Reaction Dynamics (RDX) is moving its rockets from hybrid to liquid-fuelled engines, the Longueuil, Que., company said Thursday, a switch it says will let its Aurora rocket carry more mass to orbit and streamline work on Borealis, its planned medium-lift launcher.
RDX has dropped Aurora-1, the suborbital test flight it had planned from the Koonibba Test Range in South Australia, because the flight was designed to prove a hybrid engine that is no longer part of the company’s product plans. The company is still aiming for an orbital launch from Canadian soil in the fourth quarter of 2028, and has an agreement with Maritime Launch Services for a dedicated pad at Spaceport Nova Scotia.
“Our hybrid program laid the technical foundation we’re building on today,” chief executive and co-founder Bachar Elzein said in the release. “Storable liquid propulsion extends that work: it increases Aurora’s capacity and sets us up to scale.”
The liquid-fuelled engine campaign
The company says it has completed 50 tests in its new liquid-engine program. A recent campaign of 21 hot-fire tests covered two engine variants, several injector designs, and start-up and shutdown sequences.
In the final firings, the engine reached a characteristic-velocity efficiency above 95 per cent, a measure of how close combustion comes to the theoretical best for its propellants. The company also reported strong thermal margins, meaning the hardware ran well below the temperatures it can tolerate.
RDX is sticking with storable propellants, which can be kept at ordinary temperatures. Most new rockets burn liquid oxygen, which must be held colder than minus 180 C and boils away if left in a tank. RDX’s hybrid paired solid plastic fuel pellets with hydrogen peroxide, a storable oxidizer, SpaceQ previously reported. The company says storable propellants simplify testing and launch and allow flights from remote sites, including the Arctic.
Its two rivals in Launch the North, the $105-million Department of National Defence (DND) challenge meant to give Canada its own launch capability, both plan to burn liquid oxygen: Canada Rocket Company with liquid methane, NordSpace with kerosene. The three companies split about $25 million in the first phase of the challenge in March.
Australia flight dropped
RDX announced the Koonibba flight in October 2024 as a test of its RE-102 hybrid engine in the vacuum of space, at about 125 kilometres’ altitude, with Australian range operator Southern Launch as host. The rocket passed its critical design review last November, and in July the company was preparing an integrated stage test before shipping it to Australia in standard shipping containers.
The company says Aurora-1 produced more than 350 engine firings and a ground qualification campaign, and that the team and test experience it built now go into the liquid rockets.
Instead of the suborbital flight, RDX will fire RE-X, its orbital-scale liquid engine, and the assembled rocket stages for the full length of a mission on the ground, before they fly on the first orbital launch.
Borealis and Falcon 9
RDX describes Borealis as a medium-lift rocket for sovereign, national security and commercial missions that need bigger payloads. Under NASA’s classification, medium-lift rockets carry between two and 20 tonnes to low Earth orbit. Aurora will act as a qualification platform for Borealis, flying the technology the bigger vehicle needs, the company says.
Aurora is listed on RDX’s website at about 250 kilograms to a sun-synchronous orbit, the near-polar path favoured by Earth-observation satellites.
“With the announced phase-out of Falcon 9, access to medium-lift launch is going to tighten, and Canada will need a capability of its own,” Elzein said. “Borealis is our answer.”
SpaceX chief executive Elon Musk wrote on X in August that once Starship flies reliably several times a week, it makes sense to shift resources to it, “which means winding down Falcon.” Starship reached orbit for the first time on Sept. 28, and SpaceX has reportedly stopped taking rideshare bookings beyond late 2028.
Borealis puts RDX on the same path as Canada Rocket Company and NordSpace, which have both pitched medium-lift rockets. When SpaceQ asked RDX about medium-lift in July, the company said its immediate focus was the milestones in front of it.
The road to orbit
RDX is building RE-X and plans to start hot-fire testing in November. The first campaign’s main goal is a short burn with the engine connected to its feed system, the plumbing that delivers propellant to it.
Thursday’s release was short on technical detail, but RDX says more on the liquid program and its updated roadmap will follow in the coming weeks.