A rocket launch funded entirely by Australia streaked to orbit Wednesday night from Cape Canaveral in a show of international cooperation between the U.S. military and its allies.

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"WGS is a vital piece of the MILSATCOM enterprise consisting of WGS, DSCS, AEHF, Milstar and terminals," said Charlotte Gerhart, chief of the Wideband SATCOM division in the Air Force's MILSATCOM directorate.

""WGS is providing unparalleled global communications capabilities to soldiers, sailors, marines and airmen for the United States, Australia, Canada, Denmark, Luxembourg, The Netherlands, and New Zealand. The continued success of WGS is due to the hard work and dedication from the combined government and Boeing team."

Here's a post-flight statement from Jim Sponnick, United Launch Alliance vice president of Atlas and Delta programs:

"Congratulations to the entire team on today's successful launch of the WGS 6 satellite. As with the previous five WGS missions, we have enjoyed a very strong partnership with the Air Force and all of our missions partners throughout this launch campaign,"

"We were honored to launch the first two WGS satellites on our Atlas 5 vehicle and the next four satellites in the constellation on our Delta 4 vehicle, delivering critical communications capability to orbit to support our nation’s warfighters throughout the world."

The next Delta 4 rocket launch targeted for Aug. 28 from Vandenberg Air Force Base in California. A Delta 4-Heavy will launch the National Reconnaissance Office's NROL-65 mission.

T+plus 40 minutes, 47 seconds. SPACECRAFT SEPARATION! The Wideband Global SATCOM 6 military communications satellite has been deployed into orbit from the Delta 4 rocket's upper stage, completing tonight's launch.

Liftoff occurred on-time and the flight appeared nominal.

The WGS 6 spacecraft will spend the next three months 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 6 is handed over to the Air Force.

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 36 minutes. Now more than 800 miles in altitude.

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 36,120 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, 37 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, 20 seconds. Passing an altitude of 348 miles as the rocket begins to climb upwards on its trajectory, 5,758 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 RL10.

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 6 to its targeted orbit.

T+plus 28 minutes, 20 seconds. The upper stage is readying itself for restart.

T+plus 27 minutes. Things are still looking good, no reports of any issues tonight following an on-time liftoff.

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 22 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, 40 seconds. SECO 1. Confirmation that the second stage engine has shut down after the first of two planned firings to inject the WGS 6 spacecraft into a supersynchronous transfer orbit.

T+plus 20 minutes, 10 seconds. Delta is traveling at 19,130 mph over the central Atlantic Ocean.

T+plus 19 minutes. The second stage engine continues to fire well with good chamber pressure. All is looking good.

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. Rock solid chamber pressure. Good engine controls.

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 switched from ground stations to NASA's Tracking and Data Relay Satellite System.

T+plus 14 minutes, 15 seconds. Delta is 1,773 miles east-southeast of the launch pad, traveling at 14,123 mph.

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

T+plus 12 minutes, 20 seconds. Good controls by the upper stage. Delta is 220 miles in altitude, speed in excess of 12,700 mph, 1,405 miles downrange from the launch pad.

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

T+plus 10 minutes, 45 seconds. Chamber pressure data being reported from the RL10 engine looks good as it thrusts to reach orbit.

T+plus 9 minutes, 15 seconds. Nearing 18,000 feet per second in velocity.

T+plus 9 minutes. The upper stage is the larger five-meter version that has flown previously on the Delta 4-Heavy vehicle and three 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, 20 seconds. Delta is 212 miles in altitude, 793 miles east-southeast of the launch pad. All reported nominal.

T+plus 7 minutes, 45 seconds. Delta is 202 miles in altitude, 703 miles east-southeast of the launch pad.

T+plus 7 minutes, 20 seconds. Good chamber pressure holding steady.

T+plus 6 minutes, 55 seconds. Delta is 186 miles in altitude, traveling at 16,600 feet per second, 589 miles east of the launch pad.

T+plus 6 minutes, 30 seconds. Mission events are occurring close to the expected times.

T+plus 5 minutes, 15 seconds. Delta is 133 miles in altitude, traveling at 16,600 feet per second, 342 miles east of the launch pad.

T+plus 4 minutes, 32 seconds. The cryogenic RL10B-2 upper stage engine has been lit!

T+plus 4 minutes, 19 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, 11 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, 5 seconds. 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. Delta still looking good.

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

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 into flight of Delta 363 and the sixth WGS spacecraft. Already 7 miles in altitude, 5 miles downrange.

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 the Delta 4 rocket with the WGS 6 satellite, launching Australia's contribution to the U.S. military's Wideband Global SATCOM constellation!

