RECAP STORY: Revolutionizing the way American meteorologists see the weather, likened to the advancement from black and white television to modern high definition TV, a new observatory was successfully launched today by an Atlas 5 rocket to serve as the linchpin to forecasting what tomorrow will bring.

Read our launch story.

"The next generation of weather satellites is finally here," said NOAA Administrator Kathryn Sullivan. "GOES-R will strengthen NOAA's ability to issue life-saving forecasts and warnings and make the United States an even stronger, more resilient weather-ready nation."

"We are honored that NASA and NOAA have entrusted ULA with the launch of the GOES-R satellite and grateful for the phenomenal teamwork that made today's launch a success," said Laura Maginnis, ULA vice president of Custom Services.

"ULA's Atlas and Delta vehicles successfully launched every operational GOES satellite, beginning with the launch of GOES-A in 1975,” said Maginnis. "We are proud to have partnered with NASA and NOAA in continuing to deliver this capability to millions around the globe."

The power-generating solar array on GOES-R has unfolded from its stowed launch position, completing its first major milestone in orbit.

In the coming nine days, the craft will execute five maneuvers by the main engine to circularize the orbit at geostationary altitude 22,300 miles above the equator.

It will undergo a year-long checkout and validation campaign at 89.5 degrees West longitude before drifting into one of the operational GOES orbital slots.

Solar array has begun.

The next Atlas 5 rocket launch from Cape Canaveral, a 431-configured vehicle with three solid-fuel boosters, is planned for Dec. 16 at 1:22 p.m. EST (1822 GMT). The flight will deliver the commercial EchoStar 19 broadband internet satellite into space for use across the U.S. by HughesNet.

This was the 138th successful Atlas program launch in a row spanning more than two decades and the 67th for an Atlas 5.

GOES-R has been delivered into the correct orbit by the Atlas 5 rocket.

T+plus 3 hours, 32 minutes, 5 seconds. SPACECRAFT SEPARATION! The Centaur upper stage has deployed the advanced GOES-R satellite to revolutionize weather forecasting across U.S.

T+plus 3 hours, 31 minutes. Centaur has re-oriented to to the proper condition for deploy.

T+plus 3 hours, 29 minutes, 15 seconds. MECO 3. Centaur has shut down its single Aerojet Rocketdyne RL10C engine, completing the third burn of the day to raise the orbit's low point and reduce orbital inclination for the GOES-R spacecraft.

T+plus 3 hours, 27 minutes, 44 seconds. Ignition! The RL10C-1 engine running again for its third firing during this launch. It is a planned 93-second firing.

T+plus 3 hours, 22 minutes. Five minutes away from the burn. Centaur is reorienting to the proper position for the next engine firing.

Now one hour away from the Centaur's third burn. The upper stage is performing normally as it coasts above the Indian Ocean, heading away from Earth in a highly elliptical transfer orbit.

A video replay of today's launch is posted here.

T+plus 37 minutes, Current velocity is 20,284 mph.

We will pause our live updates at this time. Check back around 10:09 p.m. EST for coverage of the third Centaur burn and deploy of the GOES-R satellite to complete today's mission.

T+plus 30 minutes. Centaur now begins a quiet three-hour coast through space, moving higher and away from the planet before the third and final burn occurs three hours and 27 minutes into flight. Deployment of GOES-R from the rocket to complete the launch is expected 3 hours, 32 minutes after launch.

T+plus 29 minutes, 30 seconds. The second burn by Centaur inserted the rocket into another precise orbit as targeted.

T+plus 27 minutes, 40 seconds. MECO 2. Main engine cutoff confirmed. Centaur has completed its second burn of the day, this one taking the next step upwards to substantially increase the altitude from the previous parking to nearly geosynchronous height.

T+plus 26 minutes, 45 seconds. Engine performance remains normal.

T+plus 25 minutes, 40 seconds. About two minutes are left in the burn to reach the next orbit. Everything continues to look nominal.

T+plus 23 minutes. Continued good engine operation is being delivered by the RL10C, no problems reported.

T+plus 22 minutes, 45 seconds. The engine is burning well. This is a planned five-and-a-half-minute firing by the Centaur's single Aerojet Rocketdyne RL10C engine.

