BY SPACEFLIGHT NOW

Follow the countdown and launch of a Boeing Delta 2 rocket with the Jason 1 and TIMED satellites. Reload this page for the very latest on the mission.

FRIDAY, DECEMBER 7, 2001

Two spacecraft that will use the unique vantage point of space to study our home planet were successfully launched into orbit Friday by the 100th Boeing Delta 2 rocket.
Read our full launch story.

Here are several video clips of the launch for our Spaceflight Now+Plus subscribers.

Video coverage for subscribers only:

   VIDEO: RE-EDIT OF FULL LAUNCH VIDEO QT or RV
   VIDEO: DELTA 2 LAUNCHES INTO MORNING SKY QT or RV
   VIDEO: ONBOARD CAMERA VIEW OF LIFTOFF QT or RV
   VIDEO: ONBOARD VIEW OF BOOSTER SEPARATION QT or RV
   VIDEO: ONBOARD VIEW OF ROCKET STAGING QT or RV
   MORE: COMPLETE SFN+ VIDEO INDEX

1714 GMT (12:14 p.m. EST)

T+plus 2 hours, 7 minutes. SPACECRAFT SEPARATION! The Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) atmospheric research satellite has been released from the Boeing Delta 2 rocket's second stage following launch today from Vandenberg Air Force Base, California. This completes the 100th launch of a Delta 2 vehicle.

The $235 million satellite mission aims to study the least explored region of Earth's atmosphere -- the Mesosphere and Lower Thermosphere/Ionosphere, or MLTI. The area extends from 40 to 110 miles above the planet.

This completes our live launch coverage. We will post a full wrap-up story, some pictures and several movies later today.

1713 GMT (12:13 p.m. EST)

T+plus 2 hours, 6 minutes. The orbiting NASA Tracking and Data Relay Satellite System has acquired the TIMED spacecraft, which would only occur if TIMED has deployed from the Delta 2 rocket. However, there still isn't confirmation of spacecraft separation from the rocket via the Nuka Hiva tracking station.

1711 GMT (12:11 p.m. EST)

T+plus 2 hours, 4 minutes. Although engineers don't have all the data via the downrange tracking station to determine precisely what the current orbit of the rocket is, it is believed the orbit achieved from the fourth burn of the second stage is good.

1709 GMT (12:09 p.m. EST)

T+plus 2 hours, 2 minutes. The rocket should be reorienting itself in preparation for release of TIMED, expected three minutes from now.

1707 GMT (12:07 p.m. EST)

T+plus 2 hours. SECO 4. The second stage has completed its fourth and final firing for delivery of its payload into space today. Deployment of TIMED will expected in five minutes.

1706 GMT (12:06 p.m. EST)

T+plus 1 hour, 59 minutes, 23 seconds. The second stage engine has restarted for a 23-second burn to circularize the orbit for TIMED by lowering the high point. The inclination also will be raised.

1705 GMT (12:05 p.m. EST)

T+plus 1 hour, 58 minutes. The remote Nuka Hiva tracking station in the Pacific has acquired the rocket's signal to cover the second stage burn.

1700 GMT (12:00 p.m. EST)

T+plus 1 hour, 53 minutes. The Delta rocket remains in its quiet coast mode. It is currently cruising over the Pacific Ocean in view of the Hawaii tracking station. The vehicle has been in a "BBQ" roll to evenly heat the stage and payload. The restart of the second stage is about five minutes away.

1617 GMT (11:17 a.m. EST)

T+plus 1 hour, 10 minutes. Another good orbit achieved by the Delta 2 rocket's second stage today. Following the third burn of the second stage, the high point is 717.5 nautical miles, low point lowered to 345.75 nautical miles and inclination raised to 71.27 degrees. The stage burned for 41.88 seconds.

The rocket will now coast for about 48 minutes before the second stage is restarted again to circularize the orbit by lowering the high point for deployment of TIMED.

1614 GMT (11:14 a.m. EST)

T+plus 1 hour, 7 minutes, 10 seconds. SECO 3. The second stage engine has completed its third firing of the day.

1614 GMT (11:14 a.m. EST)

T+plus 1 hour, 6 minutes, 30 seconds. Announcement has been made that the second stage has reignited for a 43-second burn to low one side of the orbit while increasing the orbital inclination.

