Europe is looking for a green pathway to outer space. And this pathway leads through the Evonik production plant in Rheinfelden. Here hydrogen peroxide, H2O2 for short, has been produced for decades—and in recent years it has also been produced for space travel. The Evonik product PROPULSE® is currently driving the turbo pumps of the Russian Soyuz rockets. One rocket of this type, with an output of 26 million hp, also sped the German astronaut Alexander Gerst to the International Space Station (ISS) in June. And one month later, PROPULSE® was used to fuel the space shuttle that provides the ISS crew with food and materials. The Soyuz rockets still use kerosene fuel and are thus continuing the technical tradition of the R-7 rocket that sent the first satellite, Sputnik 1, into orbit back in 1957. They are regarded as being very reliable, but their technology is already fairly old. Another category of rocket fuel is hydrazine and its derivatives, which develop their full power by means of a decomposition catalyst. A crucial disadvantage of hydrazine is that it is categorized as a carcinogenic substance and may even be banned in the European Union in the future.
The EU has promoted the idea of “green rocketry” under the name of Hyprogeo. Here hydrogen peroxide once again plays a role. H2O2 has a very high energy density and breaks down only into steam and gaseous oxygen—a fuel can’t get any cleaner than that. The explosive breakdown of hydrogen peroxide is triggered by contact with a catalyst consisting of a noble metal. As a rule, the necessary starting energy for a hybrid rocket is provided by a solid fuel in addition to the H2O2. In the Hyprogeo project, polyethylene is used. It’s a simple and clean-burning plastic that is also used for plastic bags. The advantage offered by H2O2 is that the oxygen produced by its decomposition can be used for combustion. That means there’s no need for the frozen liquid oxygen that is still used in many rockets.
Because weight plays an extremely important role in space travel, the specialists in the Active Oxygens Business Line have improved their product. The new PROPULSE® 875 already consists of 87.5 percent hydrogen peroxide by weight and only 12.5 percent water. In addition, Evonik has developed a process that generates a product consisting of 98 percent hydrogen peroxide by weight: PROPULSE® 980. In this process, water is removed from the solution step by step through crystallization. The plant in Rheinfelden has produced hydrogen peroxide for over 100 years and amassed a wealth of experience in this area. The new product has been used for the tests of Hyprogeo since 2017. H2O2 could even be used as the sole fuel in satellites—for controlling their positions in space, for example. Because using PROPULSE® brings tremendous weight reduction, it is opening up new doors for space exploration.