BY JUSTIN RAY

Follow the countdown and launch of the Boeing Delta 2 rocket with the CALIPSO and CloudSat environmental research spacecraft. Reload this page for the very latest on the mission.

Additional coverage for subscribers:
VIDEO: THE DELTA 2 ROCKET BLASTS OFF! PLAY
VIDEO: MOBILE SERVICE TOWER VIEW OF LIFTOFF PLAY
VIDEO: LAUNCH REPLAY FROM CAMERA ON BACK SIDE OF PAD PLAY
VIDEO: CALIPSO SUCCESSFULLY DEPLOYED FROM ROCKET PLAY
VIDEO: CLOUDSAT SUCCESSFULLY DEPLOYED FROM ROCKET PLAY
VIDEO: POST-LAUNCH INTERVIEW WITH NASA LAUNCH MANAGER PLAY

VIDEO: UPPER LEVEL WINDS SCRUB TUESDAY ATTEMPT PLAY
VIDEO: CLOSE-UP VIEWS OF FIRST STAGE ENGINE STEERING TEST PLAY
VIDEO: LAUNCH PAD TOWER ROLLED BACK MONDAY EVENING PLAY
VIDEO: DELTA 2 ROCKET PRE-LAUNCH CAMPAIGN PLAY
VIDEO: PRE-LAUNCH NEWS CONFERENCE DIAL-UP | BROADBAND
VIDEO: SCIENCE OF CALIPSO/CLOUDSAT DIAL-UP | BROADBAND
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FRIDAY, APRIL 28, 2006

You could say it was a dream for insomniacs but a nightmare for everyone else. A week of night-owl countdowns to launch a Boeing Delta 2 rocket loaded with two atmospheric research satellites ended in scrubs for one reason or another.

A communications snafu, scheduling troubles with a support aircraft, high-altitude winds, thick clouds and a suspect sensor together ruined six opportunities to launch the $515 million mission from Vandenberg Air Force Base, California.

But try number seven proved to be the lucky one this morning, as the Delta rocket blasted off at the precise instant in time available to launch the CALIPSO and CloudSat spacecraft.

The main engine and four kick motors mounted around the first stage fired up and pushed the 12-story vehicle on its way at 1002:16 GMT (3:02:16 a.m. PDT; 6:02:16 a.m. EDT).

"When we lifted off you could just feel the release not only watching the vehicle leave the pad but just the release that the folks had in the center here was just incredible," NASA Launch Manager Chuck Dovale said.

"It was quite a difficult mission almost from start to finish. The last week to 10 days certainly wasn't any different. We had quite a few scrubs."

Low clouds draped over the coastal launch base quickly swallowed the rocket, but mountain-top tracking cameras kept track of the ascending booster.

The solid-fuel motors burned and jettisoned within 90 seconds, and three minutes later the spent first stage separated. The second stage engine then ignited for a six-and-a-half minute firing to climb into an initial orbit around Earth.

The rocket coasted over the South Pacific, looped around Antarctica and headed northward toward Africa where the second stage's engine re-started 60 minutes after liftoff for a short 12-second burn that circularized the orbit for payload deployment.

First to be released was CALIPSO, occurring over Africa at 1104 GMT (4:04 a.m. PDT; 7:04 a.m. EDT).

The second stage continued on, cruising high above Europe and then the northern-most parts of the globe before crossing over northwestern Canada and back out over the Pacific. Then the Dual Payload Attach Fitting -- the barrel-like structure that supported CALIPSO during launch and enclosed CloudSat -- was opened up. The top portion of the DPAF was jettisoned to expose CloudSat for its release from the rocket.

CloudSat was deployed over the Pacific at T+plus 97 minutes, or 1139 GMT (4:39 a.m. PDT; 7:39 a.m. EDT), after nearly completing a full orbit of the Earth.

It marked the 119th successful Delta 2 rocket launch out of 121 flights since 1989 and extended the string of consecutive successes to 66 dating back to 1997.