T+plus 22 minutes, 6 seconds. Ignition! The Centaur's single RL10C engine has re-ignited to climb into a highly elliptical intermediate orbit on the way to the final perch later today.

T+plus 21 minutes, 56 seconds. Liquid hydrogen and liquid oxygen system prestarts are underway.

T+plus 21 minutes. Centaur getting into its pressurization sequence.

T+plus 20 minutes. Velocity currently 17,692 mph.

T+plus 19 minutes. The flight path is taking the vehicle over the equatorial Atlantic Ocean, soon to near the western coast of Africa where the next Centaur burn will occur. It will soar away from the Indian Ocean over the course of the next couple of hours before the RL10C restarts for a final time to accelerate GOES-R into the geosynchronous transfer orbit and separating the payload.

T+plus 18 minutes. Centaur is half-way through this coast period. It is completing a slow roll to keep thermal heating even across the rocket's surfaces.

T+plus 14 minutes, 30 seconds. That first burn by Centaur inserted the rocket into the precise target orbit as planned.

T+plus 12 minutes, 26 seconds. MECO 1. Centaur's main engine has shut down following its first burn today, achieving a preliminary orbit around Earth. The rocket will coast in this orbit for about 10 minutes before the RL10C engine re-ignites for the next burn.

T+plus 12 minutes, 1 second. Centaur is now orbital.

T+plus 11 minutes, 30 seconds. About one minute 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. The RL10C continues to perform well, burning liquid hydrogen and liquid oxygen propellants.

T+plus 8 minutes, 55 seconds. Vehicle traveling at 15,290 mph.

T+plus 7 minutes, 15 seconds. The rocket has performed a planned roll to improve antenna links with NASA's orbiting Tracking and Data Relay Satellite System.

T+plus 6 minutes, 30 seconds. A look at first stage performance numbers show a nominal burn by the booster.

T+plus 6 minutes. RL10C performing well.

T+plus 5 minutes. Nearly 95 percent of the rocket's liftoff mass has been shed. Centaur engine readings look good as this burn gets underway.

T+plus 4 minutes, 44 seconds. Centaur has ignited! The RL10C engine is up and running at full thrust for its first of three firings today to reach the intended geosynchronous transfer orbit.

T+plus 4 minutes, 37 seconds. The Atlas 5's Common Core Booster first stage has been jettisoned, and the Centaur upper stage's liquid hydrogen and liquid oxygen systems are being readied for engine start.

T+plus 4 minutes, 27 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, 42 seconds. The two-halves of the Atlas 5 rocket nose cone encapsulating the GOES-R spacecraft have separated, exposed the satellite to space. Also jettisoned was the Forward Load Reactor, a two-piece deck that rings the Centaur stage to support the bulbous fairing during launch.

T+plus 3 minutes, 30 seconds. The RD-180 main engine continues to fire normally, burning a mixture of highly refined kerosene and liquid oxygen.

T+plus 3 minutes. The vehicle weighs just a quarter of what it did at liftoff.

T+plus 2 minutes, 50 seconds. Reaction control system has been activated.

T+plus 2 minutes, 40 seconds. Everything still looking good on the first stage as the rocket powers downrange on the thrust being produced by the main engine.

T+plus 2 minutes, 30 seconds. Vehicle is right on course.

T+plus 1 minute, 53 seconds. All four of the Aerojet Rocketdyne-made solid rocket motors have successfully separated from the Atlas 5, having completed their job of adding a powerful kick at liftoff.

T+plus 93 seconds. Solid rocket booster burnout has occurred. But the spent motors will remain attached to the first stage for a few seconds, until the Atlas 5 reaches a point where the airborne dynamic pressure reduces to an allowable level for a safe jettison.

T+plus 60 seconds into this complex three-and-a-half-hour mission to deploy the Geostationary Operational Environmental Satellite-R in a high-perigee geosynchronous transfer orbit.

T+plus 50 seconds. A period of maximum dynamic pressure is being experienced by the rocket.

T+plus 40 seconds. The main engine is throttling down to ease the stresses on the vehicle in the lower atmosphere.

T+plus 38 seconds. Mach 1.

T+plus 30 seconds. The vehicle is heading due eastward to reach a 28-degree inclination preliminary parking orbit 12 minutes from now.

