BY SPACEFLIGHT NOW

June 9, 2001 -- Follow the preparations and launch of the Intelsat 901 communications satellite aboard an Arianespace Ariane 4 rocket. Reload this page for the very latest on the mission.

SATURDAY, JUNE 9, 2001

A predawn launch of a European Ariane 4 rocket today delivered into space the first in a new series of communications satellites to beef up Intelsat's orbiting fleet with more powerful and higher capacity craft. Read our full launch story.

0810 GMT (4:10 a.m. EDT)

Contact has been established with Intelsat 901 and telemetry was received by Intelsat's control facility in Washington, D.C. The satellite is reported to be healthy and operational.

A series of orbit raising maneuvers are ahead for the craft before it arrives in geostationary orbit 22,300 miles above the equator for parking at 18 degrees West. Intelsat says the satellite should enter commercial service in October after a checkout period, providing telecommunications to the Americas, Europe, the Middle East and Africa.

0706 GMT (3:06 a.m. EDT)

Plus+21 minutes. SPACECRAFT SEPARATION! The Intelsat 901 telecommunications satellite has been released into space from the Ariane 4 rocket's third stage, completing this morning's successful launch of Arianespace Flight 141. This marks the 62nd straight success for the Ariane 4 rocket dating back to 1995.

0705 GMT (3:05 a.m. EDT)

Plus+20 minutes. One minute from payload separation.

0704 GMT (3:04 a.m. EDT)

Plus+19 minutes, 35 seconds. Altitude is 297 km, velocity 9.67 km/sec.

0704 GMT (3:04 a.m. EDT)

Plus+19 minutes, 4 seconds. 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 901 spacecraft over the next two minutes.

0703 GMT (3:03 a.m. EDT)

Plus+18 minutes. Standing by for cutoff of the third stage. The Libreville tracking station in Africa has acquired. Altitude is 219 km, velocity 9.2 km/sec.

0702 GMT (3:02 a.m. EDT)

Plus+17 minutes. The rocket has bottomed out in its sling-shot to orbit and is now climbing higher. The altitude is 195 km, velocity 8.8 km/sec.

0701 GMT (3:01 a.m. EDT)

Plus+16 minutes. Less than three minutes left in the third stage burn. Altitude is 187 km, velocity 8.4 km/sec.

0659 GMT (2:59 a.m. EDT)

Plus+14 minutes. The Ariane rocket continues to gain speed. Altitude is 195 km, velocity 7.61 km/sec.

0657 GMT (2:57 a.m. EDT)

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 212 km, velocity 7.09 km/sec.

0656 GMT (2:56 a.m. EDT)

Plus+11 minutes, 30 seconds. Altitude is 222 km, velocity 6.78 km/sec.

0655 GMT (2:55 a.m. EDT)

Plus+10 minutes, 30 seconds. Now reaching 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 228 km, velocity 6.5 km/sec.

0654 GMT (2:54 a.m. EDT)

Plus+9 minutes, 30 seconds. All vehicle parameters reported normal. Altitude 231 km, velocity 6.23 km/sec.

0653 GMT (2:53 a.m. EDT)

Plus+8 minutes, 10 seconds. Third stage burn still on going with no problems reported. Altitude 223 km, velocity 5.9 km/sec.

0652 GMT (2:52 a.m. EDT)

Plus+7 minutes. The Natal tracking station in Brazil has picked up the rocket's signal as it travels downrange. Vehicle remains on the proper course. Altitude is 203 km, velocity 5.68 km/sec.

0651 GMT (2:51 a.m. EDT)

Plus+6 minutes. 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 901 satellite payload into orbit.

0650 GMT (2:50 a.m. EDT)

Plus+5 minutes, 30 seconds. Second stage continues to burn normally. Altitude is 158 km, velocity 5.3 km/sec.

0649 GMT (2:49 a.m. EDT)

Plus+4 minutes, 30 seconds. The payload fairing has been jettisoned since it is no longer needed to shield the Intelsat 901 spacecraft. Altitude is 123 km, velocity 3.8 km/sec.

0649 GMT (2:49 a.m. EDT)

Plus+4 minutes, 10 seconds. Altitude is 111 km, velocity 3.5 km/sec.