"With the successful launch of CloudSat and CALIPSO we take a giant step forward in our ability to study the global atmosphere," said CALIPSO Principal Investigator David Winker of NASA's Langley Research Center. "In the years to come, we expect these missions to spark many new insights into the workings of Earth's climate and improve our abilities to forecast weather and predict climate change."

"Clouds are a critical but poorly understood element of our climate," said Graeme Stephens, CloudSat principal investigator and a professor at Colorado State University. "They shape the energy distribution of our climate system and our planet's massive water cycle, which delivers the freshwater we drink that sustains all life."

CALIPSO is a $298 million joint U.S./French project to study tiny atmospheric particles called aerosols. The 1,294-pound craft carries a lidar, an imaging infrared radiometer and wide-field camera.

"With the high resolution observation that CALIPSO will provide, we will get a better understanding of aerosol transport and how our climate system works," Winker said.

The 1,870-pound CloudSat spacecraft is equipped with a cloud-profiling radar over 1,000 times more sensitive than typical weather radar. The $217 million mission will distinguish between cloud particles and precipitation.

"The new information from CloudSat will answer basic questions about how rain and snow are produced by clouds, how rain and snow are distributed worldwide and how clouds affect the Earth's climate," Stephens said.

Both satellites will fly within 15 seconds of each other in polar orbit among the so-called "A Train" of environmental monitoring spacecraft. The constellation includes NASA's Aqua and Aura Earth Observing System satellites and France's PARASOL craft.

Friday's liftoff jump-starts Boeing's stalled launch schedule that had been idle since last fall. Technical problems, concerns over batteries and a labor dispute between Boeing and machinists prevented any launches since September.

Now, things are looking up. A Delta 4 rocket is scheduled to launch the GOES-N weather observatory from Cape Canaveral on May 18, followed about a month later by a Delta 2 with an experimental military microsatellite payload. And the first Delta 4 from Vandenberg Air Force Base is slated to fly in late June.

1139 GMT (7:39 a.m. EDT)

T+plus 97 minutes, 37 seconds. SPACECRAFT SEPARATION! The CloudSat spacecraft has been released from the Boeing Delta 2 rocket's second stage, completing today's launch.

NASA's CloudSat will serve as a CAT scan to reveal the inner workings of clouds.

"The new information from CloudSat will answer basic questions about how rain and snow are produced by clouds, how rain and snow are distributed worldwide and how clouds affect the Earth's climate," said Graeme Stephens, CloudSat principal investigator from Colorado State University.

1138 GMT (7:38 a.m. EDT)

T+plus 96 minutes, 15 seconds. The Dual Payload Attach Fitting, or DPAF, has separated from the Delta 2 rocket's second stage.

The DPAF structure allows two distinctly different satellites to be flown aboard one Delta 2 rocket, a feature NASA paid Boeing to develop.

The structure is basically a cylinder with cone on its top where CALIPSO was mounted and inside resides the CloudSat payload.

1128 GMT (7:28 a.m. EDT)

T+plus 86 minutes. Separation payload adapter's upper portion to reveal CloudSat is about 10 minutes away.

1107 GMT (7:07 a.m. EDT)

T+plus 65 minutes. The second stage is coasting quietly again. Jettison of the dual payload adapter is about 30 minutes away. Release of CloudSat follows less than two minutes later.

1104 GMT (7:04 a.m. EDT)

T+plus 62 minutes, 31 seconds. SPACECRAFT SEPARATION! The CALIPSO spacecraft has been released from the Boeing Delta 2 rocket's second stage.

The Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) is a joint project between the U.S. and France that will generate a global picture of aerosol particles suspended in the atmosphere.

"With the high resolution observation that CALIPSO will provide, we will get a better understanding of aerosol transport and how our climate system works," said David Winker, CALIPSO principal investigator at NASA's Langley Research Center.

1103 GMT (7:03 a.m. EDT)

T+plus 61 minutes, 25 seconds. Deployment of CALIPSO from the second stage is expected in about one minute.

