With one more satellite needed in its new military communications system to extend blanket coverage over virtually the entire planet, the spacecraft to make the network's reach global was sent thundering into orbit Friday to join the Air Force's broadening constellation serving troops, ships, drones and civilian leaders.

Read our full story.

A spectacular gallery of launch photos is posted here.

The Wideband Global SATCOM 5 spacecraft is alive and well following its launch into space. Controllers confirmed initial contact with the spacecraft at 9:26 p.m. EDT via a ground station in Australia.

"This satellite is going to strengthen an important tool that warfighters count on to be successful and safe," said Craig Cooning, vice president and general manager of Boeing Space & Intelligence Systems.

"WGS continues to meet user requirements and provides the highest capacity of any DoD communications satellite," said Luke Scab, chief Wideband SATCOM division in the MILSATCOM Systems directorate. "WGS is a vital piece of the MILSATCOM enterprise consisting of WGS, Defense Satellite Communications System, Advanced Extremely High Frequency System, Minstar, and terminals providing diversified communications services to soldiers, sailors, marines and airmen around the world. This continued success is due to the hard work and dedication from the combined government and industry team."

Here's a post-flight statement from Jim Sponnick, United Launch Alliance vice president of mission operations:

"United Launch Alliance and our many mission partners continue to focus on mission success, one-launch-at-a-time," he said. "We are honored to work with such a strong industry and government team and deliver another critical communication capability to orbit to support our nation's warfighters throughout the world."

The next Delta 4 rocket launch is targeted for early August from the Cape with the next WGS satellite.

T+plus 40 minutes, 49 seconds. SPACECRAFT SEPARATION! The Air Force's Wideband Global SATCOM 5 military communications satellite has been deployed into orbit from the Delta 4 rocket's upper stage, completing tonight's launch.

The spacecraft will spend the next few weeks being maneuvered into a circular geosynchronous orbit by controllers at Boeing's satellite facility in El Segundo, California. The orbit raising activities will use both the conventional propellant engines as well as ion propulsion thrusters.

Boeing will oversee the craft's solar array and antenna deployments, plus complete an initial round of testing before WGS 5 is handed over to the Air Force. The military plans to conduct its own set of checks and verifications, then position the craft at its orbital slot at 52.5 degrees West to enter service at the beginning of 2014.

T+plus 39 minutes, 15 seconds. Separation will occur while soaring away from the planet over Madagascar and the Indian Ocean. The vehicle is passing over that giant island now.

T+plus 38 minutes, 45 seconds. About two minutes from separation.

T+plus 37 minutes. The rocket is coasting in orbit and will soon deploy the next Wideband Global SATCOM, continuing the modernization effort for the U.S. military's satellite communications network in space.

T+plus 36 minutes, 45 seconds. Release of the payload about 4 minutes away.

T+plus 35 minutes, 40 seconds. Delta's speed is 31,457 at an altitude of 775 miles, 7,077 miles downrange.

T+plus 34 minutes. The Delta 4 rocket has successfully reached its targeted supersynchronous transfer orbit with a perigee of 237 nautical miles and apogee of 36,125 nautical miles with an inclination of 24.00 degrees.

T+plus 33 minutes. The vehicle has re-positioning itself to the proper orientation for spacecraft separation,

T+plus 31 minutes, 41 seconds. SECO 2. The second of two firings by the upper stage during today's launch has been completed, ending the powered phase of flight.

T+plus 31 minutes, 15 seconds. The vehicle has crossed the coastline of Africa.

T+plus 31 minutes. This burn injects the rocket into a highly elliptical orbit stretching about 36,000 nautical miles in altitude at its furthest point from Earth.

T+plus 30 minutes, 30 seconds. Passing an altitude of 355 miles as the rocket begins to climb upwards on its trajectory, 5,802 miles downrange.

T+plus 29 minutes, 30 seconds. Chamber pressure is holding.

T+plus 29 minutes, 15 seconds. This burn will last just over three minutes in duration.

T+plus 28 minutes, 45 seconds. Good engine chamber pressure reported on the RL.

T+plus 28 minutes, 34 seconds. The RL10B-2 engine, fed by liquid hydrogen and liquid oxygen, has been ignited once again! This firing will propel WGS 5 to its targeted orbit.

