Mission Status Center

Still waiting and watching the weather at T-minus 5 minutes. Clocks would need to resume ticking no later than 8:38 p.m. to get the rocket airborne by the end of tonight's launch window at 8:43 p.m. EST.

The weather remains "no go" at this time.

NEW LAUNCH TIME. Liftoff will be retargeted to the very end of the launch window at 8:43 p.m. EST as the constraints continue to be worked. That will be the last moment available to launch the rocket today or else delay until tomorrow.

The latest wind data and flight profile have been loaded, the launch team reports.

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Two of the launch weather rules have gone "red" for thick clouds and flight through precipitation.

A light sprinkle is beginning to fall here at the Kennedy Space Center press site.

NEW LAUNCH TIME. Liftoff will be delayed to 8:23 p.m. EST due to the upper level winds, the thick clouds and a technical issue now being worked, officials say.

The launch weather situation is getting worse. That area of clouds moving toward the Cape from the southwest is thick enough to violate the weather criteria. Forecasters predict being "no go" on clouds from 7:40 to approximately 8:30 p.m. EST.

NEW LAUNCH TIME. Liftoff will be delayed to 7:53 p.m. EST. The most recent weather balloon data showed winds slightly out of limits.

The 81-minute launch window is now open. But the countdown is holding at T-minus 5 minutes to await additional weather balloon data on the upper level winds that the rocket will experience 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.

Tonight's launch opportunity extends from 7:22 to 8:43 p.m. EST, giving the Delta team a large window of time to get the mission underway.

NEW LAUNCH TIME. Liftoff has been retargeted for 7:37 p.m. EST.

Liftoff will be delayed beyond the 7:22 p.m. target because the upper level wind situation, ULA says. How long this extend hold will last is not yet clear.

T-minus 5 minutes and holding. The countdown has entered the planned 15-minute hold leading toward the 7:22 p.m. EST 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.

United Launch Alliance says the winds aloft are "no go" at the present time.

The final guidance update on upper level winds is waiting on further weather balloon data.

Weather continues to be acceptable at the present time. However, forecasters say there's an area of thick clouds that could become a problem about 20 minutes into this evening's window. So on-time liftoff would be best for the weather.

The weather reconnaissance aircraft is airborne to evaluate conditions and feed the real-time observations back to the launch weather team at the Air Force's 45th Weather Squadron.

T-minus 30 minutes and counting. The countdown is headed to the T-minus 5 minute point where a 15-minute hold is planned. Liftoff is targeted for 7:22 p.m., the opening of today's 81-minute launch window.

The engine slew checks have been performed successfully. The test sequence started with the upper stage RL10 engine, followed by the first stage RS-68 engine gimbaling and then some commanding checks for the strap-on solid rocket motors.

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Weather remains "go" at this time and a 70 percent chance of acceptable conditions during the launch window.

The revised forecast now includes broken decks of clouds at 4,000 and 14,000 feet, visibility of 7 miles, northwesterly winds of 8 peaking to 12 knots and a temperature around 72 degrees F.

Now moving into the final 60 minutes of the countdown.

This launch will deliver to orbit the third satellite in the Wideband Global SATCOM series. Although more spacecraft are under construction in the Block 2 phase of the program, today's deployment of WGS 3 marks the last satellite in Block 1.

"The upcoming launch of WGS is really a landmark achievement for the DOD and The Boeing Company. It completes the initial constellation of three WGS satellites that will provide vital, flexible, high-capacity communications to the U.S. warfighters and allies across the theaters of operation," said Mark Spiwak, the WGS program director at Boeing.

Boeing shipped the WGS 3 satellite from its factory in El Segundo to Cape Canaveral on September 28. Over the past two months, the craft underwent final testing, fueling and encapsulation in the shroud that will cover it during launch.

On November 14, the spacecraft was transported from the Astrotech processing facility in Titusville to Complex 37 where it was hoisted atop the Delta 4 rocket.

"It's ready to join its brothers in arms -- WGS 1 and 2 -- in providing this capability to the men and woman of our armed forces. We look forward to a great ride from ULA," said Spiwak.

The company has three additional WGS satellites currently in production for launches slated to start in 2011.

"On behalf of The Boeing Company, we are very proud to be providing them to the United States Air Force. They are a key element in the very highly flexible and capable system providing this quantum leap in communications for the warfighter."

The RS-68 first stage main engine spin start pressurization operation is about to start.

The propellant conditioning has been completed on all four cryogenic tanks. The Delta 4 rocket is fueled up and ready for today's launch window to open.

