SCIENTIFIC COOPERATION — Researching nitrous oxide (N2O)-based satellite propulsion technology with DLR for replacing hydrazine
Earlier this year, the NZ Ministry of Business Innovation and Employment (MBIE) awarded Dawn Aerospace a $1.5M grant, distributed by the Catalyst: Strategic Fund from Government Funding, to support a three-year R&D project with DLR – the German Aerospace Center.
Under the agreement, the DLR Institute of Space Propulsion, DLR Institute of Combustion Technology, and Dawn are working together on deep-tech research into nitrous (N2O)-based satellite propulsion technology. When it comes to matching applied academia and industry, this scientific cooperation is hard to beat.
The New Zealand Space Agency caught up with Stefan Powell, Dawn Aerospace CEO and CTO, to see how things are going 6-months in.
“Our first task in making transportation in space simpler and more sustainable is to replace the toxic propellant hydrazine (the dominant chemical used for in-space transportation) with something less toxic, and more easily accessible for the many new companies wanting to build satellites.”
— Stefan Powell, CEO & CTO
What does this project represent for Dawn’s long-term mission and some of the important societal challenges you’re looking to tackle?
We have a vision of sustainable and scalable space transportation at every step, from getting things to space, moving them around, and bringing them back to Earth. Currently, the dominant chemical used for in-space transportation is a toxic propellant called hydrazine. Our first task in making transportation in space simpler is to replace this fuel with something less toxic and more easily accessible for the many new companies wanting to build satellites. Fuelling a satellite with hydrazine comes with a $500,000 price tag, which is more than some satellites’ total build and launch cost. It’s an expensive, prohibitive, and highly carcinogenic product that has no place in the NewSpace industry.
Dawn is already beating hydrazine systems on price, lead time, safety, and accessibility with our green propulsion technology, but to fully replace hydrazine, we have some work to do on performance. Our thrusters are fast on track to being the ‘green’ standard for the small satellite industry, but we know many other applications would benefit from these propellants, including larger satellites, deep-space, and lunar missions. The work we are doing with DLR is to progress the fundamental understanding of these propellants, so we can push thruster limits, improve performance, and then replace hydrazine once and for all.
What outcomes do you hope to achieve through this collaboration?
The concept of N2O-based bi-propellant propulsion systems is not new. They’ve been around for a long time and extensively tested on the ground. The problem is that these engines are hard to get right, and the thermal kinetics are a real pain. Some of the nitty-gritty details, like how N2O acts as a coolant, are not well understood. Exotic materials and film cooling are typically used to solve this problem, but we additively manufacture our thrusters as a single piece using Inconel alloy 718. We want to keep doing this because the low cost, scalability, and speed of production are major advantages. What is new is that we flew the thrusters in space, which had never been done before, thus proving that our method of design, manufacture, and verification — works. Now it’s time to optimize the engine to be the best it can be. But to build the best nitrous engines in the world, there are knowledgeable gaps to fill, and a lot of the research we need does not yet exist. We aim to fill that gap through this scientific cooperation with DLR. We’ll also publish a series of scientific whitepapers with them, which is very cool.
International collaborative research projects often provide findings beyond what one team could achieve alone. In what areas do you hope to gain more skills and a better perspective of the topic you are researching?
DLR are experts at fundamental research. They have the authoritative expertise in combustion research, and this collaboration gives us a direct line to the world’s best researchers and minds in the business. At Dawn, we’ve proven ourselves in applying knowledge to build useful products that have significant commercial value. Research benefits from commercial feedback to assess what knowledge is valuable, and new products need research to make large changes from the status quo, else only incremental changes are possible. In combination, we can find solutions to extremely difficult problems that we couldn’t do alone, then turn that knowledge into world-changing products.
How will this collaboration change how you operate in the future?
We have customers asking us to support advanced deep-space missions like GTO > GEO transfers, Lunar, Mars, and asteroid insertions. These high-performance missions benefit substantially from every last percent of performance, so naturally, there is a desire to squeeze more out of them. This collaboration will help make these missions a reality and thus allow green propulsion to be more universally applied in space.
Talk to us about the match between applied academia and industry and what this means for both.
We’ve come together to create positive results for both entities. It’s a great story of bridging industry and applied academic pursuits. As the industrial participant, we get access to knowledge and experience we usually wouldn’t have access to. For DLR as the applied academia participant, they receive a timely industry problem and are able to apply their research to a product with a high technology readiness level and relevance in the market. DLR has several Ph.D. students involved in the various work packages we are doing together, and these students get to include high-pedigree research in their thesis.
With 33 thrusters in orbit, propelling eight satellites, we’ve become the world leader in commercializing N2O-based propulsion systems, and we are regularly launching hardware to space. Since the project began, we have sent eighteen B20 thrusters to space, and more are scheduled for this year. We are delivering systems for orbital transfer vehicles (OTVs), Earth observation, internet, and IoT constellations. DLR’s research outcomes will be flying on these spacecraft.
Six months in, how are things going?
Extremely well, and I’d like to highlight how great it’s been working with DLR. They have a fantastic attitude, a willingness to share their wealth of knowledge, and a cordial nature we highly respect. Four work packages are on the table, and we are well into the first two. Thorough test plans are solidified, we’ve scaled up the team, hardware is being produced, CFD models are up and running, and we’ve already experimentally demonstrated that the novel cooling techniques we want to employ work on the test bench. We’re on the right path, and the collaboration is moving at a pace that gives us great pride as a company.
What’s next after this project?
This project has been an amazing kick-start for our relationship, but it’s by no means reached its true extent. We’ve already started several other projects with DLR that are actively ongoing. For example, colleagues at the DLR Institute of Aerodynamics and Flow Technology recently conducted a plume analysis of our B20 thruster. The findings were presented at this year’s Space Propulsion 2022 conference in Portugal and were published in the paper, ‘Composition Measurements In a Freely Expanding Green Propellant Thruster Plume.’ DLR has a wealth of knowledge in certain areas of value for our reusable spaceplane project too, so I’m sure we’ll do something there in the future.
This article was originally posted at www.mbie.govt.nz/science-and-technology/space/nzspacetalk/international-research-projects/