T+plus 26 minutes. Things are still looking good.

T+plus 25 minutes, 30 seconds. The vehicle continues in the coast mode before the next firing of the upper stage engine. Re-ignition of the RL10 engine is three minutes away.

T+plus 24 minutes. To see the track the rocket is following this evening, click here.

T+plus 23 minutes, 30 seconds. The vehicle is 4,000 miles downrange.

T+plus 23 minutes. The Delta 4 rocket has successfully reached its targeted orbit with a perigee of 100 nautical miles and apogee of 3,715 nautical miles with an inclination of 25.6 degrees.

T+plus 20 minutes, 44 seconds. SECO 1. Confirmation that the second stage engine has shut down after the first of two planned firings to inject the WGS 5 spacecraft into a supersynchronous transfer orbit.

T+plus 20 minutes, 10 seconds. Delta is 3,110 miles down range.

T+plus 19 minutes. Delta is traveling over 27,000 feet per second over the central Atlantic Ocean.

T+plus 18 minutes. The upper stage's the RL10 engine working well, still firing as planned to reach the parking orbit this evening.

T+plus 17 minutes, 30 seconds. This burn will place the vehicle into an initial parking orbit around Earth. The rocket is headed for an elliptical orbit of approximately 100 by about 3,700 nautical miles with an inclination of 25.6 degrees.

T+plus 17 minutes, 15 seconds. Delta is traveling at 24,992 feet per second, more than 2,405 miles downrange from the launch pad.

T+plus 16 minutes, 40 seconds. About four minutes remain in this firing of the second stage.

T+plus 15 minutes, 50 seconds. The telemtry relay duties are being from ground stations to NASA's Tracking and Data Relay Satellite System.

T+plus 15 minutes, 20 seconds. Rock solid chamber pressure. Delta is speeding along at 22,809 feet per second, more than 1,981 miles downrange from the launch pad.

T+plus 14 minutes. The RL10 engine is burning a mixture of liquid oxygen and liquid hydrogen cryogenic propellants. Chamber pressures still look good.

T+plus 13 minutes. Delta is 1,547 miles east-southeast of the launch pad, traveling at 20,652 fps.

T+plus 11 minutes, 30 seconds. The vehicle's steep climb leveled off as it gains speed toward orbital velocity.

T+plus 11 minutes. Good controls by the upper stage. Delta is 225 miles in altitude, speed in excess of 19,209 feet per second, 1,242 miles downrange from the launch pad.

T+plus 10 minutes, 30 seconds. The second stage engine continues to fire well with good chamber pressure. All is looking good.

T+plus 10 minutes. Mission events are occurring close to the expected times.

T+plus 9 minutes. The upper stage is the larger five-meter version that has flown previously on the Delta 4-Heavy vehicle and two earlier WGS missions. It is an element that distinguishes this Medium+ (5,4) rocket configuration from other variants use four-meter upper stages for lower-weight payloads.

Today's stage has a wider liquid hydrogen tank and a lengthened liquid oxygen tank to carry additional propellants, enabling the RL10 engine to fire longer and carry heftier cargos.

T+plus 8 minutes, 25 seconds. Delta is 215 miles in altitude, 798 miles east-southeast of the launch pad, traveling at 17,480 fps.

T+plus 7 minutes, 20 seconds. Chamber pressure data being reported from the RL10 engine looks good as it thrusts to reach orbit.

T+plus 6 minutes, 30 seconds. Good chamber pressure holding steady.

T+plus 6 minutes. Delta is 163 miles in altitude, traveling at 16,600 feet per second, 459 miles east of the launch pad.

T+plus 4 minutes, 40 seconds. Good chamber pressure!

T+plus 4 minutes, 31 seconds. The cryogenic RL10B-2 upper stage engine has been lit!

T+plus 4 minutes, 20 seconds. The Common Booster Core first stage and the attached interstage have been separated in one piece. The upper stage engine's extendible nozzle is dropping into position to prepare for ignition.

T+plus 4 minutes, 10 seconds. MECO! Main engine cutoff confirmed as the RS-68 shuts down, completing another successful use in powering the Delta 4 program.

