Marking only the fourth scrub-and-rollback scenario in 25 flights from Cape Canaveral, the Atlas 5 rocket returned to the assembly hangar tonight to wait out a prolonged hold until the next available launch opportunity on the Eastern Range.

High-altitude winds and thick clouds prevent the rocket from launching Thursday and Friday evenings to deploy a U.S. Navy mobile communications satellite. But faced with a booked Eastern Range for an unidentified operation over the next several days, managers opted to move the rocket to the nearby Vertical Integration Facility instead of leaving it exposed on the pad.

The earliest possible launch date for the Atlas is next Wednesday during a window of 5:23 to 6:07 p.m. EST (2223-2307 GMT).

However, there is a possibility the Range won't be available for the launch until Friday evening during a 44-minute window opening at 5:15 p.m. EST (2215 GMT).

The Air Force-controlled Range provides all of the necessary tracking, communications and safety services for rocket flights from the Cape. Only one event can occur at a time on the Range.

The Atlas 5 program at the Florida spaceport uses a "clean-pad" concept with minimal infrastructure and no service gantry at the launch complex. Instead, stacking of the rocket stages and pre-flight work is accomplished the user-friendly confines of the VIF building. A mobile launch platform transports the Atlas between the hangar and the pad, a distance of just 1,800 feet.

Three times in the history of the Atlas 5 program has a rocket been forced to roll back after a scrub. Those instances were caused by technical troubles that required hardware removal-and-replacement jobs to be performed in the 30-story-tall VIF.

The previous rollbacks occurred on the Hellas Sat mission in 2003 to replace data instrumentation unit, the WGS 2 flight in 2009 to replace a leaky liquid oxygen valve and Intelsat 14 also in 2009 to replace an ordnance control assembly.

The Atlas 5 will be wheeled back onto the Complex 41 pad the morning prior to the next launch attempt, rolling out potentially as soon as Tuesday.

Rollback is underway out at Complex 41, as the United Launch Alliance Atlas 5 team wheels the rocket to the Vertical Integration Facility to wait out this delay.

The trackmobiles are positioning the undercarriages beneath the Atlas 5 rocket in preparation for this afternoon's departure from the launch pad and rollback to the Vertical Integration Facility.

Earlier this morning, photographers went to Complex 41 to retrieve their sound-activated cameras given the multi-day delay in the next launch attempt. Here's a gallery of pictures showing the Atlas 5 today.

Liftoff has been tentatively reset for next Wednesday at the earliest. That's the soonest the Eastern Range could be available to support another launch attempt. The Air Force-controlled Range provides all of the necessary tracking, communications and safety services for rocket flights from Cape Canaveral. Exactly what has the Range booked for the next few days hasn't been disclosed.

Here's the official post-scrub statement from United Launch Alliance.

"The launch of an Atlas 5 carrying the United States Navy’s Mobile User Objective System 1 (MUOS 1) payload was scrubbed today due to weather conditions associated with upper level winds and flight rules associated with thick clouds. Due to lack of range availability and also the forecast weather conditions for the next several days, the Atlas 5 vehicle and MUOS will return to the Vertical Integration Facility and will roll back out to the launch pad prior to launch. The launch is rescheduled for no earlier than Wednesday, Feb. 22 from Space Launch Complex 41 at Cape Canaveral Air Force Station, Fla."

Rollback has been announced. To wait on the expected several days before the Range will be available for another launch attempt, the Atlas 5 rocket will ride the rails back the third-of-a-mile to its Vertical Integration Facility to wait out the delay. Exactly when the next launch date will occur remains up in the air, but liftoff won't occur for at least the next few days.

The rollback will happen tomorrow, roughly 24 hours after the scrub to allow the vehicle to warm up from the supercold propellants that are being drained right now.

If there is a prolonged wait for the next available launch shot on the Eastern Range, officials will opt to roll the Atlas 5 rocket back to its assembly building for waiting out the delay.

Draining of the cryogenic liquid oxygen and liquid hydrogen from the Atlas 5 rocket is underway following the scrub to safe the vehicle.

