Themis flight model: assemble!
In brief
ESA’s reusable rocket demonstrator Themis started assembly before the summer at the ArianeGroup integration building in Les Mureaux, France. Themis will demonstrate rocket stage recovery and reuse technologies.
In-depth
Having finished its testing programme on the main systems at ArianeGroup’s nearby Vernon test facility in France, the reuseable rocket stage is now being built up with all the components necessary to launch, land vertically, and be reused for another mission. This includes installing the landing legs, power systems, avionics and its engine that runs on liquid methane.
The engine, called Prometheus, was installed on the launcher’s engine bay, followed by the thrust vector actuation system that allows the engine’s forces to be directed and controlled. Shortly afterwards the system was tested to verify the installation. Prometheus is a reusable engine demonstrator that can vary its thrust from 30% to short bursts of 110% thrust needed for liftoff and landing.
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The avionics system that consists of the computers, the power distribution hardware, batteries, cable harness and more is now being installed. Like most launchers and spacecrafts, Themis relies on pressurised gas to push propellant to its engine, so the pressurisation system will be installed next.
The stainless-steel tanks for the rocket’s liquid methane and oxygen propellant have been cleaned since last use on the test stand in Vernon. The tanks are now closed and ready for fitting to the rocket other main structures.
A large demonstrator
Themis comes in at 28 m tall, and its Prometheus engine is almost as powerful as the Ariane 6 Vulcain 2.1 engine. Such a large-scale prototype makes the demonstration more representative of a Europe’s next generation access to space. As a wink to the past, Themis is being built in the place where the main stages for Europe’s rocket Ariane 5 were assembled at Les Mureaux, near Paris, France. This historic building is 50 m tall and could hold the Arc de Triomphe.
Meanwhile in Sweden a launch pad gets ready
A successful flight demonstration requires more than just a launcher and preparations are underway to build the Themis test launch facility in Sweden.
Teams are now finalising the electric and fluidic ground support equipment. This includes the fuel lines, nitrogen supplies, rocket stands, flares to burn off unused fuel, and propellant tanks. To deliver the liquid oxygen and liquid methane propellants for Themis, storage and distribution systems are being constructed.
Lastly the installation of an operations centre – Themis mission control – has started in a room of an ESA building at Esrange to launch and monitor the rocket.
Themis will be transported by truck over 3000 km to the Swedish Space Corporation launch centre Esrange in the north of Sweden, where its first flight will be a small “hop” – firing Prometheus continuously but at varying throttles. This hop is set to be the first time Europe will demonstrate a vertical take-off and landing rocket element with cryogenic propulsion.
