BY SPACEFLIGHT NOW

Follow the preparations and launch of the Arianespace Ariane 4 rocket carrying the Intelsat 907 communications satellite. Reload this page for the very latest on the mission.

SATURDAY, FEBRUARY 15, 2003

Arianespace closed out its venerable Ariane 4 rocket program today with an early morning vault into space that put a shining end to one of the most successful commercial launchers in the history of the industry. Read our full story.

0727 GMT (2:27 a.m. EST)

Arianespace has declared success for today's launch of the last Ariane 4 rocket. We'll have a wrap-up story a little bit later this morning.

0721 GMT (2:21 a.m. EST)

Plus+21 minutes, 15 seconds. SPACECRAFT SEPARATION! The Intelsat 907 telecommunications satellite has been released into space from the Ariane 4 rocket's third stage, completing this morning's launch of Arianespace Flight 159.

0719 GMT (2:19 a.m. EST)

Plus+19 minutes, 40 seconds. Altitude is 287 km, velocity 9.6 km/sec.

0719 GMT (2:19 a.m. EST)

Plus+19 minutes. Confirmation of third stage shut down, completing the powered phase of flight. Orbit has been achieved. The stage will now provide the necessary pointing for deployment of the Intelsat 907 spacecraft over the next minute.

0718 GMT (2:18 a.m. EST)

Plus+18 minutes. The Libreville tracking station in Africa has acquired the rocket's signal. Altitude is 211 km, velocity 9.1 km/sec.

0717 GMT (2:17 a.m. EST)

Plus+17 minutes, 30 seconds. Altitude is 200 km, velocity 8.9 km/sec.

0716 GMT (2:16 a.m. EST)

Plus+16 minutes, 30 seconds. The rocket has bottomed out in its sling-shot to orbit and is now climbing higher. Vehicle parameters and trajectory reported normal. The altitude is 180 km, velocity 8.6 km/sec.

0716 GMT (2:16 a.m. EST)

Plus+16 minutes. About three minutes left in the third stage burn.

0714 GMT (2:14 a.m. EST)

Plus+14 minutes, 30 seconds. Velocity now 7.7 km/sec.

0712 GMT (2:12 a.m. EST)

Plus+12 minutes, 30 seconds. The Ascension Island tracking station in the Atlantic Ocean has acquired the rocket's signal as it heads eastward away from South America. Altitude is 215 km, velocity 7.05 km/sec.

0712 GMT (2:12 a.m. EST)

Plus+12 minutes. Altitude is 221 km, velocity 6.9 km/sec.

0710 GMT (2:10 a.m. EST)

Plus+10 minutes, 30 seconds. This is now the period in flight where the Ariane rocket gives up a bit of altitude in order to gain velocity like a sling-shot. Altitude is 233 km, velocity 6.4 km/sec.

0709 GMT (2:09 a.m. EST)

Plus+9 minutes, 30 seconds. Altitude 235 km, velocity 6.2 km/sec.

0708 GMT (2:08 a.m. EST)

Plus+8 minutes, 10 seconds. Third stage burn continues. Altitude 225 km, velocity 5.8 km/sec.

0707 GMT (2:07 a.m. EST)

Plus+7 minutes, 30 seconds. Vehicle remains on the proper course with system performance reported normal.

0707 GMT (2:07 a.m. EST)

Plus+7 minutes. The Natal tracking station in Brazil has picked up the rocket's signal as it travels downrange. Altitude is 205 km, velocity 5.6 km/sec.

0706 GMT (2:06 a.m. EST)

Plus+6 minutes, 30 seconds. Altitude is 193 km, velocity 5.5 km/sec.

0705 GMT (2:05 a.m. EST)

Plus+5 minutes, 51 seconds. Burnout of the second stage has occurred and the spent stage has jettisoned. The cryogenic upper stage has now ignited for its long-duration burn to deliver the Intelsat 907 satellite payload into orbit.

0705 GMT (2:05 a.m. EST)

Plus+5 minutes. Altitude is 142 km, velocity 4.4 km/sec.

0704 GMT (2:04 a.m. EST)

Plus+4 minutes, 30 seconds. The payload fairing has been jettisoned since it is no longer needed to shield the Intelsat 907 spacecraft.

0704 GMT (2:04 a.m. EST)

Plus+4 minutes, 15 seconds. Second stage is burning, all parameters reported normal. Altitude is 125 km, velocity 3.6 km/sec.

