New Milestones for Themis, the First European Reusable Rocket

On November 6, the European Space Agency (ESA) provided an update on the development of the Themis program. The first European reusable rocket demonstrator is now being assembled ahead of the first “hop” test, scheduled for 2025.

Themis

The project was first presented in 2018, with the objective of developing rocket reusability capabilities for the post-Ariane 6. Themis will also demonstrate the capabilities of the Prometheus engine, whose development program began a few years earlier.

Both programs are managed and developed by ArianeGroup. Its subsidiary, MaiaSpace, aims to produce a partially reusable rocket called Maia, based on the Themis booster.

Themis, standing 20 meters tall and equipped with a single Prometheus engine, is propelled with liquid oxygen and methane. It will feature four seven-meter landing legs produced by the German MT Aerospace.

Prometheus prototype engine test

The vehicle will be flown from the Swedish Space Corporation (SSC) launch center in northern Sweden. The site is currently under construction, with teams finalizing the installation of electrical equipment, fuel lines, nitrogen supplies, rocket stands, propellant tanks, and a mission control center.

In recent years, the engine, Themis ground model (T1G), and first flight model (TH1) have undergone various tests, including re-ignition and cryogenic tests, at ArianeGroup’s site in Vernon, France.

Themis reuseable rocket stage demonstrator ground model (T1G, left) and the first flight model (T1H, right). Credits: ArianeGroup — *Themis reusable rocket stage demonstrator ground model (T1G, left) and the first flight model (T1H, right). Credits: ArianeGroup*

Now, that the testing program is finished, the vehicle is being assembled with all components for flight, including the landing legs, grid fins, power systems, and avionics.

The future of rocket reusability in Europe

Nine years have passed since the first successful landing of a Falcon 9 first stage by SpaceX. Since then, the American company has completed over 350 landings and relaunched boosters hundreds of times. The impressive numbers achieved by Falcon 9 are even more significant when compared to the current lack of any comparable competitor, both in the U.S. and globally.

Landing of the Falcon 9 first stage at Landing-Zone 1 (LZ1) at the Cape Canaveral Space Center in the OneWeb 1 Mission. Image Credits: SpaceX via FLICKR — *Landing of a Falcon 9 first stage at Landing-Zone 1 (LZ1) at the Cape Canaveral Space Center. Credits: SpaceX*

However, many private players in the U.S., as well as countries like China and India, have recognized the importance of reusability technologies for the future of the industry. Europe, on the other hand, has lagged behind for years, showing limited interest—at least on an institutional level.

Now, finally, awareness is growing at the European level of the need to develop those capabilities. Various companies, encouraged by ESA, are working on future reusable rocket technologies, including RFA, ArianeGroup, and Isar.

Additionally, the Spanish company PLD recently announced an ambitious development program for a future family of reusable rockets, scheduled to debut in the 2030s.

The complete family of PLD's rockets. From left: MIURA 1, MIURA 5, MIURA Next, MIURA Next+Lince, MIURA Next Heavy and MIURA Super Heavy. Credits: PLD — *The complete family of PLD’s rockets. From left: MIURA 1, MIURA 5, MIURA Next, MIURA Next+Lince, MIURA Next Heavy and MIURA Super Heavy. Credits: PLD*

Although the gap with the United States and China appears to be widening, the European sector cannot afford to be less ambitious in developing reusable vehicles for the future if it wants to remain competitive in an increasingly demanding market. The path paved by SpaceX must, in some way, be followed.

^{*Cover image credits: ESA}