BY JUSTIN RAY

Follow the countdown and launch of the Boeing Delta 2 rocket with NASA's Space Infrared Telescope Facility. Reload this page for the very latest on the mission.

Coverage for subscribers only:
   VIDEO: FIVE-MINUTE MOVIE OF DELTA LAUNCHING SIRTF QT
   VIDEO: POWERFUL TRACKING CAMERA VIEW OF LAUNCH QT
   VIDEO: VIEW FROM PATRICK AIR FORCE BASE BEACH QT
   VIDEO: CAPE CANAVERAL PRESS SITE VIEW OF LIFTOFF QT
   VIDEO: REPLAY FROM LAUNCH PAD ENGINEERING CAMERA QT
   VIDEO: A CLOSE-UP VIEW OF FIRST STAGE ENGINE IGNITION QT
   VIDEO: NASA LAUNCH MANAGER RECAPS COUNTDOWN & ASCENT QT
   VIDEO: STATUS OF SIRTF ANNOUNCED AFTER LAUNCH QT

   VIDEO: MOBILE SERVICE TOWER ROLLED BACK SUNDAY QT
   VIDEO: FOOTAGE OF DELTA 2 ROCKET BEING STACKED QT
   VIDEO: NARRATED MOVIE SHOWS SIRTF LAUNCH PREPS QT
   VIDEO: WATCH FRIDAY'S PRE-LAUNCH NEWS CONFERENCE QT
   VIDEO: LEARN ABOUT SIRTF IN PRE-FLIGHT SCIENCE BRIEFING QT
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MONDAY, AUGUST 25, 2003

With a sky-lighting burst of flame and thunder, a Boeing Delta 2 rocket boosted a $1.2 billion infrared telescope into space early today, a "great observatory" designed to detect the feeble glow of infant planets, stars and galaxies in the making. Read our full story.

0706 GMT (3:06 a.m. EDT)

"I have no nails left," SIRTF project manager David Gallagher says. "We had a little extra delay there acquiring from Canberra.

"We have done a preliminary assessment of the subsystems of the observatory and everything looks to be good. We are pointing where we should be, telecomm, power, everything appears to be working.

"We believe -- this is very preliminary -- the cause of the delay was that the signal was too strong. We locked onto the carrier, the signal was too strong and we rejected that," Gallagher explained. "That is why we were having difficulty synchronizing. We are getting telemetry down now and everything looks good."

Gallagher added: "It looks like we got a good ride on the launch vehicle and SIRTF survived well."

The spacecraft will undergo a 60-day checkout period. That will be followed by 30 days of science verification tests to fine-tune the onboard instruments. The first public release of data from the SIRTF mission is expected in December -- at which time NASA will give the observatory a name.

0657 GMT (2:57 a.m. EDT)

T+plus 82 minutes. David Gallagher, the SIRTF project manager, reports the observatory is in great shape. The review of data from the spacecraft shows everything is working properly.

0647 GMT (2:47 a.m. EDT)

T+plus 72 minutes. The second stage, flying on its own, has completed a depletion burn to use up the remaining onboard fuel. This safes the stage to guard against it bursting in orbit and causing space debris.

0645 GMT (2:45 a.m. EDT)

T+plus 70 minutes. "Things are looking very good," the SIRTF team reports. The spacecraft is power positive and the post-launch activities are progressing. Officials say the Delta 2 rocket has given the Great Observatory "a good ride" into space.

0643 GMT (2:43 a.m. EDT)

T+plus 67 minutes, 15 seconds. Good data is being received from SIRTF. Everyone is breathing a lot easier now.

0642 GMT (2:42 a.m. EDT)

T+plus 66 minutes. The second stage has completed a third burn as scheduled. The quick firing moves the spent stage away from SIRTF.

0641 GMT (2:41 a.m. EDT)

T+plus 65 minutes, 30 seconds. The Canberra tracking station has finally acquired SIRTF! Analysis is underway to determine the spacecraft's health following tonight's launch.