0648 GMT (2:48 a.m. EDT)

Plus+3 minutes, 40 seconds. The four first stage main engines have shut down and stage separation confirmed. The second stage has now ignited.

0648 GMT (2:48 a.m. EDT)

Plus+3 minutes. First stage main engines continue to fire. Altitude is 62 km, velocity 2.2 km/sec.

0647 GMT (2:47 a.m. EDT)

Plus+2 minutes, 34 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.

0647 GMT (2:47 a.m. EDT)

Plus+2 minutes. Altitude is 25 km, velocity 0.9 km/sec.

0646 GMT (2:46 a.m. EDT)

Plus+90 seconds. So far so good in this flight of the Ariane 4 rocket. All engines continue to fire as the vehicle streaking into the predawn sky.

0646 GMT (2:46 a.m. EDT)

Plus+60 seconds. Altitude 4.2 km, velocity 0.2 km/sec.

0645 GMT (2:45 a.m. EDT)

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

0645 GMT (2:45 a.m. EDT)

LIFTOFF! Liftoff of the Ariane 4 rocket launching the first satellite in a new generation of telecommunications spacecraft for Intelsat. And the tower is clear!

0644 GMT (2:44 a.m. EDT)

Minus-30 seconds. The three-stage rocket is set to deliver Intelsat 901 into a geosynchronous transfer orbit of 225 km on the low end and 35,945 km on the high end, with an inclination of 7 degrees.

0644 GMT (2:44 a.m. EDT)

Minus-1 minute. Equipment aboard the Ariane 44L rocket is being switched off ground-supplied power and 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.

0643 GMT (2:43 a.m. EDT)

Minus-90 seconds and counting. The local tracking stations at the launch site should have a firm lock on the rocket at this time.

0643 GMT (2:43 a.m. EDT)

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

0642 GMT (2:42 a.m. EDT)

Minus-3 minutes and counting. Flight 141 will be the fourth of perhaps a dozen Ariane launches in 2001 and the 141st in the entire Ariane program. It will be the 104th Ariane 4 mission and the 32nd for the Ariane 44L version with four liquid strap-on rocket boosters.

0641 GMT (2:41 a.m. EDT)

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 901 spacecraft will be confirmed on internal power and declared ready for launch.

0640 GMT (2:40 a.m. EDT)

Minus-5 minutes and counting.

0639 GMT (2:39 a.m. EDT)

Minus-6 minutes. The synchronized launch sequence has started. Computers are now in control of this final segment of the launch countdown.

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 and liquid-booster engine 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 4.1 and 4.6 seconds.

0638 GMT (2:38 a.m. EDT)

Minus-6 minutes, 30 seconds. The computer-run synchronized sequence to govern the final countdown to launch will start in 30 seconds. Liftoff remains set to occur at 0645 GMT (2:45 a.m. EDT).

0637 GMT (2:37 a.m. EDT)

Minus-8 minutes and counting.

0635 GMT (2:35 a.m. EDT)

Minus-10 minutes and counting. A network of tracking stations are standing ready to relay data from the Ariane 4 rocket to engineers in Kourou. The early portion of flight will be monitored through the Kourou and Cayenne stations in French Guiana. About 6 minutes, 30 seconds into flight the Natal station in Brazil will pick up the rocket's signal as the third stage burn gets underway. At T+plus 12 minutes, 30 seconds the site on Ascension Island in the Atlantic Ocean will begin coverage. Libreville in Gabon will provide services beginning at T+plus 17 minutes, 30 seconds for spacecraft separation and the conclusion of Arianespace Flight 141.

0631 GMT (2:31 a.m. EDT)

Minus-14 minutes. The Ariane 44L rocket stands 56.3 meters tall and weighs 486 metric tons at liftoff. The Intelsat 901 spacecraft accounts for 4,723 kg (10,410 pounds) of that weight.

0628 GMT (2:28 a.m. EDT)

Minus-17 minutes. Arianespace reports all systems are "go" for an on-time launch at 0645 GMT. There are no technical problems being worked with the rocket or payload, and the weather conditions are within limits. The upper level winds are also favorable today, unlikely yesterday morning when the launch had to be scrubbed.