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 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 29 minutes past the hour by the Delta 4 rocket carrying the WGS 6 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 8:29 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 8:29 p.m. liftoff.

Assuming all systems are go, clocks will resume ticking at 8:25 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 8:29 p.m. (0029 GMT) on the WGS 6 satellite deployment mission.

T-minus 4 minutes and holding. The countdown has entered the planned 15-minute hold leading toward the 8:29 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 sun is setting here on the East Coast of Florida. Standing by to go into the final built-in hold of today's countdown.

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 WGS 6 spacecraft atop the Delta 4 is switching from ground-fed power to its internal batteries for launch.

The final weather briefing has been given and all conditions are GO for launch tonight.

Now entering the final 30 minutes until the Delta 4 rocket launch from Cape Canaveral at 8:29 p.m. EDT. Here's a look at some stats about today's mission. This will be:

• The 363rd Delta rocket launch since 1960
• The 23rd Delta 4 rocket mission since 2002
• The 32nd RS-68 main engine used
• The 33rd-36th GEM-60 solid rocket motors flown
• The 438th production RL10 engine to be launched
• The 26th RL10B-2 engine launched
• The 19th Delta 4 rocket launch from Cape Canaveral
• The 19th use of Delta 4 by the Air Force
• The fourth Medium+ 5,4 configuration to fly
• The 62nd Evolved Expendable Launch Vehicle flight
• The 73rd United Launch Alliance mission since 2006
• The 16th Delta 4 under the ULA banner
• The 7th ULA launch this year
• The 2nd launch of the Delta family in 2013
• The 6th Wideband Global SATCOM satellite
• The 3rd Block 2 WGS satellite
• The 4th WGS on Delta 4

Now moving into the final 45 minutes of the countdown to launch.

This launch will deliver to orbit the sixth satellite in the Wideband Global SATCOM series, this one being the paid contribution from the Australian Defence Force to join the system.

"The cooperation we've had with Australia has been extremely successful," said Dave Madden, the MILSATCOM director at the Air Force's Space and Missile Systems Center.

"It really helps all parties. It brings down our overall operating costs to operate the constellation and provides the capabilities to the U.S. (and) it provides critical capability that Australia needed to support its infrastructure as well as its warfighters. Third, it created interoperability between our forces. When we are deployed together we are operating on the same system. It really was a win-win, I believe, for all parties."

The Boeing Company builds the craft.

WGS 6 was completed in the factory last August and entered storage awaiting launch. Boeing shipped the satellite from its factory in El Segundo to Cape Canaveral on May 16. Fueling was completed June 11 and encapsulation in the shroud that will cover it during launch was finished June 21.

On July 23, 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 four additional WGS satellites in the pipeline for more WGS launches starting in 2015.

Countdown activities continue to track to the timeline for liftoff at 8:29 p.m.

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 RS-68 first stage main engine spin start system has been pressurized.

The flight hazard area has been established.

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 8:29 to 9:18 p.m. EDT.

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

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 launch team is entering the last 75 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 8:29 p.m. EDT.

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

L-minus 90 minutes. Radio frequency link checks between tracking facilities at the Cape and the launch vehicle are being completed.

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.

Range weather is green across the board.

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.

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

Now entering into the final two hours of the countdown to launch of Delta 363 and the sixth satellite for the WGS constellation.

The rocket stands fueled and ready for launch at 8:29 p.m. EDT today. The launch team is not reporting any significant issues, weather conditions are green and the countdown remains on schedule.

The upper stage liquid oxygen filling has been completed.

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

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

Forecasters expect that the cumulus cloud rule will be "red" for the next half-hour or so before clearing.

Current observed weather conditions are "red" again, this time due to cumulus clouds passing over the Cape at this time.

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

The launch weather forecast has been amended to remove the chance of isolated showers but add potential anvil clouds in the area. The outlook remains 80 percent favorable for tonight's launch opportunity that extends from 8:29 to 9:18 p.m. EDT.

The specifics for launch time include scattered clouds at 3,000 and 22,000 feet, good visibility and southeasterly winds of 10 gusting to 15 knots.

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

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

Now passing the three-hour mark away from today's 8:29 p.m. EDT liftoff of the United Launch Alliance Delta 4 rocket with the WGS 6 satellite payload from Cape Canaveral, Florida.

This will be the sixth 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, 2012 and this past May.

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.

No issues are being reported in the countdown as activities continue toward today's 8:29 p.m. EDT liftoff of the Delta 4 rocket and WGS 6 satellite.

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.