1103 GMT (7:03 a.m. EDT)

T+plus 61 minutes. The just-completed second stage burn was the normal duration and all appears to have gone as expected.

1102 GMT (7:02 a.m. EDT)

T+plus 60 minutes, 18 seconds. SECO 2. Engine shutdown has occurred.

1102 GMT (7:02 a.m. EDT)

T+plus 60 minutes, 6 seconds. The second stage engine has ignited for a 12-second firing to propel its spacecraft payload into the proper polar orbit.

1052 GMT (6:52 a.m. EDT)

T+plus 50 minutes. A map of the rocket's flight path is available here.

1047 GMT (6:47 a.m. EDT)

T+plus 45 minutes. At T+plus 53 minutes, the rocket is programmed to end the thermal BBQ roll and begin orienting itself into the proper position for engine ignition. This maneuver will take about five minutes to complete.

1042 GMT (6:42 a.m. EDT)

T+plus 40 minutes. The next firing by the Delta rocket's second stage is coming up in 20 minutes. The Hartebeesthoek tracking station in South Africa should acquire the rocket in about eight minutes. That will be followed by another ground site picking up the rocket's signal four minutes later to provide live confirmation of the second stage burn and release of the CALIPSO satellite.

1037 GMT (6:37 a.m. EDT)

T+plus 35 minutes. As the rocket coasts in this parking orbit, the second stage performs a "BBQ roll" maneuver to keep the thermal conditions on the vehicle equal. This maneuver was scheduled to start at about T+plus 16 minutes and conclude at T+plus 53 minutes.

1032 GMT (6:32 a.m. EDT)

T+plus 30 minutes. The rocket is coasting until the second stage restarts its engine at T+plus 60 minutes for a brief firing to circularize the orbit. Deployment of CALIPSO from the launch vehicle is expected 62 minutes after liftoff. CloudSat deploy happens at T+plus 96 minutes.

1022 GMT (6:22 a.m. EDT)

T+plus 20 minutes. The Range liftoff time was 1002:16.721 GMT.

1016 GMT (6:16 a.m. EDT)

T+plus 14 minutes. The rocket is passing out of range from the tracking plane. This creates a data blackout until the vehicle soars above the McMurdo tracking station near the South Pole about 15 minutes from now.

1014 GMT (6:14 a.m. EDT)

T+plus 12 minutes, 30 seconds. SECO 1 now confirmed. The Big Crow tracking plane crew has reported the second stage engine did shut down to complete the first of two firings to deliver CALIPSO and CloudSat into polar orbit today.

1013 GMT (6:13 a.m. EDT)

T+plus 11 minutes, 30 seconds. The initial firing of the second stage should be complete now. Everyone is waiting for confirmation, however.

1013 GMT (6:13 a.m. EDT)

T+plus 11 minutes. Big Crow reports it has a lock with the rocket. But that data is not being relayed back to Vandenberg at the moment.

1012 GMT (6:12 a.m. EDT)

T+plus 10 minutes. Engineers at Vandenberg still waiting to see the data link restored to receive rocket data via Big Crow.

1011 GMT (6:11 a.m. EDT)

T+plus 9 minutes, 15 seconds. About two minutes remain in this burn of the second stage engine to achieve the intended parking orbit.

1011 GMT (6:11 a.m. EDT)

T+plus 9 minutes. Loss of data signal via Big Crow.

1010 GMT (6:10 a.m. EDT)

T+plus 8 minutes, 30 seconds. The "Big Crow" tracking aircraft over the Pacific has acquired the rocket's telemetry signal as the Delta flies beyond Vandenberg's horizon.

1010 GMT (6:10 a.m. EDT)

T+plus 8 minutes. The second stage engine chamber pressure is normal.

1009 GMT (6:09 a.m. EDT)

T+plus 7 minutes, 40 seconds. The Delta 2 rocket is 643 miles south from the launch pad, 101 miles in altitude and traveling at 12,300 mph.

