BY JUSTIN RAY

Follow the countdown and launch of the Delta 2 rocket with first COSMO-SkyMed radar imaging satellite for Italy. Reload this page for the very latest on the mission.

0403 GMT (12:03 a.m. EDT; 9:03 p.m. PDT)

T+plus 89 minutes. The fuel depletion burn by the second stage just occurred, bringing to a close the flight of the ULA Delta 2 rocket.

This firing by the rocket engine used up the remaining propellant to safe the stage until its eventual natural re-entry into the atmosphere. Such depletion maneuvers are performed because excess fuel left in rockets can cause explosions resulting giant clouds of dangerous space debris.

0351 GMT (11:51 p.m. EDT; 8:51 p.m. PDT)

T+plus 77 minutes. The second stage has successfully completed the burn to move out of the orbital plane of COSMO. This is known as the evasive burn, and it put the rocket into an elliptical orbit of about 339 by 94 miles.

0335 GMT (11:35 p.m. EDT; 8:35 p.m. PDT)

This marks the 73rd consecutive successful flight by a Delta 2 rocket since 1997 and the 126th success overall in the 128-flight history of the workhorse booster dating back to 1989.

It was the second Delta 2 launch of the year. The next flight will send NASA's Dawn spacecraft into the asteroid belt to explore the tiny worlds of Vesta and Ceres. A Delta 2-Heavy booster is scheduled to launch the mission July 7 from pad 17B at Cape Canaveral Air Force Station, Florida.

0332 GMT (11:32 p.m. EDT; 8:32 p.m. PDT)

T+plus 58 minutes, 5 seconds. SPACECRAFT SEPARATION! The COSMO 1 spacecraft has been released from the Delta 2 rocket's second stage, completing today's launch!

Developed by Thales Alenia Space Italia for the Italian Space Agency and the Italian Ministry of Defence, the COSMO-SkyMed system is a dual civilian and military Earth-imaging program that will use a fleet of four satellites to be launched over the next few years. Each spacecraft will be equipped with an X-Band Synthetic Aperture Radar instrument for environmental monitoring, resource management and territorial surveillance.

The COSMO 2 satellite will fly aboard another Delta 2 rocket later this year or early next year.

0331 GMT (11:31 p.m. EDT; 8:31 p.m. PDT)

T+plus 57 minutes. The deployment of COSMO from the Delta second stage is a two-step process. The payload attach fitting's clampband will be released at T+plus 57 minutes, 30 seconds. A set of secondary latches then disengage at T+plus 58 minutes, allowing the satellite to physically separate from the rocket.

The second stage then performs a retro maneuver to back away from COSMO. That will be followed by a firing of the stage's engine to move the rocket further away from the spacecraft and then another firing to deplete the remaining fuel supply as a safety measure.

0330 GMT (11:30 p.m. EDT; 8:30 p.m. PDT)

T+plus 56 minutes. The second stage has achieved the proper orbit with an apogee of 340.97 miles, perigee of 334.725 miles and inclination of 97.86 degrees to the equator. All of those values are right on target.

0327 GMT (11:27 p.m. EDT; 8:27 p.m. PDT)

T+plus 53 minutes, 52 seconds. Confirmation has been received that the orbit adjustment burn was completed as planned over Madagascar.

0327 GMT (11:27 p.m. EDT; 8:27 p.m. PDT)

T+plus 53 minutes, 30 seconds. The second stage engine has ignited for the 12-second firing to propel its 4,200-pound spacecraft payload into the proper polar orbit.

0326 GMT (11:26 p.m. EDT; 8:26 p.m. PDT)

T+plus 52 minutes. The second stage has completed its BBQ roll.

0324 GMT (11:24 p.m. EDT; 8:24 p.m. PDT)

T+plus 50 minutes, 30 seconds. Hartebeesthoek has picked up the rocket's signal as it flies northbound.

0322 GMT (11:22 p.m. EDT; 8:22 p.m. PDT)

T+plus 48 minutes. The second stage will be reigniting its engine for 12 seconds over Madagascar.

0317 GMT (11:17 p.m. EDT; 8:17 p.m. PDT)

T+plus 43 minutes. The next firing by the Delta rocket's second stage is coming up in 10 minutes. The Hartebeesthoek tracking station in South Africa should acquire the rocket in about six minutes. The site will relay the rocket's signal back to Vandenberg to provide confirmation of the second stage burn and release of the COSMO satellite.

