Spaceflight Now: V129

The Ariane 42L rocket
Posted: April 17, 2000

The Ariane 4 has become the world's workhorse commercial launch vehicle. Arianespace has captured over half of the commercial satellite launch market.

The Ariane 42L vehicle is one of six family members in Arianespace's Ariane 4 rocket fleet. All six versions use the same three-stage liquid-fueled core rocket. The 42L is distinguished with its two liquid-fueled strap-on boosters attached to the first stage.

The Ariane 4 family's payload lift performance to geosynchronous transfer orbit ranges from 2,000 kg. to 4,900 kg. The Ariane 42L can carry payloads up to 3,490 kg.

Ariane 42L its maiden flight in May 1993 on Flight 56. For the launch of Galaxy 4R on Flight 129, this will be 11th use of an Ariane 42L.

Overall for Flight 129, the Ariane 42L stands 54.4 meters tall. At liftoff the rocket will weigh 482 tons and produce 5,700 kN of thrust.

First stage
The first stage is built by Aerospatiale Matra. Fitted with four Snecma-built Viking 5 engines, the stage provides the initial three minutes of powered flight toward orbit. The stage is 23.2 meters long, 3.8 meters in diameter and weighs 17.5 tons. Internally, the stage features an interstage structure at its top where the second stage is attached. Below that is the nitrogen tetroxide propellant tank. Moving further downward is an intertank structure and the hydrazine fuel tank.
First stage
Twin PALs
Attached to the first stage are the liquid-fueled strap-on boosters, nicknamed PALs. These rockets augment Ariane's liftoff thrust. The boosters are 19 meters long, 2.2 meters in diameter and weighs 4.5 tons. They are built by DaimlerChrysler Aerospace and carry one Snecma-built Viking 6 engine each.
Second stage
Ariane's second stage is built by DaimlerChrysler Aerospace. The stage has one Snecma-built Viking 4 engine and burns hydrazine and nitrogen tetroxide. Standing 11.6 meters long, 2.6 meters in diameter and weighing 3.2 tons, the stage fires for the about two minutes after the first stage is jettisoned.
Second stage
Third stage
The third stage is a powerful cryogenic upper stage used to deliver the Ariane's satellite cargo into the intended orbit around Earth. The Aerospatiale Matra-built stage used a single Snecma HM 7B engine. The stage is 11.7 meters long, 2.6 meters in diameter and weighs 1.25 tons. Internally, the stage has a liquid hydrogen and liquid oxygen tank. The stage also has the adapter and satellite cargo resting on its forward section.
Third stage
The rocket's brains, known as the vehicle equipment bay, with the guidance computer and other controlling electronics is mounted atop the third stage. The donut-shaped VEB is one-meter long, four meters in diameter, weighs 530 kg and is built by Matra Marconi Space France.
Payload fairing
Protecting the satellite cargo during the early portions of launch and ascent through the atmosphere is the payload fairing. This shroud, built by Oerlikon Contraves, is 9.6 meters long, 4 meters in diameter and weighs 740 kg.

Flight data file
Vehicle: Ariane 42L
Payload: Galaxy 4R
Launch date: April 19, 2000
Launch window: 0029-0139 (8:29-9:39 p.m. EDT on 18th)
Launch site: ELA-2, Kourou, French Guina

Pre-launch Briefing
Launch timeline - Chart with times and descriptions of the events to occur during launch.

Purpose of Galaxy 4R - PanAmSat to enhance telecoomunications services to North America.

The Galaxy 4R satellite - Overview of the Hughes-built HS601 HP model spacecraft.

Explore the Net
Arianespace - European launch services provider that uses Ariane 4 and 5 rockets to carry satellites into space.

PanAmSat - Leading satellite communications provider and operator of Galaxy 4R once in space.

Hughes Space and Communications - U.S. manufacturer of Galaxy 4R satellite.

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