1008 GMT (6:08 a.m. EDT)

T+plus 6 minutes, 30 seconds. Second stage engine performance reported normal.

1008 GMT (6:08 a.m. EDT)

T+plus 6 minutes. The Delta 2 rocket is 85 miles in altitude, 379 miles downrange, traveling over 11,000 mph.

1007 GMT (6:07 a.m. EDT)

T+plus 5 minutes, 30 seconds. The second stage is firing normally.

1007 GMT (6:07 a.m. EDT)

T+plus 5 minutes, 4 seconds. The rocket's nose cone enclosing the spacecraft has been jettisoned.

1007 GMT (6:07 a.m. EDT)

T+plus 4 minutes, 44 seconds. The Delta's second stage engine has ignited!

1006 GMT (6:06 a.m. EDT)

T+plus 4 minutes, 40 seconds. MECO. The first stage main engine cutoff is confirmed, and the spent stage has been jettisoned!

1006:16 GMT (6:06:16 a.m. EDT)

T+plus 4 minutes. First stage performance is looking good.

1005:16 GMT (6:05:16 a.m. EDT)

T+plus 3 minutes. The vehicle is 33 miles in altitude, 30 miles downrange from the launch pad and traveling at 3,500 mph.

1004 GMT (6:04 a.m. EDT)

T+plus 2 minutes, 30 seconds. The first stage main engine continues to burn normally.

1004 GMT (6:04 a.m. EDT)

T+plus 1 minute, 45 seconds. The Delta 2 rocket is 15 miles in altitude and 7.5 miles downrange from the launch pad.

1003 GMT (6:03 a.m. EDT)

T+plus 1 minute, 30 seconds. The ground-lit boosters have jettisoned from the first stage. They remained attached until the rocket cleared off-shore oil rigs.

1003 GMT (6:03 a.m. EDT)

T+plus 1 minute, 10 seconds. All four ground-start solid rocket boosters have burned out. The Delta 2's first stage RS-27A main engine is providing the sole thrust for the next few minutes.

1003 GMT (6:03 a.m. EDT)

T+plus 50 seconds. The rocket has ascended through the area of maximum aerodynamic pressure.

1002 GMT (6:02 a.m. EDT)

T+plus 30 seconds. Nearing Mach 1.

1002 GMT (6:02 a.m. EDT)

T+plus 15 seconds. Delta 314 is punching through the clouds and maneuvering to its southerly heading for the flight downrange over the Pacific. The vehicle is riding the power of its first stage main engine and all four strap-on boosters.

1002:16 GMT (6:02:16 a.m. EDT)

LIFTOFF! Liftoff of the Boeing Delta 2 rocket launching the CALIPSO and CloudSat spacecraft for new insights into Earth's clouds and weather.

1001 GMT (6:01 a.m. EDT)

T-minus 30 seconds. SRB ignitors will be armed at T-minus 11 seconds.

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 thrusters and first stage main engine start. The four ground-lit solid rocket motors then light at T-0 for liftoff.

1001 GMT (6:01 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.

1000 GMT (6:00 a.m. EDT)

T-minus 80 seconds. LOX topping to 100 percent is underway.

1000 GMT (6:00 a.m. EDT)

T-minus 1 minute, 45 seconds. The launch pad water suppression system is being activated.

1000 GMT (6:00 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.

0959 GMT (5:59 a.m. EDT)

T-minus 2 minutes, 30 seconds. The payloads have been declared "go" for launch.

0959 GMT (5:59 a.m. EDT)

T-minus 2 minutes, 40 seconds. Vehicle ordnance is being armed.

0959 GMT (5:59 a.m. EDT)

T-minus 3 minutes.

0958 GMT (5:58 a.m. EDT)

T-minus 3 minutes, 45 seconds and counting. The Delta 2 rocket's systems are now transferring to internal power for launch. And the launch pad water system is being enabled.