T+plus 15 seconds. Pitch, yaw and roll maneuvers are underway as the Atlas 5 thunders away from Cape Canaveral with its RD-180 engine and four solid rocket boosters burning.

LIFTOFF! Liftoff of the 100th Evolved Expendable Launch Vehicle and the GOES-R spacecraft for the future of weather forecasting across America!

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

T-minus 40 seconds. Centaur's liquid oxygen and liquid hydrogen tanks are stable at flight pressures.

T-minus 55 seconds. Range is green.

T-minus 1 minute. Now 60 seconds away from launching the most advanced U.S. weather satellite in history.

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 from Cape Canaveral, Florida.

Standing by to pick up the count.

The ULA launch director has given the final approval to resume the countdown.

Polling of the team by Atlas launch conductor just occurred. All systems are reported GO for flight.

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.

NASA Launch Director Omar Baez has performed the agency's clear-to-launch poll and the advisory team is working no issues.

Range issue has been resolved.

GOES-R is switching to internal battery power for launch.

But now the Eastern Range is working an issue.

Issue has been resolved! There is no concern with the GOES-R vehicle.

NASA says the upper level wind conditions are acceptable through the rest of tonight's launch window.

ULA President Tory Bruno says this particular Atlas 5 rocket appears to be fine, but test data with another rocket has called a component into question. Engineers doing due diligence to verify.

The launch window is formally open.

Tonight's available launch window extends 60 minutes to 6:42 p.m. EST (2342 GMT).

An issue with a component in ground testing has prompted the anomaly team to review the situation.

Liftoff has been delayed at least five minutes.

T-minus 4 minutes and holding. The countdown has entered the planned. But due to a technical issue that has arisen, liftoff will be delayed a few minutes at least.

T-minus 6 minutes. Standing by to go into the final built-in hold.

Here's a look at some stats about today's mission. This will be:

• The 649th launch for Atlas program since 1957
• The 354th Atlas launch from Cape Canaveral
• The 238th mission of a Centaur upper stage
• The 215th use of Centaur by an Atlas rocket
• The 474th production RL10 engine to be launched
• The 15th RL10C-1 engine launched
• The 73rd flight of an RD-180 main engine
• The 83-84-85-86th AJ-60 solid rocket booster flown
• The 67th launch of an Atlas 5 since 2002
• The 14th NASA use of Atlas 5
• The 55th launch of an Atlas 5 from Cape Canaveral
• The 7th Atlas 5 launch of 2016
• The 100th Evolved Expendable Launch Vehicle flight
• The 113rd United Launch Alliance flight overall
• The 59th Atlas 5 under United Launch Alliance
• The 27th NASA launch by United Launch Alliance
• The 81st United Launch Alliance flight from Cape Canaveral
• The 22nd 500-series flight of the Atlas 5
• The 4th Atlas 5 to fly in the 541 configuration
• The 82nd launch from Complex 41
• The 55th Atlas 5 to use Complex 41

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

GOES-R will work in geostationary orbit 22,300 miles above Earth as an operational U.S. weather observer for forecasting. The existing generation of GOES spacecraft occupies the western and eastern observation posts and the spare slot in the middle. GOES-R will be assigned one of the functional slots in about six months, after initial on-orbit testing.

Weather is observed GO for liftoff based on the current conditions and forecast to stay favorable for an 5:42 p.m. EST (2242 GMT) launch today.

Just 30 minutes until liftoff time. Standing by for the final status check on the weather.

The 1.2-million-pound Atlas 5 rocket now stands fully fueled for launch as the countdown continues on schedule for a liftoff at 5:42 p.m. EST (2242 GMT).

Today's launch uses the 541 version of the Atlas 5 rocket, generating the necessary power to lift the GOES-R weather satellite into a customized geosynchronous transfer orbit.

The United Launch Alliance Atlas 5 rocket will come off the pad on 2.4 million pounds of thrust produced by the RD-180 main engine and four solid-fuel strap on boosters.

It stands 197 feet tall.

The 541 has flown three times before, all successfully, to launch NASA's Curiosity rover to Mars in 2011 and a pair of classified National Reconnaissance Office missions in 2014.

