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 10R on Flight 126, this will be 10th use of an Ariane 42L.

Overall for Flight 126, 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.
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.
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.
VEB 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.