0703 GMT (2:03 a.m. EST)

Plus+3 minutes, 40 seconds. The four first stage main engines have shut down and the spent stage was jettisoned. And the second stage has now ignited.

0703 GMT (2:03 a.m. EST)

Plus+3 minutes, 15 seconds. Altitude is 73.9 km, velocity 2.6 km/sec.

0702 GMT (2:02 a.m. EST)

Plus+2 minutes, 35 seconds. The four liquid-propellant strap-on boosters have shut down and separated from the Ariane 4's first stage. The spent casings fall into the Atlantic Ocean. The first stage main engines are still burning to continue the climb to orbit.

0702 GMT (2:02 a.m. EST)

Plus+2 mintues. All engines continue to fire. Vehicle system parameters reported normal by Arianespace.

0701 GMT (2:01 a.m. EST)

Plus+60 seconds. The heaviest and most powerful version of the Ariane 4 rocket is thundering its way toward space. No problems reported in this initial minute of flight.

0700 GMT (2:00 a.m. EST)

Plus+30 seconds. Ariane has pitched to the proper eastward trajectory away from the launch pad. The rocket is riding the thrust of eight engines -- four main engines and four liquid-fueled strap-on boosters.

0700 GMT (2:00 a.m. EST)

LIFTOFF! The Ariane 4 rocket's chapter in space history draws to a close as the commercial launcher blasts off for the final time.

0659 GMT (1:59 a.m. EST)

Minus-1 minute. The Ariane 44L rocket is being switched from ground-supplied power to onboard batteries for launch.

In the final seconds of the countdown, activities will include releasing the inertial platform at minus 9 seconds, and the release command to the retraction system for the two cryogenic arms will be given at Minus-5 seconds.

0658 GMT (1:58 a.m. EST)

Minus-2 minutes and counting. The third stage liquid oxygen tank has been pressurized for the launch.

0656 GMT (1:56 a.m. EST)

Minus-4 minutes and counting. The launch team is monitoring the final topping off of liquid oxygen and liquid hydrogen supplies aboard the rocket's third stage.

In the next half-minute, the launch time will be loaded aboard the Ariane rocket's guidance system. Also, the Intelsat 907 spacecraft will be confirmed on internal power and declared ready for launch.

0654 GMT (1:54 a.m. EST)

Minus-6 minutes and counting. Computers are now taking control of this final portion of the countdown as the Synchronized Launch Sequence has started. Liftoff is set for 0700 GMT (2:00 a.m. EDT).

During the next six minutes, the Ariane 44L rocket, satellite payload and ground systems will be configured for launch. There are two master computers running the countdown. One is responsible for fluids and propellants and the other for final preparation of the electrical systems such as initiating the flight program, activation of the engine steering systems and power transfer from ground supplies to onboard batteries. The computers will control until minus 5 seconds when a majority logic sequencer takes over for first stage engine and liquid strap-on booster start at zero seconds. Engine performance checks are done in parallel by the two computers starting at plus 2.8 seconds. Finally, the command will be issued to open the launch table clamps for liftoff between ignition +plus 4.4 and 4.6 seconds.

0645 GMT (1:45 a.m. EST)

Minus-15 minutes. The status panel in the Jupiter control center green across the board, indicating all systems are "go" at this time as engineers monitor systems on the Ariane 4 rocket, the spacecraft and ground support equipment.

0640 GMT (1:40 a.m. EST)

Minus-20 minutes. The countdown is entering the final minutes for this morning's launch of the Arianespace Ariane 44L rocket with the Intelsat 907 communications satellite. The three-stage rocket stands fueled and ready for liftoff at 0700 GMT from the ELA-2 pad at the Guiana Space Center in Kourou, French Guiana. The site is located on the northeastern coast of South America.

0407 GMT (11:07 p.m. EST Fri.)

The Ariane 4 rocket's third stage is being loaded with super-cold cryogenic liquid hydrogen and liquid oxygen as the countdown continues for the overnight launch from South America. The first two stages were fueled with storable rocket propellants earlier this week. Liftoff is scheduled to occur at 0700 GMT (2:00 a.m. EST).

FRIDAY, FEBRUARY 14, 2003

With an improvement in wind conditions, liftoff of the Ariane 4 rocket has been scheduled for early Saturday at 0700 GMT (2 a.m. EST). The launch window will extend for 61 minutes to 0801 GMT (3:01 a.m. EST).

We'll post updates here on the final countdown and 21-minute flight.