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

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

Now 50 minutes from liftoff. Today marks the 67th flight for Atlas 5, born of the Air Force's competition to develop next-generation Evolved Expendable Launch Vehicles. In its previous 66 missions since debuting in August 2002, the Atlas 5 has flown 25 flights dedicated to the Defense Department, 15 commercial missions, 13 for the National Reconnaissance Office and 13 for NASA.

First stage liquid oxygen tank is 80 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 after rollout yesterday.

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.

Now 60 minutes from liftoff.

Today marks the 17th launch of an operational GOES weather satellite for the U.S. since 1975. At 11,500 pounds and equipped with massive technological upgrades, GOES-R is the largest, most sophisticated and most capable one ever fielded.

"This is a quantum leap that we've not seen since introduction of geostationary program in the 70s," said Greg Mandt, NOAA's GOES-R program manager.

The first stage liquid oxygen tank has reached the 50 percent mark.

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.

The Centaur engine chilldown sequence is being initiated.

Centaur liquid oxygen tank has reached flight level.

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.

Now at the 80 percent level on the Centaur upper stage's liquid oxygen tank.

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.

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 48,800 gallons of cryogenic oxidizer for the RD-180 main engine.

Now half-full on the Centaur upper stage's liquid oxygen tank.

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

Passing the 10 percent level on the Centaur upper stage's liquid oxygen tank.

Filling of the Centaur upper stage with about 4,150 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 will perform three firings required to propel the GOES-R spacecraft into the proper orbit today.

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 2 hours and counting! The launch countdown has resumed for today's flight of the Atlas 5 rocket to deploy the GOES-R weather satellite.

Clocks have one more built-in hold planned at T-minus 4 minutes. During that 6-minute pause, the final "go" for launch will be given. All remains targeted for liftoff at 5:42 p.m. EST (2242 GMT) 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 READY status during the pre-fueling readiness poll. The ULA launch director also voiced his approval for moving forward with the countdown today.

The loading of nearly 66,000 gallons 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.

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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Nine minutes are being moved from the later T-minus 4 minute hold and added to this current hold. That will give the team a bit more time to finish up the checklists before fueling. It will not impact the launch time.

The final hands-on work has wrapped up at the launch pad and technicians are departing the complex.

T-minus 2 hours and holding. The countdown has just entered the first of two planned, 15-minute holds over the course of the day that will lead to the 5:42 p.m. EST (2242 GMT) launch of the Atlas rocket. The holds give the team some margin in the countdown timeline to deal with technical issues or any work that is running behind. The final hold is scheduled to occur at T-minus 4 minutes.

In the pre-fueling briefing, the launch weather officer from the Air Force reports conditions remain favorable this afternoon at Cape Canaveral.

The odds of acceptable weather have improved to 100 percent.

The outlook now predicts just scattered low-level clouds, good visibility, northwesterly winds of 14 to 18 knots and a temperature of 74 degrees F.

The early portion of the countdown has progressed at Cape Canaveral towards the launch of GOES-R at 5:42 p.m. EST (2242 GMT).

At around 3:24 p.m. EST (2024 GMT), the launch team will be polled for readiness to begin fueling the Atlas 5 rocket. Tanking is scheduled to start a short time later.

Launch of GOES-R is just four hours away now. The heart of the satellite is the ABI -- the Advanced Baseline Imager -- made by Harris Corp. and integrated into the Lockheed Martin-built spacecraft.

ABI will produce 95 percent of the data from GOES-R, downlinking the equivalent of 210 HD movies every day.

"The primary purpose is imaging so that you get the cloud pictures that you see on the weather (during the news) every night. Right now, what you see is what has been happening. Every half hour you get a clip and you make a nice loop," said Greg Mandt, NOAA's GOES-R program manager.

"(With GOES-R), we will be able to take the whole hemisphere every five minutes or, better yet, a hurricane or a big thunderstorm, we'll be able to focus in and do updates every 30 seconds. And we get the data to forecasters in seconds to minutes.

"In a sense, they will have almost like watching a camera real-time, so they really can watch what's going on and how it's unfolding and make much more precise warnings of significant weather events."

