. EDT (1836-1854 GMT).

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TUESDAY, MARCH 24, 2015
The ninth new-generation satellite for the Global Positioning System and its United Launch Alliance Delta 4 rocket booster have been cleared for blastoff into the navigation network Wednesday from Cape Canaveral.

The GPS 2F-9 spacecraft is targeting an 2:36 p.m. EDT launch from Complex 37. An 18-minute window extending to 2:54 p.m. EDT will be available if conditions prevent an on-time liftoff.

Managers gathered this morning for the Launch Readiness Review that culminated with the consensus to proceed with picking up the countdown Wednesday morning.

"ULA is proud to be the launch provider and serve in an essential role in placing this critical capability in orbit," said Ron Fortson, United Launch Alliance's director of mission management. "Thanks to all our mission partners who have worked tirelessly to make this launch a success."

We will have complete live coverage of the count and launch here in our Mission Status Center.

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Boeing developed a dozen Block 2F satellites to sustain and further upgrade the Global Positioning System for the U.S. Air Force. The first was launched in May 2010.

They feature improved accuracy, enhanced internal atomic clocks, better anti-jam resistance, a civil signal for commercial aviation, a longer design life and reprogrammable onboard processors to evolve with future needs.

"Significant investments to modernize the GPS constellation are in work, to include higher power from space, military receivers that are more resistant to jamming, new encryption algorithms, key management agility and innovative software processing to increase resistance to spoofing," said Brig. Gen. Bill Cooley, director of Space and Missile Systems Center's Global Positioning Systems Directorate.

"We are focused on mission success and stand ready to launch the ninth GPS 2F space vehicle, this will continue modernization of the GPS constellation and maintain the high level of accuracy required by the GPS system."

About three-and-a-quarter hours after liftoff Wednesday, the Delta 4 rocket will deliver the satellite directly to the GPS constellation's altitude 11,047 nautical miles high, inclined 55 degrees to the equator.

MONDAY, MARCH 23, 2015
The weather is looking favorable for launching the Delta 4 rocket on Wednesday afternoon from Cape Canaveral, with forecasters giving an 80 percent chance of meeting the launch rules.

"A weak front will move into the area Monday bringing showers and just a slight chance of a thunderstorm. No severe weather is expected. The front will move off to the east Tuesday, and high pressure will build in to the north improving weather," the Air Force weather team reports.

"On launch day, the high pressure a rea to the north will move east causing winds to shift to the southeast and increase through the day. The onshore wind along with low-level moisture will cause isolated morning coastal showers, but showers will decrease by the afternoon launch window.

"The primary concern for launch are flight through precipitation and cumulus clouds."

The specifics include scattered clouds, good visibility, southeasterly winds of 15 gusting to 22 knots and a temperature of 76 degrees F.

SUNDAY, MARCH 22, 2015
PREVIEW: The final year of launches in the current breed of Global Positioning System navigation satellites kicks off Wednesday afternoon aboard a Delta 4 rocket from Cape Canaveral.

GPS 2F-9 is slated for liftoff during a window of 2:36 to 2:54 p.m. EDT and will follow a flight azimuth of 46 degrees, heading up the Eastern Seaboard.

Read our preview story.