0309 GMT (11:09 p.m. EDT; 8:09 p.m. PDT)

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.

0304 GMT (11:04 p.m. EDT; 8:04 p.m. PDT)

T+plus 30 minutes. The rocket is coasting until the second stage restarts its engine at T+plus 53 minutes, 27 seconds for a brief 12-second firing to put the vehicle into a near-circular orbit 340 miles above Earth. Deployment of COSMO from the launch vehicle is expected 58 minutes after liftoff.

0257 GMT (10:57 p.m. EDT; 7:57 p.m. PDT)

T+plus 23 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 19 minutes, 20 seconds and conclude at T+plus 51 minutes, 25 seconds.

0252 GMT (10:52 p.m. EDT; 7:52 p.m. PDT)

T+plus 18 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 a South African ground station a half-hour from now.

0248 GMT (10:48 p.m. EDT; 7:48 p.m. PDT)

T+plus 14 minutes. The Range liftoff time was 0234:00.561 GMT.

0246 GMT (10:46 p.m. EDT; 7:46 p.m. PDT)

T+plus 12 minutes, 5 seconds. SECO 1 now confirmed. The second stage's Aerojet-made engine has completed its initial burn for the launch.

0245 GMT (10:45 p.m. EDT; 7:45 p.m. PDT)

T+plus 11 minutes, 30 seconds. Standing by for confirmation from the P-3 aircraft that the second stage engine shutdown has occurred as planned.

0243 GMT (10:43 p.m. EDT; 7:43 p.m. PDT)

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

0242 GMT (10:42 p.m. EDT; 7:42 p.m. PDT)

T+plus 8 minutes, 30 seconds. A P-3 instrumented aircraft over the Pacific is tracking the rocket's telemetry signal as the Delta flies beyond Vandenberg's horizon.

0241 GMT (10:41 p.m. EDT; 7:41 p.m. PDT)

T+plus 7 minutes, 10 seconds. The Delta 2 rocket is 566 miles south from the launch pad and 100 miles in altitude.

0240 GMT (10:40 p.m. EDT; 7:40 p.m. PDT)

T+plus 6 minutes, 30 seconds. A look at the first stage data indicates good performance.

0240 GMT (10:40 p.m. EDT; 7:40 p.m. PDT)

T+plus 6 minutes. The second stage is firing normally.

0239 GMT (10:39 p.m. EDT; 7:39 p.m. PDT)

T+plus 5 minutes, 30 seconds. The Delta 2 rocket is 80 miles in altitude, 318 miles downrange, traveling over 10,760 mph.

0238 GMT (10:38 p.m. EDT; 7:38 p.m. PDT)

T+plus 4 minutes, 55 seconds. The rocket's nose cone enclosing the spacecraft has been jettisoned.

0238 GMT (10:38 p.m. EDT; 7:38 p.m. PDT)

T+plus 4 minutes, 42 seconds. The Delta's second stage engine has ignited!

0238 GMT (10:38 p.m. EDT; 7:38 p.m. PDT)

T+plus 4 minutes, 38 seconds. MECO. The first stage main engine cutoff is confirmed, and the spent stage has been jettisoned!

0237 GMT (10:37 p.m. EDT; 7:37 p.m. PDT)

T+plus 3 minutes, 55 seconds. The vehicle is 45 miles in altitude, 100 miles downrange from the launch pad and traveling at 7,000 mph.

0237 GMT (10:37 p.m. EDT; 7:37 p.m. PDT)

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

0237 GMT (10:37 p.m. EDT; 7:37 p.m. PDT)

T+plus 3 minutes. The vehicle is 34 miles in altitude, 36 miles downrange from the launch pad and traveling at 3,770 mph.

0236 GMT (10:36 p.m. EDT; 7:36 p.m. PDT)

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

0235 GMT (10:35 p.m. EDT; 7:35 p.m. PDT)

T+plus 1 minute, 35 seconds. The Delta 2 rocket is 15 miles in altitude and 5.3 miles downrange from the launch pad.

0235 GMT (10:35 p.m. EDT; 7:35 p.m. PDT)

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

0235 GMT (10:35 p.m. EDT; 7:35 p.m. PDT)

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

0234 GMT (10:34 p.m. EDT; 7:34 p.m. PDT)

T+plus 50 seconds. The rocket has flown through the area of maximum aerodynamic pressure in the lower atmosphere.