1609 GMT (11:09 a.m. EST)

T+plus 1 hour, 2 minutes. Upcoming is another burn by the second stage engine in about four minutes. This firing will be the first of a two-step process to lower the rocket's orbit from that desired for Jason 1 (around 715 miles) to the orbit required for TIMED (around 340 miles).

1607 GMT (11:07 a.m. EST)

T+plus 59 minutes, 50 seconds. Confirmation has been received that the Dual Payload Attach Fitting, or DPAF, has separated from the Delta 2 rocket's second stage. The Astrium-built structure is flying for the second time on this launch. It allows two distinctly different satellites to be flown aboard one Delta 2 rocket, a feature NASA paid Boeing to have developed.

DPAF is basically a cylinder with cone on its top where Jason 1 was mounted and inside resides the TIMED payload. The in-flight separation occurs at the base of barrel-like cylinder as six springs push the structure above and clear of TIMED.

1605 GMT (11:05 a.m. EST)

T+plus 58 minutes. The next event will be jettisoning the Dual Payload Attach Fitting that is currently enclosing the TIMED spacecraft. This is expected in about 100 seconds.

1603 GMT (11:03 a.m. EST)

T+plus 55 minutes, 40 seconds. SPACECRAFT SEPARATION! The joint French/U.S. Jason 1 oceanography spacecraft has been released from the Boeing Delta 2 rocket's second stage following launch today from Vandenberg Air Force Base, California.

The $185 million satellite mission will continue the legacy that the Topex/Poseidon spacecraft began nearly 10 years ago of measuring the ocean surface topography for climate research.

1601 GMT (11:01 a.m. EST)

T+plus 54 minutes. The orbit achieved following the second burn of the second stage has a high point of 717.93 nautical miles, low point of 712.62 nautical miles and inclination of 66.03 degrees -- a near-perfect orbit.

1600 GMT (11:00 a.m. EST)

T+plus 52 minutes, 30 seconds. A nice clean burn reported for the second stage. The rocket will now maneuver itself to the proper orientation in preparation for deployment of Jason 1 three minutes from now.

1600 GMT (11:00 a.m. EST)

T+plus 51 minutes, 55 seconds. SECO 2. The second stage engine has shut down for the second time of this launch.

1559 GMT (10:59 a.m. EST)

T+plus 51 minutes, 28 seconds. Second stage restart has occurred. The liquid-fueled engine is firing again for an approximate 24-second burn to raise the circularize the orbit.

1557 GMT (10:57 a.m. EST)

T+plus 50 minutes. The Hartebeesthock tracking station in has picked up the Delta 2 rocket flying off the southeast coast of South Africa. Coming up on second stage engine reignition.

1552 GMT (10:52 a.m. EST)

T+plus 45 minutes. The vehicle will soon come within communications range of the Hartebeesthoek tracking station in South Africa. That site will relay data from the rocket back to Vandenberg so engineers can monitor the restart of the second stage engine, which is six minutes away.

Two additional tracking sites will also acquire the rocket's signal over following minutes -- Malindi in Kenya and Diego Garcia on an island in the Indian Ocean -- to cover separation of Jason 1 and the payload attach fitting cylinder enclosing the TIMED spacecraft.

1527 GMT (10:27 a.m. EST)

T+plus 20 minutes. The Delta rocket is currently flying above the Central Pacific Ocean on generally a southeastward trajectory. It will pass close to Antarctica before as it begins a northeast pass across the Indian Ocean just off the coast of Africa. You can see some maps of the trajectory here.

1519 GMT (10:19 a.m. EST)

T+plus 12 minutes. The orbit achieved by the Delta rocket is right as targeted with a high point of 725 nautical miles, low pont of 116 nautical miles and inclination of 66.18 degrees. The next firing of the second stage in about 40 minutes from now will boost the low point to circularize the orbit for deployment of the Jason 1 spacecraft.

1517 GMT (10:17 a.m. EST)

T+plus 10 minutes, 20 seconds. SECO 1. The second stage engine has shut down as planned. The Delta 2 rocket with Jason 1 and TIMED has arrived into a preliminary orbit around Earth.

The Delta rocket is now in a coast period that will last until the second stage restarts at about T+plus 51 minutes, 25 seconds.

1516 GMT (10:16 a.m. EST)

T+plus 9 minutes. About one minute left in this first firing of the Delta 2's second stage.