0958:16 GMT (5:58:16 a.m. EDT)

T-minus 4 minutes and counting! Clocks are ticking down the final moments for liftoff of Delta 314 with the CALIPSO and CloudSat spacecraft. Launch is set for 1002:16 from Vandenberg Air Force Base, California.

0957 GMT (5:57 a.m. EDT)

Now five minutes from launch! Standing by for release of the hold in one minute. All the polling has been completed with the decision made to resume the countdown for an on-time launch today.

0955 GMT (5:55 a.m. EDT)

Three minutes are remaining before the countdown resumes.

0954 GMT (5:54 a.m. EDT)

The launch team has been polled. Everyone answered with "ready."

Now, the team members are receiving countdown procedure instructions.

0953 GMT (5:53 a.m. EDT)

Now half-way through this 10-minute built-in hold. Standing by for the final pre-flight poll of the Boeing launch team to confirm all systems are "go" to resume the countdown for liftoff.

0952 GMT (5:52 a.m. EDT)

NASA Launch Manager Chuck Dovale has performed his clear-to-proceed poll with no problems reported by the space agency.

0949 GMT (5:49 a.m. EDT)

The CALIPSO and CloudSat spacecraft are undergoing their final re-configuration for launch.

0948:16 GMT (5:48:16 a.m. EDT)

T-minus 4 minutes and holding. The countdown has entered the final planned built-in hold. This is a scheduled 10-minute pause leading to today's liftoff time of 3:02:16 a.m. local (6:02:16 a.m. EDT; 1002:16 GMT) for the Boeing Delta 2 rocket with two NASA spacecraft.

During the hold, officials will poll the various team members in the "soft blockhouse," Range Operations Control Center and Mission Directors Center.

At this point, all appears set for launch today. There have been no technical problems reported and the weather is observed and forecast "go" for launch.

0943 GMT (5:43 a.m. EDT)

The first stage kerosene fuel tank is being pressurized for launch.

0940:16 GMT (5:40:16 a.m. EDT)

T-minus 12 minutes. The Range Safety test was completed.

0938 GMT (5:38 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 veer off course or malfunction during the launch.

0932:16 GMT (5:32:16 a.m. EDT)

T-minus 20 minutes and counting. Countdown clocks are running again following the planned 20-minute hold. The count will continue to the T-minus 4 minute mark where another hold is scheduled. Launch remains set to occur on time today.

0928 GMT (5:28 a.m. EDT)

The Boeing launch team members were just polled. All responded with a "ready."

0925 GMT (5:25 a.m. EDT)

NASA Launch Manager Chuck Dovale has polled his agency team, with everyone reporting a "go" status to proceed with the countdown. "Team is ready to release the count at T-minus 20," Dovale said.

0922 GMT (5:22 a.m. EDT)

Now half-way through this built-in hold at T-minus 20 minutes. Once the countdown resumes, clocks will tick down to the T-minus 4 minute mark where a 10-minute hold is planned.

0915 GMT (5:15 a.m. EDT)

The launch weather officer just gave a short briefing to managers. Conditions are currently acceptable and forecast to remain within limits for this morning's liftoff.

Meanwhile, Range Safety's checks of computer models, based on today's wind conditions and other factors, show the toxics and debris from an explosion early in the Delta rocket's flight would remain away from populated areas. So there is no constraint to launch today.

0912 GMT (5:12 a.m. EDT)

T-minus 20 minutes and holding. Clocks have entered the first of two planned hold periods during the last 20 minutes of the Terminal Countdown for today's 3:02 a.m. PDT (6:02 a.m. EDT; 1002 GMT) launch. This pause will last 20 minutes in duration.

These holds are designed to give the launch team a chance to deal with any problems and catch up on work that could be running behind schedule. But at this point, there are no significant issues being reported with the Delta rocket or spacecraft.

0908 GMT (5:08 a.m. EDT)

The first stage engine steering checks are complete.

0907 GMT (5:07 a.m. EDT)

T-minus 25 minutes and counting. The countdown is nearing a planned 20-minute built-in hold at the T-minus 20 minute mark.