0234 GMT (10:34 p.m. EDT; 7:34 p.m. PDT)

T+plus 15 seconds. Delta 324 has cleared the tower and started maneuvering to its southerly heading for the flight downrange over the Pacific. The vehicle is riding the power of its first stage main engine and the four strap-on boosters.

0234 GMT (10:34 p.m. EDT; 7:34 p.m. PDT)

LIFTOFF! Liftoff of the Delta 2 rocket and COSMO 1 as Italy begins a new era of observing the Earth from space.

0233 GMT (10:33 p.m. EDT; 7:33 p.m. PDT)

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 four ground-lit solid rocket motors then light at T-0 for liftoff.

0233 GMT (10:33 p.m. EDT; 7:33 p.m. PDT)

T-minus 1 minute. The Range has given its final clear-to-launch.

0232 GMT (10:32 p.m. EDT; 7:32 p.m. PDT)

T-minus 80 seconds. First stage liquid oxygen topping to 100 percent is underway.

0232 GMT (10:32 p.m. EDT; 7:32 p.m. PDT)

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

0232 GMT (10:32 p.m. EDT; 7:32 p.m. PDT)

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.

0231 GMT (10:31 p.m. EDT; 7:31 p.m. PDT)

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

0231 GMT (10:31 p.m. EDT; 7:31 p.m. PDT)

T-minus 2 minutes, 45 seconds. Vehicle ordnance is being armed.

0231 GMT (10:31 p.m. EDT; 7:31 p.m. PDT)

T-minus 3 minutes. All remains "go" for launch.

0230 GMT (10:30 p.m. EDT; 7:30 p.m. PDT)

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

0230 GMT (10:30 p.m. EDT; 7:30 p.m. PDT)

T-minus 4 minutes and counting! Clocks are ticking down the final moments for liftoff of Delta 324 with the first COSMO-SkyMed spacecraft. Launch is set for 7:34 p.m. local time from Vandenberg Air Force Base, California.

0229 GMT (10:29 p.m. EDT; 7:29 p.m. PDT)

Now five minutes from launch! The "go" has been given for release of the hold in one minute.

0227 GMT (10:27 p.m. EDT; 7:27 p.m. PDT)

A ULA spokesman says the technical issues appears to be resolved.

0227 GMT (10:27 p.m. EDT; 7:27 p.m. PDT)

Three minutes remaining in this hold.

0225 GMT (10:25 p.m. EDT; 7:25 p.m. PDT)

The launch team readiness poll has been re-performed. All members voiced "ready" to pick up the count, including the launch director.

0223 GMT (10:23 p.m. EDT; 7:23 p.m. PDT)

Some sort of technical problem is being worked by engineers. If the issue can be resolved in time, the launch team will resume the count at 7:30 p.m. for a liftoff at 7:34 p.m. local (10:34 p.m. EDT; 0234 GMT).

0219 GMT (10:19 p.m. EDT; 7:19 p.m. PDT)

NEW LAUNCH TIME. Liftoff has been rescheduled for the end of today's window at 7:34 p.m. local (10:34 p.m. EDT; 0234 GMT). There has been no word on the problem that has forced this delay.

0217 GMT (10:17 p.m. EDT; 7:17 p.m. PDT)

There is no estimate on how long this extended hold will last. The count must resume ticking by 0230 GMT in order for the Delta 2 rocket to launch by the close of today's opportunity at 0234 GMT.

0216 GMT (10:16 p.m. EDT; 7:16 p.m. PDT)

Today's launch window is 13 minutes in length. So this hold can be extended for that amount of time. Otherwise, the launch would have to be delayed until tomorrow.

0215 GMT (10:15 p.m. EDT; 7:15 p.m. PDT)

The launch team was just instructed not to resume the count. Clocks will remain holding at T-minus 4 minutes.

0215 GMT (10:15 p.m. EDT; 7:15 p.m. PDT)

The count is supposed to resume ticking in two minutes. However, the team is awaiting a "go" from the launch director.

0213 GMT (10:13 p.m. EDT; 7:13 p.m. PDT)

All systems are reported "ready" by the launch team. However, the launch director has given a "not ready."

0212 GMT (10:12 p.m. EDT; 7:12 p.m. PDT)

Now half-way through this 10-minute built-in hold. Standing by for the final pre-flight poll of the launch team.

0211 GMT (10:11 p.m. EDT; 7:11 p.m. PDT)

Now 10 minutes from launch of the first COSMO-SkyMed satellite.