The radio frequency link checks between the rocket and ground have been completed and verified satisfactory.

The safety system checks are being performed at this point in the countdown.

Upper stage liquid oxygen topping has commenced. That puts all four cryogenic fuel tanks aboard the Delta 4 rocket in topping mode.

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 mostly quiet. Team members are monitoring systems while the clocks tick down.

In the immediate future, the rocket's safety system will be checked and a series of engine steering tests will occur.

Everything continues to proceed on schedule at Cape Canaveral for liftoff at 7:22 p.m. EST. The weather is only thing being watched right now.

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

Launch of the Delta 4 rocket with the third Wideband Global SATCOM spacecraft is just two hours away.

The first two WGS satellites were hauled into space aboard Atlas 5 rockets. But WGS 3 is riding atop the Delta 4, the other rocket in the Air Force's Evolved Expendable Launch Vehicle fleet. Both vehicles are produced by United Launch Alliance, the firm created three years ago this month that joined Lockheed Martin's Atlas and Boeing's Delta rockets under one organization.

"This mission is symbolic of why ULA formed for a couple of reasons," says James Bell, ULA's WGS mission manager.

"First, it exemplifies why the government brought the Atlas and Delta programs together. The first two WGS satellites were launched on our Atlas vehicles and for WGS 3, instead of our Delta 4 team having to start from scratch, ULA was proactive in implementing a seamless integration and processing services for this repeat customer.

"Also, because I was the WGS mission manger for those two Atlas launches, I was able to share the knowledge we gained from those launches with our Delta team. This is not only a tremendous benefit for ULA but also for our Air Force mission partners who are relying on us to provide them assured access to space. This simply wasn't possible prior to ULA.

"Second, this mission marks the 36th launch for ULA in 36 months, which is quite a record of reliability and mission success. When ULA was formed, our primary goal was to provide safe and reliable assured access to space with mission success paramount in everything we do."

The upper stage liquid oxygen tank has been filled up, now making the Delta 4 a fully fueled rocket.

The countdown remains on track and current weather conditions are within limits for today's liftoff at 7:22 p.m. EST. Three of the cryogenic tanks of the rocket has been filled -- the first stage and upper stage liquid hydrogen supplies and the first stage liquid oxygen tank. The launch team continues to load upper stage liquid oxygen, which is about 67 percent full right now.

The first stage liquid hydrogen tank is being placed into its topping phase.

The weather board is still looking good. No constraints are posted. The updated forecast for launch time now includes scattered clouds at 3,000 feet, broken decks at 6,000 and 12,000 feet, visibility of 7 miles, northwesterly winds of 8 peaking to 12 knots and a temperature around 68 degrees F.

The rocket team is not tracking any technical issues of note.

The first stage liquid hydrogen tank has been loaded. Vent and relief checks will be completed before topping is initiated.

Post-filling tests on the first stage liquid oxygen system are complete and the tank is in topping mode. The upper stage tanks continue to be loaded.

A check of the current weather conditions shows none of the launch rules are being violated. The weather reconnaissance aircraft will be taking off around 6 p.m. EST to verify that the cloud thickness is not an issue. But so far, so good.

Now entering the last three hours of the countdown. Fueling of the Delta 4 rocket continues in work for the 7:22 p.m. EST launch of the WGS 3 military communications satellite from Cape Canaveral, Florida.

The upper stage conditioning on the liquid oxygen side has finished. Loading of the tank is starting. This is the last of the rocket's four cryogenic supplies to be filled in today's countdown to launch.

Now three-and-a-half hours till launch.

The chilldown of the upper stage stage liquid hydrogen system is reported complete, clearing the way for loading the rocket's tank.

To recap, the Delta 4 rocket's Common Booster Core first stage has been loaded with supercold liquid oxygen. The filling of liquid hydrogen propellant into the first stage is continuing along with the precursor preps for fueling the upper stage stage.

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

The loading of liquid oxygen into the Common Booster Core first stage has been completed out at launch pad 37B as activities proceed toward a 7:22 p.m. EST liftoff of the Delta 4 rocket.

Ahead in the countdown, the launch team plans to conduct vent and relief checks following the first stage LOX tanking and begin chilldown procedures for the upper stage liquid oxygen system.

The launch team has gotten the approval to start chilldown conditioning of the upper stage liquid hydrogen system.

First stage liquid oxygen loading continues in progress. The rocket's tank will be loaded with 40,000 gallons of the supercold oxidizer that's chilled to Minus-298 degrees F.

