BY JUSTIN RAY

Additional coverage for subscribers:
VIDEO: DELTA 2 ROCKET LIFTS OFF WITH NOAA-N PRIME PLAY
VIDEO: LAUNCH REPLAYS: PAD CAMERA NO. 1 PLAY
VIDEO: LAUNCH REPLAYS: PAD CAMERA NO. 2 PLAY
VIDEO: LAUNCH REPLAYS: PAD CAMERA NO. 3 PLAY
VIDEO: CONFIRMATION OF A SUCCESSFUL LAUNCH PLAY

VIDEO: LAUNCH PAD'S SERVICE TOWER ROLLED BACK PLAY
VIDEO: WEDNESDAY'S LAUNCH ATTEMPT SCRUBBED PLAY
VIDEO: HIGHLIGHTS OF THE DELTA 2'S LAUNCH CAMPAIGN PLAY
VIDEO: HIGHLIGHTS OF THE SATELLITE LAUNCH CAMPAIGN PLAY
VIDEO: NOAA-N PRIME MISSION OVERVIEW FILM PLAY
VIDEO: PRE-LAUNCH NEWS BRIEFING PLAY
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FRIDAY, FEBRUARY 6, 2009
1245 GMT (7:45 a.m. EST; 4:45 a.m. PST)

A last-of-its-kind weather observatory with roots reaching back to the earliest days of U.S. space exploration rocketed into orbit this morning to keep logging environmental records until a long-delayed new generation of satellites is ready.

Read our full story.

1212 GMT (7:12 a.m. EST; 4:12 a.m. PST)

"Today's launch showcased some of the everyday, modern conveniences provided by our spacelift capabilities," said Col. David Buck, 30th Space Wing commander at Vandenberg Air Force. "Whether it is through improved weather forecasting or high resolution Earth imagery, our launch range is helping provide ordinary citizens across the globe with services which people often take for granted."

1203 GMT (7:03 a.m. EST; 4:03 a.m. PST)

After NOAA-N Prime successfully arrived in space, the craft was renamed NOAA-19.

"NOAA-19 is in a nominal orbit with all spacecraft systems functioning properly," said Wayne McIntyre, NASA's Polar Operational Environmental Satellite project manager.

1150 GMT (6:50 a.m. EST; 3:50 a.m. PST)

"We are proud to celebrate the 20th anniversary of Delta 2 by successfully launching this critically important spacecraft for both NASA and NOAA and we congratulate our mission partners on their success," said Jim Sponnick, United Launch Alliance's vice president of the Delta Product Line. "Now with 138 successful launches, the Delta 2 is the proven worldwide leader of the medium class market."

The venerable rocket debuted on February 14, 1989, deploying a Global Positioning System satellite. Over the past two decades, the rocket has launched the entire GPS constellation, performed over three dozen commercial missions and dispatched numerous scientific spacecraft and probes.

"Everyone associated with the Delta 2 product line can take pride in its impressive success record and the contributions they made to scientific exploration, national defense and economic prosperity since 1989," Sponnick said. "Our Delta 2 team realizes they didn't do this alone and only succeeded due to the tremendous support from our government mission partners, suppliers and commercial customers."

1137 GMT (6:37 a.m. EST; 3:37 a.m. PST)

T+plus 75 minutes. The NOAA-N Prime satellite's 20-foot-long, 9-foot-wide solar array is unfurling at this time, NASA reports. This 10-panel array was folded up during launch, then extends accordion-style in orbit to generate power for the spacecraft.

Also upcoming in the next few minutes, three antennas and an instrument sunshade will be deployed. The antennas are used to receive data from ground weather transmitters, send the satellite's imagery to receivers on Earth and hear search and rescue beacons.

All of these critical deployments are accomplished via autonomous functions by the spacecraft itself.

An initial report on the satellite's state of health is expected later this morning.

1133 GMT (6:33 a.m. EST; 3:33 a.m. PST)

T+plus 71 minutes. This is the 85th consecutive successful Delta 2 rocket launch dating back to May 1997. The Delta 2's overall history since debuting in 1989 has achieved 138 successes in 140 flights.

The next Delta 2 rocket launch is planned for the evening of March 5 from Cape Canaveral, Florida. That mission will dispatch NASA's Kepler space observatory in a search of habitable planets in our galaxy.

1131 GMT (6:31 a.m. EST; 3:31 a.m. PST)

T+plus 69 minutes. "The flight was just awesome. We hit the orbit right on the money. The apogee, perigee and inclination of the spacecraft looks right where we wanted it," NASA launch manager Omar Baez says.

1127 GMT (6:27 a.m. EST; 3:27 a.m. PST)

T+plus 65 minutes, 56 seconds. SPACECRAFT SEPARATION! The NOAA-N Prime weather observatory has been released from the Delta 2 rocket's second stage, completing today's launch!

The polar-orbiting satellite will track weather systems around the globe and add to decades of environmental records.

1126 GMT (6:26 a.m. EST; 3:26 a.m. PST)

T+plus 64 minutes. The Malindi tracking station in Kenya is following the rocket. The African ground station will be used to relay the rocket's telemetry back to Vandenberg to provide confirmation of the NOAA-N Prime satellite separating from Delta.

1123 GMT (6:23 a.m. EST; 3:23 a.m. PST)

T+plus 61 minutes. The rocket is maneuvering itself to the proper orientation for release of NOAA-N Prime.

1121 GMT (6:21 a.m. EST; 3:21 a.m. PST)

T+plus 59 minutes, 49 seconds. SECO 2. The orbit adjustment burn was completed as the rocket neared the east-central coast of Africa, headed northbound.

1121 GMT (6:21 a.m. EST; 3:21 a.m. PST)

T+plus 59 minutes, 35 seconds. The second stage engine has ignited for the 13-second firing to propel its 3,100-pound spacecraft payload into the proper polar orbit.

1117 GMT (6:17 a.m. EST; 3:17 a.m. PST)

T+plus 55 minutes. The second stage has completed its BBQ roll. The rocket now will reorient itself into the proper position for the upcoming engine firing.

1112 GMT (6:12 a.m. EST; 3:12 a.m. PST)

T+plus 50 minutes. The next firing by the Delta rocket's second stage is coming up in 9 minutes. The Hartebeesthoek tracking station in South Africa has acquired the rocket's signal as it flies northbound.

1109 GMT (6:09 a.m. EST; 3:09 a.m. PST)

T+plus 47 minutes. Photos from the press viewing location of this morning's launch are available here.

