The same umbilicals allow the fuel to be drained safely if a launch is aborted.

Each arm is 13 m long and weighs 20 metric tons. One arm supplies liquid hydrogen at -250°C, the other supplies liquid oxygen at -180°C. When Ariane 6 lifts off, these arms will disconnect from the rocket and then pivot away quickly, in just 2.6 seconds, to avoid interfering with the rocket's ascent.

This maneuver requires great precision. Almost simultaneously it is necessary to disconnect the arms, protect the supply hoses from gas ejections from the boosters and allow the launch vehicle to pass while avoiding any contact with it.

A 50-metric ton counterweight inside the mast speeds up the retraction of the arms. A smart damping system allows the arms to brake before the end of their swing backwards in order to protect the mechanical links with the mast.

Keeping the fluid supplies connected with the rocket until the moment of liftoff guarantees the best availability and simplification of the interface with the launch vehicle.

The disconnection of the cryo-arms from Ariane 6 is much faster than it is from Ariane 5, where the maneuver comes six seconds before liftoff. This means the sequence for Ariane 6 can be triggered at the latest possible moment in the countdown, reducing the chance of unnecessary disconnects in the event of an aborted launch.

Technical qualification tests are continuing. The objective now is to complete the qualification process of the hydrogen and oxygen filling lines and launcher interfaces for the lower, core stage.

Read more from original source...