1516 GMT (10:16 a.m. EST)

T+plus 8 minutes, 30 seconds. A P-3 tracking aircraft has aquired the signal of the Delta 2 rocket as it streaks southward from its Central California launch site.

1515 GMT (10:15 a.m. EST)

T+plus 7 minutes, 30 seconds. Second stage engine continues to fire as planned. No problems reported in today's flight of the Delta 2 rocket.

Today's official liftoff time was 1507:35.560 GMT (10:07:35.560 a.m. EST).

1514 GMT (10:14 a.m. EST)

T+plus 6 minutes, 30 seconds. Altitude is 120 miles, downrange distance 542 miles., velocity 12,800 miles per hour.

1512 GMT (10:12 a.m. EST)

T+plus 4 minutes, 55 seconds. The protective payload fairing enclosing the Jason 1 and TIMED satellites atop the rocket has separated with no recontact detected.

1512 GMT (10:12 a.m. EST)

T+plus 4 minutes, 45 seconds. Second stage engine ignition has been confirmed.

1512 GMT (10:12 a.m. EST)

T+plus 4 minutes, 35 seconds. MECO. The first stage main engine cutoff confirmed, and the spent stage has been jettisoned.

1511 GMT (10:11 a.m. EST)

T+plus 4 minutes, 10 seconds. Coming up on staging. Altitude is 75 miles, downrange distance 156 miles., velocity 9,700 miles per hour.

1510 GMT (10:10 a.m. EST)

T+plus 3 minutes. The first stage still performing normally. Velocity is now 5,100 miles per hour. Altitude is 51 miles, downrange distance 52 miles.

1509 GMT (10:09 a.m. EST)

T+plus 2 minutes, 20 seconds. All three air-lit solid rocket boosters have burned out and jettisoned.

1509 GMT (10:09 a.m. EST)

T+plus 1 minute, 45 seconds. All six spent ground-start solid rocket motors have been jettisoned. The rocket continues to power toward space on the first stage liquid fueled main engine and the three air-lit solid rocket boosters.

1508 GMT (10:08 a.m. EST)

T+plus 1 minute, 5 seconds. All six ground-start solid rocket boosters have burned out. Separation will occur once the vehicle passes into a safe drop zone. The three remaining motors strapped to the base of the Delta 2 vehicle have now ignited and will burn for the next minute.

1508 GMT (10:08 a.m. EST)

T+plus 40 seconds. The Delta rocket has passed Mach 1. The period of maximum dynamic pressure is upcoming in a few seconds.

1507:55 GMT (10:07:55 a.m. EST)

T+plus 20 seconds. Vehicle has rolled to the proper trajectory.

1507:35 GMT (10:07:35 a.m. EST)

LIFTOFF! Liftoff of the 100th Delta 2 rocket and a dual satellite cargo to study the oceans and atmosphere of planet Earth. And the vehicle has cleared the tower.

1507:05 GMT (10:07:05 a.m. EST)

T-minus 30 seconds. Hydraulics and electronics reported go. Launch pad water system has been activated. 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 engines and first stage main engine start. The three solid rocket motors then light at T-0 for liftoff.

1506:35 GMT (10:06:35 a.m. EST)

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.

1506:05 GMT (10:06:05 a.m. EST)

T-minus 90 seconds. At the telemetry receiving areas where data from the rocket will be transmitted the data recording charts have gone to high speed.

1505:35 GMT (10:05:35 a.m. EST)

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.

And the final "go for launch" has been received from the spacecraft management team.

1504:35 GMT (10:04:35 a.m. EST)

T-minus 3 minutes and counting. The safety destruct safe and arm devices are being armed.

1503:35 GMT (10:03:35 a.m. EST)

T-minus 4 minutes and counting. Now in the final phase of the countdown the Delta 2 rocket's systems begin transferring to internal power for launch.

Launch of the Jason 1 and TIMED spacecraft remains set to occur at 1507:35 GMT from SLC-2 West at Vandenberg Air Force Base in California. No problems are standing in the way of the 289th Delta rocket launch, the 100th for a Delta 2 and seventh and final of 2001.

1502:35 GMT (10:02:35 a.m. EST)

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. And the TIMED spacecraft has been verified to be in its correct launch configuration.

1601 GMT (10:01 a.m. EST)

The TIMED spacecraft is now switching off ground power and switching to internal battery power for launch.