It appears another launch attempt will not be made tomorrow. But still awaiting official word on rescheduling.

SCRUB. Launch of the Atlas 5 rocket carrying the U.S. Navy's next-generation mobile communications satellite has been scrubbed due to a combination of thick clouds and high-altitude winds that make it unsafe to fly the towering booster tonight.

Officials decided resuming the count and taking it down to the wire wasn't going to be worth it since the winds and cloud situations were not going to improve by launch time.

Exactly when another launch attempt will be made, whether tomorrow is an option or not on the Range, remains to be seen.

The ULA launch director and Air Force mission director have given their "go" to resume the countdown in hopes winds and clouds improve. Count will stop at T-minus 1 minute if final balloon is red.

Just like last night, officials are preserving options to fly at the very end of the window. The launch team will picking up with countdown activities while separate engineers finish analyzing the final weather balloon data and wait on the clouds. If the conditions become green, launch will happen at 6:25 p.m. EST. If they remain out of limits, a scrub will be called at T-minus 1 minute.

Just 10 minutes away from the end of tonight's launch window.

Now change on the two constraints that are preventing liftoff -- thick clouds and upper level winds.

A direct link to our text updates.

END OF LAUNCH WINDOW of 6:25 p.m. EST now being targeted for liftoff, the very last minute to fly today.

Weather balloons are released periodically throughout the countdown to measure the speed and direction of winds aloft. That information is computed and compared with the rocket's flight profile to ensure it is safe for the Atlas' ascent. At the current time, the situation is "red" while engineers assess the data.

NOW TARGETING 6:15 p.m. EST.

Tonight's launch opportunity to send the Atlas 5 rocket with MUOS into the proper place in space closes at 6:25 p.m. EST, a minute earlier than previously advertised.

NEW TIME of 6:10 p.m. EST has been established as the no-sooner-than launch target.

Weather officer now reports that the optimism for clearing the thick cloud rule has faded. Conditions remain "red" on the status board.

NEW TIME of 6:05 p.m. EST has been targeted. Meteorologists thinking the thick cloud rule will go "green" shortly for a brief window to fly. Then it'll be a matter of getting an acceptable upper wind profile.

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NEW TIME. The new target launch time is 6:00 p.m. EST as engineers work with the upper level wind data and the rocket's flight program to steer through the conditions aloft. And also waiting for clouds to thin out.

So to recap, the thickness of clouds over the launch site and high-altitude winds remain constraints that are preventing the countdown from proceeding into the final four minutes to liftoff of the Atlas 5 rocket. Current hoped-for launch time is 5:55 p.m. EST.

HOLD EXTENDED. Weather remains "no go" and liftoff has been pushed back to 5:55 p.m. EST.

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

• The 611th launch for Atlas program since 1957
• The 323rd Atlas to occur from Cape Canaveral
• The 200th mission for Centaur upper stage
• The 177th use of Centaur by an Atlas rocket
• The 29th launch of an Atlas 5 since 2002
• The 25th Atlas 5 to occur from the Cape
• The 21st Atlas 5 under United Launch Alliance
• The 8th Atlas 5 launch overseen by the Air Force
• The 9th 500-series flight of the Atlas 5
• The 3rd Atlas 5 to fly in the 551 configuration
• The 1st Atlas launch of 2012

Polling of the team by Atlas launch conductor just occurred. The only constraint reported was the thick clouds.

The weather reconnaissance aircraft up in the skies examining the cloud cover for the Air Force meteorologists.

NEW TIME targeting liftoff at 5:50 p.m. EST.

NEW TIME for launch now targeting 5:47 p.m. EST. Cloud thickness and now upper level winds are the constraints delaying liftoff at least five minutes.

HOLD EXTENDED due to upper level winds! Today's available launch opportunity extends to 6:26 p.m. EST.

Cumulus clouds and disturbed weather rules are "green" now. Thick clouds remain "no go" for now.

The latest update from the launch meteorologist indicates two of the "reds" for cumulus and disturbed weather is about to clear. But thick clouds remain a problem.