0640 GMT (2:40 a.m. EDT)

T+plus 65 minutes. The SIRTF test control center at the Cape is now being fed some data.

0637 GMT (2:37 a.m. EDT)

T+plus 62 minutes. From the data engineers have it appears SIRTF did separate from the Delta 2 rocket. However, ground controllers are having trouble picking up the signal from the observatory via NASA's Deep Space Network tracking station in Australia.

0635 GMT (2:35 a.m. EDT)

T+plus 60 minutes. Canberra is still reporting difficulty locking onto the signal from SIRTF.

0631 GMT (2:31 a.m. EDT)

T+plus 56 minutes, 10 seconds. The Deep Space Network tracking site in Canberra, Australia reports it sees a signal from SIRTF. However, it has not yet locked onto the spacecraft.

0630 GMT (2:30 a.m. EDT)

T+plus 55 minutes. Second stage data looks normal for the current coast period.

0629 GMT (2:29 a.m. EDT)

T+plus 54 minutes. The tracking site in Guam has picked up the second stage data. SIRTF should be acquired via NASA's Deep Space Network momentarily.

0627 GMT (2:27 a.m. EDT)

T+plus 52 minutes. There is currently no way to confirm release of SIRTF from the launch vehicle. The Australian tracking station was unable to lock onto the rocket's signal. The Guam tracking station is next to pick up the Delta 2's data in a few minutes.

0626 GMT (2:26 a.m. EDT)

T+plus 51 minutes. The orbital data from the second burn of the second stage indicates a good burn. The perigee is 93 nautical miles, inclination of 31.5 degrees and a velocity of 36,036 feet per second. There is no apogee since SIRTF has been launched into an orbit around the Sun.

0625 GMT (2:25 a.m. EDT)

T+plus 50 minutes. The point of spacecraft deployment is now. However, the Dongara tracking station has not yet acquired the rocket's signal.

0624 GMT (2:24 a.m. EDT)

T+plus 49 minutes. Still waiting on live data from Dongara.

Thirty seconds before SIRTF separates from the Delta 2 rocket, the clamp band holding the spacecraft to the second stage will be released. A half-minute will pass to allow any motions to damp out. Then latches will be disengaged to deploy the observatory. This is a minimum tip-off separation sequence to leave SIRTF in a stable attitude. The rocket stage will then back away from the telescope.

0621 GMT (2:21 a.m. EDT)

T+plus 46 minutes. The rocket has now passed out of range from the tracking ship. The next telemetry coverage zone will be provided from the Dongara station in Australia. Deployment of SIRTF is four minutes away.

0620 GMT (2:20 a.m. EDT)

T+plus 45 minutes, 20 seconds. SECO 2. The liquid-fueled Aerojet engine has finished its second firing of the launch to put SIRTF on the trajectory for its Earth-trailing orbit.

0619 GMT (2:19 a.m. EDT)

T+plus 44 minutes. The engine firing continues with nominal pressures reported.

0618 GMT (2:18 a.m. EDT)

T+plus 43 minutes. The stage should fire for another two minutes or so.

0618 GMT (2:18 a.m. EDT)

T+plus 42 minutes, 25 seconds. Telemetry is now available at the Cape. The data shows the burn is in progress!

0616 GMT (2:16 a.m. EDT)

T+plus 41 minutes. The Delta second stage should be firing again. However, that event cannot be confirmed because live data is still not being received at the Cape.

0614 GMT (2:14 a.m. EDT)

T+plus 39 minutes. Ignition of the second stage is about 90 seconds away. Engineers are awaiting acquisition of signal from the tracking vessel.

0609 GMT (2:09 a.m. EDT)

T+plus 34 minutes. The vehicle has crossed over southern Africa and is now headed above the Indian Ocean. A U.S. military tracking ship is positioned in the ocean to received live telemetry from the Delta rocket and relay it back to the Cape during the upcoming burn by the second stage engine.

