A rocket launch to serve the world blasted off Friday night from Florida carrying a new Global Positioning System satellite to transmit omnipresent navigation and timing information to users across the planet.

Read our launch story.

MISSION SUCCESS! The Centaur upper stage completed its second burn and released the Global Positioning System 2F-7 satellite into the navigation network to complete tonight's launch of the Atlas 5 rocket.

"Congratulations to the U.S. Air Force and all of our mission partners on the successful launch of the Atlas 5 carrying the GPS 2F-7 satellite," said Jim Sponnick, ULA vice president, Atlas and Delta Programs. "ULA launch vehicles have delivered all of the current generation of GPS satellites, which are providing ever-improving capabilities for users around the world."

We will pause our live updates at this time. Check back later for confirmation of the second Centaur burn and deploy of the GPS 2F-7 satellite to complete today's mission.

T+plus 17 minutes, 30 seconds. MECO 1. Centaur's main engine has shut down following its first burn today, achieving a transfer orbit to reach the GPS network around Earth. The rocket will coast in this orbit for about 3 hours before the RL10 engine re-ignites to circularize the orbit and then deploys the satellite.

T+plus 16 minutes, 50 seconds. Centaur systems continue to be in good shape as the rocket nears the planned orbit.

T+plus 16 minutes, 25 seconds. The rocket traveling at 20,142 mph.

T+plus 16 minutes, 15 seconds. Everything looking normal with one minute to go in this burn.

T+plus 15 minutes, 25 seconds. RL10 engine parameters still look good.

T+plus 14 minutes, 45 seconds. The rocket traveling over 17,000 mph.

T+plus 13 minutes. Centaur remains on course and looking good.

T+plus 12 minutes, 15 seconds. About five minutes are left in this burn of Centaur.

T+plus 10 minutes. All systems reported stable as the Centaur fires to reach an initial Earth orbit.

T+plus 9 minutes. Centaur performance is reported right on target.

T+plus 7 minutes, 45 seconds. The rocket is tracking right down the planned flight path.

T+plus 5 minutes. Centaur engine readings look good as this burn gets underway.

T+plus 4 minutes, 37 seconds. The two halves of the four-meter-diameter Atlas 5 rocket nose cone encapsulating the spacecraft have separated.

T+plus 4 minutes, 25 seconds. Centaur has ignited! The RL10 engine is up and running at full thrust to power the vehicle into orbit.

T+plus 4 minutes, 15 seconds. The Atlas 5's Common Core Booster has been jettisoned, completing the first stage of flight, and the Centaur upper stage's liquid hydrogen and liquid oxygen systems are being readied for engine start.

T+plus 4 minutes, 8 seconds. BECO. Booster Engine Cutoff is confirmed as the RD-180 powerplant on the first stage completes its burn. Standing by to fire the retro thrusters and separate the spent stage.

T+plus 3 minutes, 45 seconds. Atlas now weighs just a quarter of what it did at liftoff.

T+plus 2 minutes, 45 seconds. Reaction control system has been activated.

T+plus 2 minutes, 35 seconds. Atlas continues tracking on course.

T+plus 2 minutes, 30 seconds. Atlas now weighs half of what it did at liftoff.

T+plus 2 minutes, 15 seconds. Vehicle systems looking good.

T+plus 1 minutes, 45 seconds. The RD-180 main engine continues to fire normally, burning a mixture of highly refined kerosene and liquid oxygen.

T+plus 100 seconds. Now passing through the region of maximum aerodynamic pressure on the vehicle as its accelerates through the dense lower atmosphere.

T+plus 85 seconds. All looks good aboard Atlas as it passes Mach 1.

T+plus 60 seconds. One minute into the ascent of GPS 2F-7.

T+plus 40 seconds. The Atlas 5 is sending a thunderous roar across Florida's spaceport as it climbs into a clear night sky over Cape Canaveral.

T+plus 15 seconds. The Atlas 5 rocket has cleared the tower on 860,000 pounds of thrust from the RD-180 main engine. Pitch, yaw and roll maneuvers are underway to put the rocket on the proper heading.

T-minus 10, 9, 8, 7, 6, 5, 4, 3, engine ignition, 1, 0 and LIFTOFF! Liftoff of the Atlas 5 rocket with a new GPS navigation satellite to serve the world. And the vehicle has cleared the tower!

T-minus 20 seconds. "Go Atlas" and "Go Centaur" was just called by launch team during a final status check.