T+plus 4 minutes, 3. The main engine is throttling down to 57 percent thrust for the rest of its firing in today's launch.

T+plus 3 minutes, 37 seconds. Now above the discernible atmosphere, the protective nose cone enclosing the WGS 5 satellite atop the rocket has jettisoned.

T+plus 3 minutes, 10 seconds. Vehicle now traveling at Mach 10.

T+plus 3 minutes. Delta is 53 miles in altitude, 84 miles downrange from the launch pad.

T+plus 2 minutes, 30 seconds. The main engine continues to burn, consuming its liquid hydrogen and liquid oxygen propellants.

T+plus 2 minutes, 10 seconds. Vehicle now traveling at Mach 5.

T+plus 2 minutes. The RS-68 is consuming nearly a ton of propellants per second as the powerplant pushes the Delta 4 rocket closer to space.

T+plus 1 minute, 55 seconds. Now weighs half of what it at liftoff.

T+plus 1 minute, 44 seconds. Solid motor separation! The spent boosters have been shed from the first stage. Delta 4 continues powering its way on the thrust generated by the RS-68 main engine.

T+plus 1 minute, 38 seconds. The four solid rocket boosters have burned out of their propellant. Standing by for jettison.

T+plus 60 seconds.

T+plus 50 seconds. Now passing through the region of maximum aerodynamic pressure.

T+plus 36 seconds. The launcher has broken through the sound barrier.

T+plus 20 seconds. The Delta 4 rocket is thundering away from the spaceport with its main engine firing at full throttle and the four strap-on motors burning.

LIFTOFF! Liftoff of Delta 4 with WGS 5, broadening the reach of the Wideband Global SATCOM constellation to cover the Americas. And the vehicle has cleared the tower!

T-minus 12 seconds. Residual hydrogen burnoff ignitors have been fired beneath the main engine.

T-minus 22 seconds. The steering system for the solid rocket motor nozzles has been activated.

T-minus 25 seconds. Green board. All systems remain "go" for launch.

T-minus 40 seconds. Upper stage liquid hydrogen tank is confirmed at flight level.

T-minus 55 seconds. The Air Force-controlled Eastern Range has given its "go" for launch.

T-minus 1 minute and counting. The ignition conditions for the RS-68 main engine are "go." The terminal countdown sequencer will take control at T-minus 8.5 seconds. Ignition of the RS-68 powerplant will follow at T-minus 5.5 seconds. The engine powers up to the 102 percent level of thrust for a computer-controlled checkout before liftoff.

T-minus 75 seconds. The liquid hydrogen fuel tank on the upper stage is being secured for launch.

T-minus 80 seconds. Upper stage liquid oxygen tank has been secured at flight level.

T-minus 1 minute, 40 seconds. The first stage liquid hydrogen tank has reached flight level and pressure.

T-minus 2 minutes. The rocket's upper stage liquid oxygen tank is being secured.

T-minus 2 minutes, 30 seconds. The liquid oxygen tank in the first stage is confirmed at the proper level and pressure for flight.

T-minus 3 minutes and counting. Ordnance devices aboard the vehicle are being armed.

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.

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.

T-minus 4 minutes and counting! Now into the final phase of the countdown for liftoff at 27 minutes past the hour by the Delta 4 rocket carrying the WGS 5 spacecraft from pad 37B at Cape Canaveral Air Force Station.

The WGS spacecraft is configured for its ride into orbit tonight aboard the Delta 4 rocket.

The launch pad swing arm retraction system pins are being pulled. The three arms will be rotated away from the Delta 4 rocket at liftoff.

Permission to launch has been granted by the ULA launch director and Air Force mission director.

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 8:27 p.m. EDT.

Standing by for the launch team readiness check for continuing the countdown.

Now just 10 minutes from opening of the launch window. The team is being briefed on instructions for the remainder of the count.

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 8:27 p.m. liftoff.

Assuming all systems are go, clocks will resume ticking at 8:23 p.m. local time. During those final four minutes, the rocket will switch to internal power, ordnance will be armed, all four propellant tanks will be secured and the Range will announce a clear-to-launch.

