BY JUSTIN RAY

Follow the countdown and launch of the Boeing Delta 2 rocket with five replacement satellites for the Iridium communications system. Reload this page for the very latest on the mission. Use our text only page for faster downloads.

MONDAY, FEBRUARY 11, 2002

Five new satellites that will help keep the resurrected Iridium mobile communications system operating through the decade rode into space Monday aboard a Boeing Delta 2 rocket. Read our full launch story.

1908 GMT (2:08 p.m. EST)

T+plus 85 minutes, 5 seconds. SPACECRAFT SEPARATION! The fifth and final Iridium satellite carried into space today by the Boeing Delta 2 rocket has been deployed into orbit. This completes the 101st launch of a Delta 2 vehicle and the 12th dedicated to the Iridium mobile communications satellite network.

These five new satellites will serve as orbiting spares for the Iridium system. When a primary Iridium satellite should fail in the future, one of these spares will then enter the constellation and fill the hole.

This completes our live launch coverage. We will post a full wrap-up story later today.

For our Spaceflight Now Plus subscribers, here are some movies of this Delta 2 launch:

Video coverage for subscribers only:

   VIDEO: BOEING DELTA 2 ROCKET BLASTS OFF QT or RV
   VIDEO: INCREDIBLE AERIAL VIEW OF LAUNCH QT or RV
   VIDEO: INFRARED CAMERA VIEW OF ROCKET STAGING QT or RV
   VIDEO: ANIMATION PREVIEW OF THIS DELTA 2 FLIGHT QT or RV
   VIDEO: PRE-LAUNCH PREPARATIONS OF ROCKET QT or RV
   MORE: COMPLETE SFN+ VIDEO INDEX

1904 GMT (2:04 p.m. EST)

T+plus 81 minutes. SPACECRAFT SEPARATION! The fourth Iridium satellite has been released from the dispenser on the second stage of the Boeing Delta 2 rocket.

1902 GMT (2:02 p.m. EST)

T+plus 79 minutes. The Thule tracking station in Greenland is next to acquire the rocket's signal as it travels around the world during today's launch of five Iridium satellites. Three of the spacecraft have been released. The final two are due to release over the next six minutes.

1900 GMT (2:00 p.m. EST)

T+plus 77 minutes. SPACECRAFT SEPARATION! The third Iridium satellite has been released from the Delta 2 rocket.

Two more spacecraft are left to deploy -- at about T+plus 80 minutes, 50 seconds and T+plus 85 minutes.

1857 GMT (1:57 p.m. EST)

T+plus 73 minutes, 30 seconds. SPACECRAFT SEPARATION! Boeing reports the second Iridum satellite has been been deployed from the Delta 2 rocket.

The next satellite is due to separate at about T+plus 76 minutes, 40 seconds.

1854 GMT (1:54 p.m. EST)

T+plus 71 minutes. The Kiruna tracking station in Sweden will be acquiring the signal from the Delta rocket in about one minute to relay data back to Boeing engineers to confirm deployment of the second Iridium satellite. Satellite separation is expected at about T+plus 72 minutes, 30 seconds.

1850 GMT (1:50 p.m. EST)

T+plus 67 minutes. Boeing engineers report the orbit of the first Iridium satellite is 345.8 by 343.3 nautical miles, which is near-perfect.

The second stage should be reorienting itself at this time in preparation for deployment of the second satellite, which is expected in about five minutes. The stage will perform a reorientation maneuver before deploying each satellite.

1847 GMT (1:47 p.m. EST)

T+plus 64 minutes. SPACECRAFT SEPARATION! Confirmation has been received that the first of five Iridium satellites has been released from the Boeing Delta 2 rocket's second stage following launch today from Vandenberg Air Force Base, California.

The four remaining spacecraft will be deployed over the next 21 minutes.

1846 GMT (1:46 p.m. EST)

T+plus 63 minutes. The first Iridium spacecraft should have been deployed by this point. However, Boeing engineers do not have enough data to confirm that yet.

1842 GMT (1:42 p.m. EST)

T+plus 59 minutes. SECO 2. Confirmation has been received that the second stage engine shut down following the second firing of this launch, completed the powered phase of flight to deliver the Iridium satellites into low-Earth orbit.

The five satellites will deploy individually from a special dispenser mounted atop the Delta 2 rocket's second stage. Separation times are approximately T+plus 62 minutes, 72, 76, 80 and 85 minutes

1842 GMT (1:42 p.m. EST)

T+plus 58 minutes, 30 seconds. Second stage restart has occurred. The liquid-fueled engine is firing again for an approximate 16-second burn to raise and circularize the current orbit in preparation for deployment of the five Iridium satellites.

1841 GMT (1:41 p.m. EST)

T+plus 57 minutes. Coming up on restart of the second stage in one minute.

