Canadian launch company Reaction Dynamics has completed a thirty-second test fire of the RE-101 hybrid propulsion system for its Aurora small-lift rocket.
The company said that this concludes developmental testing of the engine, and that it is moving on to prepare for actual launch attempt testing, with a goal of reaching orbit.
In an interview with SpaceQ, Reaction Dynamics CEO and CTO Bachar Elzein provided more details about the significance of the testing, what makes the RE-101 different from other engines, and what’s coming next.
Hybrid engine and regenerative cooling
The RE-101 is a hybrid rocket engine; it uses a combination of a solid fuel source and a liquid oxidizer. In SpaceQ coverage last year, Elzein had said that the fuel source actually consists of recycled nontoxic plastics, which will not only make the rocket more environmentally friendly with much less of a carbon footprint, but will ensure that the fuel is comparatively easy and safe to store over the medium to long-term when compared to other kinds of rocket fuels. He also noted that a hybrid engine can be much simpler than liquid engines, that it is “a rocket engine made out of [only] three parts,” while being far safer and more controllable than solid rocket engines.
The engine itself is 3D-printed, which not only allows for faster iterative development, but also reduces the cost of production significantly, while reducing the carbon footprint of engine production as well.
In his recent comments, Elzein explained that the principal difference of the RE-101 is in its use of a regeneratively cooled thrust chamber assembly, and that it was this regeneratively-cooled nozzle that was the most critical subject of the recent testing. He said that the propellant is “circulated through channels around the nozzle before it enters the combustion chamber” in this kind of cooling. The propellant absorbs heat from the nozzle walls, he said, “reducing the temperature of the nozzle and preventing it from melting or weakening,” while also pre-heating the propellant in a way that ensures better combustion.
This regenerative approach to cooling is commonly used in liquid-fueled rockets; one of Reaction Dynamics’ innovations is using it in a hybrid engine, which allows for more consistent thrust pressure and much less nozzle erosion than is generally believed to be possible in hybrid engines. In the case of the RE-101, the oxidizer is used for cooling, rather than the fuel.
RE-101 development testing concluded
This successful thirty-second burn concludes “an intensive three year period of development, testing, and demonstrations,” Elzein said, including over fifty hot fire tests.
It might be surprising that Elzein said that a 30-second test was an appropriate conclusion to testing, and he elaborated on why that was the case. He said that the test validates that the engine “is operating nominally after the thrust chamber has transitioned from the ignition phase to Steady-State Operation, where the propulsion system produces a consistent and stable thrust.” The process of transitioning from ignition to steady operation causes increasing thermal and pressure stresses, so the engine must be tested long enough to ensure that there are no leaks, no problems with the seals, and that the cooling systems are working properly.
Elzein said that the transition “often occurs in a shorter time frame” than thirty seconds, but that a longer test was necessary because the company needed to prove that the engine’s regenerative cooling was up to the job over a longer period of time. “Achieving success in this test is crucial,” he said, “as it demonstrates the propulsion system’s ability to perform according to specs under extended operational conditions.”
For Reaction Dynamics’ Aurora launcher, it’s especially important, as its RE-101 engines are expected to have a thirty second burn time during ascent in its inaugural flight.
Next steps for Reaction Dynamics
As also mentioned in the earlier SpaceQ coverage, Reaction Dynamics has signed a letter of intent with Maritime Launch Services (MLS) to launch the Aurora from MLS’s still-in-development commercial spaceport, Spaceport Nova Scotia.
Reaction Dynamics will be doing both suborbital and orbital test launches from the Spaceport during its “Phase One” development period, where it’s suitable for small launchers and is still developing the infrastructure for medium-lift launchers. If successful, this will be a significant milestone for the Canadian space industry, pairing a made-in-Canada launcher with a Canadian spaceport. Elzein said that the timeframe for the first suborbital flight is now scheduled for “the last quarter of 2024.”
He said that “we remain in talks with our partners” regarding the details of the launches. This includes talks with MLS, and with online launch marketplace Precious Payload. Precious Payload will be connecting Reaction Dynamics with customers for these suborbital and (eventually) orbital launches. Elzein said that “this opportunity may appeal to entities involved in academic research, technology demonstrations, and similar fields seeking access to space.”
He also said that Reaction Dynamics would have a new announcement related to a “new development project” coming very soon, “so stay tuned.”
Finally, when asked about the search for all-too-scarce space industry talent, he admitted that “hiring in 2023 has not been without its challenges, and I anticipate that these challenges will persist into 2024.” He added that Reaction Dynamics has “demonstrated creativity in navigating these complexities,” however, and that he recognizes that “the demand for skilled engineers and talented professionals will remain high in our industry.”