At T-minus 14 seconds, the sparkler-like radial outward firing ignitors -- or ROFIs -- are started beneath the main engine nozzle. The Terminal Countdown Sequencer will grab control at T-minus 8.5 seconds to manage events in the crucial last seconds and oversee the rocket's status. The ignition sequence for the RS-68 powerplant follows at T-minus 5.5 seconds as the main hydrogen fuel valve is opened. As fuel floods through the engines, spectacular flame erupts at the base of the rocket as free hydrogen reaches the ROFIs.

The oxygen valve in the engine is opened at T-minus 2 seconds as the RS-68 begins roaring to life. The engine must rev up to full throttle -- 102 percent thrust level -- and undergo a rapid computer-controlled health check to ensure all parameters are met.

If any problem is detected before T-minus 40 milliseconds, the engine will shut down and the rocket prevented from lifting off.

A successful engine startup leads to T-0 as the four hold-down bolts that have been restraining the rocket to Earth finally detonate. The 20-story vehicle blasts off at 8:27 p.m. (0027 GMT) on the WGS 5 satellite deployment mission.

The WGS 5 spacecraft atop the Delta 4 is switching from ground-fed power to its internal batteries for launch.

Now moving into the final 30 minutes of the countdown to launch.

This launch will deliver to orbit the fifth satellite in the Wideband Global SATCOM series to extend the constellation's reach to cover the world. This craft will serve the Americas.

"It gives us the CONUS coverage we don't have today," said Luke Schaub, chief of the Wideband SATCOM division of the MILSATCOM Systems directorate at the Space and Missile Systems Center in Los Angeles.

"We have four in operation today. Those four are pretty much located on the other side of the globe from the United States. They're really located strategically between the eastern Atlantic and the western Pacific. Today, we do not have any WGS capability over the continental United States."

The Boeing Company builds the craft for the U.S. Air Force.

Boeing shipped the WGS 5 satellite from its factory in El Segundo to Cape Canaveral in early March. Over the past two months, the craft underwent final testing, fueling and encapsulation in the shroud that will cover it during launch.

On May 7, the spacecraft was transported from the Astrotech processing facility in Titusville to Complex 37 where it was hoisted atop the Delta 4 rocket.

The company has five additional WGS satellites in the pipeline for more launches in the coming years, including WGS 6 just around the corner in early August.

"WGS is the DOD's highest capacity communications satellite system. These satellites provide tremendous operational flexibility to deliver the needed capacity, coverage and connectivity in support of demanding operational scenarios for DOD and allied forces worldwide," said Boeing WGS Program Director Mark Spiwak.

A load relief file based on the upper level winds is being transmitted to the Delta 4 rocket's flight computer. This program informs the rocket on the wind conditions it can expect to see during ascent.

The ULA launch team and management are guiding the countdown from the Delta Operations Center, located about 9,200 feet from the pad. The engineers overseeing the rocket and ground systems are located on the third floor and the Mission Directors Center room is on the fourth floor. Both rooms have a view of pad 37B and the Delta 4 rocket out their windows. Other rooms are also set up for engineering support.

The DOC was formerly built to support the Titan-Centaur program but was refurbished to support Delta 4.

T-minus 4 minutes and holding. The countdown has entered the planned 45-minute hold leading toward the 8:27 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. A series of management polls will be conducted during the hold to give approval to proceed with the launch.

The proper flight conditioning of the first stage liquid hydrogen supply has been achieved. All four tanks on the vehicle has hit this milestone.

Now entering the final 60 minutes until the Delta 4 rocket launch from Cape Canaveral at 8:27 p.m. EDT. Here's a look at some stats about today's mission. This will be:

• The 362nd Delta rocket launch since 1960
• The 22nd Delta 4 rocket mission since 2002
• The 31st RS-68 main engine used
• The 29th-32nd GEM-60 solid rocket motors flown
• The 436th production RL10 engine to be launched
• The 25th RL10B-2 engine launched
• The 18th Delta 4 rocket launch from Cape Canaveral
• The 18th use of Delta 4 by the Air Force
• The third Medium+ 5,4 configuration to fly
• The 60th Evolved Expendable Launch Vehicle flight
• The 71st United Launch Alliance mission since 2006
• The 15th Delta 4 under the ULA banner
• The 5th ULA launch this year
• The first launch of the Delta family in 2013
• The 5th Wideband Global SATCOM satellite
• The second Block 2 WGS satellite
• The third WGS on Delta 4

There are no Collision Avoidance, or COLA, periods during today's launch window. A COLA is a moment in which liftoff cannot occur because the rocket's trajectory would take it too close another object already in space. The overall launch window extends from 8:27 to 8:57 p.m. EDT.