0601 GMT (2:01 a.m. EDT)

T+plus 26 minutes, 15 seconds. The Delta 2 has flown out of range from Ascension.

0558 GMT (1:58 a.m. EDT)

T+plus 23 minutes. The telemetry from Delta being relayed back to Cape Canaveral via the Ascension tracking station appears fine. The rocket is quietly coasting about 90 miles above Earth.

0555 GMT (1:55 a.m. EDT)

T+plus 20 minutes. Normal data is being received from the vehicle.

0554 GMT (1:54 a.m. EDT)

T+plus 19 minutes, 10 seconds. The tracking station on Ascension Island in the Atlantic has picked up the Delta rocket's signal as it continues in the parking orbit coast.

0550 GMT (1:50 a.m. EDT)

T+plus 15 minutes. The official Range liftoff time was 1:35:39.231 a.m. EDT.

0548 GMT (1:48 a.m. EDT)

T+plus 12 minutes, 50 seconds. The vehicle has now passed out of range from the Antigua tracking station.

0545 GMT (1:45 a.m. EDT)

T+plus 10 minutes, 30 seconds. The Delta rocket is in a normal coast mode. A good flight is being reported by Boeing.

The launcher will continue to coast over the Atlantic Ocean and Africa before re-igniting above the southern Indian Ocean to accelerate SIRTF into its Earth-trailing orbit. Engine restart is expected at T+plus 40 minutes, 25 seconds for four-and-a-half minute burn. Deployment of SIRTF to complete the launch is targeted for T+plus 50 minutes.

0544 GMT (1:44 a.m. EDT)

T+plus 9 minutes. The parking orbit achieved is right on target. The apogee is 89.99 nautical miles, perigee is 89.56 nautical miles and orbital inclination is 31.5 degrees.

0543 GMT (1:43 a.m. EDT)

T+plus 7 minutes, 50 seconds. SECO 1. The second stage engine has shut down as planned. The Delta 2 rocket with SIRTF has arrived in a preliminary orbit around Earth following launch tonight.

0542 GMT (1:42 a.m. EDT)

T+plus 6 minutes, 30 seconds. Second stage chamber pressure looks good. Altitude 90 miles, downrange distance 783 miles, velocity 16,091 miles per hour.

0541 GMT (1:41 a.m. EDT)

T+plus 6 minutes. Second stage continues to fire. This will be a relatively short first burn for the Delta 2 rocket's second stage.

0540 GMT (1:40 a.m. EDT)

T+plus 5 minutes. The protective payload fairing enclosing the SIRTF observatory atop the rocket has separated as planned. It is no longer needed.

0540 GMT (1:40 a.m. EDT)

T+plus 4 minutes, 45 seconds. The Aerojet AJ118-K liquid-fueled second stage engine has ignited.

0540 GMT (1:40 a.m. EDT)

T+plus 4 minutes, 30 seconds. MECO. The Delta 2 rocket's Rocketdyne RS-27A first stage main engine has shut down and the spent stage has been jettisoned.

0539 GMT (1:39 a.m. EDT)

T+plus 4 minutes. The vehicle is tracking right on course.

0538 GMT (1:38 a.m. EDT)

T+plus 3 minutes, 20 seconds. First stage main engine continues to fire. Altitude 47 miles, downrange distance 155 miles, velocity 8,500 miles per hour.

0538 GMT (1:38 a.m. EDT)

T+plus 2 minutes, 45 seconds. The three air-start solid rocket boosters have burned out and separated. The rocket continues its trek to orbit on the power of the first stage liquid-fueled main engine.

0537 GMT (1:37 a.m. EDT)

T+plus 1 minute, 50 seconds. Altitude is 18 miles, downrange distance 40 miles, velocity 3,700 miles per hour.

0537 GMT (1:37 a.m. EDT)

T+plus 1 minute, 30 seconds. All six ground-start solid rocket boosters have burned out and separated. The three remaining motors strapped to first stage have ignited to continue assisting the rocket's RS-27A main engine on the climb to space.