T-minus 4 minutes and holding. The countdown has entered the planned 10-minute hold to give the launch team a chance to review all systems before pressing ahead with liftoff. The clocks will remain here until the weather improves. There's currently three "reds" for clouds and disturbed weather.

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

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

Now just 20 minutes away from launch.

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Today's liftoff begins the sophisticated MUOS system -- to be fully assembled with four more launches over the next several years -- that was created around the commercial third-generation cellular telephone architecture to substantially increase the number of users and amount of communications that can be routed to military forces.

"MUOS is a next-generation narrowband military satellite communications system that supports a worldwide, multi-service population of users in the Ultra High Frequency band. As a next-generation system, MUOS offers significantly enhanced capabilities, such as increased capacity, link availability and, for the first time, UHF (satellite-based) communications on-the-move capability," said Mark Pasquale, Lockheed Martin vice president and MUOS program manager.

"In the current (with Navy's Ultra High Frequency Follow-On satellite fleet) environment, ground users must be stationary with an antenna positioned directly toward the satellites to send out information. With MUOS, not only will users be able to connect with the satellites while on-the-move, the satellites will be connected to ground-based receiving stations that provide connectivity to the Global Information Grid, enabling users to send and receive data, calls and video worldwide.

"The system transitions from a circuit switch to an all-IP dynamic network which supports on demand, ad-hoc and priority based planning. MUOS also provides users with predetermined priority which allows bandwidth to be shared efficiently."

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

Thirty minutes from liftoff. The countdown clocks are heading to the T-minus 4 minute mark where a planned 10-minute hold will occur. Launch of Atlas 5 remains scheduled for 5:42 p.m. EST, weather permitting.

Pre-launch checks of the rocket's safety system have been completed.

The current observed weather conditions at Cape Canaveral now have three launch rules in the "red" column -- cumulus clouds, thick clouds and disturbed weather.

The venerable U.S. upper stage rocket -- the Centaur -- that created the pathway to the Moon and every planet across the solar system will be making its 200th flight today in a milestone mission to boost the U.S. Navy's sophisticated new mobile communications satellite to orbit.

Originally developed by General Dynamics under the direction of NASA at the dawn of the space age, Centaur was conceived to power payloads with a high-energy cryogenic engine fed with liquid hydrogen and liquid oxygen.

See our special feature story on this landmark launch.

The launch pad is getting soaked as a rain shower moves over Complex 41.

The liquid hydrogen tank in the Centaur upper stage just reached the 97 percent level. Topping is now beginning.

The latest briefing to mission managers shows the weather odds remain at 40 percent favorable for launching the Atlas 5 rocket sometime during today's 44-minute window running for 5:42 to 6:26 p.m. EST.

Still calling for scattered clouds at 2,000 feet, broken decks at 3,500 and 9,000 feet, overcast skies at 20,000 feet, rain showers in the area, 5 miles of visibility, northerly winds of 10 to 15 knots and a temperature of 70 degrees F.

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

A second weather rule has gone "red" for cloud thickness. The cumulus cloud rule also remains "no go" at the current time.

Now 60 minutes from liftoff. Fueling of the Atlas rocket with cryogenic liquid oxygen and liquid hydrogen is proceeding as planned for a liftoff at 5:42 p.m. EST.

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Centaur's liquid hydrogen tank is half full. The cryogenic propellant will be consumed with liquid oxygen by the stage's Pratt & Whitney Rocketdyne-made RL10 engine.

Now at 80 percent full on the first stage liquid oxygen tank.

Rain really starting to come down here at the Kennedy Space Center Press Site about four miles away from the Atlas pad.

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.

First stage liquid oxygen tank is 50 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-and-a-quarter minutes of flight today. The 25,050 gallons of RP-1 were loaded into the rocket earlier.

The first stage liquid oxygen tank has reached the 30 percent mark.

Upper stage liquid oxygen has reached flight level.

Now just 90 minutes away from launch.

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The Centaur liquid oxygen tank reached the 95 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 12,320 gallons of the cryogenic propellant.

