BY SPACEFLIGHT NOW

Follow the preparations and launch of the Arianespace Ariane 4 rocket carrying the NSS 6 communications satellite. Reload this page for the very latest on the mission.

TUESDAY, DECEMBER 17, 2002

Amidst its latest troubles with the Ariane 5 rocket, Arianespace came one step closer to phasing out its Ariane 4 predecessor Tuesday night as the venerable rocket continued its streak of successful launches. Read our launch story.

2329 GMT (6:29 p.m. EST)

Arianespace says today's launch has successfully placed NSS 6 into the proper orbit, marking the 73rd straight success for the Ariane 4 rocket.

We'll have a complete wrap-up story a little later tonight.

2324 GMT (6:24 p.m. EST)

Plus+20 minutes, 47 seconds. SPACECRAFT SEPARATION! The NSS 6 telecommunications satellite has been released into space from the Ariane 4 rocket's third stage, completing today's launch of Arianespace Flight 156.

2324 GMT (6:24 p.m. EST)

Plus+20 minutes, 30 seconds. The upper stage is orienting for spacecraft deployment. Altitude is 353 km, velocity 9.52 km/sec.

2323 GMT (6:23 p.m. EST)

Plus+19 minutes, 20 seconds. Altitude is 271 km, velocity 9.7 km/sec.

2322 GMT (6:22 p.m. EST)

Plus+18 minutes, 55 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 NSS 6 spacecraft over the next minute.

2322 GMT (6:22 p.m. EST)

Plus+18 minutes. The rocket has bottomed out in its sling-shot to orbit and is now climbing higher. Vehicle parameters and trajectory reported normal.

2320 GMT (6:20 p.m. EST)

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

2319 GMT (6:19 p.m. EST)

Plus+15 minutes. Altitude is 189 km, velocity 8.0 km/sec.

2318 GMT (6:18 p.m. EST)

Plus+14 minutes. Altitude is 198 km, velocity 7.6 km/sec.

2316 GMT (6:16 p.m. EST)

Plus+12 minutes, 35 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 7.09 km/sec.

2315 GMT (6:15 p.m. EST)

Plus+11 minutes, 30 seconds. Altitude is 226 km, velocity 6.76 km/sec.

2314 GMT (6:14 p.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 232 km, velocity 6.4 km/sec.

2313 GMT (6:13 p.m. EST)

Plus+9 minutes, 30 seconds. Altitude 234.7 km, velocity 6.19 km/sec.

2313 GMT (6:13 p.m. EST)

Plus+9 minutes. Third stage burn continues. Altitude 233 km, velocity 6.0 km/sec.

2312 GMT (6:12 p.m. EST)

Plus+8 minutes. Altitude is 224 km, velocity 5.6 km/sec.

2311 GMT (6:11 p.m. EST)

Plus+7 minutes. The Natal tracking station in Brazil has picked up the rocket's signal as it travels downrange. Altitude is 206 km, velocity 5.6 km/sec.

2309 GMT (6:09 p.m. EST)

Plus+5 minutes, 52 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 NSS 6 satellite payload into orbit.

2309 GMT (6:09 p.m. EST)

Plus+5 minutes, 30 seconds. Altitude is 159 km, velocity 5.29 km/sec.

2309 GMT (6:09 p.m. EST)

Plus+5 minutes. No problems reported in the flight of Ariane 5. Altitude is 141 km, velocity 4.4 km/sec.

2308 GMT (6:08 p.m. EST)

Plus+4 minutes, 20 seconds. The payload fairing has been jettisoned since it is no longer needed to shield the NSS 6 spacecraft.

2308 GMT (6:08 p.m. EST)

Plus+4 minutes. Second stage is burning, all parameters reported normal. Altitude is 105 km, velocity 3.3 km/sec.

2307 GMT (6:07 p.m. EST)

Plus+3 minutes, 37 seconds. The four first stage main engines have shut down and the spent stage was jettisoned. And the second stage has now ignited.

2307 GMT (6:07 p.m. EST)

Plus+3 minutes. Altitude is 63.4 km, velocity 2.2 km/sec.

2306 GMT (6:06 p.m. EST)

Plus+2 minutes, 31 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.

2306 GMT (6:06 p.m. EST)

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

2305 GMT (6:05 p.m. EST)

Plus+90 seconds. Altitude is 12.2 km, velocity 0.45 km/sec.

2305 GMT (6:05 p.m. EST)

Plus+60 seconds. Trajectory reported normal. Altitude is 4.0 km, velocity 0.2 km/sec.