Developed by Thales Alenia Space Italia for the Italian Space Agency and the Italian Ministry of Defence, the COSMO-SkyMed system is a dual civilian and military Earth-imaging program that will use a fleet of four satellites to be launched over the next few years. Each spacecraft will be equipped with an X-Band Synthetic Aperture Radar instrument for environmental monitoring, resource management and territorial surveillance.

0207 GMT (10:07 p.m. EDT; 7:07 p.m. PDT)

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 7:21 p.m. local (10:21 p.m. EDT; 0221 GMT) for the Delta 2 rocket with COSMO 1.

During the hold, officials will poll the various team members in the "soft blockhouse," Range Operations Control Center and Mission Directors Center to verify all systems are ready to enter into the final phase of the countdown.

0206 GMT (10:06 p.m. EDT; 7:06 p.m. PDT)

The COSMO 1 spacecraft is undergoing final configuring for launch.

0205 GMT (10:05 p.m. EDT; 7:05 p.m. PDT)

The launch weather officer reports conditions are "go" for liftoff.

0202 GMT (10:02 p.m. EDT; 7:02 p.m. PDT)

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

0156 GMT (9:56 p.m. EDT; 6:56 p.m. PDT)

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 hold is scheduled. Launch remains set to occur on time today at 7:21 p.m. local (10:21 p.m. EDT; 0221 GMT).

0152 GMT (9:52 p.m. EDT; 6:52 p.m. PDT)

The launch team members were just polled. All responded with a "ready" to press ahead with the countdown this evening.

0146 GMT (9:46 p.m. EDT; 6:46 p.m. PDT)

Now half-way through this built-in hold at T-minus 15 minutes. Once the countdown resumes, clocks will tick down to the T-minus 4 minute mark where a 10-minute hold is planned.

0136 GMT (9:36 p.m. EDT; 6:36 p.m. PDT)

T-minus 15 minutes and holding. Clocks have entered the first of two planned hold periods during the final quarter of the Terminal Countdown for today's launch. This pause will last 20 minutes in duration.

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

0132 GMT (9:32 p.m. EDT; 6:32 p.m. PDT)

The first stage engine steering checks are complete.

0128 GMT (9:28 p.m. EDT; 6:28 p.m. PDT)

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

0126 GMT (9:26 p.m. EDT; 6:26 p.m. PDT)

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.

0121 GMT (9:21 p.m. EDT; 6:21 p.m. PDT)

Now one hour away from the scheduled liftoff of the Delta 2 rocket from Space Launch Complex 2 at Vandenberg Air Force Base along the central coastline of California.

Over the next few minutes, the "slew" or steering checks of the first and second stage engines will be performed.

0114 GMT (9:14 p.m. EDT; 6:14 p.m. PDT)

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

0111 GMT (9:11 p.m. EDT; 6:11 p.m. PDT)

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 7:21 p.m. local (10:21 p.m. EDT; 0221 GMT).

0104 GMT (9:04 p.m. EDT; 6:04 p.m. PDT)

Loading of the Delta 2 rocket's first stage liquid oxygen tank was completed at 0104:28 GMT. The operation took 27 minutes and zero seconds today. The tank will be replenished through the countdown to replace the super-cold liquid oxygen that naturally boils away.

The rocket is now fully fueled for launch. The vehicle's first stage was successfully loaded with RP-1 kerosene fuel earlier today. The second stage was filled with its storable nitrogen tetroxide and Aerozine 50 fuels earlier in the week. And the four strap-on booster rockets are solid-propellant.

0057 GMT (8:57 p.m. EDT; 5:57 p.m. PDT)

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.

0052 GMT (8:52 p.m. EDT; 5:52 p.m. PDT)

The bottom of the rocket is icing over as the super-cold liquid oxygen continues to flow into the first stage.

0047 GMT (8:47 p.m. EDT; 5:47 p.m. PDT)

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

0042 GMT (8:42 p.m. EDT; 5:42 p.m. PDT)

The bright white plume of vapors is streaming from a vent on the rocket as the liquid oxygen loading proceeds.

0037 GMT (8:37 p.m. EDT; 5:37 p.m. PDT)

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

0035 GMT (8:35 p.m. EDT; 5:35 p.m. PDT)

The second stage helium and nitrogen system pressurization has been accomplished. And the fuel and oxidizer tanks, which were filled with storable propellants earlier this week, have been pressurized for flight.

0034 GMT (8:34 p.m. EDT; 5:34 p.m. PDT)

The rocket's guidance system activation is reported complete.