0905 GMT (5:05 a.m. EDT)

The second stage engine slews are complete. First stage tests have begun.

0903 GMT (5:03 a.m. EDT)

The launch team is beginning 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.

0902 GMT (5:02 a.m. EDT)

Now one hour away from the scheduled liftoff time for the Boeing Delta 2 rocket from Space Launch Complex 2 at Vandenberg Air Force Base along the central coastline of California. The base is located about half-way between Los Angeles and San Francisco. The rocket will head southward and could be visible to Southern California, if the weather permits.

Over the next few minutes, the "slew" or steering checks of the first and second stage engines will be performed. And the RF link tests between the Range and rocket are scheduled.

0852 GMT (4:52 a.m. EDT)

T-minus 40 minutes and counting. Countdown clocks are continuing to the T-minus 20 minute mark where a 20-minute built-in hold is planned. A final 10-minute hold at T-minus 4 minutes will lead to the target liftoff time of 1002 GMT.

0843 GMT (4:43 a.m. EDT)

Loading of the Delta 2 rocket's first stage liquid oxygen tank was completed at 0842:34 GMT. The operation took 23 minutes and 50 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 earlier. The second stage was filled with its storable nitrogen tetroxide and Aerozine 50 fuels last week. And the four strap-on booster rockets are solid-propellant.

0838 GMT (4:38 a.m. EDT)

Liquid oxygen loading has been underway for 20 minutes. Once the first stage tank is 95 percent full, the "rapid load" valve will be closed and the slower "fine load" phase will continue to fill the rocket.

0832 GMT (4:32 a.m. EDT)

The countdown is entering the final 90 minutes to liftoff.

0830 GMT (4:30 a.m. EDT)

Now 12 minutes into the LOX tanking. The bottom of the rocket is icing over as the super-cold liquid oxygen flows into the first stage.

0826 GMT (4:26 a.m. EDT)

Eight minutes into this approximate 25-minute process to fill the first stage liquid oxygen tank.

0823 GMT (4:23 a.m. EDT)

The rocket's guidance system has been activated this morning.

0818 GMT (4:18 a.m. EDT)

Cryogenic liquid oxygen, chilled to Minus-298 degrees F, has started flowing from a 28,000-gallon storage tank at Space Launch Complex 2-West, through plumbing and into the bottom of the Boeing Delta 2 rocket. The LOX will be consumed by the first stage main engine during the first four-and-a-half minutes of flight along with the 10,000 gallons of RP-1 kerosene already loaded aboard the vehicle.

0815 GMT (4:15 a.m. EDT)

The Range reports that the C-band beacon checks are complete. The beacon is used to track the Delta 2 rocket during launch.

0813 GMT (4:13 a.m. EDT)

The launch team has a "go" to begin preparations for loading the rocket's first stage liquid oxygen tank as planned.

0810 GMT (4:10 a.m. EDT)

Second stage propellant tank pressurization has been completed.

0806 GMT (4:06 a.m. EDT)

NASA Launch Manager Chuck Dovale has given a status update and everything is "go" for liftoff, including the Delta 2, payloads, Range and upper level winds. The space agency's management team has given its approval for liquid oxygen loading.

0801 GMT (4:01 a.m. EDT)

Weather conditions are acceptable for launch this morning. There is a zero percent chance of violating the launch weather rules, Air Force meteorologists report.

0735 GMT (3:35 a.m. EDT)

The second stage helium and nitrogen system pressurization has been accomplished. And the "go" was just given for fuel tank pressurization. The stage was filled with its storable propellants early last week.

0732 GMT (3:32 a.m. EDT)

Launch time is now two-and-a-half hours away.

The first stage fuel tank of the Boeing Delta 2 rocket was loaded with 9,987 gallons of a highly refined kerosene prior to entering into this morning's countdown.

Called RP-1, the propellant will be guzzled along with liquid oxygen by the first stage RS-27A main engine and twin vernier steering thrusters during the initial four-and-a-half minutes of flight.

