ASTRIS is an optional add-on stage for Ariane 6. A payload can be mounted on top of ASTRIS inside the rocket’s fairing offering more mission possibilities as it can extend the rocket’s flight –in duration and distance – and so carry payloads farther. Whereas the Ariane 6 upper stage can reignite up to four times thanks to its Vinci engine, ASTRIS can add even more ignitions to the mission, allowing for more mission flexibility.

With ASTRIS, Ariane 6 will be able to:

• insert payloads precisely on orbits even farther from Earth (Moon, Mars, asteroid orbits).

• offer more ridesharing missions where several small payloads are launched together, even with differing destinations.

• increase the number of payloads that it can take to different low Earth orbits on a single launch.

ASTRIS will use a 5 kN engine called BERTA (an abbreviation from the German Bi-ergoler Raumtransport-antrieb). The engine runs on storable propellants that stay liquid over a wide range of temperatures both on Earth and in space. The two fluids, a fuel and an oxidiser, react immediately upon contact in BERTA’s combustion chamber without an igniter or starter. This leads to a simple engine design and reliable reignitions, making it ideal for long flights and the various use cases of ASTRIS.

ASTRIS also allows for more ‘ride-sharing’ options, launching two payloads to two different destinations on a single launch.

There are many options available but one mission profile would see a first payload at the top position of the fairing which is released once the Ariane 6 upper stage puts it in orbit. Next ASTRIS – with a second payload on top – separates from Ariane 6 and uses its own propulsion system to take the second payload to its final destination.

The ASTRIS design includes two pairs of propellant tanks. Their size can be adapted to mission needs, optimising ASTRIS’s weight. Combined with BERTA’s reignition capability, ASTRIS can even deliver satellites for a small constellation directly into their operational orbits, allowing for the satellites to be smaller and cheaper to build as they won't need to use their own resources to travel to their final orbit.

ASTRIS is part of ESA’s Ariane 6 product adaptations programme, which is improving Ariane 6’s capabilities to meet changing market demands and support European autonomy in science, as well as in Moon and Mars exploration programmes.

The design and production of ASTRIS is supported by several ESA member states, participating states for the initial design are Germany, Austria, Belgium, France, Switzerland and Spain.

Technical details

ASTRIS stage

Berta engine

European collaboration