T-minus 55 seconds. Range is green.

T-minus 1 minute. Now 60 seconds away from launch of GPS 2F-7.

T-minus 90 seconds. The rocket's safety system has been armed.

T-minus 1 minute, 45 seconds. Liquid oxygen and liquid hydrogen propellant topping to the Centaur upper stage is being secured.

T-minus 1 minute, 55 seconds. The launch sequencer has been commanded to start.

T-minus 2 minutes. The Atlas first stage and Centaur upper stage are now switching from ground power to internal batteries.

T-minus 2 minutes, 30 seconds. The first stage RP-1 kerosene fuel tank and the liquid oxygen have stepped up to proper flight pressure levels.

T-minus 3 minutes. The Atlas first stage liquid oxygen replenishment is being secured so the tank can be pressurized for launch.

T-minus 3 minutes, 50 seconds. The ground pyrotechnics are enabled.

T-minus 4 minutes and counting. Clocks have resumed for the final minutes of today's countdown to launch the Atlas 5 rocket with a new spacecraft for the GPS network from Cape Canaveral, Florida.

Standing by to pick up the count.

ULA launch director and Air Force mission director have given their respective final approvals to resume the countdown.

Polling of the team by Atlas launch conductor just occurred. All systems are "go" for a liftoff today at 11:23 p.m. EDT.

Standing by for the final readiness check to be conducted. The launch team will be polled for a "go" or "no go" to proceed with the count.

All is quiet in the countdown.

This will be...

• The 629th launch for Atlas program since 1957
• The 337th Atlas to occur from Cape Canaveral
• The 218th mission for the Centaur upper stage
• The 195th use of Centaur by an Atlas rocket
• The 450th production RL10 engine to be launched
• The 53rd flight of the RD-180 main engine
• The 47th launch of an Atlas 5 since 2002
• The 74th Evolved Expendable Launch Vehicle flight
• The 17th Department of Defense launch of Atlas 5
• The 39th Atlas 5 to occur from the Cape
• The 86th United Launch Alliance flight overall
• The 39th Atlas 5 under United Launch Alliance
• The 31st 400-series flight of the Atlas 5
• The 23rd Atlas 5 to fly in the 401 configuration
• The 5th Atlas launch of 2014
• The 67th GPS satellite to launch
• The 43rd Boeing-built GPS satellite
• The 7th GPS Block 2F satellite
• The 12th GPS launch on an Atlas rocket
• The 2nd Block 2F launch on Atlas 5

The first stage liquid oxygen tank and Centaur's liquid oxygen and liquid hydrogen tanks are reported at flight level.

T-minus 4 minutes and holding. The countdown has entered the planned 20-minute hold to give the launch team a chance to review all systems before pressing ahead with liftoff.

T-minus 5 minutes. Standing by to go into the final built-in hold.

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Just 30 minutes until liftoff time. The Atlas 5 rocket launching GPS 2F-7 is known as the 401 model. It has a common first stage with no solid rocket boosters, a cryogenic, single-engine Centaur upper stage, and a 4-meter-diameter payload shroud.

The first stage is fueled by RP-1, a highly refined kerosene, and supercold liquid oxygen. The RD-180 main engine, made by NPO Energomash, generates about 860,000 pounds of thrust. Known as the Common Core Booster, or CCB, the stage measures 42 feet in length and 10 feet diameter.

The Centaur stage features a restartable Aerojet Rocketdyne RL10A-4-2 engine burning liquid hydrogen and liquid oxygen. The total thrust is 22,300 pounds.

Protecting the payload during atmospheric ascent is the payload fairing measuring 39 feet in length and 14 feet in diameter. It is an aluminum nose cone built in two halves.

The Atlas 5 stands 189 feet tall and weighs about 745,000 pounds at liftoff.

The fuel-fill sequence for the first stage main engine is starting.

Now 45 minutes from liftoff. Today marks the 47th flight for Atlas 5, born of the Air Force's competition to develop next-generation Evolved Expendable Launch Vehicles. In its previous 46 missions since debuting in August 2002, the tally shows 16 flights dedicated to the Defense Department, 11 for NASA, 10 with spy satellites for the National Reconnaissance Office. and 9 commercial missions with communications spacecraft

A check of the weather shows all the current observed conditions are GO and the forecast GO.

Fast-filling of the first stage liquid oxygen tank has been completed. Topping mode is now underway.