1837 GMT (1:37 p.m. EST)

T+plus 54 minutes. The Delta 2 continues in its normal coast mode. Good data is being received via the Malindi tracking station in Kenya, Africa.

1823 GMT (1:23 p.m. EST)

T+plus 40 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 health of the vehicle. The Malindi site in Kenya will then acquire to cover the second stage engine restart, which is 18 minutes away.

1812 GMT (1:12 p.m. EST)

T+plus 29 minutes. The quiet coast period continues for the Delta 2 rocket and five Iridium satellites onboard. You can see what is left to come, including restart of the second stage and deployment of the spacecraft, on our launch timeline page.

1803 GMT (1:03 p.m. EST)

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

1755 GMT (12:55 p.m. EST)

T+plus 11 minutes, 30 seconds. The second stage engine has shut down as planned. The Delta 2 rocket with the Iridium satellites 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 58 minutes, 36 seconds.

1754 GMT (12:54 p.m. EST)

T+plus 10 minutes, 30 seconds. About one minute left in this first firing of the Delta 2's second stage.

1752 GMT (12:52 p.m. EST)

T+plus 8 minutes, 30 seconds. Smooth flight continues for the Delta 2 rocket with the five Iridium satellites.

1750 GMT (12:50 p.m. EST)

T+plus 6 minutes, 30 seconds. Second stage engine continues to fire normally.

1749 GMT (12:49 p.m. EST)

T+plus 5 minutes, 40 seconds. Altitude is 82 miles, downrange distance 410 miles, velocity 11,900 miles per hour.

1748 GMT (12:48 p.m. EST)

T+plus 5 minutes. The protective payload fairing enclosing the five Iridium satellites atop the rocket has separated with no recontact detected.

1748 GMT (12:48 p.m. EST)

T+plus 4 minutes, 41 seconds. Second stage engine ignition has been confirmed.

1748 GMT (12:48 p.m. EST)

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

1747 GMT (12:47 p.m. EST)

T+plus 4 minutes. Coming up on staging.

The official liftoff time was 1743:44.382 GMT.

1746 GMT (12:46 p.m. EST)

T+plus 3 minutes. The first stage main engine and twin vernier thrusters are performing normally. Altitude is 38 miles, downrange distance 59 miles.

1746 GMT (12:46 p.m. EST)

T+plus 2 minutes, 15 seconds. All three air-lit solid rocket boosters have burned out and jettisoned.

1745 GMT (12:45 p.m. EST)

T+plus 1 minute, 40 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.

1744 GMT (12:44 p.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.

1744 GMT (12:44 p.m. EST)

T+plus 50 seconds. Now passing through the area of maximum aerodynamic dynamic pressure on the rocket as it climbs into the dense lower altitudes.

1744 GMT (12:44 p.m. EST)

T+plus 35 seconds. The Delta rocket is now supersonic, traveling more than 700 miles per hour.

1744 GMT (12:44 p.m. EST)

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

1743:44 GMT (12:43:44 p.m. EST)

LIFTOFF! Liftoff of the Boeing Delta 2 rocket -- boosting five backup spacecraft into orbit for the Iridium mobile communications satellite constellation. And the vehicle has cleared the tower.

1743:14 GMT (12:43:14 p.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 six solid rocket motors then light at T-0 for liftoff.

1742:44 GMT (12:42:44 p.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. Also, the first stage liquid oxygen tank is being topped off at 100 percent.

1742:14 GMT (12:42:14 p.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.

1741:44 GMT (12:41:44 p.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.

1741:14 GMT (12:41:14 p.m. EST)

T-minus 2 minutes, 30 seconds and counting. The five Iridium satellites atop the Delta 2 rocket have switched to internal power. And the final "go for launch" has been received from the spacecraft management team.

1740:44 GMT (12:40:44 p.m. EST)

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

1739:44 GMT (12:39:44 p.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.

This 12th launch of the Iridium satellites aboard a Delta 2 rocket remains set to occur at 1743:44 GMT from SLC-2 West at Vandenberg Air Force Base in California.

Again, the Air Force-controlled Range reported in the last few minutes that the solid rocket booster nozzle cover impact area was no longer a safety concern, clearing the way for liftoff.

1738:44 GMT (12:38:44 p.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 today.

1737 GMT (12:37 p.m. EST)

Range is GO! The nozzle cover is has been resolved, safety officials just announced.

1736 GMT (12:36 p.m. EST)

The rocket launch team has been polled with no problems reported. Still waiting final word from Range Safety.

1734:44 GMT (12:34:44 p.m. EST)

Now half-way through this 10-minute built-in hold. Range remains "no go" for launch. Standing by for the poll of the launch team.