The flight slews and commanding tests for the vehicle steering systems are complete. 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.

The launch team is kicking off the steering checks for the RS-68 main engine and RL10 upper stage engine, plus commanding tests with the solid rocket motors.

The flight hazard area has been established.

The RS-68 first stage main engine spin start system pressurization operation is being conducted.

The launch team is entering the last 90 minutes of the countdown. With fueling of the Delta 4 rocket completed, this phase of the count is fairly quiet.

Everything continues to proceed on schedule at Cape Canaveral for liftoff at 8:27 p.m. EDT.

Flight conditioning has been achieved on the upper stage liquid oxygen and liquid hydrogen tanks.

The thermal insulation inspections have been completed following fueling and there were no problems reported today.

Radio frequency link checks between tracking facilities at the Cape and the launch vehicle were just performed.

Countdown activities continue to track to the scheduled timeline for liftoff at 8:27 p.m.

The upper stage liquid oxygen tank has entered its topping phase after the post-fueling tests were accomplished. That means all four cryogenic tanks aboard the Delta 4 rocket have gone through loading, post-filling checks and achieved topping mode after a smooth fueling operation today.

Now entering into the final two hours of the countdown to launch of Delta 362 and the fifth satellite for the WGS constellation.

The rocket stands fueled and ready for launch at 8:27 p.m. EDT today. The launch team is reporting no significant issues, weather conditions are green and the countdown remains on schedule.

Engineers are conducting the standard evaluation of the Delta 4 rocket's thermal insulation following the loading of supercold propellants into the vehicle.

Now putting the upper stage's liquid hydrogen system in topping mode.

The upper stage liquid oxygen filling has been completed, now heading into post-loading tests.

The first stage liquid oxygen system has been topped off and conditioned for flight.

Post-filling tests on the hydrogen side of the first stage are complete. The tank will be entering topping mode.

Now passing the three-hour mark away from today's 8:27 p.m. EDT liftoff of the United Launch Alliance Delta 4 rocket with the WGS 5 satellite payload from Cape Canaveral, Florida.

This will be the fifth spacecraft in the growing constellation of Wideband Global SATCOM communications satellites for the U.S. military. United Launch Alliance has deployed all of them, using Atlas 5 rockets in 2007 and 2009 and the Delta 4 in 2009 and 2012.

"WGS was the first constellation of satellites to launch on both the Delta 4 and the Atlas 5 vehicles since the formation of ULA. We are privileged to work closely with our Air Force partners in integrating these important WGS satellites. The first two were launched on an Atlas, and now WGS 5 will be the third launched on a Delta," said ULA Vice President Mission Operations Jim Sponnick.

"Our ability to integrate and launch satellites successfully and efficiently on two launch systems provides operational flexibility was the primary reason ULA was formed."

Loading of the upper stage liquid hydrogen tank has been accomplished as fueling proceeds very smoothly this afternoon at Complex 37.

Post-filling tests on the first stage liquid oxygen system are complete. The tank will be entering topping mode.

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.

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.

The "go" has been given for the upper stage liquid oxygen chilldown in advance of filling that tank.

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.

The chilldown of the upper stage liquid hydrogen system is reported complete, clearing the way for loading the rocket's tank. The launch team is actively loading the upper stage's liquid hydrogen tank with propellant for the RL10 engine.

Fast-filling of the first stage liquid hydrogen tank is wrapping up. 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.

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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.

No issues are being reported in the countdown as activities continue toward today's 8:27 p.m. EDT liftoff of the Delta 4 rocket and WGS 5 satellite.

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.

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.

The rocket's tracking beacon has completed its interrogation checks.

First stage liquid hydrogen tanking operation is switching from "slow-fill" to "fast-fill" mode.

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.

Liquid hydrogen flow to the first stage is confirmed. Some 110,000 gallons of LH2 will fill the rocket's tank.