1057 GMT (5:57 a.m. EST; 2:57 a.m. PST)

T+plus 35 minutes. The rocket is crossing Antarctica now as it flies in a polar orbit around Earth. A map of the rocket's planned flight path is available here.

1052 GMT (5:52 a.m. EST; 2:52 a.m. PST)

T+plus 30 minutes. The rocket is coasting until the second stage restarts its engine at T+plus 59 minutes, 21 seconds for a brief 13-second firing to put the vehicle into a near-circular orbit 464 nautical miles above Earth. Deployment of NOAA-N Prime from the launch vehicle is expected to be confirmed nearly 66 minutes after liftoff.

1049 GMT (5:49 a.m. EST; 2:49 a.m. PST)

T+plus 27 minutes. "So far, the mission looks very good. We launched right at the beginning of the window. So far, the booster performance was right on the money, right as expected. And the second stage is in orbit now and coasting to apogee where we will do a restart burn and then separate the spacecraft," said Rich Murphy, the mission director from United Launch Alliance.

1042 GMT (5:42 a.m. EST; 2:42 a.m. PST)

T+plus 20 minutes. As the rocket coasts in this parking orbit, it performs a "BBQ roll" maneuver to keep the thermal conditions on the vehicle equal. This maneuver was scheduled to start at about T+plus 18 minutes, 30 seconds and conclude at T+plus 54 minutes, 10 seconds.

1036 GMT (5:36 a.m. EST; 2:36 a.m. PST)

T+plus 14 minutes. As the rocket passes out of range from the tracking plane, a data blackout is created until the Delta's signal is acquired via the next ground station in about 35 minutes.

1034 GMT (5:34 a.m. EST; 2:34 a.m. PST)

T+plus 12 minutes, 10 seconds. The Delta 2 rocket is 100 miles in altitude, 1,478 miles south from the launch pad with a velocity of 17,098 mph.

1033 GMT (5:33 a.m. EST; 2:33 a.m. PST)

T+plus 11 minutes, 55 seconds. SECO 1 has been confirmed. The second stage's Aerojet-made engine completed its initial burn for the launch. Delta and NOAA-N Prime have reached orbit.

1032 GMT (5:32 a.m. EST; 2:32 a.m. PST)

T+plus 10 minutes, 50 seconds. The rocket is 102 miles up, traveling at 15,325 mph.

1032 GMT (5:32 a.m. EST; 2:32 a.m. PST)

T+plus 10 minutes. An instrumented P-3 aircraft positioned over the Pacific has acquired the rocket's telemetry signal as the Delta travels away from Vandenberg.

The Navy tracker is outfitted with equipment needed to receive the stream of data from the Delta 2's second stage after the rocket flies beyond the horizon of Vandenberg's ground station and reaches a preliminary parking orbit around the planet.

1031 GMT (5:31 a.m. EST; 2:31 a.m. PST)

T+plus 9 minutes, 30 seconds. About two minutes remain in this burn of the second stage engine to achieve the intended parking orbit.

1030 GMT (5:30 a.m. EST; 2:30 a.m. PST)

T+plus 8 minutes, 20 seconds. Delta is 101 miles in altitude, 641 downrange from the launch pad and traveling at 12,149 mph.

1029 GMT (5:29 a.m. EST; 2:29 a.m. PST)

T+plus 7 minutes. The second stage is firing normally as the rocket nears 100 miles in altitude.

1028 GMT (5:28 a.m. EST; 2:28 a.m. PST)

T+plus 6 minutes. Now 86 miles up, 383 miles downrange and speeding along at 10,750 mph.

1027 GMT (5:27 a.m. EST; 2:27 a.m. PST)

T+plus 5 minutes, 20 seconds. Delta is 69.3 miles in altitude, 241 miles downrange from the launch pad and traveling at 10,128 mph.

1027 GMT (5:27 a.m. EST; 2:27 a.m. PST)

T+plus 5 minutes, 2 seconds. The rocket's 10-foot-diameter nose cone enclosing the NOAA-N Prime spacecraft has been jettisoned.

1026 GMT (5:26 a.m. EST; 2:26 a.m. PST)

T+plus 4 minutes, 45 seconds. The Delta's second stage engine has ignited!

1026 GMT (5:26 a.m. EST; 2:26 a.m. PST)

T+plus 4 minutes, 41 seconds. MECO. The first stage main engine cutoff has occurred, followed moments later by shutdown of the twin vernier steering thrusters. The spent stage then jettisoned.

1026 GMT (5:26 a.m. EST; 2:26 a.m. PST)

T+plus 4 minutes, 15 seconds. The vehicle is 45 miles in altitude, 104 miles downrange from the launch pad and traveling at 7,950 mph.

1025 GMT (5:25 a.m. EST; 2:25 a.m. PST)

T+plus 3 minutes, 30 seconds. The first stage main engine still firing well. The Pratt & Whitney Rocketdyne powerplant consumes kerosene fuel and liquid oxygen to produce about 200,000 pounds of thrust.

1025 GMT (5:25 a.m. EST; 2:25 a.m. PST)

T+plus 3 minutes, 5 seconds. The rocket is 30.6 miles in altitude and traveling at 3,254 miles per hour.

1024 GMT (5:24 a.m. EST; 2:24 a.m. PST)

T+plus 2 minutes, 35 seconds. The first stage main engine continues to burn normally.

1024 GMT (5:24 a.m. EST; 2:24 a.m. PST)

T+plus 2 minutes, 5 seconds. The Delta 2 rocket is 19.9 miles in altitude and traveling over 1,500 mph.

1023 GMT (5:23 a.m. EST; 2:23 a.m. PST)

T+plus 1 minute, 50 seconds. The ground-lit boosters have jettisoned from the first stage. They remained attached until the rocket cleared off-shore oil rigs.

1023 GMT (5:23 a.m. EST; 2:23 a.m. PST)

T+plus 1 minute, 5 seconds. The trio of ATK-made solid rocket boosters ignited on the launch pad have burned out of propellant. The Delta 2's first stage RS-27A main engine will be providing the sole thrust for the next few minutes.

1022 GMT (5:22 a.m. EST; 2:22 a.m. PST)

T+plus 50 seconds. The rocket has flown through the area of maximum aerodynamic pressure in the lower atmosphere. The vehicle is riding the power of its first stage main engine and the three strap-on boosters.

1022 GMT (5:22 a.m. EST; 2:22 a.m. PST)

T+plus 15 seconds. The Delta 2 rocket is lighting up the central coast of California on its way toward a polar orbit.