1559 GMT (9:59 a.m. EST)

The Boeing launch team has been polled by the Launch Conductor. Again, all systems were confirmed "go" for today's 1507:35 GMT liftoff.

1558 GMT (9:58 a.m. EST)

Now half-way through this 10-minute built-in hold.

1457 GMT (9:57 a.m. EST)

NASA Launch Manager Chuck Dovale has polled his team for a final "go" for liftoff. No problems were reported. Polls of the Boeing launch team and mission management are still to come.

1455 GMT (9:55 a.m. EST)

The Jason spacecraft has been verified ready for launch. It is on internal power for flight. The TIMED satellite will switch to internal power at launch-minus six minutes.

1453:35 GMT (9:53:35 a.m. EST)

T-minus 4 minutes and holding. The countdown has entered the final planned hold. This is a planned 10-minute hold leading to today's liftoff time of 1507:35 GMT (10:07:35 a.m. EST; 7:07:35 a.m. PST).

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

At this point there are no problems being reported and weather remains "go" for launch. The upper level winds are also acceptable today.

1448 GMT (9:48 a.m. EST)

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

1447:35 GMT (9:47:35 a.m. EST)

T-minus 10 minutes and counting. The countdown is heading to T-minus 4 minutes for a 10-minute hold. Liftoff the Boeing Delta 2 rocket from Vandenberg Air Force Base is still slated to occur at 1507:35 GMT with the Jason 1 and TIMED science satellites.

For this launch, Boeing is using a model 7920-10 Delta 2 rocket. The expendable launch vehicle consists of two stages, nine strap-on solid rocket boosters and a 10-foot diameter payload fairing. The rocket stands 126 feet tall. See our rocket fact sheet for more.

1443 GMT (9:43 a.m. EST)

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 and malfunction during the launch.

1439 GMT (9:39 a.m. EST)

The Jason 1 oceanography spacecraft atop the Boeing Delta 2 rocket is now switching from the ground-fed power supply to its internal batteries for launch. Liftoff is now 28 minutes away.

1437:35 GMT (9:37:35 a.m. EST)

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 for 1507:35 GMT.

1433 GMT (9:33 a.m. EST)

The Boeing Launch Conductor has polled the launch team for a "go" to pick up the countdown as planned. No problems were announced. Clocks are set to resume in four minutes.

1430 GMT (9:30 a.m. EST)

NASA Launch Manager Chuck Dovale just polled his team to verify the space agency is "go" to continue with the countdown. No one reported any problems, including the Jason 1 and TIMED team members.

There are no technical issues with the rocket or payloads being addressed and the team is simply waiting for the countdown clock to resume at 1437 GMT as scheduled.

1427:35 GMT (9:27:35 a.m. EST)

Now half-way through this 20-minute built-in hold in the countdown. The sun is just beginning to rise at Vandenberg Air Force Base, California. Although windy, it is a beautiful morning at the launch site with just a few high clouds, unrestricted visibility and a temperature of 59 degrees F.

1422 GMT (9:22 a.m. EST)

The Launch Weather Officer has just provided another update to mission managers. A wind gust was recently seen at 32 knots, but that is still below the current launch limit of 34 knots. The launch time forecast is now calling for winds from the northeast at 18 gusting to 25 knots. There is a 30 percent chance the winds will prohibit today's launch.

1417:35 GMT (9:17:35 a.m. EST)

T-minus 20 minutes and holding. The countdown has entered into the first of two planned hold periods during the last 20 minutes of the Terminal Count for today's 1507:35 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. At this point, the countdown is reported to be going well with no significant technical problems.

Engineers have just completed gimbal checks of the nozzles on the first stage main engine and twin vernier engines and second stage engine. This test is performed to ensure the engines will be able to steer the rocket during launch.

The latest check on the ground winds indicates conditions remain within limits for launch. The winds this morning have shifted to a more northeasterly direction, which allows for a higher limit for launch. Winds are currently blowing at around 25 knots, below the limit of 34 knots. Should the winds become more easterly, the limit is 23 knots.

1407:35 GMT (9:07:35 a.m. EST)

Now exactly one hour from the scheduled liftoff time for the Boeing Delta 2 rocket from Space Launch Complex 2-West at Vandenberg Air Force Base along the central coastline of California. The base is located about 140 miles northwest of Los Angeles.