0031 GMT (8:31 p.m. EDT; 5:31 p.m. PDT)

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

0020 GMT (8:20 p.m. EDT; 5:20 p.m. PDT)

Mission managers will soon give the approval to start liquid oxygen loading.

0010 GMT (8:10 p.m. EDT; 5:10 p.m. PDT)

All is quiet right now as the countdown continues to tick.

THURSDAY, JUNE 7, 2007
2351 GMT (7:51 p.m. EDT; 4:51 p.m. PDT)

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

2346 GMT (7:46 p.m. EDT; 4:46 p.m. PDT)

First stage pressurization is complete.

2340 GMT (7:40 p.m. EDT; 4:40 p.m. PDT)

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

The early fuel loading was performed to give the rocket added weight and stability in the high wind conditions experienced after the tower was retracted, leaving the Delta exposed to the weather.

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

Filling of the stage with cryogenic liquid oxygen will begin about an hour from now.

2333 GMT (7:33 p.m. EDT; 4:33 p.m. PDT)

A view of the Delta rocket standing on the launch pad following mobile service tower rollback is available here.

2326 GMT (7:26 p.m. EDT; 4:26 p.m. PDT)

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

2321 GMT (7:21 p.m. EDT; 4:21 p.m. PDT)

T-minus 150 minutes and counting. The Terminal Countdown has been initiated for today's launch of the COSMO 1 spacecraft aboard the Delta 324 vehicle.

Pre-flight activities are proceeding apace for the evening liftoff from Vandenberg Air Force Base in California. The site is on the Pacific coastline, about 140 miles northwest of Los Angeles.

Following liftoff, the vehicle will head southward as it climbs into orbit on a 58-minute flight to deploy the Italian satellite cargo.

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.

Today's 13-minute launch window runs from 7:21 to 7:34 p.m. local time (10:21-10:34 p.m. EDT; 0221-0234 GMT).

Weather conditions are "go" at this time.

2312 GMT (7:12 p.m. EDT; 4:12 p.m. PDT)

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

2306 GMT (7:06 p.m. EDT; 4:06 p.m. PDT)

"Man stations for Terminal Count." That was the message just announced to the launch team in preparation for starting the Terminal Countdown some 15 minutes from now. Liftoff of the Delta 2 rocket remains targeted to occur ontime at 7:21 p.m. local time (10:21 p.m. EDT; 0221 GMT).

2251 GMT (6:51 p.m. EDT; 3:51 p.m. PDT)

Now 30 minutes through this scheduled hour-long hold in the countdown.

2245 GMT (6:45 p.m. EDT; 3:45 p.m. PDT)

The SLC-2W launch pad restricted area is being cleared of all personnel for the rest of the countdown. A short time ago, the launch pad water pumps were successfully brought online for the count, technicians reported.

2235 GMT (6:35 p.m. EDT; 3:35 p.m. PDT)

Today's launch will be:

• The 324th Delta rocket launch since 1960
• The second of 2007
• The 128th Delta 2 rocket mission since 1989

2221 GMT (6:21 p.m. EDT; 3:21 p.m. PDT)

T-minus 150 minutes and holding. The countdown has just entered a planned 60-minute built-in hold at Vandenberg Air Force Base in California. The Terminal Countdown will begin once this hold is concluded. Launch remains on schedule for 7:21 p.m. local time (10:21 p.m. EDT; 0221 GMT).

2200 GMT (6:00 p.m. EDT; 3:00 p.m. PDT)

Mission managers are arriving at their consoles in the directors' center to oversee today's launch operation. At the pad, meanwhile, final touches are being put on the facility before all workers clear the area for the hazardous portion of the count.

2102 GMT (5:02 p.m. EDT; 2:02 p.m. PDT)

The 177-foot tall mobile service tower has been retracted from the ULA Delta 2 rocket at Vandenberg Air Force Base's Space Launch Complex-2 West pad, completing a crucial step in the preparations for liftoff later this evening.

The gantry was used to stack the two-stage vehicle, the four strap-on solid rocket motors and the COSMO 1 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 7:21 p.m. local time (10:21 p.m. EDT; 0221 GMT).

2053 GMT (4:53 p.m. EDT; 1:53 p.m. PDT)

Rollback of the mobile service tower at the Space Launch Complex-2 West pad just got underway. Crews are moving the tower into its launch position, revealing the Delta 2 rocket for today's countdown.