1022 GMT (5:22 a.m. EST; 2:22 a.m. PST)

LIFTOFF! Liftoff of the NOAA-N Prime weather observatory, the final satellite in a distinguished series of environmental monitors.

1021 GMT (5:21 a.m. EST; 2:21 a.m. PST)

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 launch team member triggers the engine start switch. The process begins with ignition of the two vernier thrusters and first stage main engine start. The three ground-lit solid rocket motors then light at T-0 for liftoff.

1021 GMT (5:21 a.m. EST; 2:21 a.m. PST)

T-minus 1 minute. All remains "go" for the first Delta 2 rocket launch of the year.

1020 GMT (5:20 a.m. EST; 2:20 a.m. PST)

T-minus 75 seconds. First stage liquid oxygen topping to 100 percent is underway.

1020 GMT (5:20 a.m. EST; 2:20 a.m. PST)

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

1020 GMT (5:20 a.m. EST; 2:20 a.m. PST)

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.

1019 GMT (5:19 a.m. EST; 2:19 a.m. PST)

T-minus 2 minutes, 30 seconds. The NOAA-N Prime payload have been declared "go" for launch.

1019 GMT (5:19 a.m. EST; 2:19 a.m. PST)

T-minus 3 minutes and counting. This new NOAA-N Prime weather observatory will replace the aging NOAA-18 satellite that was launched by another Delta 2 rocket in May 2005. That spacecraft flew over Vandenberg about 30 minutes ago, passing just east of the launch site on a southerly trajectory.

At liftoff time, NOAA-18 will be nearing the coast of Antarctica at 76.1 degrees South and 169.3 degrees West.

1018 GMT (5:18 a.m. EST; 2:18 a.m. PST)

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

1018 GMT (5:18 a.m. EST; 2:18 a.m. PST)

T-minus 4 minutes and counting! Clocks are ticking down the final moments to liftoff of the Delta 2 rocket with the NOAA-N Prime spacecraft. Launch is set for 2:22 a.m. local time from Vandenberg Air Force Base, California.

Following liftoff, the vehicle will head southward as it climbs into orbit on a 65-minute flight to deploy the polar-orbiting weather satellite.

1017 GMT (5:17 a.m. EST; 2:17 a.m. PST)

Now five minutes from launch! The "go" has been given to resume the countdown for launch.

1014 GMT (5:14 a.m. EST; 2:14 a.m. PST)

The launch team poll confirms all systems are "ready" for liftoff of the Delta 2 rocket and NOAA-N Prime spacecraft.

1012 GMT (5:12 a.m. EST; 2:12 a.m. PST)

Now 10 minutes from launch. This will be:

• The 338th Delta rocket launch since 1960
• The second Delta of 2009
• The 140th Delta 2 rocket mission since 1989
• The 8th Delta 2 rocket fly in the 7320 configuration
• The 35th Delta 2 rocket launch from Vandenberg AFB

1010 GMT (5:10 a.m. EST; 2:10 a.m. PST)

NASA launch manager Omar Baez just completed his final pre-launch poll. No constraints were voiced by the space agency managers.

1008 GMT (5:08 a.m. EST; 2:08 a.m. PST)

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 2:22 a.m. local (5:22 a.m. EST; 1022 GMT) for the Delta 2 rocket with NOAA-N Prime.

1007 GMT (5:07 a.m. EST; 2:07 a.m. PST)

The NOAA-N Prime spacecraft is undergoing final configuring for launch.

1006 GMT (5:06 a.m. EST; 2:06 a.m. PST)

The launch weather officer says the current conditions are acceptable for liftoff of the Delta 2 rocket this morning.

1003 GMT (5:03 a.m. EST; 2:03 a.m. PST)

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

1000 GMT (5:00 a.m. EST; 2:00 a.m. PST)

The next weather balloon also shows winds aloft have come within limits for launch.

0957 GMT (4:57 a.m. EST; 1:57 a.m. PST)

T-minus 15 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 planned hold is scheduled. Launch remains set to occur at 2:22 a.m. local time (5:22 a.m. EST; 1022 GMT).

0953 GMT (4:53 a.m. EST; 1:53 a.m. PST)

A readiness poll of the launch team has resulted in a "go" to restart the countdown as scheduled.

0947 GMT (4:47 a.m. EST; 1:47 a.m. PST)

Good news from the newest weather balloon data to be reported. All upper level wind conditions are now green and go for launch. Earlier balloons had been showing a concern in the lower altitudes. But now each region of flight has acceptable winds based on the rocket's structural limits, ability to control and fairing clearances.

0937 GMT (4:37 a.m. EST; 1:37 a.m. PST)

T-minus 15 minutes and holding. Clocks have entered the next planned hold period during the Terminal Countdown. 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.

0933 GMT (4:33 a.m. EST; 1:33 a.m. PST)

The first stage engine steering checks just finished.

0929 GMT (4:29 a.m. EST; 1:29 a.m. PST)

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

0927 GMT (4:27 a.m. EST; 1:27 a.m. PST)

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.

0923 GMT (4:23 a.m. EST; 1:23 a.m. PST)

The newest weather balloon data shows winds in the lower altitudes now far out of limits for the rocket's controls. The conditions are 61 percent above the acceptable range. It had been just six percent based on the previous balloon.

But there's still several more balloons to relay data before launch time.

0922 GMT (4:22 a.m. EST; 1:22 a.m. PST)

Launch is one hour away, weather permitting. The countdown is proceeding on schedule for liftoff at 2:22 a.m. local (5:22 a.m. EST; 1022 GMT).

0920 GMT (4:20 a.m. EST; 1:20 a.m. PST)

The checks of the rocket's safety systems are complete and normal.

0905 GMT (4:05 a.m. EST; 1:05 a.m. PST)

Loading of the Delta 2 rocket's first stage liquid oxygen tank has been accomplished. The process took 26 minutes and 28 seconds today, concluding at 1:04:57 a.m. local time. 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 Thursday evening. The second stage was filled with its storable nitrogen tetroxide and Aerozine 50 fuels last Saturday. And the three strap-on booster rockets are solid-propellant.

0903 GMT (4:03 a.m. EST; 1:03 a.m. PST)

The tank has reached the 95 percent mark.

0858 GMT (3:58 a.m. EST; 12:58 a.m. PST)

Liquid oxygen loading is continuing. 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.

0852 GMT (3:52 a.m. EST; 12:52 a.m. PST)

Now just 90 minutes away from the scheduled launch of the Delta 2 rocket to deliver the NOAA-N Prime spacecraft into orbit.