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

1352 GMT (8:52 a.m. EST)

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 1507:35 GMT today for the Boeing Delta 2 rocket.

The P-3 Orion instrumented aircraft has arrived in its position over the Pacific Ocean to the southwest of Vandenberg for relaying data from the Delta rocket back to the launch site during the first firing of the second stage. The final portion of burn will occur as the rocket heads out of range from the Vandenberg tracking station.

In fact, there are several other ground sites around the world that will support data relay today during the two-hour, five-minute mission that will include several firings of the upper stage and deployment of Jason 1 and TIMED.

1352 GMT (8:52 a.m. EST)

The launch team reports the loading of the Delta 2 rocket's first stage liquid oxygen tank has been completed. The tank will be replenished through the remainder of the countdown to replace the liquid oxygen that naturally boils away.

The rocket is now fully fueled for launch today at 1507:35 GMT (7:07 a.m. PST; 10:07 a.m. EST) from Vandenberg Air Force Base in California to deliver the Jason 1 and TIMED satellite payloads into space.

The vehicle's first stage was successfully loaded with RP-1 kerosene fuel along with the liquid oxygen this morning. The second stage was loaded with its storable nitrogen tetroxide and Aerozine 50 fuels on Tuesday; and the nine strap-on booster rockets are solid-propellant.

There are no technical problems being reported by the launch team, the weather forecast is favorable and the countdown remains on schedule.

1345 GMT (8:45 a.m. EST)

First stage liquid oxygen tanking continues smoothly. The "rapid load" phase of filling the tank will continue to the 95-percent level before the slower "fine load" takes over to reach the 99-percent mark.

Meanwhile, activities to turn on the Delta rocket's Redundent Inertial Flight Control Assembly guidance computer, or RIFCA, have been completed.

1334 GMT (8:34 a.m. EST)

Now about 10 minutes into this approximate 25-minute process to fill the first stage liquid oxygen tank.

The latest launch weather forecast calls for unrestricted visibility, a few cirrus clouds at 25,000 feet with 1/8ths sky coverage and tops at 27,000 feet and a temperature of 59 degrees F.

1326 GMT (8:26 a.m. EST)

Cryogenic liquid oxygen, chilled to Minus-298 degrees F, is now 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 along with RP-1 kerosene loaded aboard the vehicle a little while ago.

Meanwhile, all of the downrange support stations have reported in and are ready for launch today. Also, the initial check of high-altitude winds indicates favorable conditions.

1322 GMT (8:22 a.m. EST)

Activities to load the first stage liquid oxygen tank is now underway as the countdown continues for liftoff at 1507:35 GMT today.

1311 GMT (8:11 a.m. EST)

The NASA launch management team has been polled and given its "go" to begin loading the rocket's first stage liquid oxygen tank.

An update briefing from the Launch Weather Officer reports that winds are currently at 19 gusting to 24 knots from the northeast. From this specific direction, the launch time limit is 34 knots. If the winds become more easterly, the limit is 23 knots.

Earlier this morning the winds topped out at 44 knots. But those conditions have eased over the past 90 minutes or so.

Overall, there is now a 70 percent chance of acceptable launch weather today. The concern is, you guessed it, the winds.

1230 GMT (7:30 a.m. EST)

The first stage fuel tank of the Boeing Delta 2 rocket has been fully loaded with nearly 10,000 gallons of a highly refined kerosene, called RP-1, for today's planned 1507:35 GMT liftoff from Vandenberg Air Force Base in California.

With the extra weight, the Delta 2 can now safely withstand 48 knots winds on the launch pad, an increase in the limit from 43.3 knots when the rocket was not fueled.

The winds, however, are now significantly less than that. The latest check indicated winds at 28 knots.

In a worst-case scenario, high winds could topple the unbolted Delta 2 rocket off the launch pad.

1207:35 GMT (7:07:35 a.m. EST)

The Terminal Countdown has begun for today's launch of Boeing Delta 2 rocket with the Jason 1 oceanography satellite and TIMED atmospheric research spacecraft. Liftoff remains scheduled for 1507:35 GMT (10:07:35 a.m. EST; 7:07:35 a.m. PST) from Vandenberg Air Force Base in California, weather permitting.