0625 GMT (2:25 a.m. EDT)

Minus-20 minutes and counting down to today's predawn blastoff of the Ariane 44L rocket with Intelsat 901. The three-stage rocket is fully fueled and poised for launch at 0645 GMT from the Guiana Space Center in South America.

Launch team members are watching systems on the Ariane 4 rocket, spacecraft payload and ground support equipment. There are no problems being worked and all systems are "go" for this morning's launch.

0608 GMT (2:08 a.m. EDT)

Good morning and welcome to our live coverage of the launch of Arianespace Flight 141. The Ariane 44L rocket is scheduled to lift off with the Intelsat 901 communications satellite at 0645 GMT from Kourou, French Guiana in South America. We should begin getting countdown updates from the launch site in about 15 minutes.

FRIDAY, JUNE 8, 2001
1830 GMT (6:30 p.m. EDT)

With upper level wind conditions improving, Arianespace has decided to start a second countdown for the launch of Flight 141 to deliver the Intelsat 901 communications satellite into orbit.

Liftoff is now set for 0645 GMT (2:45 a.m. EDT) on Saturday. The available launch window extends one hour.

Today's launch attempt was called off with about 25 minutes left in the countdown because the high-altitude winds were out of limits and not expected to improve within the one-hour window.

Weather officials monitored the winds throughout the day and say conditions will be better for a predawn launch on Saturday.

We will begin our live coverage in the final half-hour of the countdown and continue through the entire 21-minute flight of the Ariane 44L rocket.

0623 GMT (2:23 a.m. EDT)

SCRUB! Arianespace has scrubbed this morning's scheduled launch of the Ariane 4 rocket carrying the Intelsat 901 telecommunications satellite. Officials called off the countdown a few minutes ago due to unfavorable high-altitude winds at the Kourou launch site.

Plans call for the third stage cryogenic upper stage of its super-cold liquid hydrogen and liquid oxygen to be drained, and Arianespace will make the call later this afternoon whether to make another launch attempt early Saturday morning.

"We will monitor the weather conditions, and if the situation looks better tomorrow, we will try again," said Jacques Rossignol, Arianespace's chief operating officer.

THURSDAY, JUNE 7, 2001

An Ariane 44L rocket is sitting on its South American launch pad, poised to haul a high-power international telecommunications satellite into orbit early Friday.

Arianespace Flight 141 will take to the skies from the ELA-2 launch pad in Kourou, French Guiana, along South America's northeast coast. The 60-minute launch window opens at 0644 GMT (2:44 a.m. EDT) on Friday. The launch marks the 141st Ariane launch in the history of the program, as well as it being the 104th Ariane 4 launch and the 32nd flight of the Ariane 44L version.

Flight 141's launch vehicle also represents one of the 13 Ariane 4's remaining to be launched before being taken out of commission in favor of the new heavy-lift Ariane 5 rocket.

The mission's payload -- Intelsat 901 -- is the first in a new, more powerful series of communications satellites for the International Telecommunications Satellite Organization, or Intelsat. The new Series 9 satellites will provide enhanced voice, video and data transmission services across the globe.

Positioned in geostationary orbit at 18 degrees West over the Atlantic Ocean, Intelsat 901 will use 44 C-band and 12 Ku-band transponders to provide television relay and other telecommunications services to parts of Europe, Africa, the Middle East and the Americas. The expected life span of the satellite is around 13 years.

Intelsat 901 was built by Space Systems/Loral, based in Palo Alto, California, and is based on their FS1300 Extended series of satellite buses. At liftoff, the spacecraft tucked away in the Ariane rocket's payload fairing will weigh in at 10,410 pounds. With the craft's propellants subtracted from the total mass, the satellite's mass is 4,338 pounds.

When fully deployed and operational, the bird's solar panels will stretch almost 100 feet tip-to-tip and will produce around 10 kilowatts of electricity at the beginning of the satellite's life in orbit.

Intelsat 901 is the 18th Intelsat spacecraft ever launched by an Ariane launch system. Arianespace is slated to launch at least six of the seven Series 9 spacecraft over the coming years. Intelsat 901 is also the first of 10 satellites that Intelsat plans to launch over the next two years.