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

Centaur liquid oxygen is three-quarters loaded.

The Centaur upper stage's liquid oxygen tank is 60 percent full.

And now the cumulus cloud rule has gone "red" again. So weather, at the present time, is out of limits for launch. But meteorologists will continue tracking conditions over the next couple of hours in hopes the situation improves. Weather had been "green" for the past 65 minutes or so.

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 48,745 gallons of cryogenic oxidizer for the RD-180 main engine.

Now approaching the one-third level of the Centaur's liquid oxygen tank.

The Centaur liquid oxygen tank has reached the 10 percent mark already.

Filling of the Centaur upper stage with about 4,075 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 to propel the payload -- initially into a parking orbit, then into a highly elliptical intermediate orbit and eventually to the targeted geosynchronous transfer orbit this evening.

Now exactly two hours until launch! Weather remains "go" at this time.

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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 is continuing on schedule for today's flight of the Atlas 5 rocket with the MUOS 1 mobile communications satellite to serve the U.S. Defense Department.

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 5:42 p.m. EST 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.

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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 5:42 p.m. EST launch of the Atlas rocket. This initial pause lasts 30 minutes, giving 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 and will last for 10 minutes.

Confirmation from safety officials has been made that the Complex 41 pad and the danger area are clear of all workers for the remainder of the countdown.

And all weather rules are "green" once again. The weather team compares the current observed conditions against the rules throughout the countdown and lets managers know where things stand. Of course, it only matters if the rules are "red" or "green" when the clocks get down to launch time.

The final hands-on work has wrapped up at the launch pad and technicians are departing the complex now as the countdown progresses smoothly this afternoon.

In the pre-fueling weather briefing, the launch meteorologist reports that the cold front is draped right across Central Florida this afternoon. A weather reconnaissance aircraft will be patrolling the skies later in the countdown for real-time assessment of the cloud cover.

Current conditions are "red" but expected to flip back to "green" status shortly.

For the 44-minute launch window opening at 5:42 p.m. EST, the weather team is calling for scattered clouds at 2,000 feet, broken decks at 3,500 and 9,000 feet, overcast skies at 20,000 feet, rain showers in the area, 5 miles of visibility, northerly winds of 10 to 15 knots and a temperature of 70 degrees F.

Overall, there's still a 40 percent chance that weather will allow the rocket to fly today. The concerns will be cumulus clouds, thick clouds and disturbed weather.

Now entering the final three hours of the countdown to launch. The guidance system testing has been reported complete.

In the ever-changing weather picture here at the Space Coast, the cumulus cloud and field mill rules are "green" again. However, the disturbed weather and the cloud thickness rules are "red" now.

A second weather rule has gone into the "red" column along with cumulus clouds at the present time -- the field mill criteria that measures the electrical potential in the air for lightning.

The earlier red on the disturbed weather rule did go back to "green" a little while ago.

The hazard area roadblocks around the launch site's safety perimeter are being established now. And the launch team has started configuring the pad's water deluge system.

Testing of the C-band system used to track the rocket during ascent, plus hydraulic and propulsion system preps on the Atlas first stage just wrapped up as the countdown continues on schedule towards today's 5:42 p.m. EST launch. Officials will be keeping a close eye on the weather, obviously, but things are pressing ahead in hope conditions permit a liftoff this afternoon.

In the countdown, the launch team has completed preps to the Atlas first stage liquid oxygen system for fueling this afternoon. Also, checks of the vehicle's internal batteries have been performed as planned. And testing of the S-band system for telemetry relay from rocket as it flies downrange is underway.

Good afternoon from Cape Canaveral where it is a very gloomy weather day. Skies are dark and overcast as a cold front sweeps through the area. A current check of the launch rules shows a "red" condition at the present time for violation of the cumulus cloud criteria and disturbed weather.

Today's launch of the Atlas 5 rocket at 5:42 p.m. EST will be the third flight of the vehicle's 551 configuration, which is distinguished by the combination of a five-meter payload fairing, five solid rocket boosters and a single-engine Centaur upper stage, the most powerful version of the Atlas 5 currently available.