The winds are really kicking up along California's Central Coast this morning. The forecast had not predicted such gusty winds, so officials have ordered the rocket's first stage be fueled early to give the vehicle more weight. The early fueling will allow the rocket's safety limit for high winds winds to be raised slightly, however that does not change the limit for launch. The winds are currently around 31 knots, but "trending" downward, the Launch Weather Officer reports.

The countdown is being controlled from the "soft blockhouse" located about 8 miles from the Space Launch Complex-2 West pad. Senior launch officials are stationed in the Mission Directors Center located on South Base of Vandenberg, a good distance from the pad.

With the countdown underway, the activities planned over the next hour include clearing the hazard danger area, activating the rocket's Redundant Inertial Flight Control Assembly guidance computer, pressurizing the first and second stage helium and nitrogen systems and second stage fuel tanks and checking the C-band tracking beacon on the rocket.

The loading of RP-1 kersone fuel into the rocket's first stage continues at this time. This operation will be followed by loading of super-cold liquid oxygen at 1322 GMT (8:22 a.m. EST; 5:22 a.m. PST).

Overnight, the 177-foot tall mobile service tower was wheeled back from around the rocket and the fully assembled Delta 2 was exposed for launch. The gantry is used to stack the vehicle and provides the primary weather protection and access to the rocket during its stay on the oceanside complex.

1201 GMT (7:01 a.m. EST)

The loading of RP-1 fuel into the Boeing Delta 2 rocket's first stage is now underway at Vandenberg Air Force Base for today's launch attempt. The early fueling will allow the wind safety limit for the rocket be raised slightly, however that does not change the limit for launch. The winds are currently around 31 knots, but "trending" downward, the Launch Weather Officer just reported.

1155 GMT (6:55 a.m. EST)

The Boeing engineering team has recommended loading the RP-1 fuel, a highly refined kerosene, into the Delta 2 rocket's first stage earlier than planned in an effort to weight down the vehicle on the launch pad. This will make the vehicle more stable and allow the ground wind safety limit to be raised a bit.

In a worst-case scenario, high winds could topple the unbolted Delta 2 rocket off the launch pad.

1140 GMT (6:40 a.m. EST)

It is launch day for the Boeing Delta 2 rocket carrying the Jason 1 and TIMED spacecraft. However, the winds at Vandenberg Air Force Base are much higher this morning than forecast, prompting officials to discuss whether to proceed with the countdown.

Over the past hour or so, winds have been seen above 30 knots, with a gust recorded at 43 knots, NASA Launch Manager Chuck Dovale reports. The limit for launch is 23 knots if from the easterly direction.

Not only is this a constraint to launch, but managers also want to ensure the safety of the rocket is risked by the high winds.

THURSDAY, DECEMBER 6, 2001

A spacecraft that will make global measurements of Earth's oceans for climate research and a satellite designed to study a mysterious region of the atmosphere are scheduled for launch into space Friday atop a Boeing Delta 2 rocket.

The Jason 1 and TIMED spacecraft will ride the 100th Delta 2 in a mission from Vandenberg Air Force Base in California. Liftoff is planned for 1507:35 GMT (10:07:35 a.m. EST; 7:07:35 a.m. PST), the optimum launch time for placement of Jason into its orbit.

The weather forecast is near-perfect with a 90 percent chance of acceptable launch conditions. The only slight concern is ground winds violating the 23-knot limit.

The launch time conditions are expected to include cirrus clouds at 25,000 feet with just 2/8ths sky coverage, unrestricted visibility, winds of 15 to 20 knots and a temperature of 48 to 50 degrees F.

Prelaunch activities were to get underway Thursday evening with a weather briefing at 0200 GMT (9 p.m. EST) and the retraction of the mobile service tower from around the rocket at the Space Launch Complex-2 West pad by 0600 GMT (1 a.m. EST). Pad securing work will continue overnight in preparation for starting the Terminal Countdown at 1207:35 GMT (7:07:35 a.m. EST) from the T-minus 150 minute mark. Two built-in holds are planned during count. The first will occur at T-minus 20 minutes for a duration of 20 minutes; the second happens at T-minus 4 minutes and should last 10 minutes.

For a complete preview of the events that will occur during the two-hour, five-minute launch, overviews of the Delta 2 rocket, both satellite payloads and the SLC-2W pad, see the links in the right-hand column of this page.

We will provide complete live coverage throughout Friday's countdown and the entire flight of the Delta. Watch this page!