Now 60 minutes from liftoff. Fueling of the Atlas rocket with cryogenic liquid oxygen and liquid hydrogen is progressing smoothly as the countdown continues on schedule for a liftoff at 11:23 p.m. EDT.The weather is forecast to be acceptable.

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The liquid hydrogen tank in the Centaur upper stage just reached the 96 percent level. Topping is now beginning.

Centaur's liquid hydrogen tank is 30 percent full. The cryogenic propellant will be consumed with liquid oxygen by the stage's Aerojet Rocketdyne-made RL10 engine.

Chilldown of the liquid hydrogen system has been accomplished. The launch team has received the "go" to begin filling the Centaur upper stage with the supercold fuel.

First stage liquid oxygen tank is 40 percent full thus far. Chilled to Minus-298 degrees F, the liquid oxygen will be used with RP-1 kerosene by the RD-180 main engine on the first stage during the initial four minutes of flight today. The 25,000 gallons of RP-1 were loaded into the rocket prior to today.

The first stage liquid oxygen tank has reached the 20 percent mark.

The first stage liquid oxygen loading is transitioning from slow-fill to fast-fill mode.

The Centaur liquid oxygen tank reached the 96 percent level. The topping off process is starting now.

The chilldown conditioning of liquid hydrogen propellant lines at Complex 41 is starting to prepare the plumbing for transferring the Minus-423 degree F fuel into the rocket. The Centaur holds about 12,300 gallons of the cryogenic propellant.

Centaur liquid oxygen is 75 percent loaded.

The conditioning of the systems for the first stage liquid oxygen tank have been completed. And a "go" has been given to begin pumping supercold liquid oxygen into the Atlas 5's first stage.

The Common Core Booster stage's liquid oxygen tank is the largest tank to be filled today. It holds 48,750 gallons of cryogenic oxidizer for the RD-180 main engine.

Passing the 30 percent level on the Centaur upper stage's liquid oxygen tank.

Filling of the Centaur upper stage with about 4,100 gallons of liquid oxygen has begun at Cape Canaveral's Complex 41 following the thermal conditioning of the transfer pipes.

The liquid oxygen -- chilled to Minus-298 degrees F -- will be consumed during the launch by the Centaur's single RL10 engine along with liquid hydrogen to be pumped into the stage a little later in the countdown.

The Centaur liquid oxygen pad storage area has been prepped. The next step is conditioning the transfer lines, which is now beginning to prepare the plumbing for flowing the cryogenic oxidizer.

T-minus 120 minutes and counting! The launch countdown has resumed for today's flight of the Atlas 5 rocket on the GPS 2F-7 mission.

Clocks have one more built-in hold planned at T-minus 4 minutes. That pause will last 10 minutes during which time the final "go" for launch will be given. All remains targeted for liftoff at 11:23 p.m. EDT from Cape Canaveral's Complex 41.

In the next couple of minutes, chilldown thermal conditioning of the mobile launch platform upon which the rocket stands will begin. This is meant to ease the shock on equipment when supercold cryogenic propellants start flowing into the rocket.

All console operators have reported GO status during the pre-fueling readiness poll. The ULA launch director also voiced his approval for moving forward with the countdown as scheduled today.

Loading of cryogenic liquid oxygen and liquid hydrogen into the Atlas 5 rocket will be getting underway a short time from now.

The ULA launch conductor at the Atlas Spaceflight Operations Center is briefing his team on procedures before entering into the final two hours of the countdown.

Man stations for cryogenic tanking, that's the call now going out.

The final hands-on work has wrapped up at the launch pad and technicians have departed the complex. Safety officials just confirmed that the surrounding danger area has been cleared of all workers for the remainder of the countdown.

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T-minus 2 hours and holding. The countdown has just entered the first of two planned holds over the course of the day that will lead to the 11:23 p.m. EDT launch of the Atlas 5 rocket.

This initial pause was designed to give the team some margin in the countdown timeline to deal with technical issues or any work that could fall behind schedule before fueling starts.

The final hold will occur at T-minus 4 minutes.

Guidance system testing has been accomplished as the countdown goes on today at Cape Canaveral.

The hazard area roadblocks around the launch site's safety perimeter have been established. Also, the launch team is configuring the pad's water deluge system.

The brief Phase 2 has been cancelled.

A new Phase 2 has just been issued.