0848 GMT (3:48 a.m. EST; 12:48 a.m. PST)

This approximate 25-minute process to fill the first stage liquid oxygen tank has been underway for 10 minutes. A bright white plume of vapors have begun streaming from a vent on the rocket and the bottom of the vehicle is icing over as the super-cold liquid oxygen continues to flow into the first stage.

0838 GMT (3:38 a.m. EST; 12:38 a.m. PST)

LOX loading begins. Cryogenic liquid oxygen, chilled to Minus-298 degrees F, has started flowing from a 28,000-gallon storage tank at Space Launch Complex 2, through plumbing and into the bottom of the 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.

0834 GMT (3:34 a.m. EST; 12:34 a.m. PST)

Work to turn on and configure the Delta's onboard guidance computer has been completed.

0832 GMT (3:32 a.m. EST; 12:32 a.m. PST)

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

0826 GMT (3:26 a.m. EST; 12:26 a.m. PST)

NASA launch manager Omar Baez just polled the agency team for a "go" to begin loading the rocket's first stage liquid oxygen tank.

"The NASA team is ready for cryo tanking," Baez reported.

0823 GMT (3:23 a.m. EST; 12:23 a.m. PST)

The launch weather officer just completed a briefing to mission managers.

The current conditions at the pad include southeasterly winds of 15 knots, clouds broken at 6,000 feet and overcast at 7,000 feet and a temperature of 53 degrees. There's some light rain showers moving up from the south, and the leading edge of clouds from the next front is expected to reach the pad about an hour before launch.

Thick clouds and cumulus clouds are among the main concern for launch time. Surface winds could be gusting to 25 knots in some of the rain showers, but that's below the 28-knot limit.

Upper-level winds, as noted earlier, are being watched closely as well.

0758 GMT (2:58 a.m. EST; 11:58 p.m. PST)

The latest weather balloon still shows the wind conditions in the first 20,000 feet of flight to be just slightly out of the rocket's control limits.

But this new data is a little better than the previous balloon results. The first balloon showed a nine-percent excursion and the second one was six-percent over the limit.

All of the other regions of flight are showing acceptable winds.

0752 GMT (2:52 a.m. EST; 11:52 p.m. PST)

Two hours, 30 minutes and continuing to count down for launch. A weather briefing is coming up at 12:17 a.m. PST.

0749 GMT (2:49 a.m. EST; 11:49 p.m. PST)

The first stage helium and nitrogen systems have been pressurized.

0726 GMT (2:26 a.m. EST; 11:26 p.m. PST)

The rocket's control system and guidance computer are being turned on.

And the launch is starting the steps to pressurize the first and second stage helium and nitrogen systems and the second stage fuel and oxidizer tanks.

0722 GMT (2:22 a.m. EST; 11:22 p.m. PST)

The three-hour Terminal Countdown sequence has started for the Delta rocket. Between now and the 2:22 a.m. launch time, the rocket's guidance system will be activated, onboard tanks pressurized, the liquid oxygen supply loaded into the first stage, checks performed on the safety system, steering tests conducted on the engines, then the final switches to internal power and arming of the ignitors.

0714 GMT (2:14 a.m. EST; 11:14 p.m. PST)

The launch team has been polled to ensure all stations are manned and systems are set for the Terminal Countdown. Each team member voiced his or her "ready" to begin the count.

0700 GMT (2:00 a.m. EST; 11:00 p.m. PST)

Data has been posted from the early weather balloon that was sent up to measure wind speeds and directions. The winds are slightly out of limits for the rocket's controls through the first 20,000 feet of flight.

However, several more balloons will be released through the rest of the countdown to monitor the conditions aloft.

0622 GMT (1:22 a.m. EST; 10:22 p.m. PST)

T-minus 150 minutes and holding. The countdown just entered the first of three planned holds that will occur over the course of the night. This first pause is 60 minutes long.

The two later holds -- at the T-minus 15 minute and the T-minus 4 minute points -- will give the launch team some time to deal with issues and catch up on any work running behind. Those two holds will last 20 minutes and 10 minutes in duration, respectively.

0600 GMT (1:00 a.m. EST; 10:00 p.m. PST)

Mission managers and the launch team members are getting seated for the final hours of the countdown. Clocks continue to target a 2:22 a.m. (5:22 a.m. EST; 1022 GMT) launch from Vandenberg Air Force Base, California.

Out at Space Launch Complex 2, workers are finishing up the pre-flight checklist before everyone clears the restricted area for the remainder of the countdown.

The Delta 2 is gently swaying in the evening breeze at its coastal pad, something that is perfectly normal for this rocket. Unlike some other vehicles that are anchored to the pad by restraints, the Delta 2 rests unbolted atop its launch mount, free to fly when the main engine and trio of solid-fuel motors ignite.

0350 GMT (10:50 p.m. EST; 7:50 p.m. PST)

The United Launch Alliance Delta 2 rocket stands illuminated by powerful lights at Vandenberg Air Force Base tonight following retraction of the pad's mobile gantry.

The service structure, riding on rails at Space Launch Complex 2, has been rolled away from the 12-story rocket as the pace of preparations increases for the overnight liftoff.

Launch remains scheduled for 2:22 a.m. local time (5:22 a.m. EST; 1022 GMT).

The 65-minute flight by the two-stage rocket will place the NOAA-N Prime weather observatory into space. The polar-orbiting satellite will track weather systems around the globe and add to decades of environmental records.

0230 GMT (9:30 p.m. EST; 6:30 p.m. PST)

The Delta 2 rocket's first stage has been refilled with 10,000 gallons of highly refined kerosene propellant, called RP-1.

Flowing from a storage reservoir at the Space Launch Complex 2 pad, the fuel entered at the base of the rocket and traveled up to the first stage tank located in the center of the slender 12-story vehicle.

The kerosene will be consumed with liquid oxygen by the Pratt & Whitney Rocketdyne RS-27A main engine and twin vernier steering thrusters during the initial four-and-a-half minutes of flight. The liquid oxygen will be loaded aboard the rocket a little after 12:30 a.m. PST.

THURSDAY, FEBRUARY 5, 2009
2125 GMT (4:25 p.m. EST; 1:25 p.m. PST)

The Delta 2 rocket and its weather satellite cargo have been cleared for launch early Friday morning at 2:22 a.m. local time (5:22 a.m. EST; 1022 GMT).

It will be the third attempt to launch the mission. Wednesday's countdown was scrubbed by a faulty relay card in the pad's gaseous nitrogen purging system and this morning's opportunity was called off late Wednesday night because of trouble with the equipment that blows conditioned air into the rocket's payload shroud.