1731 GMT (12:31 p.m. EST)

Range reports it is "no go" for launch due to the solid rocket booster nozzle cover constraint. The three boosters strapped to the base of the Delta 2 rocket that are ignited about a minute into launch have covers over their nozzles for protection during the initial portion of flight. Those covers are ejected as the motors are lit and can fall on Vandenberg Air Force Base depending winds and other factors. Computer models show that the covers could land on the beach near the Titan launch pads south of the Delta's launch site.

1729:44 GMT (12:29:44 p.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 1743:44 GMT (12:43:44 p.m. EST).

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.

We're still waiting to get a final update from Range Safety on the solid rocket booster nozzle impact zone, which had been predicted earlier to potentially fall in populated areas.

The Delta 2 rocket is in good shape for launch and weather conditions are favorable at Vandenberg Air Force Base in California for today's liftoff.

1725 GMT (12:25 p.m. EST)

The vent of the first stage RP-1 fuel tank is being closed and the tank is being pressurized for launch.

1723:44 GMT (12:23:44 p.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 1743:44 GMT with five satellites to serve as orbiting spares for the Iridium mobile communications network, which provides telephone, data and paging services to subcribers anywhere on the planet.

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 127 feet tall. See our rocket fact sheet for more.

1720 GMT (12:20 p.m. EST)

Inhibited checks are 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.

1713:44 GMT (12:13:44 p.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 1743:44 GMT.

1710 GMT (12:10 p.m. EST)

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

There is one issue -- with the liquid oxygen fill and drain valve -- that the launch team has been discussing. It does not appear to be a big concern. Engineers will need to verify the valve is closed at T-minus 15 seconds or else call an abort.

1703:44 GMT (12:03:44 p.m. EST)

Now half-way through this 20-minute built-in hold in the countdown.

Range Safety's checks of the computer models, based on today's wind conditions and other factors, show that the nozzle covers from the air-lit solid rocket boosters will land on the beach to the west of the Titan rocket launch pads at Space Launch Complex 4. However, the modeling will be re-computed as the countdown continues.

The nozzle covers from the air-lit solid rocket motors, which are ignited a minute into flight, are always a concern for Delta launches from Vandenberg. The Delta pad is positioned on the north part of the base and the rocket heads south to polar orbit along the Vandenberg coastline where the Titan, Atlas and SLC-6 pads are located.

Meanwhile, the launch weather officer reports the forecast has been improved to a 90 percent chance of acceptable conditions. The only slight concern is surface winds.

1653:44 GMT (11:53:44 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 precise 1743:44 GMT launch time. 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 with the rocket or spacecraft.

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.

1643:44 GMT (11:43:44 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 half-way between Los Angeles and San Francisco.

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.

1633:44 GMT (11:33:44 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 1743:44 GMT today for the Boeing Delta 2 rocket.

1624 GMT (11:24 a.m. EST)

The launch team reports the loading of the Delta 2 rocket's first stage liquid oxygen tank was completed at 1623:46 GMT for a duration for 23 minutes and 47 seconds. 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 1743:44 GMT (12:43:44 p.m. EST; 9:43:44 a.m. PST) from Vandenberg Air Force Base in California to deliver five Iridium replacement satellite payloads into space. There are no technical problems being reported with the rocket or payload, and the weather is looking promising.

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 last Tuesday; and the nine strap-on booster rockets are solid-propellant.

1610 GMT (11:10 a.m. EST)

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

Also in the countdown the launch team has completed the work to turn on the rocket's guidance computer.

1600 GMT (11:00 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 during the first four-and-a-half minutes of flight along with the nearly 10,000 gallons of RP-1 kerosene loaded aboard the vehicle during the past hour.

1545 GMT (10:45 a.m. EST)

The Air Force launch weather officer has just briefed managers on current and forecast conditions for today's launch of the Boeing Delta 2 rocket. At the 1743 GMT liftoff time today there is now an 80 percent chance of meeting the launch weather rules. The 20 percent concern is for ground winds. Conditions are acceptable at the moment.

The conditions are expected to include cirrus clouds at 30,000 to 32,000 feet with 3/8ths sky coverage, unrestricted visibility, winds from east-southeast at 10 to 15 knots and a temperature in the upper 50s to lower 60s F.

1528 GMT (10:28 a.m. EST)

The first stage fuel tank of the Boeing Delta 2 rocket has been fully loaded for today's planned 1743:44 GMT (12:43:44 p.m. EST; 9:43:44 a.m. PST) liftoff from Vandenberg Air Force Base in California. The tank was loaded with 9,996 gallons of a highly refined kerosene, called RP-1, during a 20-minute, 9-second process today that concluded at 1528:01 GMT.

The next major task in the countdown will be loading super-cold cryogenic liquid oxygen into the first stage starting at about 1600 GMT.