0536 GMT (1:36 a.m. EDT)

T+plus 60 seconds. Altitude is 6 miles, speed 1,900 miles per hour.

0536 GMT (1:36 a.m. EDT)

T+plus 40 seconds. The rocket has reached Mach 1.

0535 GMT (1:35 a.m. EDT)

T+plus 20 seconds. The Delta rocket has maneuvered to the proper heading as it streaks into the night sky. The six ground-lit solid rocket motors and liquid-fueled first stage main engine are all firing.

0535:39 GMT (1:35:39 a.m. EDT)

LIFTOFF! Liftoff of the 300th Delta rocket and NASA's Space Infrared Telescope Facility -- extending the history of Boeing's launch vehicle family while lofting a new window on the Universe.

0535 GMT (1:35 a.m. EDT)

T-minus 30 seconds. Hydraulics and electronics status checks are reported "go."

The launch ignition sequence will begin at T-minus 2 seconds when a Boeing engineer triggers the engine start switch. The process begins with ignition of the two vernier engines and first stage main engine start. The six ground-lit solid rocket motors then light at T-0 for liftoff.

0534 GMT (1:34 a.m. EDT)

T-minus 1 minute. The Range has given its final clear-to-launch. The Delta 2 rocket's second stage hydraulic pump has gone to internal power after its pressures were verified acceptable.

0533 GMT (1:33 a.m. EDT)

T-minus 2 minutes. The first stage liquid oxygen vents are now being closed so the LOX tank can be pressurized for launch. Puffs of vapor from a relief valve on the rocket will be seen in the remainder of the countdown as the tank pressure stabilizes.

0533 GMT (1:33 a.m. EDT)

T-minus 2 minutes, 30 seconds. The SIRTF spacecraft has been declared "go" for launch.

0532 GMT (1:32 a.m. EDT)

T-minus 3 minutes and counting. The rocket's safe and arm devices are being armed.

0531 GMT (1:31 a.m. EDT)

T-minus 3 minutes, 40 seconds and counting. The Delta 2 rocket's systems are now transferring to internal power for launch.

0531:39 GMT (1:31:39 a.m. EDT)

T-minus 4 minutes and counting. The Terminal Countdown has entered its final phase for tonight's launch of the 300th Delta rocket and NASA's fourth and final Great Observatory. Liftoff remains set to occur at 1:35:39 a.m. EDT from pad 17B at Cape Canaveral Air Force Station in Florida.

The rocket will head eastward from the coast on a 105-degree flight azimuth. It should achieve a 90-mile high parking orbit inclined 31.5 degrees to the equator about seven minutes into flight.

0530 GMT (1:30 a.m. EDT)

Now less than five minutes from launch! Standing by for release of the hold in one minute.

0529 GMT (1:29 a.m. EDT)

The Space Infrared Telescope Facility spacecraft cargo atop the Delta 2 rocket is switching to internal power for launch.

0528 GMT (1:28 a.m. EDT)

Countdown clocks will resume ticking in three minutes. All systems remain "go" for tonight's 1:35 a.m. launch!

The launch team is now receiving instructions for the rest of the countdown and safing operations.

0527 GMT (1:27 a.m. EDT)

The Boeing launch conductor has polled the entire launch team to ensure all is set for liftoff. "Ready" was the report from everyone.

0526 GMT (1:26 a.m. EDT)

Launch Weather Office Joel Tumbiolo has confirmed with Boeing and NASA that the conditions are "go" and there is no worries about the one rainshower that was being monitored.

0523 GMT (1:23 a.m. EDT)

NASA Launch Manager Omar Baez has performed his readiness poll to proceed with the countdown. No problems were announced. "NASA is ready to release the hold at T-minus 4," Baez then reported.

0523 GMT (1:23 a.m. EDT)

Now 12 minutes from launch of Delta 300 and SIRTF.