Precautionary contamination checks have been performed at the launch pad. The samples taken in the air system and inside the Delta's nose cone found no hydrocarbon contamination, a NASA spokesman said.

With the good results from the contamination checks and the air conditioning equipment now fixed, mission managers concluded their mid-day meeting with the decision to proceed into another countdown this evening, officials said.

The only question mark heading into the countdown is the weather. There's a 60 percent chance that conditions would scrub the launch on Friday morning, or a 40 percent chance the weather will be acceptable. Cumulus clouds and rain over the launch site are the two main worries.

A reminder that if you will be away from your computer but would like to receive occasional updates on the countdown, 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.)

1845 GMT (1:45 p.m. EST; 10:45 a.m. PST)

Weather forecasters say there's a 40 percent chance that conditions will be within limits for the Delta 2 rocket launch early Friday morning from Vandenberg Air Force Base.

"A cold front will push through the central California coast today, leaving unstable, showery weather behind for tonight's launch attempt. As a result, cumulus clouds and precipitation will be the primary concern for T-0," the weather team reported this morning.

The outlook for the 2:22 a.m. local time launch also includes low-, mid- and high-level decks of clouds, six miles of visibility, rain showers in the area and a temperature of 50-55 degrees F. Ground winds will be southeasterly at 10-15 knots with gusts to 20 knots and the upper-level winds should max out around 30,000 feet at 90 knots.

If the launch should slip an additional 24 hours to Saturday morning, the odds of acceptable weather remain at 40 percent.

"The unstable weather pattern will continue into Friday, and Friday night's weather will be a near carbon-copy of tonight's," forecasters said. "Showery weather will persist through T-0 Friday night, and cumulus clouds and precipitation will be the main concern again. There is also an increased chance of thunderstorms Friday afternoon through early Saturday morning, and there is a slight chance lightning and anvil clouds could impact launch, as well. Winds will be lighter Friday evening, only 10-15 knots from the southwest. Max upper-level winds are expected to be 45 knots at 25,000 feet."

0645 GMT (1:45 a.m. EST; 10:45 p.m. PST)

A problem with the equipment that feeds conditioned air into the Delta 2 rocket's payload shroud has cancelled Thursday morning's opportunity to send the NOAA-N Prime weather observatory into orbit from Vandenberg Air Force Base.

While officials believe there was no harm done to the satellite nestled inside the rocket's nose cone, precautionary contamination checks have been ordered.

"Though unlikely, the payload team needs additional time to be assured that an unacceptable level of hydrocarbons have not been introduced into the spacecraft environment within the fairing," a NASA spokesman said.

The spacecraft crews will perform their assessments while other workers make repairs to the air conditioning compressor that failed.

The ground-based equipment is designed to provide cool, dry air inside the nose cone prior to launch. A bright yellow hose extends from the pad's umbilical tower to the Delta's 10-foot-diameter shroud, then separates as the rocket lifts off.

A meeting is planned for mid-day Thursday to confirm when the next launch attempt will be made. Liftoff could occur as early as Friday morning at 2:22 a.m. local time (5:22 a.m. EST; 1022 GMT).

0504 GMT (12:04 a.m. EST; 9:04 p.m. PST)

SCRUB. Officials have cancelled Thursday morning's launch attempt. More details to follow.

0240 GMT (9:40 p.m. EST; 6:40 p.m. PST)

Launch try No. 2 is officially underway at Vandenberg Air Force Base for the Delta 2 rocket and the NOAA-N Prime weather observatory.

Controllers have pumped 10,000 gallons of rocket-grade kerosene back into the Delta's first stage from storage tanks at the pad. The propellant was drained from the vehicle after the launch postponement Wednesday morning.

The next big event in this evening's activities will be retraction of the mobile service tower. The gantry was returned to its position surrounding the rocket as part of post-scrub procedures.

WEDNESDAY, FEBRUARY 4, 2009
2145 GMT (4:45 p.m. EST; 1:45 p.m. PST)

With the hardware glitch at the launch pad now fixed and the weather forecast a bit more favorable, officials have decided to begin another countdown this evening for launch of the Delta 2 rocket.

Liftoff on Thursday morning from Vandenberg Air Force Base is scheduled for 2:22 a.m. local time (5:22 a.m. EST; 1022 GMT), which is the opening of a 10-minute window.

"We are going to take another run at it tonight," a NASA spokesman said.

The launch pad gaseous nitrogen purging system has been repaired since this morning's scrub. NASA says the issue is solved and the hardware is ready for the next countdown.

"They found the problem as a failed relay. They have removed and replaced the relay," the spokesman said.

Air Force meteorologists report there's now a 40 percent chance that weather will be acceptable for the overnight blastoff. Thick clouds associated with a Pacific weather system coming ashore in California will be the main concern. A weather reconnaissance aircraft will be aloft during the countdown to evaluate the clouds.

1730 GMT (12:30 p.m. EST; 9:30 a.m. PST)

Following this morning's scrub, the Delta 2 rocket was safed and crews moved the mobile service tower back around the vehicle. Mission officials plan a mid-day meeting to review the ground support equipment problem that caused the launch delay and receive the latest update on the weather forecast. Managers could decide to either try another launch attempt tomorrow or possibly delay further. We'll pass along the official news as it becomes available.

1030 GMT (5:30 a.m. EST; 2:30 a.m. PST)

Troubles with a critical support system at the launch pad scrubbed this morning's planned liftoff of a Delta 2 rocket from Vandenberg Air Force Base in California.

"Shortly after we finish (liquid oxygen) loading, we do a decay check. And we noticed that we weren't able to charge our facility gaseous nitrogen system, which controls all of the purges going out into the tower and feeding the rocket," NASA launch manager Omar Baez said.

"It puts us in an unsafe condition. If we lose all of this gaseous nitrogen pressure, we won't be able to detank and so forth."

The result was a launch postponement for the day so that crews could head into the pad and begin troubleshooting the problem.

"Unfortunately, we've got a decay rate or a leak somewhere or a stop in the system that's not allowing us to flow the gaseous nitrogen," Baez said.

Another launch attempt could occur tomorrow, assuming the problem is quickly identified and fixed.

"We'll have to see. We'll hope for the best and try to pull that off," Baez said.

Aside from overcoming the technical problem, another hurdle tomorrow is expected to be the weather. Meteorologists say an incoming low-pressure system from the Pacific Ocean will bring clouds, rain and gusty winds to the central coast of California. There's an 80 percent chance that the bad weather will violate the launch rules.