Depending on a payload's weight and desired orbit, mission planners add strap-on solid boosters to the United Launch Alliance-made rocket to incrementally increase the vehicle's performance.

Atlas 5 vehicles are capable of flying with as many as five boosters, an option that was employed to generate as much thrust as possible to launch NASA's New Horizons space probe bound for Pluto in 2006 and NASA's Juno to Jupiter last August. For this particular mission, the weight of MUOS drove the selection of the 551 and the plan to fire the Centaur upper stage three times instead of the usual two burns.

"Weighing nearly 15,000 pounds, MUOS 1 is the heaviest satellite launched to date by an Atlas launch vehicle. Our customers for this mission asked for a mission design that would launch this very heavy and capable satellite in a manner that would minimize the amount of energy (and propellant) that the satellite would have to consume to position itself into the final geosynchronous orbit," said Jim Sponnick, United Launch Alliance's vice president of mission operations.

"Considering all of the commodities and capabilities of the Centaur, our mission design team developed this three-burn mission profile to provide an optimal solution for the MUOS customer. The third burn accomplishes both perigee raising and a substantial reduction in the orbit inclination at an altitude of 15,000 nautical miles above the earth, which provides substantial performance benefits to the mission. The three burn mission design for MUOS provides 1,000 lbs greater lift capability than a conventional 2-burn geosynchronous transfer orbit."

The Russian RD-180 first stage main engine will ignite at T-minus 2.7 seconds, shooting a giant cloud of steam from the pad's main exhaust duct while undergoing a check to ensure its vital signs are healthy. The five strap-on solid rocket boosters are lit at T+plus 0.8 seconds, leading to liftoff at T+plus 1.1 seconds.

The combined power will send the 20-story Atlas vehicle thundering into the sky in a hurry. Its fast speed off the launch pad will be remarkably different than other Atlas 5 missions without solid boosters that appear majestically slow.

The Aerojet-made solid boosters will burn for about 90 seconds to assist the RD-180 in propelling the rocket. The SRB casings remain attached to the first stage for a few additional seconds before separating.

Once out of the discernible atmosphere, the bulbous nose cone encapsulating the MUOS payload can be shed at T+plus 3 minutes, 22 seconds. The fairing was made by Ruag Space of Switzerland.

The kerosene-fueled first stage will continue to fire until T+plus 4 minutes, 24 seconds. The bronze stage separates about six seconds later, leaving the hydrogen-fueled Centaur upper stage to ignite for a burn lasting nearly 8 minutes that will inject itself into a preliminary orbit of 90 by 337 nautical miles high, tiled 28 degrees to the equator.

Centaur completes its first burn over the central Atlantic Ocean and enters an 8-minute coast. The Pratt & Whitney Rocketdyne RL10 cryogenic engine then restarts for a firing to propel the spacecraft to the second step on its way to the planned orbit. This six-minute burn put the rocket into a 104 by 18,600 nautical mile orbit inclined 26 degrees.

Then begins a lengthy coast away from the planet for two-and-a-half hours, flying to a point about 15,000 nautical miles above the far eastern Indian Ocean where the final burn will occur.

One final push nearly two hours and 57 minutes into flight will raise the orbit's low point and reduce the inclination closer to the equator. The burn, lasting less than a minute, places the payload into a 1,870 by 19,323 nautical mile orbit at 19 degrees inclination.

The satellite separation from Centaur is expected at 8:43 p.m. EST (0143 GMT), given an on-time launch, to complete the ascent sequence.

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Various versions of the Atlas rocket launched earlier constellations of U.S. Navy communications satellites, and now the family's biggest booster will begin deploying a new generation of spacecraft today.

Towering 206 feet tall and generating two-and-a-half-million pounds of thrust at launch, the rocket will place the 15,000-pound satellite into its preliminary geosynchronous transfer orbit three hours into flight.

Get know the Atlas 5 in our background feature story.