2304 GMT (6:04 p.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.

2304 GMT (6:04 p.m. EST)

LIFTOFF! Liftoff of the penultimate flight of Ariane 4 and the NSS 6 communications satellite. And the vehicle has cleared the tower!

2303 GMT (6:03 p.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.

2302 GMT (6:02 p.m. EST)

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

2300 GMT (6:00 p.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 NSS 6 spacecraft will be confirmed on internal power and declared ready for launch.

2258 GMT (5:58 p.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 2304 GMT (6:04 p.m. EST).

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.

2249 GMT (5:49 p.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.

2245 GMT (5:45 p.m. EST)

Minus-19 minutes. The countdown is entering the final minutes for today's launch of the Arianespace Ariane 44L rocket with the NSS 6 communications satellite. The three-stage rocket stands fueled and ready for liftoff at 2304 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.

TUESDAY, DECEMBER 17, 2002

As investigators begin searching for clues into last week's Ariane 5 rocket failure, the penultimate flight of the Ariane 4 booster is set to launch today.

Liftoff from the Guiana Space Center's ELA-2 launch complex is set for 2304 GMT (6:04 p.m. EST). The launch window extends for about two hours.

After today's mission, just one more Ariane 4 launcher is set to fly early next year, closing out a program dating back to the 1980's that has amassed 72 consecutive successes dating back to 1995. In 114 flights, the booster has had three total failures.

The Ariane 4 is being retired after its final launch in early 2003 in favor of the more powerful new-generation Ariane 5 rocket, which has now flown 14 times with three total failures and one partial mishap.

On Monday, Arianespace announced the members of the board responsible for determining why the Ariane 5 went out of control last Wednesday night, destroying two satellites cargos as it plummeted into the Atlantic. The team will be lead by Wolfgang Koschel of the German Aerospace Center, with Michel Courtois of Alcatel Space, Fabrizio Felici and Robert Laine of ESA and Remy Hergott of CNES.

Arianespace says the inquiry's report shall be submitted on Monday, January 6. That is six days before the next planned Ariane 5 flight, which will launch ESA's Rosetta cometary mission.

Today's launch -- Arianespace Flight 156 -- will use the most powerful Ariane 4 version called the Ariane 44L, with a set of four liquid-fueled boosters strapped to the first stage to provide additional thrust early in the mission.

Sitting atop the rocket and poised to begin a 14-year mission is the NSS-6 communications bird for New Skies Satellites.

NSS-6 will be released in an egg-shaped geostationary transfer orbit by the Ariane 4 third stage. The craft will then use its propulsion system to gradually circularize that orbit to 22,300 miles high. NSS-6's final slot will be at 95 degrees East along the equator above the Indian Ocean near Indonesia.

From that vantage point, NSS-6 will reach users stretching halfway around the world including the Mediterranean Sea, the Middle East, southern Africa, Australia, and vast regions of Asia as far east as Japan.

Fifty Ku-band transponders will be utilized by the telecommunications industry to serve a number of markets that range from large broadcasting firms to small businesses and direct-to-home programming customers.

NSS-6 also brings Ka-band to the table with 12 Ka-band uplink beams that can be connected to the Ku-band payload for media outlets and Internet providers to have the capability for two-way interactive networking among other services.

The satellite was built by Lockheed Martin Commercial Space Systems and is based on their A2100 AX satellite platform. NSS-6 weighs 10,065 pounds at liftoff with its fuel tanks full of maneuvering propellant.

Looking ahead to the events of launch day, the final countdown will begin at 1034 GMT (5:34 a.m. EST). At 1729 GMT (12:29 p.m. EST), workers will begin the process of rolling the Ariane 4's service gantry away from the rocket and into its launch position. Liquid hydrogen and liquid oxygen propellant will begin flowing into the launcher's third stage at 1929 GMT (2:29 p.m. EST). The rocket's telemetry, radar transponder, and telecommand systems will be activated at 2159 GMT (4:59 p.m. EST). Six minutes prior to liftoff, the synchronized launch sequence will commence. Following this crucial milestone, a series of fast-paced events culminating with the ignition of the Viking engines of the first stage and liquid boosters at T-0. Liftoff will occur about four seconds later.

The four liquid-fed boosters will burn for two minutes, 29 seconds before being jettisoned. The first stage will fire for another minute before it is released. The Ariane 44L's second stage will ignite for a two-minute burn, during which time the payload fairing will be jettisoned. A marathon 13-minute firing of the third stage will finish the job of injecting NSS-6 into its elliptical geostationary transfer orbit. Spacecraft separation is expected 20 minutes, 44 seconds into flight.

Stay with Spaceflight Now for live play-by-play updates during the final countdown and launch of the Ariane 44L rocket on Flight 156.