The Phase 2 lightning warning for the launch pad has ended and technicians are again working to get the Atlas 5 rocket readied for launch tonight. There's an 80 percent chance of acceptable conditions for tonight's launch window.

The countdown begins now for tonight's launch of the Atlas 5 rocket to deploy the Global Positioning System 2F-7 satellite.

Clocks are picking up the seven-hour sequence of work that will prepare the booster, payload and ground systems for blastoff at 11:23 p.m. EDT (0323 GMT).

Soon the launch team will begin powering up the rocket to commence standard pre-flight tests. Over the subsequent few hours, final preps for the Centaur's liquid oxygen and liquid hydrogen systems will be performed, along with a test of the rocket's guidance system and the first stage propulsion and hydraulic preps, internal battery checks and a test of the S-band telemetry relay system. The Complex 41 site will be cleared of all personnel at 8:18 p.m.

A planned half-hour hold begins at 8:33 p.m. when the count reaches T-minus 120 minutes. Near the end of the hold, the team will be polled at 8:51 p.m. to verify all is in readiness to start fueling the rocket for launch.

Supercold liquid oxygen begins flowing into the Centaur upper stage around 9:20 p.m., followed by the first stage filling around 9:33 p.m. Liquid hydrogen fuel loading for Centaur will be completed a short time later.

A final hold is scheduled at the T-minus 4 minute mark starting at 10:59 p.m. That 20-minute pause will give everyone a chance to finish any late work and assess the status of the rocket, payload, Range and weather before proceeding into the last moments of the countdown.

The launch window opens at 11:23 and extends to 11:41 p.m. EDT (0323-0341 GMT).

An Atlas 5 rocket has been rolled out to its launch pad at Cape Canaveral for blastoff Friday to deploy a replacement satellite to strengthen the Global Positioning System for U.S. military forces and the worldwide economy.

A photo gallery of today's rollout is posted here.

The United Launch Alliance booster was wheeled to Cape Canaveral's Complex 41 shortly after 8 a.m. EDT today aboard a mobile platform, emerging from the assembly building where the rocket's two stages and the payload were integrated over the past month.

This slow half-hour drive from the 30-story Vertical Integration Facility to the launch pad used a pair of specially-made "trackmobiles" to carry the rocket's 1.4-million pound mobile launching platform along rail tracks for the 1,800-foot trip.

The 189-foot-tall satellite booster was moved to Complex 41 for launch of GPS 2F-7, the latest satellite to replenish and upgrade the navigation network.

The rocket is flying the 401 vehicle configuration for the 23rd time in 47 flights. The version features just two stages, no solid rocket boosters and a four-meter-diameter nose cone. It is powered off the launch pad by an RD AMROSS RD-180 main engine and the Centaur upper stage is equipped with an Aerojet Rocketdyne RL10.

Countdown clocks begin ticking Friday at 4:13 p.m. EDT, leading to activation of the rocket, final testing and system preps. Fueling operations start at 9:13 p.m.

The day's available launch opportunity begins at 11:23 p.m. and closes at 11:41 p.m. EDT to send the rocket on a northeasterly heading into the GPS constellation.

There is an 80 percent chance of acceptable weather.

Watch this page for live updates throughout the countdown and flight, plus live streaming video.

If you will be away from your computer but would like to receive occasional status checks, sign up for our Twitter feed to get text message updates sent to your cellphone. U.S. readers can also sign up from their phone by texting "follow spaceflightnow" to 40404. (Standard text messaging charges apply.)

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The Launch Readiness Review was held today and reported all systems are proceeding for liftoff of the Atlas 5 rocket on Friday.

Liftoff is planned for 11:23 p.m. EDT at the opening of an 18-minute launch window.

The rocket will be rolled from its assembly building to the launch pad at Cape Canaveral's Complex 41 on Thursday morning at 8 a.m. EDT. The countdown begins Friday at 4:23 p.m. EDT, followed by the start of fueling at 9:23 p.m. EDT.

The weather forecast calls for a 70 percent chance of acceptable conditions.

It will the second flight this week for United Launch Alliance after Monday's successful Delta 4 rocket mission.

The next Global Positioning System satellite was mated atop its booster rocket today, marking a critical step towards the planned July 31 launch into space.

The GPS 2F-7 satellite will ride a United Launch Alliance Atlas 5 rocket into the navigation network from Cape Canaveral, Florida.

The direct-insertion launch will be possible during a nighttime window of 11:27 to 11:45 p.m. EDT.

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