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.

And fueling operations have begun. The hydrogen system's cold gas chilldown conditioning is underway.

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.

The Delta 4 rocket's RIFCA flight computer is powered up for flight and alignment is stable. And interrogation checks are getting started on the C-band beacon used for tracking the vehicle during its flight downrange.

T-minus 5 hours, 15 minutes and counting! The Terminal Countdown has commenced for this evening's scheduled launch of the Delta 4 rocket to deliver a new communications satellite into orbit for the United States military.

The count has a planned built-in hold at T-minus 4 minutes, leading to liftoff at 8:27 p.m. EDT (0027 GMT).

Technicians have finished all hands-on work at the launch pad and Complex 37 has been cleared of personnel in advance of fueling the rocket's two stages this afternoon. Pad systems and equipment stand ready for fueling activities, which should kick off shortly.

The launch team has been polled to verify all consoles are manned and ready to begin the Terminal Countdown when this hold ends at 2:27 p.m.

The call to "man stations" has gone out to the launch team in preparation for fueling operations and the Terminal Count.

T-minus 5 hours, 15 minutes and holding. The countdown has entered a 15-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 Terminal Countdown phase of today's launch operation will begin.

In the pre-fueling weather briefing to mission managers, the current observed conditions are excellent and the forecast for the rest of the day looks favorable. The atmosphere is significantly drier today, making thunderstorm development unlikely.

Good afternoon and welcome to our live coverage of today's Delta 4 rocket launch. The launch pad has been cleared of workers, the restricted area around Complex 37 has been established and console operators are preparing the hydrogen and oxygen systems for fueling. The rocket's avionics have been turned on for launch and the countdown is ticking along on schedule for a liftoff at 8:27 p.m. EDT.

The issue with the helium pressurization line on the pad has been resolved and the launch team is proceeding with the countdown for this evening's Delta 4 rocket flight from Cape Canaveral, Florida.

Yesterday's launch attempt was interrupted and then scrubbed prior to the start of fueling. Technicians were working a problem that could not be resolved in the limited amount of time available and still make the day's launch window.

But a new day is here and activities are moving forward. Tonight's launch opportunity extends from 8:27 to 8:57 p.m. EDT (0027-0057 GMT) to deliver the WGS 5 military communications satellite into orbit.

A key weather briefing occurs just before 2 p.m. EDT as the mission managers decide whether to commit to the fueling process. The weather officer will give officials the latest information about the kind of conditions that the rocket could face during the afternoon hours while it sits exposed during the propellant loading.

Assuming the weather is deemed favorable to proceed, the Terminal Countdown will begin ticking at 2:27 p.m. EDT, leading to the multi-hour process of filling 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 45-minute build-in hold is slated for T-minus 4 minutes, during which teams will go through final polling to grant the official authority 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 5.5 seconds.

The launch weather officer now projects an 80 percent chance that conditions will be acceptable for this evening's liftoff.

"A front will move through Florida today, and, although dryer air moves in, there is a slight risk of a shower with the front," Air Force meteorologists report.

The launch time outlook includes scattered clouds at 3,400 and 30,000 feet, isolated showers in the vicinity, good visibility, easterly winds of 10 to 15 knots and a temperature around 76 degrees.

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Check out the gantry rollback photo gallery taken by Justin Ray earlier today.

The weather forecast for Friday evening's 8:27 p.m. EDT launch time calls for clouds scattered at 2,500 feet and broken at 30,000 feet, showers in the vicinity, good visibility, north-northeasterly winds of 10 to 15 knots and a temperature around 71 degrees.

The odds of acceptable weather are 80 percent, with only a slight concern for storm clouds.

United Launch Alliance confirms that the issue prompting the scrub is with a ground support system helium pressurization line. Technicians will be going into the launch pad and working the problem as the afternoon continues.

SCRUBBED. Tonight's liftoff of the Delta 4 rocket has been postponed for 24 hours. There is not sufficient time to troubleshoot the problem at the pad and get into fueling operations to make a launch during the available window this evening.

The flight is reset for Friday at 8:27 p.m. EDT. Weather forecasters predict an 80 percent chance of favorable weather during the 30-minute window.