0521 GMT (1:21 a.m. EDT)

T-minus 4 minutes and holding. The countdown has entered the final planned hold point for tonight's launch attempt. During this 10-minute, 39-second hold, officials will poll the various team members in the soft blockhouse, Range Operations Control Center and Mission Directors Center. If all systems are go, the countdown will resume for liftoff at 1:35:39 a.m. EDT.

At this point, there are no problems being reported.

0519 GMT (1:19 a.m. EDT)

Launch Weather Office Joel Tumbiolo has verified the local conditions are "go" for liftoff tonight.

0519 GMT (1:19 a.m. EDT)

The launch pad's facility water tanks are now being pressurized.

0517 GMT (1:17 a.m. EDT)

The first stage fuel tank vent is being closed and the tank is being pressurized for launch.

0515 GMT (1:15 a.m. EDT)

T-minus 10 minutes and counting. The safety checks have been completed.

This will be the 300th Delta rocket launch. The Delta era began in May 1960. Although its initial attempt to reach space failed, Delta began racking up successes with its second flight a few months later. Today, the Delta family boasts a remarkable record of 283 successes and 16 failures.

Six launches have been performed in 2003 -- five on Delta 2 rockets and one Delta 4 mission.

Another Delta 4 is awaiting liftoff later this week, followed by three more Delta 2s before year's end.

0511 GMT (1:11 a.m. EDT)

Inhibited checks are now beginning for the Range Safety command destruct receivers that would be used in destroying the Delta rocket should the vehicle malfunction during the launch.

0505 GMT (1:05 a.m. EDT)

T-minus 20 minutes and counting. The planned pause in the countdown has been completed. Clocks will now tick down to T-minus 4 minutes where the final hold is scheduled. That hold will last 10 minutes and 39 seconds, leading to tonight's launch time of 1:35:39 a.m. EDT.

0501 GMT (1:01 a.m. EDT)

The launch team poll to pick up the countdown has been performed. The count is set to resume at 1:05 a.m. EDT as planned.

0457 GMT (12:57 a.m. EDT)

NASA Launch Manager Omar Baez has just completed a poll of the space agency's management team for a readiness to continue with the countdown. No problems were reported.

0455 GMT (12:55 a.m. EDT)

Now half-way through this built-in hold at T-minus 20 minutes. A series of readiness polls of the various teams will be performed upcoming in the next few minutes before the countdown picks up again.

0447 GMT (12:47 a.m. EDT)

Launch Weather Officer Joel Tumbiolo has completed another briefing to managers. There is a small shower to the south of the Cape. It is moving toward the Cape but meteorologists are not too concerned about it. If it holds together and makes it to the Cape, the shower is expected to pass about five miles to the west of pad 17B.

0445 GMT (12:45 a.m. EDT)

T-minus 20 minutes and holding. The countdown has entered the 20-minute built-in hold. This pause is designed to give the launch team a chance to work any problems or catch up on activities that might be running behind schedule. Engineers will also have time to examine all of the data collected during the just-completed steering tests.

Launch is still slated for 1:35:39 a.m. EDT.

0442 GMT (12:42 a.m. EDT)

The gimbal checks of the Delta 2 rocket's first stage main engine nozzle is now finished.

The countdown will be going into a planned hold at the T-minus 20 minute mark in just three minutes.

0437 GMT (12:37 a.m. EDT)

The second stage steering checks have been completed. First stage testing is now underway.

0435 GMT (12:35 a.m. EDT)

The Space Infrared Telescope Facility is now just 60 minutes away from the start of its $1.2 billion mission to give astronomers a powerful new view of the Universe. Liftoff atop a two-stage Boeing Delta 2 rocket is targeted for 1:35:39 a.m. EDT from pad 17B at Cape Canaveral Air Force Station on Florida's east-central coast. This is the 300th flight of a Delta rocket dating back to 1960.