The satellite also carries the first Geostationary Lightning Mapper, a high-speed camera to detect in-cloud and cloud-to-ground lightning over the Americas and surrounding ocean areas to increase the warning time for severe weather.

"That's basically looking at the Earth and taking pictures 200 times per second and comparing one to the next so that you capture every element of a lightning flash," said Mandt.

"What the researchers have found is that where you have a tremendous growth in the number of flashes going on, that is where the severe storms are really starting to grow. By getting the data to the forecasters in seconds, they get an earlier indication of tornado formation.

"You can also be more confident in a forecast. Today, we over-warn like 80 percent of the time. This, hopefully, will cut that in half, so people will know if they get a tornado warning, indeed, they want to react."

Now just five hours away from the launch of GOES-R, a high-tech satellite to improve the collection of weather data and revolutionize forecasting across the U.S.

GOES-R is equipped with six Earth and space weather instruments, including a state-of-the-art camera to provide almost real-time high-resolution imagery of storms.

"NOAA's GOES-R satellite, with its advanced technologies, will be a game changer for weather forecasting and climate science for many years to come," said Stephen Volz, NOAA associate administrator for satellite and information services.

"For decades now, NOAA satellites have been the backbone of our increasingly accurate and timely weather and climate forecasts. However, this new four-satellite GOES series is really a quantum leap above any satellite NOAA has ever flown. Without a doubt, GOES-R will revolutionize weather forecasting as we know it."

Officials estimate GOES-R will transmit more data in six months of operation than all previous GOES weather satellites combined, and they expect to produce 1.75 terabytes of data products daily for the National Weather Service and other users.

"NOAA's GOES-R will scan the sky five times faster than the current GOES system with four times the spatial resolution and with three times the spectral bands....This means we'll have better quality data at high resolution far more often than we do today," said Joe Pica, director of the National Weather Service Office of Observations.

"And when we see an evolving weather system, we'll be able to zoom in and use that high spatial resolution to take pictures in 16 different spectral channels every 30 seconds," Pica said.

"This spectral imagery, combined with our doppler radar data, for example, will improve our understanding of whether a storm is growing or decaying. It'll help us track severe storms, including tornadoes, forecast wildfire movement, track plumes from volcanic eruptions and tell whether a hurricane is intensifying."

In this morning's first weather update, the outlook remains good for launching the Atlas 5 rocket later today at 5:42 p.m. EST (2242 GMT). Odds of acceptable weather during the 60-minute launch window stand at 90 percent.

"A dry and stable airmass over the Florida peninsula will erode an approaching cold front as the front tracks southeastward through the panhandle today and through Central Florida during the late evening/overnight hours," the Air Force meteorology team reports.

"Weather remains favorable during the count and window with only a small isolated shower threat. Winds will be from the northwest with gusts in the mid-teens during the count and upper teens during the window."

The outlook predicts just a few low-level clouds and scattered high-level clouds, good visibility, northwesterly winds of 14 to 19 knots and a temperature of 74 degrees F.

The management team will be briefed periodically during the countdown -- an hour after the clock starts, prior to fueling and a last scheduled status 30 minutes before the launch window opens.

The countdown just began for today's launch of the Atlas 5 rocket to deploy the long-awaited GOES-R satellite that represents the single biggest advancement in technology since the first geostationary weather observatory was deployed 41 years ago.

Clocks are picking up the seven-hour sequence of work that will prepare the booster, payload and ground systems for blastoff at 5:42 p.m. EST (2242 GMT).

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 testing of the GPS metric tracking system used to follow the rocket as it flies downrange, plus a test of the S-band telemetry relay system.

A planned 15-minute hold begins when the count reaches T-minus 2 hours. Near the end of the hold, the team will be polled to verify all is in readiness to start fueling the rocket for launch.

Supercold liquid oxygen begins flowing into the Centaur upper stage, followed by the first stage filling. 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. That 15-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 today lasts one hour to 6:42 p.m. EST (2342 GMT).

GOES-R will provide the National Weather Service forecasters vivid images of the weather five times faster with four times greater resolution and use triple the number of spectral channels compared with today's current GOES spacecraft.

The seven-hour countdown begins Saturday morning for the sequence of final preparations, testing and fueling of the United Launch Alliance Atlas 5 rocket that will propel the GOES-R weather observatory into space to track conditions across the U.S. with unprecedented resolution and speed.