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

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. 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 will be filled in a little while. It receives the cryos from the middle swing arm that extends from the Fixed Umbilical Tower to the front-side of the rocket.

The start of liquid hydrogen fueling of the first stage is now 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 start 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 first stage liquid oxygen chilldown is complete. Fueling is beginning in the "slow-fill" mode to load a small percentage of the tank. The process then speeds up to the "fast-fill" mode until the tank is nearly full.

We have posted another photo gallery from this morning. This new page features beautiful up-close views of the Delta 4 as it gets ready to fly in a configuration with four solid rocket boosters that's not been seen before.

A "go" has been given to start the cold gas chilldown conditioning of the first stage liquid hydrogen system.

Live streaming video of the Delta 4 rocket can be viewed on your iPhone. Check it out!

Chilldown of the first stage liquid oxygen system is beginning. This preps the tank and pumping to guard against shock when the supercold oxidizer begins flowing into the rocket a short time from now.

The launch director has given approval for the start of fueling operations as planned today.

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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 countdown has one planned built-in hold at T-minus 5 minutes lasting some 15 minutes, leading to liftoff at 7:22 p.m. EST (0022 GMT).

The launch pad has been verified evacuated of all 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.

No technical problems are being reported in the countdown and the weather looks favorable. The launch pad has been buttoned up and the area cleared for the rest of the countdown.

The launch team has been polled to verify all consoles are manned and ready to begin the Terminal Countdown when this hold ends at 1:52 p.m. A briefing on countdown procedures is now underway.

The weather outlook is looking more optimistic as that cold front continues to move deeper into South Florida and away from the Cape. As a result, Air Force meteorologists have increased the odds of acceptable conditions during the launch window to 70 percent.

Current observations show no violation of the cloud rules, there's no rain in the area and ground winds are within limits.

The revised forecast for this evening's window calls for some scattered low clouds and a broken deck above that, northwesterly winds of 8 peaking to 12 knots and a temperature around 68 degrees F.

Checks of the C-band beacon are beginning. This system is used in tracking the rocket during the flight downrange.

The call to "man stations for Terminal Count" just went out to the launch team.

T-minus 5 hours, 15 minutes and holding. The countdown has just entered a planned 60-minute built-in hold, giving the team time to catch up on any work that could be running behind schedule. Once the clocks resume ticking at 1:52 p.m. EST, the Terminal Countdown phase of today's launch operation will begin.

A gallery of photographs taken at the Complex 37 launch pad this morning when the mobile service gantry was retracted to unveil the Delta 4 rocket is posted here.

"It's truly my pleasure to be a member of this WGS launch team. The long hours and hard work the entire team has dedicated to ensuring we're able to place this incredible warfighting capability on-orbit is truly amazing," Lt. Col. Dave Hook, commander of the 5th Space Launch Squadron at Cape Canaveral, told reporters at a recent briefing.

"With the successful launch (today), our government and industry team will continue this momentum into the next year and continue to successfully deliver these vitally important national assets to orbit for our joint forces deployed around the world."

Hook's squadron is responsible for overseeing operations to fly the United Launch Alliance Atlas 5 and Delta 4 rocket fleets from the Eastern Range at the Florida spaceport.

"For this mission alone, the 5th Space Launch Squadron monitored 380 critical ULA technical procedures over the span of seven months. The vital oversight of ULA procedures we provide ensures mission assurance is correctly and safely conducted throughout the duration of the entire launch flow."

The skies are clearing as that weather system continues to slowly drift southward. After the rainy and gloomy start the morning, the sun is now shining on Central Florida.

The outlook for the launch still predicts a 60 percent chance of acceptable conditions. Meteorologists are concerned that the cold front will stall and allow the rain to move back northward.

During this evening's window, the forecast calls for broken low clouds, overcast mid- and high-level clouds, showers in the vicinity, northerly winds of 8 peaking to 12 knots and a temperature around 68 degrees F.

In the event of a 24-hour delay to Friday, the odds of good weather drop considerably to only 30 percent due to concerns about thick clouds and rain in the rocket's flight path.

The 330-foot tall mobile service tower has been retracted from the Delta 4 rocket at Cape Canaveral's pad 37B for today's launch that will place the third Wideband Global SATCOM military satellite into Earth orbit.

The wheeled structure was 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 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 this afternoon.

Liftoff remains scheduled for 7:22 p.m. EST, the opening of an 81-minute window that extends to 8:43 p.m. EST (0022-0143 GMT).

Tower rollback is underway.

