Europe’s Reusable Rocket Program: Themis Shows Signs of Life
The European Space Agency (ESA) and its contractors have been working on developing reusable rockets for several years now, but progress has been slow. However, the latest development in the Themis program is a step forward, and it seems that Europe is finally making some credible headway.
The Long Road to Reusability
Reusable rockets have been a game-changer in the space industry since SpaceX landed its first orbital rocket in December 2015. Blue Origin followed suit by landing the New Shepard vehicle after a suborbital hop just weeks earlier. This marked a significant milestone for the industry, and it was clear that reusable launch technology was on the horizon.
The European Space Agency had already committed to developing a new medium-lift rocket, the Ariane 6, but at that time, they were not planning to incorporate any elements of reuse into its design. However, by mid-2017, the ESA began to initiate programs that would eventually lead to a reusable launch vehicle.
The Prometheus Engine
One such program was the development of the Prometheus engine, which is fueled by methane and liquid oxygen. The thrust of this engine is comparable to SpaceX’s Merlin 1-D engine. Designed by ArianeGroup, the Prometheus engine has completed two long test firing campaigns this year.
The Callisto Program
Another program that started in late 2017 was the Callisto program, which is a collaboration between France, Germany, and Japan to develop a subscale demonstrator of vertical takeoff and vertical landing technologies. This vehicle is smaller than SpaceX’s Grasshopper and uses propulsion based on liquid hydrogen and oxygen.
Although the Callisto program has faced several delays, it will now occur no earlier than 2027. The Themis program, on the other hand, started later but is further along in development.
The Themis Program
After its adoption by member states in November 2019, the ESA contracted directly with ArianeGroup to build a first-stage rocket with landing legs and using the Prometheus engine. This program aimed to be less experimental than Callisto and feed directly into a rocket that could succeed the Ariane 6.
The Themis T1H vehicle has now been integrated on a launch pad in Sweden, marking a significant milestone for the program. Low-altitude hop tests are expected to start late this year or early next year, with the goal of developing a rocket’s first stage that can vertically land after an orbital launch.
The Road Ahead
The Themis T1H vehicle will likely undergo short hops initially, about 100 meters. A follow-up vehicle, Themis T1E, is intended to fly medium-altitude tests at a later date. Some of the learnings from these prototypes will feed into a smaller reusable rocket intended to lift 500 kg to low-Earth orbit.
This is under development by MaiaSpace, a subsidiary of ArianeGroup. The European Space Agency would like to use technology developed as part of Themis to develop a new line of reusable rockets that will succeed the Ariane 6 rocket.
Conclusion
Although Themis is making progress, it’s worth noting that the program is several years behind schedule. At its inception in late 2019, Themis was intended to make its first hop tests in 2022. This underscores how far Europe has fallen behind SpaceX and other competitors in reusable launch technology.
SpaceX began its first Grasshopper tests in 2012, landed an orbital booster in 2015, and re-flighted a first stage for the first time in 2017. Other US companies, including Blue Origin, Rocket Lab, and Stoke Space, plan to launch and land orbital rockets in the next two years, along with a host of Chinese companies.
The European Space Agency and its contractors have been working on reusable rocket technology for several years now, but progress has been slow. However, the latest development in the Themis program is a step forward, and it seems that Europe is finally making some credible headway.