To perform some troubleshooting, technicians will need to regain access to the Fixed Umbilical Tower. The launch team is configuring the pad to permit a safe entry for the workers.

The team is going to extend this current hold while a couple of technical issues are assessed. They can reduce the length of the final, 45-minute hold at T-minus 4 minutes by the corresponding amount and still hit the planned launch time for 8:27 p.m. EDT.

The call to "man stations" has gone out to the launch team in preparation for fueling operations and the Terminal Count.

T-minus 5 hours, 15 minutes and holding. The countdown has entered a 15-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 Terminal Countdown phase of today's launch operation will begin.

Weather forecasters report that the development of storms this afternoon are the main concern to impact the countdown to launch tonight. Current conditions are favorable.

The launch time outlook includes scattered clouds at 2,500 feet, broken decks at 8,000 and 30,000 feet, thunderstorms in the vicinity, good visibility, south-southwesterly winds of 10 to 15 knots and a temperature around 76 degrees

The odds of acceptable weather for launch are 40 percent acceptable. The number jumps to 80 percent for the backup launch opportunity tomorrow.

The 330-foote tall mobile service tower has been retracted from the Delta 4 rocket at Cape Canaveral's pad 37B for tonight's launch that will place the Air Force's WGS 5 satellite into Earth orbit.

The wheeled structure just 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 vehicle later today.

The Terminal Countdown will begin ticking at mid-afternoon, leading to the multi-hour process of loading 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 built-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 5.5 seconds.

Liftoff remains scheduled for 8:27 p.m. EDT, the opening of a 30-minute window that extends to 8:57 p.m. EDT (0027-0057 GMT).

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The tower is rolling again!

After rolling a short bit, the tower retraction was stopped so technicians ciuld examine a possible issue. So rollback is paused at the moment.

Tower rollback is underway to reveal the 217-foot-tall Delta 4 rocket for flight.

Good morning from the Cape Canaveral Air Force Station where launch day has dawned for the first Delta 4 rocket flight since October. It will place a communications satellite into orbit for the Defense Department to cover the United States and all of the Americas.

Out at Complex 37, ground technicians are making final preps to retract the dual-purpose assembly gantry and mobile shelter away from the United Launch Alliance-made rocket for today's countdown to blastoff.

Photographers are gathering right now to enter the launch pad and set up their sound-activated cameras to capture tonight's liftoff. We'll also grab some pre-launch shots while we're out there to post a little later this morning

The fifth Wideband Global SATCOM military communications satellite and its Delta 4 rocket booster are poised for launch minutes after sunset Thursday from Cape Canaveral.

The WGS 5 spacecraft is targeting an 8:27 p.m. EDT liftoff from Complex 37, about 15 minutes after sunset. A 30-minute launch opportunity extending to 8:57 p.m. EDT will be available if conditions prevent an on-time liftoff.

Managers gathered this morning for the Launch Readiness Review, which culminated with the consensus to proceed with picking up the countdown Thursday.

We will have complete live coverage of the count and launch on this page.

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Forecasters are predicting a 40 percent chance of allowable weather, with the concerns being anvil clouds, cumulus clouds and cloud thickness.

"There is an area of high pressure off the east coast of the U.S., and a surface ridge extending across the Carolinas. This pattern is causing southeasterly flow across the Florida coast which is enhanced by a sea breeze each afternoon. An upper-level low over North Florida is causing showers and potential for thunderstorms along the Space Coast this morning. By the mid-afternoon, the sea breeze will push slightly inland, but weather will likely threaten the coast on and off through the afternoon" Air Force meteorologists say.

"Thursday, the pattern changes as the high pressure ridge to the north moves into Florida due to an upper level trough moving into the Southeast U.S. With this, afternoon inland thunderstorms will develop and migrate toward the east coast of Florida. Afternoon and evening thunderstorms are possible and are a risk to launch."

The launch time outlook includes scattered clouds at 2,500 feet, broken decks at 8,000 and 30,000 feet, thunderstorms in the vicinity, good visibility, south-southwesterly winds of 10 to 15 knots and a temperature around 76 degrees F.

The forecast for Friday's backup launch opportunity improves to 60 percent favorable.

