The European Space Agency has announced that it will begin testing a carbon fibre-reinforced plastic liquid oxygen tank that will be used aboard the Ariane 6 Icarus upper stage.
In May 2019, ESA signed an agreement with ArianeGroup and MT Aerospace to develop Phoebus, a prototype of an upgraded Ariane 6 upper stage called Icarus (a rather unfortunate name for something that is supposed to fly reliably). The Icarus upper stage will boost the payload capacity of Ariane 6 while reducing its production costs. In May 2021, ArianeGroup received an initial €14.6 million to begin developing the stage, which was followed by another €50 million in November 2022.
On 24 October, ESA announced that it had successfully completed the test readiness review for Phoebus the week prior. Testing of a two-metre-wide model oxygen tank will, as a result, begin shortly. The tank will be “tested as if it were really flying.”
Testing of the oxygen tank will begin at a Rheinmetall military test site in Unterlüß, Germany. According to ESA lead engineer on the project, Kate Underhill, the location was selected as the facility is “used to handling explosions.” “When working with liquid oxygen, if things go wrong, they go wrong very quickly.”
The first step of testing will see the tank pressurized with nitrogen. This process will then be repeated with helium, which will help to identify any leaks in the tank. The team will then begin testing with oxygen.
Once testing of the oxygen tank has been successfully completed, testing of a hydrogen tank of a similar scale will begin. This is expected to occur next year. Testing of a full-scale structural demonstrator of the upper stage is then expected to begin in 2025.