The Ariane 44L launcher's first stage, second stage, and fourliquid-fueled strap-on boosters were fueled with their hypergolic propellants on Wednesday, setting the stage for the final countdown later today.

Looking ahead to the key pre-launch events, the final countdown will commence at 1814 GMT (2:14 p.m. EDT). The 321-foot tall mobile service gantry will begin rolling back into its launch position at around 0109 GMT (9:09 p.m. EDT). The service gantry provides workers access to the rocket and also protects critical systems from possible violent weather. The operations to fuel the Ariane 4's third stage with its cryogenic liquid hydrogen and liquid oxygen propellant will begin at 0309 GMT (11:09 p.m. EDT). The launcher's telemetry, telecommand, and radar transponder systems will be brought to life at 0539 GMT (1:39 a.m. EDT). At Minus-6 minutes, controllers in the Jupiter launch control room will start the Synchronized Launch Sequence. Following this important milestone, a series of fast-paced events will occur, culminating in the ignition of the first stage and liquid-fueled boosters, followed four-and-a-half seconds later by liftoff.

Flight 141 will take a normal Ariane 44L ascent profile. The four strap-on boosters will have used their propellant and will be jettisoned 2 minutes, 30 seconds into the flight. The first stage will separate just over a minute later. The payload fairing will be jettisoned around four-and-a-half minutes into flight, followed one minute later by the separation of the second stage. The third stage will then burn for 13 minutes before shutting down. Spacecraft separation will occur just under 21 minutes after liftoff.

Stay with Spaceflight Now for live play-by-play updates during the final countdown and ascent into space.

TUESDAY, JUNE 5, 2001

After a three-month lull in flights, Arianespace has entered the final stretch of preparations for Friday's predawn launch of an Ariane 4 rocket carrying the Intelsat 901 telecommunications satellite.

Liftoff of Arianespace Flight 141 is set for a one-hour window opening at 0644 GMT (2:44 a.m. EDT). The flight of the Ariane 44L -- fitted with four liquid-fueled strap-on boosters -- will originate from the ELA-2 launch complex at the Guiana Space Center in Kourou, French Guiana.

Processing for Arianespace's fourth launch of 2001 began on April 26 with the raising of the Ariane's first stage into the vertical position on its launch table. This event was followed a day later with the stacking of the rocket's second stage.

The flight's Intelsat 901 communications satellite payload arrived in Kourou on May 2 to begin its final testing and checkout phase before launch.

Back in the launcher integration building, the Ariane 44L's four liquid-fueled boosters were placed into position around the base of the rocket's first stage beginning on May 2. The process was completed on May 7, the same day that the launcher's third stage was lifted and placed atop the vehicle's second stage.

The nearly complete Ariane 44L was rolled the one-kilometer distance from its assembly building to the Ariane 4's launch pad on May 18. Shortly after arrival, the protective mobile service tower was rolled into position around the rocket.

As part of the final segment of payload processing, the Intelsat 901 spacecraft was fueled with its toxic maneuvering propellant beginning on May 21.

On May 29, the payload was encapsulated inside of its shroud-like payload fairing, followed on the next day by the transfer of the entire payload unit -- with the fairing, payload, and adapter -- to the launch pad. The payload composite was attached to the rocket on May 31.

A final launch rehearsal was conducted on Friday, as launch controllers fine-tune their skills in the final week before launch.

Officials held the Launch Readiness Review on Tuesday and confirmed all systems were go for Friday's liftoff. The meeting cleared the way for workers to arm the rocket and load storable propellant into the first and second stages and strap-on boosters on Wednesday. The countdown will begin Thursday afternoon.

Built by Space Systems/Loral, the Intelsat 901 satellite will be parked in geostationary orbit 22,300 miles above the equator at 18 degrees West. There, it will be operated by the International Telescommunications Satellite Organization, or Intelsat, to relay communications and television transmissions to its coverage areas in North and South America, Europe, Africa and the Middle East. The craft carries 44 C-band and 12 Ku-band transponders.

Stay with Spaceflight Now for the latest news on this launch and live play-by-play updates during the final countdown and climb to orbit.