Good morning from soggy Cape Canaveral Air Force station were the heavy overnight rains have pushed to the south but the skies remain gray and overcast. Out at Complex 37, ground technicians are making final preps to retract the dual-purpose assembly gantry and mobile shelter away from the Delta 4 rocket for today's countdown to launch.

The Delta 4 rocket and its military communications satellite payload are waiting through a 24-hour hiatus today, letting a line of heavy weather pass through the launch area while remaining tucked safely inside the gantry at Cape Canaveral's Complex 37.

"The launch vehicle and satellite are very healthy. So we're waiting on Mother Nature to get done with her rumblings," said Mark Spiwak, the Wideband Global SATCOM program director at Boeing.

The launch weather officer projects a 60 percent chance that conditions will be acceptable for a liftoff Thursday evening during the opportunity extending from 7:22 to 8:43 p.m. EST. Thick clouds and rain in the rocket's flight path will be the concerns.

"Strong line of thunderstorms currently over the Gulf of Mexico will move through central Florida this evening," Air Force meteorologists reported. "Cold frontal boundary will slow as it passes through the area during the day tomorrow, while becoming stationary over southern Florida. Cloud cover and precipitation will still be a concern as warm, moist air flows over the shallow cool surface layer left in the wake of the frontal boundary. Coverage of rain will increase from south to north Thursday night and Friday as upper level impulses ride along the stalled frontal boundary from west to east.

"The primary concern on launch day and the following day will be the Thick Cloud Rule and flight through precipitation. Vehicle exposure pre-liftoff and liftoff wind constraints are not expected to be at risk."

Launch day activities will begin with final preparations for retracting the 330-foot mobile service tower away from the Delta 4 vehicle. The gantry, which should be rolled back a little after 7 a.m. EST, was used to gain access to the rocket during pre-flight work, plus served as a protective structure to shield the booster from adverse weather conditions during its stay at the pad.

A key weather briefing occurs a little after 1:20 p.m. EST Thursday as the launch team decides whether to commit to the fueling process. The weather officer will give managers 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 1:52 p.m. EST, 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 15-minute build-in hold is slated for T-minus 5 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.

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The forecast of dismal weather and bleak odds of launching the Delta 4 rocket Wednesday evening from Cape Canaveral have led mission managers to postpone the flight by 24 hours.

Liftoff will be retargeted for Thursday during a window stretching from 7:22 to 8:43 p.m. EST.

Meteorologists are predicting stormy conditions to sweep across Central Florida during the afternoon and evening hours on Wednesday. That system is expected to slide southward by Thursday, giving better chances of acceptable weather for the rocket then.

The Launch Readiness Review was held today and officials reported that the weather was the only hurdle for the Delta 4 rocket and its Wideband Global SATCOM spacecraft payload.

A hotrod version of the Delta 4 rocket, souped up with extra solid-fueled boosters, takes its first trip into space Wednesday evening on a mission for the U.S. military.

Read our preview story.

The threat of stormy weather sweeping across Central Florida during Wednesday's countdown means meteorologists are giving slim odds for an on-time launch of the scheduled Delta 4 rocket launch carrying a U.S. military communications satellite.

Liftoff from Complex 37 will be possible during an 80-minute window extending from 7:21 to 8:41 p.m. EST (0021-0141 GMT).

But Air Force forecasters are predicting only a 20 percent chance that conditions will permit a liftoff due to anvil clouds, strong winds and other possible violations of the launch rules.

"Model guidance continues to indicate a deep low pressure system developing over the Western Gulf of Mexico on Tuesday. This system will quickly travel east-northeast during this timeframe. Strong cold front will move through the area late Wednesday or early Thursday. Showers and potentially strong squall line thunderstorms will precede the front during the countdown Wednesday afternoon and evening," the weather officer says.

"Vehicle exposure and liftoff wind constraints will also be at risk as the squall line moves across Central Florida."

The launch window outlook includes low-, mid- and high-level decks of clouds, showers and thunderstorms in the area, southerly winds of 15 peaking to 25 knots and a temperature of 72 to 74 degrees F.

The odds for favorable weather on Thursday evening, should the launch be delayed 24 hours, flip to the good side. Meteorologists predict the cold front will be south of the Cape, leave significantly improving conditions in its wake and an 80 percent chance of launching.

When the rocket does fly, it will deliver into a supersynchronous transfer orbit the Air Force's third Wideband Global SATCOM spacecraft, a powerful communications satellite that will be parked over the Atlantic Ocean to cover Europe, Africa and the Middle East.

Check back tomorrow for a mission preview and watch this page for live coverage throughout the countdown and launch!