A new booster engine is being tested


WASHINGTON — Stoke Space has test-fired a highly efficient engine it is developing for the first stage of its fully reusable launch vehicle.
The engine, designed to produce up to 100,000 pounds-force of thrust, went up to 50% of its rated thrust in the two-second test.
The goal of the test was to see how the engine started up and shut down, Andy Lapsa, chief executive of Stoke, said in an interview.
Lapsa said Stoke chose this approach because it was needed for rapidly reusable launch vehicles.
Stoke plans to use seven of the engines on the first stage of Nova, the fully reusable medium-lift launch vehicle it is developing.
Lapsa said there is some commonality between the booster and upper stage engines in areas like technology used in the engines’ turbomachinery, as well as analysis tools.
“In a lot of ways all systems are go and the last big question mark that I felt carrying on my shoulders was the first stage engine, and specifically getting the engine through the transients and back successfully,” he said.
He noted that the test took place just 18 months after the company started to design the engine.


WASHINGTON— Stoke Space conducted a test firing of a highly efficient engine that will be used in the launch vehicle’s first stage, which will be fully reusable.

The Kent, Washington-based company revealed on June 11 that on June 5 it conducted a short engine firing at a test site in Moses Lake, Washington. In the two-second test, the engine—which is rated for 100,000 pounds of thrust—went up to 50% of its maximum capacity.

Andy Lapsa, the CEO of Stoke, stated in an interview that the test’s objective was to observe how the engine started and shut down. He claimed that the startup and shutdown transients carried all of the complexity and risk. Because the objective of the test was to demonstrate the transient and then back out, it was brief. “.

The engine is designed with a process known as full-flow staged combustion, in which the oxidizer (liquid oxygen) and engine fuel (liquified natural gas) pass through independent preburners before entering the main combustion chamber. More development work is required for that strategy, which provides longer engine life and increased efficiency. It is exclusively utilized on SpaceX’s Starship vehicle’s Raptor engines at the moment.

Stoke selected this strategy, according to Lapsa, because it was required for quickly reusable launch vehicles. “You need high performance in a world of rapid reuse,” he declared. “You get the best performance possible in the least taxing circumstances with full-flow stage combustion. “.

The engine’s testing at the moment is concentrated on the brief conditions during startup and shutdown. In order to conduct longer tests, including a complete qualification test campaign, the company is constructing a larger test stand, which will be finished later this summer.

Stoke is developing a fully reusable medium-lift launch vehicle called Nova, which will use seven of the engines on its first stage. In order to enable the upper stage to make a powered landing, it uses a completely different engine technology. Liquid oxygen and liquid hydrogen power an engine that is integrated into an actively cooled heat shield. The prototype “hopper” was flown by the company in September of last year to test the system.

The technology utilized in the engines’ turbomachinery and analysis tools, according to Lapsa, are areas where the booster and upper stage engines have some things in common. Other than that, the system is essentially brand-new and unique. “.

Stoke is improving the car in other areas. He stated that the company is performing a “design iteration” on the upper stage and that flight avionics and software were utilized during the engine tests. The company raised a $100 million Series B round last October to fund that work.

“In many respects, everything is operating as it should, but there was one last major concern that I felt burdened with: the first stage engine, and more especially, successfully navigating the engine through the transients and returning,” he observed.

Following the hopper test in September of last year, Lapsa stated that the company’s internal objective was to start orbital flight testing in 2025, with the intention of expediting that timeline if feasible. He declined to provide an updated timeline following this engine test, stating that it would depend on when the business can begin construction on the vehicle’s launch site, which is Launch Complex 14 in Cape Canaveral, which Stoke was given by the Space Force last year.

He mentioned that only eighteen months had passed since the company began working on the engine’s design. He predicted that eventually, “just as fully rapidly reusable rockets will render all others obsolete, I think that these high-performing engines that make that mission possible will render the lower performing variants also obsolete.”. “I believe it’s a technological mountain that needs to be ascended, and I can’t wait to get there. “.

scroll to top