The launch weather officer says the outlook for subsequent days is 60 percent, 60 percent and 40 percent "no go" for Friday, Saturday and Sunday mornings, respectively.

The daily launch time will remain 2:22 a.m. local (5:22 a.m. EST; 1022 GMT).

1002 GMT (5:02 a.m. EST; 2:02 a.m. PST)

The problem is with the gaseous nitrogen purge system at the launch pad. Another launch attempt could be made tomorrow if the issue can be resolved in time. However, the weather outlook is not favorable.

0955 GMT (4:55 a.m. EST; 1:55 a.m. PST)

A problem has developed at the launch pad that will preclude liftoff today. We're awaiting further details on the issue.

0952 GMT (4:52 a.m. EST; 1:52 a.m. PST)

SCRUB. Today's launch attempt has been scrubbed, NASA just announced.

0947 GMT (4:47 a.m. EST; 1:47 a.m. PST)

Now 35 minutes away from launch of the NOAA-N Prime spacecraft aboard the Delta 2 rocket.

In the pre-flight news briefing, Wayne Higgins, director of NOAA's Climate Prediction Center, talked about the importance of this new satellite:

"The data from polar-orbiting satellites such as NOAA-N Prime will be vital to our mission as we move forward to monitor and to predict not only current conditions in the atmosphere and oceans but also to keep tabs on the longer term climate trends. In particular, what I'm speaking of there is putting current conditions in the proper historical context to the extent that we can," Higgins said.

"We also use satellite data very importantly in the validation of climate forecasts to determine how useful and in particular how skillful there are."

Data from the NOAA-N Prime satellite will help forecasters with services ranging from U.S. precipitation and temperature outlooks to El Nino and La Nina predictions.

Instruments on NOAA-N Prime will also provide information about changes in ice and snow coverage.

"This information in conjunction with the satellite's observations of atmospheric temperatures, precipitation and the ocean sea surface temperatures, all of these help us monitor and attribute, for example, Arctic glacial and sea ice changes, as well as changes to Arctic and sub-Arctic snow cover. So understanding these features is key, if you will, to accelerating improvements in climate models and hence to delivering more skillful climate forecasts to the public both at polar latitudes as well as here at home," Higgins said.

0937 GMT (4:37 a.m. EST; 1:37 a.m. PST)

T-minus 15 minutes and holding. Clocks have entered the first of two planned hold periods during the final portion of the Terminal Countdown. This pause will last 20 minutes in duration.

The countdown has been going very smoothly thus far, NASA says. But 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.

0933 GMT (4:33 a.m. EST; 1:33 a.m. PST)

The first stage engine steering checks just finished.

0929 GMT (4:29 a.m. EST; 1:29 a.m. PST)

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

0927 GMT (4:27 a.m. EST; 1:27 a.m. PST)

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.

0922 GMT (4:22 a.m. EST; 1:22 a.m. PST)

Pressurization of the second stage's fuel and oxidizer tanks is reported complete as the clocks continue to target liftoff 60 minutes from now.

0920 GMT (4:20 a.m. EST; 1:20 a.m. PST)

The checks of the rocket's safety systems have been completed satisfactorily. Next up in the countdown will be engine steering tests.

0912 GMT (4:12 a.m. EST; 1:12 a.m. PST)

T-minus 40 minutes and counting. Countdown clocks are continuing to the T-minus 15 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 2:22 a.m. local (5:22 a.m. EST; 1022 GMT).

0906 GMT (4:06 a.m. EST; 1:06 a.m. PST)

Loading of the Delta 2 rocket's first stage liquid oxygen tank has been accomplished. 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 Tuesday afternoon. The second stage was filled with its storable nitrogen tetroxide and Aerozine 50 fuels last Saturday. And the three strap-on booster rockets are solid-propellant.

0858 GMT (3:58 a.m. EST; 12:58 a.m. PST)

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.

0852 GMT (3:52 a.m. EST; 12:52 a.m. PST)

Liftoff is just 90 minutes away. The Delta 2 rocket is poised to soar away from California at 2:22 a.m. local time to deliver the NOAA-N Prime spacecraft into orbit.

0850 GMT (3:50 a.m. EST; 12:50 a.m. PST)

Now 12 minutes into this approximate 25-minute process to fill the first stage liquid oxygen tank. A bright white plume of vapors have begun streaming from a vent on the rocket and the bottom of the vehicle is icing over as the super-cold liquid oxygen continues to flow into the first stage.

0838 GMT (3:38 a.m. EST; 12:38 a.m. PST)

LOX loading begins. Cryogenic liquid oxygen, chilled to Minus-298 degrees F, has started flowing from a 28,000-gallon storage tank at Space Launch Complex 2, through plumbing and into the bottom of the 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.

0836 GMT (3:36 a.m. EST; 12:36 a.m. PST)

Work to turn on and configure the Delta's onboard guidance computer has been completed.

0832 GMT (3:32 a.m. EST; 12:32 a.m. PST)

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

0826 GMT (3:26 a.m. EST; 12:26 a.m. PST)

NASA launch manager Omar Baez just polled the agency team for a "go" to begin loading the rocket's first stage liquid oxygen tank. No constraints were voiced.

"The NASA team is ready for cryo tanking," Baez reported.

0822 GMT (3:22 a.m. EST; 12:22 a.m. PST)

The launch weather officer just gave an update to mission managers. The wind forecast has improved to just 6-10 knots, much less than the earlier forecast that included gusts up to 20 knots. That change means there's now a 100 percent chance of acceptable conditions for launch today.

The revised forecast for launch time calls for cirrus clouds at 25,000 feet with 3/8ths sky coverage, visibility of 7 miles, variable winds of 6-10 knots and a temperature of 46-50 degrees F.

0810 GMT (3:10 a.m. EST; 12:10 a.m. PST)

NOAA-N Prime is the final satellite in a remarkably long program. The spacecraft's family tree can be traced to 1960 and the launch of TIROS, the first Television Infrared Observation Satellite.

In a pre-flight interview, Gary Davis, director of the Office of Systems Development at NOAA's Satellite and Information Service, talked about the ending of this era:

"The first TIROS was launched April 1, 1960. So it literally is 50 years of TIROS data. Of the last series, which is the advanced TIROS-N series, which is the NOAA series that we're now flying, N Prime is the last of that series of spacecraft. We have had a very, very good relationship with what started as RCA building it, then they were bought out by GE, then they were bought out by Martin Marietta, then by Lockheed to become Lockheed Martin. Our relationship with NASA and the contractor has been very, very good.