THURSDAY, FEBRUARY 13, 2003

For the third day running, high winds have forced Arianespace to cancel plans to launch the final Ariane 4 rocket. The problem is strong winds aloft over the South American launch site.

"The prevailing winds continue to exceed established limits for launch operations, leading to a weather hold that prevented the final countdown from being initiated," Arianespace said in a statement.

Liftoff had been planned for early Friday morning local time.

WEDNESDAY, FEBRUARY 12, 2003

Arianespace won't make a launch attempt tonight for the Ariane 4 rocket and Intelsat 907 communications satellite. Officials said the upper level winds remains unfavorable, forcing a delay for a second straight day.

0325 GMT (10:25 p.m. EST Tues.)

SCRUB! The middle-of-the-night launch of the last Ariane 4 rocket from South America has been postponed due to unfavorable high-altitude winds. Liftoff had been planned for 0700 GMT (2 a.m. EST) Wednesday to deliver the Intelsat 907 communications satellite into Earth orbit.

Arianespace has not announced a new launch date.

"Flight 159's Ariane 4 and the Intelsat 907 satellite payload have been put in a safe mode, ready for the next launch attempt - the timing of which will depend on the evolving weather conditions," the launch service provider said in a statement.

TUESDAY, FEBRUARY 11, 2003

Marking the end of the road for one of the most successful commercial rockets in history, the final Ariane 4 rocket is due to launch early Wednesday morning from its South American spaceport.

Liftoff of Flight 159 and the Ariane 4 from Kourou, French Guiana's ELA-2 launch pad is set for the opening of an hour-long window at 0700 GMT (2:00 a.m. EST) Wednesday.

The last Ariane 4 will fly in the venerable launcher's most powerful configuration -- the Ariane 44L. This version uses four liquid-fueled boosters to help boost heavier payloads into space.

This will be the 116th Ariane 4 to be flown dating back to 1988 and the 40th for the Ariane 44L version.

Perched inside the Ariane 4's protective payload shroud is the high-capacity Intelsat 907 satellite, ready to begin its 13-year mission as an international communications relay and broadcast spacecraft.

After being released from the Ariane 4 third stage in a highly elliptical orbit, Intelsat 907 will begin a series of thruster firings over the next few weeks to gradually nudge itself higher and into its precise geostationary orbit 22,300 miles high that matches the Earth's rotation.

Intelsat 907's parking spot will be at 27.5 degrees West longitude over the central Atlantic Ocean, where it will assume the duties of the aging Intelsat 605 satellite.

Using C-band and Ku-band transponders, the craft will beam voice and video broadcasting between the Americas, Europe, and Africa. Other services will include Internet networking, data transmission and multimedia products, and telephony solutions provided back and forth across the Atlantic.

Built by Space Systems/Loral, Intelsat 907 is based on that manufacturer's FS1300 Extended series of spacecraft platforms. The satellite's launch weight is 10,307 pounds and its electricity-producing solar arrays will extend about 100 feet tip-to-tip when fully deployed.

Looking ahead to the activities of launch day, the final countdown will get underway at 1830 GMT (1:30 p.m. EST). The mobile service gantry at the ELA-2 launch pad will begin rolling back away from the Ariane 4 at 0125 GMT Wednesday (8:25 p.m. EST Tuesday).

At 0325 GMT (10:25 p.m. EST), super-cold liquid oxygen and liquid hydrogen propellant will begin flowing into the Ariane 4's third stage in preparation for launch.

The rocket's telemetry, telecommand, and radar transponder systems will be brought to life at 0555 GMT (12:55 a.m. EST Wednesday).

Six minutes before liftoff, the countdown will reach a critical milestone called the start of the synchronized launch sequence, when computers officially begin controlling the count. Following that point, a series of fast-paced events occur that culminate in the ignition of the Ariane 4's Viking engines on the first stage and four liquid-fueled boosters, followed four seconds later by liftoff.

Two-and-a-half minutes into launch, the four strap-on boosters burn out and are jettisoned. First stage separation occurs about a minute later. The second stage then comes to life to burn for just over two minutes, during which time the payload fairing shielding the satellite is released. Once the second stage's job is completed, the third stage ignites just shy of six minutes into flight to begin a 13-minute burn to finish the task of placing the payload into its intended orbit. Intelsat 907 is to be deployed at a point almost 21 minutes after liftoff.

Stay with Spaceflight Now for live play-by-play updates during the final countdown and launch of the Ariane 44L rocket on Flight 159.