"This is a huge leap," said Greg Mandt, NOAA's GOES-R program manager.

"This is like going from black and white television to HDTV -- just the crispness of what we are seeing...the sharpness of the pictures and the resolution."

Liftoff is targeted for 5:42 p.m. EST (2242 GMT) at the opening of a one-hour launch window.

The rocket was positioned atop Cape Canaveral's Complex 41 launch pad on Friday morning, following rollout from the vehicle assembly building.

See ULA photos of the rocket rollout.

Weather forecasters predict a 90 percent chance of acceptable conditions for the launch opportunity.

"On launch day, high pressure continues over Central Florida as the next relatively dry cold front pushes into the Florida panhandle Saturday morning. Weather remains favorable during the count and window with a small isolated shower threat. Winds will be from the north and north-northwest with gusts in the mid to upper teens during the count and mid-teens during the window," forecasters say.

The launch time outlook calls for scattered low- and high-level clouds, good visibility, northwesterly winds of 10 to 15 knots and a temperature of 74 degrees F.

Watch this page for live coverage throughout the countdown and flight of the Atlas-Centaur rocket.

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The Atlas 5, designated AV-069, will be making its 67th flight since 2002 and flying for the fourth time in the particular 541 configuration with four side-mounted solid rocket boosters. Stacking began Oct. 24.

The GOES-R spacecraft, since arriving at Kennedy Space Center from Lockheed Martin's Denver factory on Aug. 22, has undergone a series of final checks and the loading of 6,000 pounds of maneuvering fuel. It was encapsulated on Oct. 21 and mated atop the Atlas 5 on Nov. 9.

ROLLOUT: The 100th rocket in America’s Evolved Expendable Launch Vehicle program, the current fleet of boosters used by the nation to get its critical assets into space, was rolled to the pad this morning for a vital mission on Saturday.

Read our full story.

LRR: Mission managers today gave approval for rollout of the United Launch Alliance Atlas 5 rocket to its pad on Friday morning, leading to liftoff Saturday of the most advanced U.S. weather satellite in history.

The GOES-R observatory is scheduled for liftoff at 5:42 p.m. EST (2242 GMT) at the opening of a one-hour launch window.

Following a successful Flight Readiness Review on Tuesday, leaders gathered again today for the Launch Readiness Review that culminated with the formal consensus to proceed with the remaining pre-launch preparations based on the progress of work schedules and the lack of any technical issues.

"We completed our Launch Readiness Review this morning, and we plan to roll the vehicle out of the Vertical Integration Facility about 9:30 in the morning," said Omar Baez, the NASA launch director.

The GOES-R is the next in a long line of U.S. operational geostationary weather satellites that dates back to 1975. But this craft promises more data at better resolution streaming down quicker than ever before.

On Friday, the Atlas 5 rocket aboard its mobile launch platform will be rolled from the vertical assembly building to the pad at Cape Canaveral's Complex 41. The move, which covers 1,800 feet of rail track, should take about 40 minutes to complete.

The seven-hour countdown starts Saturday morning.

The launch will be the 67th for the Atlas 5.

Weather forecasters are optimistic, predicting a 90 percent chance of acceptable conditions.

"High pressure persists over Central Florida with favorable weather expected into launch day," Air Force forecasts said in the latest launch outlook this morning.

"Although slight, the primary concern for launch is cumulus clouds."

Clouds will be scattered, winds will be northwesterly at 10 to 15 knots and the temperature at 74 degrees F.

After three burns by the Centaur upper stage over three-and-a-half hours, the GOES-R spacecraft will be released into a transfer orbit, headed towards its final destination in geostationary orbit 22,300 miles above Earth.

The satellite will undergo six months of system testing and another six months of data validations before being ready for full operations.

PREVIEW: A new generation of spacecraft with unprecedented clarity and speed to observe the weather, improve forecasting and enhance tracking of severe storms across the United States begins with the launch of an Atlas 5 rocket on Saturday.

Read our full story.

WEATHER: Near-perfect weather for launching a rocket into space is expected at Cape Canaveral on Saturday when an Atlas 5 rocket is scheduled to fly.

Read our full story.