Sustainable propulsion systems boost spaceflight
The space industry is going places: The need to achieve technological progress and deliver sustainable propulsion systems is producing a host of new players that are driving these innovations inexorably forward. Evonik Active Oxygens’ environmentally compatible propellant, PROPULSE®, has an important role to play here.
Fast internet, communication, or navigation – satellite data is not just making life on Earth easier. Space-based data and technologies can also be used as tools for addressing the global challenges of our time. Earth observation from space plays a key role in combating climate change or in sustainably managing agricultural land, for example through “smart farming”. There are also numerous aerospace technology innovation projects aimed at making spaceflight itself more sustainable, for example, by using more environmentally compatible propellants.
One such innovative propellant is PROPULSE®, manufactured by the Active Oxygens business line at Evonik. Uses of the highly concentrated hydrogen peroxide (H2O2) marketed under this brand name include launching space rockets and, in the future, navigating satellites. Unlike conventional propellants, its degradation process does not produce any substances that are harmful to humans or the natural world, just water, oxygen, and plenty of energy. The oxygen released can continue reacting downstream with organic material and thus generate additional power. In fact, this advantage is utilized in hybrid rockets, where the oxygen reacts with polymer-based solid fuels.
EU’s “ENVOL” project is working on a hybrid rocket system
Evonik is therefore also naturally involved in the development of sustainable rocket propulsion systems, contributing its experience in this field to major research projects. One example is the Horizon 2020 HYPROGEO (Hybrid Propulsion Module for transfer to GEO) project, funded by the European Commission. This already-completed project was dedicated to building a hybrid rocket engine that uses 98-percent hydrogen peroxide as a propellant. Solutions with such high concentrations contain virtually no water: Less ballast on the way into space means less energy required, less waste of resources, and lower costs.
The Active Oxygens business line is currently involved in a second EU project called ENVOL (European Newspace Vertical Orbital Launcher). Here, nine private companies from seven European countries have formed a consortium led by Evonik’s Norwegian partner Nammo Raufoss AS. The objective is to develop a reliable, environmentally compatible hybrid rocket system for the European space market that can carry mini satellites weighing up to 500 kilograms into space. The propellant used is – of course – PROPULSE®.
The experts at Active Oxygens know from decades of experience how to handle and store hydrogen peroxide. This is exactly the expertise they bring to the ENVOL team. “Among other things, we conduct material compatibility tests at our laboratories in Germany,” explains Anna Kunkel, Senior Marketing Manager for Evonik Active Oxygens’ aerospace business. The first rocket launches are to be carried out from the Andoya Space Port in Norway.
“As far as launch vehicles and low orbit space transportation are concerned, the potential of hydrogen peroxide is massive,” says Kristian Lium, Vice President of Nammo Raufoss Space. “It is the only really sustainable alternative available today that is affordable and which has been technologically proven over the course of decades. We rely on Evonik’s PROPULSE® for our rockets.”
DLR uses H2O2 in the development of hybrid rocket engines
Stefan May, Head of Testing at the German Aerospace Center (DLR), and Thino Eggers, Head of the DLR’s spacecraft department, take a similar view. “We opted to use hydrogen peroxide as an oxidizer when we were developing our hybrid rocket engines,” says May. “Early on in our research, we identified the benefits that hydrogen peroxide offers, compared to previous conventional providers of oxygen. It is non-cryogenic, non-toxic, can be stored, and is potentially high energy,” the solid fuel and hybrid rocket engine expert explains.
When exposed to atmospheric pressure, cryogenic liquids, such as helium, hydrogen, or oxygen, are only liquid at very cold temperatures. Major technical and energy inputs are required to produce, store and handle them. “Hydrogen peroxide therefore enables much safer testing operations with greatly reduced environmental protection requirements. This is also reflected in the development and operating costs of such engines.”
The DLR Institute of Aerodynamics and Flow Technology has been working on the development of efficient rocket propulsion systems for more than ten years. The institute uses Evonik’s PROPULSE® product for testing purposes at the DLR test site in Trauen on Lüneburg Heath in Germany. “Evonik has supported our research work from the very beginning by providing both PROPULSE® and expertise in handling and storing hydrogen peroxide,” says May. As its contribution to green rocketry, the institute is planning to enhance PROPULSE®-based technology for hybrid rocket engines over the next few years until it is deemed to be airworthy – with the support of the newly established Responsive Space Cluster Competence Center, among others.
“New Space” is taking the space market to another level
And other players in the space industry are also opting to use this environmentally compatible propellant. This is because the market is undergoing radical change. Under the heading “New Space”, more and more private-sector space businesses and startups are entering the market, which was previously dominated by large government organizations like the United States’ National Aeronautics and Space Administration (NASA) or the European Space Agency (ESA). “The private sector alignment of the space market is helping to shift the focus away from military toward industrial, commercial use,” points out Anna Kunkel from Evonik Active Oxygens.
And that is creating the ideal development conditions for PROPULSE®. “Numerous startups around the world are already using our PROPULSE® product as an environmentally compatible propellant in their latest generations of rockets,” the spaceflight expert is pleased to report. “This means that the new companies now entering the market are playing a key role in the development of advanced rocket technology.” Previous technologies are being enhanced in a competitive environment to make their use as part of all processes more sustainable, productive, and therefore more cost effective.
Careful use of resources to make spaceflight more sustainable
For example, research is being conducted into reusing rockets or individual components. Other approaches to reduce costs and increaseresource efficiency include the use of standardized components, serial production and miniaturization, as the Office of Technology Assessment at the German Parliament (TAB) states in its “New Space – new dynamics in space exploration” study (german) dated October 2020. National space agencies have been partnering with innovative private-sector players for a long time. NASA and ESA are key clients of many new space companies, thanks in part to the relaxation of regulations governing the award of contracts.
“By developing new technologies and business models, commercial businesses are stepping up the pace of innovation in the spaceflight sector,” the study reports. New space companies are operating “on the one hand in the traditional space industry’s established business areas, e.g., communication, navigation, and Earth observation, while opening up entirely new fields of activity on the other.” These include, for example, private manned spaceflight or even the “development of new space habitats”.
Demand for environmentally compatible, safe propellants is also growing due to safety concerns and increasingly stringent regulations. This dynamic is compelling the market to realign. “In addition to the development of small launch vehicles, we are observing aspirations to ensure space is kept clean and to deliver sustainable propulsion systems,” Kunkel explains. As far as launch vehicle applications and low-orbit space transportation are concerned, the potential of hydrogen peroxide is therefore massive.
* Source: “New Space – new dynamics in space exploration” study (german), Office of Technology Assessment at the German Parliament (TAB)
Evonik Active Oxygens offers its customers a complete package of solutions
However, Evonik Active Oxygens wants to do more than just supply hydrogen peroxide. The company also aims to provide companies with an entire package of solutions. “It’s a complex issue,” says Kunkel. “There are a lot of technologies, propulsion options, and different rocket sizes out there. Our PROPULSE® product needs to be tailored specifically to the various application options in each case.”
The H2O2 experts have already mentored plenty of startups right from the beginning, visited their facilities, and advising them. Evonik Active Oxygens assists them not only with packaging and transportation but also with logistics and technical support. Support is provided right from initial discussions through the first deliveries for engine tests and rocket launches. “Ideally,” says Kunkel, “we would be present every time the ground shakes and a rocket lifts off into space.”
