\tEnabling & Support<\/p>\n
\t\t\t\t\t\t16\/10\/2025
\n\t\t\t\t1139 views
\n\t\t\t\t\t\t\t\t\t\t20 likes<\/p>\n
\t\tIn brief<\/p>\n
Progress is being made on the Phoebus project\u2019s carbon fibre hydrogen tanks for a potential future application on Ariane 6 and spin-off industrial applications<\/p>\n
Smaller scale models have proven this world-first technology is possible<\/p>\n
A 2600-l carbon-fibre reinforced plastic hydrogen tank is now in the final stages of production<\/p>\n
A new test facility in Trauen, Gemany, passed a preliminary design review in June and is being prepared for testing with hydrogen from April 2026<\/p>\n
\tIn-depth<\/p>\n
\t\t\t\t\t\t\tPhoebus upper stage in orbit<\/a><\/p>\n Phoebus is a European Space Agency (ESA) project together with ArianeGroup and MT Aerospace. It aims to assess the feasibility and benefits of replacing the metallic tanks on ESA\u2019s Ariane 6 upper stage with carbon-fibre reinforced-plastic tanks. While this lightweight material offers the possibility of saving several tonnes of mass, such an approach has never been implemented before and presents significant technical challenges.<\/p>\n The central core of ESA\u2019s Ariane 6 rocket runs of liquid oxygen and liquid hydrogen, which are two very different molecules, so the Phoebus project needs to develop and produce two types of tanks able to withstand extremes. This article focusses on progress made on the hydrogen tank, other Phoebus news is linked at the end of this article.<\/p>\n \tLet it freeze<\/p>\n \t\t\t\t\t\t\tPhoebus hydrogen tank in final stages of production<\/a><\/p>\n Hydrogen is the smallest molecule in the Universe, and when used as fuel on the Ariane 6 rocket it has to be cooled to \u2212253 \u00b0C, just 20 degrees above absolute zero, the coldest temperature in the Universe.<\/p>\n Generally, carbon fibre composites do not like it that cold, like your skin in winter. With the cold your skin gets dry and brittle such that when you move it can crack. This is the same for carbon fibre tanks: when filled with cool propellants under pressure, small cracks can form which is not what you want on a rocket tank.<\/p>\n With these extreme conditions the Phoebus project team overcame many technical hurdles \u2013 not only on development and tank concepts but also on measurement – there are no off-the-shelf devices that accurately measure miniscule leak rates at cryogenic temperatures as low as \u2013253 \u00b0C.<\/p>\n Phoebus has already proved it is possible: small 60-l demonstration \u2018bottle\u2019 tanks have shown that carbon-fibre reinforced-plastic can hold hydrogen in liquid form \u2013 without leaking<\/a>.<\/p>\n \tIncreasing the ice-cold pressure to cracking point<\/p>\n