Phoebus thrust frame

Phoebus model showing thrust frame. The Phoebus project has developed a carbon-fibre propellant tank that could be used in the Ariane 6 rocket or others.

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’s 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.

The central core of ESA’s Ariane 6 rocket runs on liquid oxygen and liquid hydrogen, two very different molecules, so the Phoebus project is developing and producing two versions of the same carbon fibre tank concept. The Ariane 6 rocket upper stage’s engine is attached to the oxygen tank via a “thrust frame” with pipes running down it from the tanks to the engine. ArianeGroup has come up with an innovation that allows the fuel pipes to be a part of the thrust frame structure – two functions in one part equals a lighter launcher. 

Phoebus is part of ESA’s Future Launchers Preparatory Programme (FLPP), that helps develop the technology for future for space transportation systems. By conceiving, designing and investing in technology that doesn’t exist yet, this programme is reducing the risk entailed in developing untried and unproven projects for space.