"TIROS-N was launched in 1978. That was the prototype for this series, and that was actually funded by NASA. NOAA picked up the operational spacecraft starting with NOAA-6 and going all the way out to NOAA-18. And now NOAA-N Prime will become NOAA-19.

"We had one launch failure in that series with NOAA-B, and that happened in 1980. Building this series of spacecraft with pretty much the same NASA and contractor team has been a very good experience. We did have the one problem with the drop of this spacecraft in September of 2003. A true accident. But we were able to work through that with good cooperation with NASA and Lockheed Martin to stay within our budget and be able to launch this satellite when we're launching it."

0747 GMT (2:47 a.m. EST; 11:47 p.m. PST)

Typically at this point in a Delta 2 rocket countdown, the launch team loads 10,000 gallons of highly refined kerosene fuel into the first stage. However, this operation was completed Tuesday afternoon prior to rollback of the mobile service tower.

The early fuel loading was performed to give the rocket added weight and stability while the Delta is exposed to the weather.

The kerosene, called RP-1, will be consumed 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 an hour from now.

0740 GMT (2:40 a.m. EST; 11:40 p.m. PST)

A check of the weather shows all conditions are "go" for launch.

The launch time forecast calls for some cirrus clouds at 25,000 feet with 3/8ths sky coverage, visibility of 7 miles, southeasterly winds of 10-15 knots gusting to 20 knots from a direction between 110 and 140 degrees on the compass and a temperature of 41-45 degrees F.

0722 GMT (2:22 a.m. EST; 11:22 p.m. PST)

T-minus 150 minutes and counting. The Terminal Countdown is being started for the overnight launch of the Delta 2 rocket and the NOAA-N Prime weather observatory from Vandenberg Air Force Base in California.

Liftoff remains scheduled for 2:22 a.m. local time (5:22 a.m. EST; 1022 GMT), which is the opening of a 10-minute launch opportunity.

The countdown clocks currently stand at T-minus 150 minutes and counting. Two planned holds -- at the T-minus 15 minute and the T-minus 4 minute points -- will give the launch team some time to catch up on any work running behind. The first hold will last 20 minutes in duration, the second extends 10 minutes.

Coming up shortly, the launch team will begin activating of the rocket's guidance system, as well as the pressurization steps for the first and second stage helium and nitrogen systems and second stage fuel tanks.

0650 GMT (1:50 a.m. EST; 10:50 p.m. PST)

A NASA spokesman says everything is looking good for launch overnight.

The Delta rocket will be flying in its configuration known as the 7320-10 vehicle. The two-stage launcher is fitted with three strap-on solid-propellant motors and a 10-foot diameter composite nose cone.

After quickly dashing away from its coastal pad, the rocket will head southward over the Pacific Ocean. The three solid boosters give the Delta added thrust through the first 9 nautical miles of ascent, then leave the kerosene-powered main engine to continue pushing the rocket to an altitude of 56 miles.

The spent first stage will jettison to let the hydrazine-fueled second stage ignite and achieve an initial 100 x 468 nautical mile parking orbit a little over 11 minutes into flight.

The rocket will settle into a quiet coast along a trajectory the cruises above the South Pacific before crossing Antarctica and then proceeding northbound toward Africa. The second stage reignites its engine for 13 seconds just off the east-central coast of Africa to climb into a near-circular polar orbit 464 nautical miles above the planet.

The 1.5-ton payload is expected to be released from the rocket 65 minutes and 40 seconds after blastoff.

0622 GMT (1:22 a.m. EST; 10:22 p.m. PST)

T-minus 150 minutes and holding. Clocks have been paused for a planned 60-minute built-in hold.

The Terminal Countdown remains scheduled to start at 11:22 p.m. local time (2:22 a.m. EST), beginning the formal three-hour process to bring the rocket to life, load the liquid oxygen for the first stage main engine, conduct extensive final testing and then send the 12-story vehicle soaring on its mission.

0522 GMT (12:22 a.m. EST; 9:22 p.m. PST)

The countdown is entering the final five hours until the Delta 2 rocket soars away from the central coast of California carrying a new weather spacecraft.

A successful launch and deployment of the NOAA-N Prime satellite to replace the aging NOAA-18 spacecraft will extend the polar-orbiting network into the next decade.

"The mission objective of the POES system is to provide an uninterrupted flow of global environmental data for products such as imagery, atmospheric temperature and humidity profiles and land and ocean surface temperature observations for near-term applications like weather forecasting, input into numerical weather models, as well as to establish long-term data sets for climate monitoring and assessment," said Mike Mignogno, NOAA's program manager of the Polar Operational Environmental Satellites.

"Some other objectives of the mission include the collection of upper atmosphere ozone data and space environment observations," he added.

0420 GMT (11:20 p.m. EST; 8:20 p.m. PST)

A collection of photos from tonight's rollback of the mobile service tower can be seen here.

0235 GMT (9:35 p.m. EST; 6:35 p.m. PST)

The pad's service gantry has wheeled away from the United Launch Alliance Delta 2 rocket and reached its parking spot to allow final pre-flight preparations to proceed.

The 177-foot tall mobile service tower was used to stack the two-stage vehicle, the three strap-on solid rocket motors and the NOAA-N Prime payload 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.

Ground teams will spend the next couple of hours getting the pad secured in advance of the Terminal Countdown. Launch remains targeted for 2:22 a.m. local time (5:22 a.m. EST; 1022 GMT).

A reminder that if you will be away from your computer but would like to receive occasional updates on the countdown, 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.)

0226 GMT (9:26 p.m. EST; 6:26 p.m. PST)

Rollback of the launch pad tower has begun.

0200 GMT (9:00 p.m. EST; 6:00 p.m. PST)

The sun has set at Vandenberg Air Force Base, and soon the mobile service tower at Space Launch Complex 2 will begin slowly retracting to reveal the Delta 2 rocket for tonight's countdown.

TUESDAY, FEBRUARY 3, 2009
1845 GMT (1:45 p.m. EST; 10:45 a.m. PST)

In this morning's update from the launch weather team, good conditions are forecast for today's countdown activities and Wednesday's early morning 2:22 a.m. PST (5:22 a.m. EST) liftoff of the new U.S. weather satellite aboard a Delta 2 rocket.

"High pressure will remain in control for one last day along the California coast. A strengthening low pressure system will be approaching the coast but will have minimal impact on launch day," forecasters reported.