WEDNESDAY, DECEMBER 5, 2001

Launch of the Boeing Delta 2 rocket with the Jason 1 and TIMED spacecraft remains on scheduled for Friday. Officials held the Launch Readiness Review today and gave approval for activities to continue for the mission.

There was one minor issue discussed today involving outgasing inside the rocket's nose cone. However, the issue is not considered a problem and engineers formally put the topic to rest by late in the day.

The weather forecast for Friday's 1458:35 to 1518:35 GMT (9:58:35 to 10:18:35 a.m. EST) launch window calls for a 90 percent chance of acceptable conditions.

Meteorologists say there will be just some high-level clouds at 25,000 feet, unrestricted visibility, northeasterly winds at 15 to 20 knots and a temperature of 51 degrees F.

We will have a complete mission preview available on Thursday. And watch this page for live coverage of the countdown and launch.

TUESDAY, DECEMBER 4, 2001

The 100th Delta 2 rocket is awaiting launch on Friday to deliver two Earth-research satellites into orbit from Vandenberg Air Force Base in California.

The Boeing-built booster is scheduled for liftoff during launch windows of either 1458:35 to 1507:35 GMT (9:58:35 to 10:07:35 a.m. EST) or 1509:35 to 1518:35 GMT (10:09:35-10:18:35 a.m. EST) from Space Launch Complex-2 West.

The rocket will fly a complex two-hour, five-minute flight to place its two payloads into two distinctly different orbits around Earth. A barrel-like "Dual Payload Attach Fitting" will be used to stack the two satellites within the rocket's nose cone.

First, the French/American oceanography satellite, called Jason 1, will be released into an orbit about 722 nautical miles above the Earth inclined 66 degrees to the equator.

The upper stage engine will then perform two additional firings to lower the altitude while raising the inclination to deploy NASA's Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) atmospheric research satellite into a 340 nautical mile orbit inclined 74.1 degrees.

Preparations remain on track for the launch, which will be the seventh and final Delta mission of 2001. On Tuesday, workers loaded the rocket's second stage with storable propellants and the launch team conducted a mission dress rehearsal.

Jason 1 is being launched to replace the aging Topex/Poseidon spacecraft that provides precise measurements of ocean surface heights -- the data needed to monitor world ocean circulation and improve climate predictions.

"Jason 1 will be a tremendous asset to our oceanography program. It will build upon the research and development efforts done so successfully on Topex/Poseidon, adding operational utility and function," said Dr. Ghassem Asrar, associate administrator for NASA's Earth Science Enterprise, NASA Headquarters, Washington, D.C.

TIMED aims to study the least explored region of Earth's atmosphere -- the Mesosphere and Lower Thermosphere/Ionosphere, or MLTI. The area extends from 40 to 110 miles above the planet.

The MLTI has been virtually impossible for scientists to study because it's too high for most airplanes and balloons, yet too low for satellites to fly through and probe.

So TIMED will carry four instruments to remotely measure the composition, temperature and winds of the region, as well as the solar ultraviolet irradiance and emitted infrared light.

"It is imperative that we learn more about the dynamics of the MLTI because the Sun's energy often has profound effects on the areas directly above and below this region," said Sam Yee, TIMED project scientist at The Johns Hopkins University Applied Physics Laboratory. "With TIMED, scientists will be able to develop better predictive models of space weather's effects on communications, satellite tracking, spacecraft lifetimes and degradation of spacecraft materials."

The Delta 2 rocket debuted on February 14, 1989 when it launched a NAVSTAR Global Positioning System military navigation satellite. Since then, the vehicle has completed a total of 97 successful flights in 99 tries.

The users of the medium-lift launcher have varied between government and commercial customers.

On the government side, some 38 missions were flown for the U.S. military, including 35 GPS launches, 22 missions were performed for NASA to deploy various science spacecraft including five Mars probes, and one flight was dedicated to the U.S. National Reconnaissance Office, the government agency that operates the country's spy satellite fleet.

Delta 2 has flown 38 purely commercial flights, including 11 to deploy Iridium satellite telephone satellites and 7 for the rival Globalstar network.

To date, 80 of the Delta 2 launches have occurred from Cape Canaveral Air Force Station in Florida and the other 19 from Vandenberg Air Force Base in California.

We will have comprehensive coverage of Friday's countdown and launch with play-by-play updates on this page.