After high-altitude wind conditions kept the Atlas 5 rocket anchored on the pad Thursday night, a second launch attempt is getting underway today to deploy the vehicle's heaviest payload ever -- the first bird in the U.S. Navy's newest generation of mobile communications spacecraft -- on this the 200th flight for the Centaur upper stage.

The countdown clocks just began ticking, beginning a seven-hour sequence of work that will prepare the rocket, payload and ground systems for today's blastoff at 5:42 p.m. EST (2242 GMT).

The day's 44-minute launch window opens at 5:42 p.m. and closes at 6:26 p.m. EST.

Here's a timeline of the countdown's key events:

 HR:MM..Eastern...Event
T-6:20..10:42am...Countdown begins with rocket power up
T-5:30..11:32am...Weather briefing
T-4:55..12:07pm...Start clearing assembly building area
T-4:20..12:42pm...C-band tracking beacon testing
T-3:40...1:22pm...S-band telemetry link checks
T-2:55...2:07pm...Establish blast danger area roadblocks
T-2:20...2:42pm...Weather briefing
T-2:15...2:47pm...Clear the pad
T-2:00...3:02pm...T-120 minutes and holding (for 30min)
T-2:00...3:27pm...Launch conductor briefing to team
T-2:00...3:29pm...Readiness poll for fueling
T-2:00...3:32pm...Resume countdown
T-1:50...3:42pm...Centaur LOX transfer line chilldown
T-1:43...3:49pm...Begin Centaur liquid oxygen loading
T-1:30...4:02pm...Begin Atlas first stage LOX loading
T-1:25...4:07pm...Centaur LH2 transfer line chilldown
T-1:10...4:22pm...Centaur RL10 engine chilldown
T-1:02...4:30pm...Begin Centaur liquid hydrogen loading
T-0:40...4:52pm...FLight termination system final test
T-0:16...5:16pm...RD-180 engine fuel fill sequence
T-0:10...5:22pm...Weather briefing
T-0:04...5:28pm...T-4 minutes and holding (for 10min)
T-0:04...5:35pm...Readiness poll for launch
T-0:04...5:38pm...Resume countdown
T-0:00...5:42pm..LAUNCH

It is an overcast kind of day here at Cape Canaveral. The latest words from the launch weather officer this morning:

"Today, a cold front will continue to edge southward into Central Florida with an increasing threat for showers, isolated thunderstorms and cloudiness as the day progresses. By launch time, winds will be north to northeasterly gusting in the low teens. The primary concerns for launch are cumulus clouds, disturbed weather and thick clouds."

The Air Force weather team has issued an updated outlook for launch opportunities on Friday and Saturday evenings, predicting odds of 40 percent and then 60 percent on those two days, respectively, of having acceptable conditions for liftoff.

"A cold front will stall in Central Florida on Friday with showers and considerable cloudiness expected throughout the day. A slight threat for isolated thunderstorms also exists associated with the front during Friday afternoon/evening. By launch time, winds will be north to northeasterly gusting in the low teens. The primary concerns for launch are cumulus clouds, disturbed weather and thick clouds," meteorologists report.

The specifics include scattered clouds at 2,000 feet, broken decks at 2,500 and 9,000 feet, overcast skies at 20,000 feet, rain showers and isolated thunderstorms in the area, 5 miles of visibility, northerly winds of 10 to 15 knots and a temperature of 70 degrees F.

"In the event of a 24-hour delay, the front over Central Florida will return northward during the day on Saturday. Conditions will gradually improve over the area Saturday afternoon/evening; however, scattered showers and isolated thunderstorms remain a threat. By launch time, winds will be southeasterly gusting in the upper teens. The primary concerns for a 24-hour delay are cumulus clouds, disturbed weather and thick clouds."

Draining of the cryogenic liquid oxygen and liquid hydrogen from the Atlas 5 rocket is nearing completion out at Complex 41 following tonight's scrub for upper level winds. No other technical issues of note were reported during the count, but at the final minute the launch conductor halted the clocks due to high-altitude wind conditions.

Liftoff is rescheduled for Friday at 5:42 p.m. EST. We'll be back right here on this page with live updates and streaming video.

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Read our earlier status center coverage.