"Friday, weather may improve some as the upper level trough and surface trough move off the coast, but the atmosphere is still unstable and there is still potential for showers or thunderstorms in the area for a 24-hour delay," today's forecast reads.

United Launch Alliance is preparing for its second rocket flight for the Air Force in just eight days, a Thursday evening blastoff from Cape Canaveral that returns the Delta 4 rocket to action carrying a military communications satellite to serve the Americas.

The Delta 4 fleet has been idle since last October when the launch of the GPS 2F-3 navigation satellite suffered a low-thrust condition on its upper stage RL10B-2 engine on the way to successfully reaching the proper orbit.

Although the seven-month inquiry into that close-call has not yet been closed, the Delta 4 rocket has been cleared for flight this week.

Read our preview story.

The weather forecast for Thursday's launch attempt of the Delta 4 rocket predicts a 40 percent chance of acceptable conditions to fly due to coastal showers and thunderstorms along the Space Coast.

Also, the advertised launch window has been tweaked slightly, opening at 8:27 and closing at 8:59 p.m. EDT (0027-0059 GMT).

The latest outlook issued this morning calls for scattered clouds at 2,500 feet, broken decks at 8,000 and 30,000 feet, showers in the vicinity, visibility of 7 miles, south-southwesterly winds of 10 gusting to 15 knots and a temperature of 76 degrees F.

The odds for Friday's backup launch window, however, are 60 percent favorable.

DELAY. This week's flight of the United Launch Alliance Delta 4 rocket has been pushed back a day, to Thursday evening, so technicians at Cape Canaveral's Complex 37 pad can replace a control box on the RS-68 main engine.

"During acceptance testing for another mission, an avionics box that is used for controlling the Delta booster RS-68 engine experienced an anomaly. ULA is replacing the engine control unit on the WGS-5 vehicle with one that has been inspected and confirmed to not have the suspect condition that caused the recent anomaly in acceptance testing," the company said in a statement late Sunday.

The launch window on Thursday evening extends from 8:28 to 9:00 p.m. EDT (0028-0100 GMT).

Weather forecasters are predicting a 40 percent chance of acceptable conditions.

The early weather outlook for Wednesday night's Delta 4 rocket launch from Cape Canaveral shows the military mission will have to contend with Earthly and solar concerns.

Air Force meteorologists this morning issued their first forecast and predict a 40 percent of acceptable conditions to launch. Flight through precipitation, cumulus clouds, thick clouds and space weather are the primary worries for violating launch constraints.

"A surface high pressure area is located to the east over the Atlantic with a ridge extending across the Florida/Georgia border. This pattern is causing southeasterly flow across the Florida coast which is enhanced by a sea breeze each afternoon. Moisture is increasing over the Florida Peninsula, and afternoon west and east coast sea breezes may converge in center of the peninsula causing inland showers and thunderstorms. Monday, thunderstorms may be closer to the east coast as a short wave moves through in the upper levels," the launch weather team says.

"By Wednesday, an upper level trough will move into the area, and a surface trough will also develop over South Florida, and a significant amount of moisture will advect into Florida from the southeast. This may cause coastal showers and thunderstorms along the Space Coast on launch day as well as for a 24-hour delay.

"As for space weather, two complex sunspots will be in a favorable location for earthward-directed coronal mass ejections, and sunspot 1748 has produced several M- and X-class flares within the past week. If either of these sunspots produce an X-class flare, there is a chance of exceeding the solar constraint for launch."

For Wednesday's launch opportunity that extends from 8:26 to 8:58 p.m. EDT, the outlook calls for scattered clouds at 2,500 and 8,000 feet, a broken deck at 30,000 feet, showers in the area, visibility of 4 miles, southeasterly winds of 16 gusting to 22 knots and a temperature of 74 degrees F.

The target liftoff time is just 16 minutes after sunset.

Pushing forward with plans to launch the Air Force's fifth Wideband Global SATCOM communications satellite on May 22 to give the expanding constellation worldwide coverage, the craft departed its cleanroom Monday night and headed for the Delta 4 rocket's launch pad.

United Launch Alliance workers at Cape Canaveral's Complex 37 hoisted the spacecraft atop the booster on Tuesday to complete assembly of the 217-foot-tall rocket.

Read our full story.