"As the low pressure area offshore moves eastward high clouds will increase. Southeasterly winds are expected to be between 10 and 15 knots overnight into Wednesday morning, with isolated higher gusts up to 20 knots possible. Visibility will be favorable, and no precipitation is forecast at the pad or along the flight path. Max upper-level winds will be southwesterly at 65 knots at 55,000 feet with weak directional wind shear through the vertical."

The specifics for launch time include some cirrus clouds at 25,000 feet with 3/8ths sky coverage, visibility of 7 miles, southeasterly winds blowing from a direction between 120 and 150 degrees on the compass and a temperature of 46-49 degrees F.

In contrast to the good weather during Wednesday's launch opportunity, the odds of Mother Nature cooperating with the backup launch window Thursday morning appear to be a long shot.

"A strong low pressure system moves onshore early Thursday morning. Gusty southerly winds, thick clouds, and rain will accompany the system and will lead to unfavorable launch conditions," forecasters say.

"Winds will increase as the low pressure area moves onshore, with southerly winds increasing to 15-25 knots during the day. The strengthening winds will impact MST roll and higher gusts could impact launch. At T-0, broken-overcast layered clouds are likely from 1,500 feet through 25,000 feet. Moderate precipitation is expected below 10,000 feet, and precipitation is expected above 10,000 feet, as well. Max upper-level winds will increase to southwesterly at 105 knots at 35,000 feet."

MONDAY, FEBRUARY 2, 2009

The smooth launch campaign is continuing at Vandenberg Air Force Base for Wednesday's predawn blastoff of the Delta 2 rocket carrying the NOAA-N Prime weather satellite for the U.S. government.

"Today, we successfully held our Launch Readiness Review...and all things are going well," said NASA launch manager Omar Baez.

Meteorologists are predicting good conditions for the launch attempt. "Weather for launch night does look favorable," said Capt. Noah Rich, the Air Force launch weather officer.

The forecast for the 2:22 a.m. local (5:22 a.m. EST) launch time calls for some high cirrus clouds, good visibility at 7 miles and winds of 12 knots with occasional gusts up to 18 knots.

Overall, there's just a 20 percent chance that conditions would violate one of the launch weather rules. "That's for an off-chance in case we get a wind gust a little bit higher than expected values," Rich said.

The outlook for the backup launch window on Thursday morning still looks dismal. An approaching low-pressure system is expected to bring an extensive cloud cover, increased wind speeds, precipitation and an 80 percent chance of weather prohibiting launch.

"Hopefully we'll be gone on the first day," Rich said.

Technicians were finishing rocket testing and beginning ordnance connections today. The NOAA satellite's own countdown sequence is scheduled to start at 9 p.m. local time (12 midnight EST) this evening, Baez said.

Final preps at NASA's Space Launch Complex 2 pad will get underway Tuesday afternoon when crews load 10,000 gallons of highly refined kerosene propellant into the Delta rocket's first stage. The fueling is expected to occur around 3:30 p.m. local (6:30 p.m. EST) while the rocket remains enclosed by its protective service gantry.

Officials decided to take advantage of their option to load fuel several hours earlier than spelled out in the pre-launch timeline. The propellant will give the rocket extra weight and stability in the wind once the pad's mobile tower is rolled back to expose the Delta at 6 p.m. local (9 p.m. EST).

Mission managers will be on-station by 9 p.m. local (12 midnight) to oversee the final hours of the pre-flight procedures. All workers should be out of the pad area by 10:30 p.m. local (1:30 a.m. EST). And the Terminal Countdown commences at 11:22 p.m. local (2:22 a.m. EST), leading to liftoff exactly three hours later.

Watch this page for live updates throughout the countdown and NOAA-N Prime's trek to orbit aboard the Delta 2 rocket.

If you will be away from your computer and still want occasional 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.)

SUNDAY, FEBRUARY 1, 2009

A half-billion dollar climate observatory, having weathered the storied perils of its past, is finally poised for launch early Wednesday aboard a Delta 2 rocket from Vandenberg Air Force Base, California. Read our preview story.

Air Force meteorologists are forecasting an 80 percent chance of good weather for the launch. The outlook predicts scattered clouds at 3,000 feet, southeasterly winds of 12 to 18 knots and a temperature of 54 degrees F.

If the launch is delayed for some reason, poor weather is expected during the backup launch opportunity on Thursday morning. The forecast calls for an 80 percent of unacceptable launch conditions due to the arrival of an incoming weather system from the Pacific Ocean.

At Space Launch Complex 2, the Delta 2 rocket and the NOAA-N Prime weather satellite remain in good shape for the liftoff.

"All activities scheduled to be completed at this point are finished," a NASA spokesman says. "There are no issues or concerns going into Monday's Launch Readiness Review."

SATURDAY, JANUARY 31, 2009

Storable hypergolic propellants are being loaded into the Delta 2 rocket's second stage today in preparation for Wednesday's early morning launch.

Technicians at Vandenberg Air Force Base's Space Launch Complex 2 are filling the stage a hydrazine propellant mixture and nitrogen tetroxide oxidizer. The fuels will power the stage's Aerojet-made main engine during the two firings needed to deliver the NOAA-N Prime weather satellite into polar orbit.

The Launch Readiness Review will be held on Monday morning for senior management to discuss the progress of pre-flight work, any technical issues and the status of the rocket, payload and ground support systems. The meeting concludes with officials giving the formal approval to proceed with Wednesday's launch, assuming there are no outstanding problems.

Other activities planned for Monday include testing of the Delta 2 rocket's guidance system and the Range Safety equipment and a steering check of the vehicle's hydraulics.

Closeouts of the rocket's compartments will continue through Tuesday, leading to retraction of the mobile service gantry around 5:30 p.m. local time (8:30 p.m. EST).

The early weather outlook predicts generally favorable conditions for Wednesday's launch, but becoming less favorable the following day due to an approaching low pressure system, a NASA spokesman said.

FRIDAY, JANUARY 30, 2009

The Delta 2 rocket and its civilian weather satellite cargo passed the Flight Readiness Review on Thursday, and a countdown dress rehearsal is underway today to practice launch day scripts and procedures.

"There are no issues or concerns toward completing final launch preparations," NASA says.

The NOAA-N Prime spacecraft was enclosed within the rocket's 10-foot diameter nose cone earlier this week. Final testing of the satellite is scheduled for today.

Launch remains targeted for 2:22 a.m. local time (5:22 a.m. EST; 1022 GMT) on Wednesday from Vandenberg Air Force Base in California.