Filling of the stage with cryogenic liquid oxygen will begin about 45 minutes from now.

0727 GMT (3:27 a.m. EDT)

First stage pressurization is complete.

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

Activation of the rocket's Redundant Inertial Flight Control Assembly guidance computer is beginning now. Also, the launch team is starting pressurization steps for the first and second stage helium and nitrogen systems and second stage fuel tanks.

0702:16 GMT (3:02:16 a.m. EDT)

T-minus 150 minutes and counting. The Terminal Countdown has been initiated for today's launch of the CALIPSO and CloudSat spacecraft aboard a Boeing Delta 2 rocket. Liftoff is scheduled for 3:02:16 a.m. local time (6:02:16 a.m. EDT; 1002:16 GMT) from Space Launch Complex 2 at Vandenberg Air Force Base in California. The site is on the Pacific coastline, about 140 miles northwest of Los Angeles.

0653 GMT (2:53 a.m. EDT)

The launch team has been polled to ensure all stations are manned and systems are ready to proceed with the countdown this morning. No problems were voiced.

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

"Man stations for Terminal Count." That was the message just announced to the launch team in preparation for starting the Terminal Countdown in 15 minutes.

The full team is back and ready to count down for launch of Delta 314.

0632 GMT (2:32 a.m. EDT)

Now half-way through this scheduled hour-long hold in the countdown. The pace of activity will be picking up soon as readiness polls are conducted before resuming the count.

0623 GMT (2:23 a.m. EDT)

The SLC-2W launch pad restricted area is being cleared of all personnel for the rest of the countdown. So it would appear the pump issue was resolved quite quickly, allowing the crews to depart.

0610 GMT (2:10 a.m. EDT)

Pad technicians are looking at an issue with one of the water pumps at the complex.

0602 GMT (2:02 a.m. EDT)

T-minus 150 minutes and holding. The countdown has just entered a planned 60-minute built-in hold at Vandenberg Air Force Base in California. The Terminal Countdown will begin once this hold is concluded. Launch remains on schedule for 1002:16 GMT (3:02:16 a.m. PDT; 6:02:16 a.m. EDT).

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

Clocks at Vandenberg Air Force Base are counting down to the T-minus 150 minute mark where a one-hour hold is planned to begin at 0602 GMT.

0502 GMT (1:02 a.m. EDT)

Now entering the final five hours in the countdown to launch. Mission managers have begun arriving on console in the directors center to govern this morning's launch operation.

0300 GMT (11:00 p.m. EDT Thurs.)

Night has fallen at Vandenberg. A crowd of pad technicians is working at the base of the Delta 2 rocket right now. They will be putting the final touches on the vehicle, and then remove platforms around the launch mount.

0120 GMT (9:20 p.m. EDT Thurs.)

The 177-foot tall mobile service tower has been retracted from the Boeing Delta 2 rocket at Vandenberg Air Force Base's Space Launch Complex 2-West pad, marking a crucial milestone in the preparations for liftoff overnight.

The gantry was used to stack the two-stage vehicle, the four strap-on solid rocket motors and the CALIPSO and CloudSat payloads atop the pad's launch mount. The tower also provided the primary weather protection and worker access to the rocket during its stay at the oceanside complex on North Vandenberg. Processing for this mission began last June with the erection of the first stage.

It has been a long road to get this mission launched. Technical troubles and a labor strike postponed the flight from last fall. And six launch opportunities since last week have ended in scrubs. But maybe tonight will be the night. Countdown activities are proceeding toward the one-second launch window at 1002 GMT (3:02 a.m. PDT; 6:02 a.m. EDT).

0108 GMT (9:08 p.m. EDT Thurs.)

The mobile service tower at Space Launch Complex 2-West is now in motion. Crews are rolling the tower into its launch position, revealing the Delta 2 rocket for tonight's countdown.

Read our earlier Mission Status Center coverage.