Although windy, it is a beautiful afternoon at the launch site.

1820 GMT (2:20 p.m. EDT; 11:20 a.m. PDT)

Launch team members are filling the first stage with kerosene propellant this morning as preparations continue for launch. The fueling is occurring earlier than normal in order to give the rocket added weight and stability in the high winds conditions expected today once the mobile service tower is retracted.

A ULA spokesman said preparations to retract the tower will begin at 2030 GMT with the tower expected to move at 2130 GMT, pending allowable winds.

1640 GMT (12:40 p.m. EDT; 9:40 a.m. PDT)

It is launch day for the Delta 2 rocket and COSMO 1 spacecraft. The wild card continues to be the forecast of high winds today at the Vandenberg Air Force Base launch site. Preparations are pressing ahead as officials monitor the weather situation.

WEDNESDAY, JUNE 6, 2007

A planned Thursday evening rocket launch from California will begin assembling an Italian-built constellation of observation satellites that will use radar to image the Earth for commercial and military uses.

Liftoff of the first COSMO-SkyMed spacecraft aboard a United Launch Alliance Delta 2 rocket is scheduled for 7:21 p.m. local time (10:21 p.m. EDT; 0221 GMT) from Vandenberg Air Force Base.

The chief worry heading into the launch attempt, however, is predicted to be strong winds during the countdown. Mission officials were planning to discuss the forecast and the strategy for dealing with the winds during the Launch Readiness Review scheduled for this afternoon.

"We'll just have to see how it goes. As far as the rocket goes, though, everything is proceeding to plan," Ken Heinly, director of Boeing launch products and services, said in an interview earlier today.

United Launch Alliance is conducting the rocket flight while Boeing manages the commercial contract for the Italian customer. ULA was formed last December to merge Boeing's Delta and Lockheed Martin's Atlas rocket families under one joint venture to cut the cost for U.S. government space launches.

The parent companies have retained the ability to sell the rockets on the commercial marketplace, and the launch of COSMO 1 will be the first such commercial flight since ULA began.

Thursday's launch activities begin with retraction of the protective mobile service gantry from around the Delta rocket at the Space Launch Complex-2 West pad. Air Force meteorologists say the winds should be within limits for the morning rollback. However, stronger winds are predicted to whip up later in the day. That will bring into question whether the conditions violate the safety rules governing the time in which the rocket stands exposed on the pad.

"A strong low-pressure system is moving through the western U.S., and northwesterly winds on the central California coast have strengthened in its wake. These gusty northwest winds will persist on the Western Range through launch day," forecasters reported in their launch outlook.

"Winds are forecast to be below (gantry) roll constraints Thursday morning, but will increase during the late morning, peaking between 12:00 - 5:00 (p.m.) local. During this timeframe, northwest winds are forecast to violate vehicle exposure constraints at times, with max wind gusts of 35 knots expected."

The weather team says the winds will ease in the early evening, with only a 20 percent chance that the conditions will be out of limits at launch time.

Friday's outlook is similar for the afternoon hours, but the launch time forecast has no wind concerns. In fact, there is a zero percent chance of weather problems Friday evening.

A large delegation of Italian officials has traveled to Vandenberg to watch the launch. Good visibility, with only some thin, low clouds is expected for a Thursday launch. But the view for spectators could be hampered on Friday due to dense fog that frequently shrouds Vandenberg.

The Delta rocket is flying in its configuration known as the 7420-10 vehicle. The two-stage launcher is fitted with four strap-on solid-propellant motors and a 10-foot diameter composite nose cone.

After quickly climbing away from its coastal pad, the rocket will soar southward over the Pacific Ocean. The four solid boosters burn out and separate less than 90 seconds into the flight, leaving the kerosene-powered main engine to continue pushing the rocket to an altitude of 60 miles. The spent stage then jettisons to let the hydrazine-fueled second stage ignite.

Within 12 minutes, the vehicle settles into an initial parking orbit 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 12 seconds over Madagascar to reach a near-circular polar orbit 340 miles above the planet.

The 4,200-pound payload is expected to be released from the rocket 58 minutes after blastoff.

Developed by Thales Alenia Space Italia for the Italian Space Agency and the Italian Ministry of Defence, the COSMO-SkyMed system is a dual civilian and military Earth-imaging program that will use a fleet of four satellites to be launched over the next few years. Each spacecraft will be equipped with an X-Band Synthetic Aperture Radar instrument for environmental monitoring, resource management and territorial surveillance.