The countdown continues smoothly this morning with no significant problems being worked. The weather is also currently acceptable at Vandenberg.

1525 GMT (10:25 a.m. EST)

The first stage fuel tank has been loaded with 9,000 gallons so far. Once the tank is filled with 9,796 gallons, or 98 percent, the "rapid load" valve will be closed and the slower "fine load" phase will top off the tank to 9,996 gallons for launch.

1521 GMT (10:21 a.m. EST)

The launch team has computed that the full load for the first stage fuel tank is 9,996 gallons. Over 7,000 gallons are already aboard.

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

Now about six minutes into this approximate 20-minute process to load the rocket's first stage with about 10,000 gallons of refined kerosene. Just over 3,000 gallons have been loaded to this point.

Called RP-1, the propellant will be guzzled along with liquid oxygen (to be pumped into the rocket a little later this morning) by the first stage Rocketdyne RS-27A main engine and twin vernier steering thrusters during the initial four-and-a-half-minutes of flight.

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

Fueling of the Delta 2 rocket's first stage is now underway. Nearly 10,000 gallons of a highly refined kerosene fuel, called RP-1, are being pumped into the rocket from a 15,000-gallon storage tank at the Space Launch Complex 2-West pad.

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

The sensors that were in the spotlight yesterday have all indicated "dry" conditions this morning as expected.

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

As scheduled at this point in the countdown, the Boeing launch team is beginning the steps to prepare for loading the Delta 2 rocket's first stage RP-1 fuel tank. After verifying valves, sensors, flow meters and equipment are ready, the highly refined kerosene fuel will start flowing into the vehicle.

It was at this point yesterday that one of three fuel depletion sensors on the first stage tank was found to be faulty. The sensors detect when the tank is emptied of fuel, thus telling the rocket's onboard computer when to shut down the main engine during launch.

Following the scrub and subsequent troubleshooting, officials decided all three sensors should be replaced. That work was completed last evening.

1443:44 GMT (9:43:44 a.m. EST)

The Terminal Countdown has begun for today's launch of Boeing Delta 2 rocket with five replacement satellites for the orbiting Iridium mobile communications network. Liftoff remains scheduled for 1743:44 GMT (12:43:44 p.m. EST; 9:43:44 a.m. PST) from Space Launch Complex-2 West at Vandenberg Air Force Base in California.

The weather is currently acceptable at the launch site.

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 verifying the hazard danger area is cleared, 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 will begin in about 20 minutes. This operation will be followed by loading of super-cold liquid oxygen at about 1600 GMT (11 a.m. EST; 8 a.m. PST).

1436 GMT (9:36 a.m. EST)

The launch team has been polled by the Boeing Launch Conductor to ensure everyone is on console and all systems are ready to start the Terminal Countdown. There were no problems reported. Today's liftoff is scheduled for 1743:44 GMT (12:43:44 p.m. EST; 9:43:44 a.m. PST).

1428 GMT (9:28 a.m. EST)

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

1330 GMT (8:30 a.m. EST)

It is launch day, try number 4, for this 12th flight of Iridium mobile communications satellites aboard a Boeing Delta 2 rocket. The countdown activities are well underway at Vandenberg Air Force Base's Space Launch Complex 2-West in California.

Overnight, the 177-foot tall mobile service tower at the Space Launch Complex 2-West pad was wheeled back from around the rocket. 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.

Liftoff remains scheduled for 1743:44 GMT (12:43:44 p.m. EST; 9:43:44 a.m. PST) today.

0230 GMT (9:30 p.m. EST Sun.)

Boeing will try again Monday to launch the Delta 2 rocket and five Iridium satellites from Vandenberg Air Force Base in California.

Technicians have removed and replaced all three fuel sensors, cables and associated electronics for the rocket's first stage propellant tank, the company says.

Testing of the new equipment is now underway at the Space Launch Complex 2-West launch pad. Assuming the checkout goes well, the countdown will be started early Monday for liftoff at 1743:44 GMT (12:43:44 p.m. EST; 9:43:44 a.m. PST).

The weather forecast calls for a 90 percent chance of favorable conditions for the five-second launch window. Air Force meteorologists are calling for just a few clouds at 25,000 feet, unrestricted visibility, east-southeasterly winds at 10 to 15 knots and a temperature of 60 to 64 degrees F.

Watch this page for live updates throughout the countdown and launch.

For our Spaceflight Now Plus subscribers, here are two movies to preview this Delta 2 launch:

Video coverage for subscribers only:

   VIDEO: ANIMATION PREVIEW OF THIS DELTA 2 FLIGHT QT or RV
   VIDEO: PRE-LAUNCH PREPARATIONS OF ROCKET QT or RV
   MORE: COMPLETE SFN+ VIDEO INDEX

Read our earlier status center coverage.