The launch team will soon begin the "slew" or steering checks of the first and second stage engines. These are gimbal tests of the nozzles on the first stage main engine and twin vernier engines and second stage engine to ensure the rocket will be able to steer itself during launch.

And in the next few minutes, RF link tests between the Range and rocket are scheduled.

0419 GMT (12:19 a.m. EDT)

The launch team reports the loading of the Delta 2 rocket's first stage liquid oxygen tank was completed at 12:19:41 a.m. EDT. The operation took 27 minutes and 25 seconds today. The tank will be replenished through the countdown to replace the super-cold liquid oxygen that naturally boils away.

The rocket is now fully fueled for launch. The vehicle's first stage was successfully loaded with RP-1 kerosene fuel along with the liquid oxygen over the past hour. The second stage was filled with its storable nitrogen tetroxide and Aerozine 50 fuels a few days ago. The nine strap-on booster rockets are solid-propellant.

0417 GMT (12:17 a.m. EDT)

Now 25 minutes into the liquid oxygen tanking. Rapid loading has just ended.

0410 GMT (12:10 a.m. EDT)

Cryogenic tanking of the Delta rocket's first stage continues. Once the liquid oxygen tank reaches the 95 percent full level, the "rapid load" valve will be closed and the slower "fine load" phase will continue to fill the tank.

0405:39 GMT (12:05:39 a.m. EDT)

The countdown has now entered the final 90 minutes until launch. There are no technical problems being reported by the launch team and the weather is just fine tonight. Liftoff of the Delta 2 rocket and SIRTF space telescope remains scheduled to occur at 1:35:39 a.m. EDT (0535:39 GMT).

0402 GMT (12:02 a.m. EDT)

The bottom of the Boeing Delta 2 rocket is icing over as the super-cold liquid oxygen flows into the first stage. LOX loading has passed the 10-minute mark with no trouble reported in the tanking operation.

0357 GMT (11:57 p.m. EDT Sun.)

Now five minutes into this approximate 25-minute process to fill the first stage liquid oxygen tank. A plume of white vapor is streaming from the vent port of the first stage as the cryogenic tanking proceeds.

Meanwhile, the rocket's guidance system has been activated for launch.

0352 GMT (11:52 p.m. EDT Sun.)

Super-cold liquid oxygen, chilled to Minus-298 degrees F, is being pumped into the first stage of the Boeing Delta 2 rocket as the countdown continues for tonight's 1:35 a.m. EDT launch.

The liquid oxygen is flowing from a storage tank at pad 17B, through plumbing and into the bottom of the rocket. The LOX and the RP-1 kerosene fuel -- loaded aboard the vehicle earlier this hour -- will be consumed by the first stage main engine.

0346 GMT (11:46 p.m. EDT Sun.)

The final "go" has been given to the launch team members to start the preparations for loading the rocket's first stage liquid oxygen tank.

0344 GMT (11:44 p.m. EDT Sun.)

Boeing Mission Director Rich Murphy has passed his "go" for cryogenic tanking to the company's launch operations team. Liquid oxygen loading is scheduled to begin in about five minutes or so.

0339 GMT (11:39 p.m. EDT Sun.)

NASA Launch Manager Omar Baez has polled his team and given the space agency's approval to begin liquid oxygen loading for the Delta 2 rocket's first stage.

0335:39 GMT (11:35:39 p.m. EDT Sun.)

Now two hours away from the targeted liftoff time.

0333 GMT (11:33 p.m. EDT Sun.)

Launch Weather Officer Joel Tumbiolo just gave a briefing to the management team. Conditions are near-perfect for tonight's launch opportunity.

"We have a very good evening in store for us," he said.

The only area being watched is some anvil clouds well to our southwest. But even those clouds are not expected to be a problem. The radar is clear, and winds are less than 10 knots.

0322 GMT (11:22 p.m. EDT Sun.)

The first stage fuel tank of the Boeing Delta 2 rocket has been fully loaded for tonight's planned 1:35 a.m. EDT liftoff from Cape Canaveral Air Force Station in Florida.