After chilldown of the upper stage liquid hydrogen system, the was clear for loading the rocket's tank. The launch team is actively filling the upper stage's liquid hydrogen tank with propellant for the RL10 engine.

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.

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.

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 weather conditions are back in "green" after temporarily going "red" for a detached anvil cloud passing by.

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 rocket's tracking beacon has completed its interrogation checks.

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.

The weather has temporarily gone to a "red" status as a detached anvil cloud passes through the rocket's flight path. Meteorologists monitor conditions throughout the countdown and advise launch officials if current observations violate the launch-time weather criteria.

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 being performed on the C-band beacon used for tracking the vehicle during its flight downrange.

The launch director has given the GO for fueling.

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 and its allied partners.

The count has a planned built-in hold at T-minus 4 minutes, leading to liftoff at 8:29 p.m. EDT (0029 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 countdown when this hold ends at 2:59 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 within limits and the forecast for the rest of the day looks favorable.

The outlook tonight calls for scattered clouds, good visibility, southeasterly winds of 10 gusting to 15 knots, a slight change of coastal showers and a temperature of 80 degrees F. There is an 80 percent chance of acceptable launch conditions.

The vehicle's avionics have been turned on.

The launch pad has been cleared of workers and the restricted area around Complex 37 has been established in preparation for fueling.

Activation of the rocket's main computer -- the RIFCA -- is getting started at this point in the day.

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

The 330-foot 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 WGS 6 satellite into Earth orbit for the Air Force and Australian Defence Force.

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.

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

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Right on schedule, 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 it is launch day for the Delta 4 rocket and its communications satellite cargo for use by the U.S. Defense Department and allies.

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.

A United Launch Alliance Delta 4 rocket and its military communications satellite payload, both bought by Australia, will thunder to orbit Wednesday night from Cape Canaveral in an international collaboration to strengthen partnerships between the U.S. and its allies.

Read our full story.

The early outlook for Wednesday night's Delta 4 rocket launch from Cape Canaveral shows the military mission has good odds that the weather will cooperate for the 8:29 p.m. EDT blastoff, just 21 minutes after sunset.

Air Force meteorologists this morning issued their first forecast and predict an 80 percent of acceptable conditions to launch during the evening's 49-minute window that extends to 9:18 p.m. EDT. Cumulus clouds from a stray coastal shower poses the only concern in the outlook.

"Dorian reformed into a tropical depression this morning 85 nautical miles east-northeast of Cape Canaveral. Dorian's winds are 30 knots gusting to 45 knots and are focused along the southeast and south side of the storm. Dorian is currently moving toward the north at 5 knots and is expected to remain a tropical depression as it tracks northeast away from the Space Coast. There is a slight chance Dorian could reach tropical storm strength, but intensification is not expected due to increasing northerly vertical wind shear affecting Dorian. The majority of showers related to Dorian are offshore, but there is a chance showers and isolated thunderstorms could impact the coast today," the launch weather team says.

"For the next few days, an upper level trough will pull Dorian away to the northeast, and the Bermuda High ridge will remain south. Westerly flow across Central Florida will allow afternoon storms to migrate toward the Space Coast. By Tuesday and Wednesday, the Bermuda High ridge will progress back toward Central Florida, and the gradient and mid-level winds will become weak. Surface winds will become southeasterly.

"In this weather regime, storms may develop along the East Central Florida Coast as the sea breeze first develops, but then progress inland with the sea breeze. Upper level winds will be from the northeast keeping anvils from inland thunderstorms away from the east coast. Overall, conditions are favorable for launch."

For Wednesday's launch opportunity, the forecast calls for scattered clouds at 3,000 and 20,000 feet, isolated coastal showers, visibility of 7 miles, south-southeasterly winds of 10 gusting to 15 knots and a temperature of 80 degrees F.

If the launch slips to Thursday for some reason, there is a 70 percent chance of acceptable weather for the 8:28 p.m. EDT liftoff time.

"For a 24-hour delay forecast, there is a slightly higher chance of a coastal shower causing a cumulus cloud violation," forecasters said.

The payloads are attached and final preparations are underway for two national security satellites heading for different orbits aboard United Launch Alliance Delta 4 rockets in August, one from Cape Canaveral, the other at Vandenberg Air Force Base in California.

The Air Force's sixth Wideband Global SATCOM high-capacity communications satellite was loaded aboard its Delta 4 at the Florida spaceport's Complex 37 pad last Tuesday, July 23 for blastoff Aug. 7.

The WGS 6 spacecraft, financed entirely through a partnership with Australia, will join a constellation of satellites now comprising the Defense Department's primary communications network for connectivity to forces around the world.

Read our full story.