The tank was filled with a highly refined kerosene, called RP-1, during a 21-minute, 1-second process that concluded at 11:22:14 p.m. EDT.

The next major task in the countdown will be loading super-cold cryogenic liquid oxygen into the first stage.

0316 GMT (11:16 p.m. EDT Sun.)

The launch team has computed that the full load for the first stage fuel tank is 9,963 gallons. Over 8,000 gallons are already aboard.

Once the tank is filled with 9,750 gallons, or 98 percent, the "rapid load" valve will be closed and the slower "fine load" phase will continue top off the tank.

0312 GMT (11:12 p.m. EDT Sun.)

Over 6,000 gallons of RP-1 fuel are now aboard the rocket. This approximate 20-minute process to load the rocket's first stage with about 10,000 gallons of refined kerosene fuel continues with no problems.

0306 GMT (11:06 p.m. EDT Sun.)

Now five minutes into the RP-1 loading process. About 3,000 gallons are aboard the rocket.

0301 GMT (11:01 p.m. EDT Sun.)

About 10,000 gallons of a highly refined kerosene propellant, called RP-1, are now being pumped into the base of the rocket from a storage tank at pad 17B. The fuel will be used along with liquid oxygen -- to be loaded into the rocket -- in about an hour by the first stage RS-27A main engine.

The countdown continues on schedule tonight for launch of the Delta 2 and SIRTF observatory at 1:35:39 a.m. EDT.

0256 GMT (10:56 p.m. EDT Sun.)

The Boeing launch team has been given the "go" to begin loading the Delta 2 rocket's first stage fuel tank.

The team members are currently working through the steps to prepare for fueling. After verifying valves, sensors, flow meters and equipment are ready, the highly refined kerosene fuel will start flowing into the vehicle.

0235 GMT (10:35 p.m. EDT Sun.)

T-minus 150 minutes and counting. The Terminal Countdown has begun for the launch of the Boeing Delta 2-Heavy rocket carrying NASA's Space Infrared Telescope Facility -- the fourth and final spacecraft in the Great Observatories program.

Over the next three hours, the launch team will ready the three-stage rocket, payload and ground support systems for the planned 1:35:39 a.m. EDT (0535:39 GMT) blastoff from pad 17B at Cape Canaveral Air Force Station in Florida.

Complex 17 is currently being verified cleared of workers as a safety precaution. A warning horn will be sounded at the seaside complex to alert any personnel in the area to depart and head back to road blocks.

Upcoming in the next few minutes, launch team members in the Delta Operations Building, or "soft blockhouse", located about eight miles west of the pad will oversee the pressurization of helium and nitrogen storage tanks inside the rocket's first and second stages; and the second stage fuel and oxidizer tanks will be pressurized for launch. In addition, the Delta's onboard guidance computer -- called the Redundant Inertial Flight Control Assembly, or RIFCA -- will be turned on and configured for the mission.

The loading of 10,000 gallons of RP-1 fuel into the first stage is scheduled to start about 20 minutes from now.

NASA is not reporting any technical problems and the weather is still looking good tonight.

0227 GMT (10:27 p.m. EDT Sun.)

The launch team has been polled to ensure all the console operators are in position and ready to continue with the countdown activities this evening. The Terminal Countdown is scheduled to commence in about 8 minutes.

0215 GMT (10:15 p.m. EDT Sun.)

Twenty minutes are remaining in this planned countdown hold. The launch team will be polled shortly for a readiness check before the clocks resume for tonight's 1:35:39 a.m. EDT (0535:39 GMT) liftoff of the Delta 2 rocket from Cape Canaveral.

0135 GMT (9:35 p.m. EDT Sun.)

T-minus 150 minutes and holding. Clocks at Cape Canaveral have entered a scheduled 60-minute built-in hold in advance of the Terminal Countdown. Liftoff of the Delta 2 rocket is now exactly four hours away.

Read our earlier Mission Status Center coverage.