Rocket startup Stoke Space completes static fire test of first stage engine

Stoke's Nova rocket
Stoke’s Nova rocket

The rocket startup Stoke Space revealed yesterday that it has completed a static fire test of the first stage engine it will use on its Nova rocket, shown in the graphic to the right.

The test, which was not the first for this engine, proved out several new technologies.

Stoke Space called the test significant for several reasons. It’s the first hotfire of the company’s Block 2 (flight layout) stage 1 engine, and this engine architecture — called full-flow staged combustion (FFSC) — is considered particularly challenging. Only two entities in the world — Stoke and SpaceX — have successfully developed FFSC engines. … Stoke’s stage 1 engine is a liquified natural gas/liquid oxygen engine capable of producing 100,000 pounds of thrust. The duration of the test was not revealed.

It was the first time Stoke has tested on its new vertical test stand in Moses Lake. The company’s testing philosophy is that you must “test like you fly,” and it believes vertical testing is key to engine development.

Nor is the first stage engine the only technological innovation. Nova’s second stage uses a radical design whereby the engine releases its thrust through a ring of small nozzles on the outside perimeter of the stage, rather than a single central nozzle. This design is what the company hopes will allow it to return that upper stage intact for reuse.

The four year old company has raised $100 million in investment capital, but has also faced environmental red tape from the Space Force for its launch facility at Cape Canaveral. It had previously targeted 2025 for the first test flights of Nova, but that schedule appears unlikely because of this red tape.

Rocket startup Stoke Space is saddled with the same red tape as SpaceX

Stoke's Nova rocket
Stoke’s Nova rocket

We’re from the government and we’re here to help you! The rocket startup Stoke Space appears to be struggling with the same kind of environmental red tape that is hindering SpaceX, though in Stoke’s case the red tape appears absurdly unnecessary.

Stoke is the only company besides SpaceX developing a rocket with both its first and second stages returning to Earth to land vertically and then be reused. Unlike SpaceX Starship/Superheavy, which is gigantic and revolutionary in all ways, Stoke’s Nova rocket is comparable in size to the hundreds of rockets that have launched from Florida since the 1960s. Based on that six-decade track record, it would seem that getting rights to launch Nova (but not for its return) would be considered basic and routine, requiring little complex bureaucracy.

Hah! Fooled you!

Before any of this can take place, the Space Force must complete its “environmental assessment” of the company’s plans at LC-14 [the launchpad used for John Glenn’s first orbital mission and many others subsequently], in order to evaluate how repeat launches will affect local flora and fauna. These assessments are mandatory under federal law, and they can often take months — but the upside is that they provide a closer look at a company’s operational plans.

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Update on Cape Canaveral work by multiple launch companies

Link here. The article provides a nice summary of the construction work by Blue Origin, Stoke Space, and SpaceX at the cape, all leading to future launches and greater capabilities.

Blue Origin is still pushing for a September 29, 2024 first launch of its New Glenn orbital rocket. SpaceX is continuing work on its new Starship/Superheavy facilities as well as installing upgrades to its Falcon launchpads. The most interesting tidbit however is was about Stoke Space and its proposed Nova rocket:

The first two flights of Nova are planned for 2025, while 10 flights are planned for both 2026 and 2027. Initial flights of Nova will be expendable, with full reusability of the first and second stages coming later.

Stoke’s primary goal has been to make this rocket entirely reusable. It apparently plans to begin launching and do recovery tests as it goes until it achieves that reusability later.

Space Force adds Stoke Space and Blue Origin to its list of smallsat launch companies

The Space Force has now added rocket startups Stoke Space and Blue Origin to its list of launch companies who are now approved to bid on launches of the military’s small satellites.

The two firms join 10 other vendors in the OSP-4 pool: ABL Space Systems, Aevum, Astra, Firefly Aerospace, Northrop Grumman, Relativity Space, Rocket Lab, SpaceX, United Launch Alliance (ULA), and X-Bow.

This program is designed for launches that are not critical and can be used to help new rocket companies, while also encourage all the companies to move more quickly, as the contracts are designed to be require a launch within 12 to 24 months after award, and sometimes much sooner. For example, several recent Firefly launches required the company to deliver the payload to the assembly building and get it mounted in less than a few days, and to do so only when told by the military.

This military smallsat launch program is also wholly different than the Space Force’s large payload launch program, which presently only allows SpaceX, ULA, and Blue Origin to bid on launches. With both programs however it appears the military is no longer limiting the companies that can bid to as small a number as possible — which had been its policy for the first two decades of this century — but instead is eagerly expanding the number over time to increase competition and its own options. With the large payload program the Pentagon intends to revisit its list yearly to widen it as new companies mature.

Stoke Space test fires its first stage engine for the first time

The rocket startup Stoke Space has successfully completed the first static fire test of the methane-fueled rocket engine that will be used on the first stage of its entirely reusable Nova rocket.

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. “All of the complexity and a lot of the risk is in that startup transient and shutdown transient,” he said. “The duration of the test was short because the goal was to demonstrate the transient and then back out.”

The engine uses a design called full-flow staged combustion, where both the engine’s fuel and oxidizer — liquified natural gas and liquid oxygen, respectively — go through separate preburners before going into the main combustion chamber. That approach offers greater efficiency and a longer engine life, but is more complex to develop. It is currently used only on SpaceX’s Raptor engines that power its Starship vehicle.

The rocket’s upper stage uses hydrogen as its fuel, as well as a radical nozzle design. Instead of a single large nozzle, the thrust is released from a ring of tiny outlets at the permeter of the stage. It is hoped this design will better protect the system during re-entry from orbit, while allowing for more precise control upon landing, and thus make it possible to reuse the upper stage.

The first test launch is presently scheduled for 2025. This new engine test makes that date more realistic.

Update on rocket startup Stoke Space’s effort to make completely reusable rocket

Link here. This Nasaspaceflight.com article provides an excellent update on the status of the development of Stoke’s Nova rocket, which will have a radical new engine design in its upper stage, using a ring of small nozzles rather than one single central one. That design will allow the upper stage to return to Earth for reuse, something that no other rocket now in use at present can do.

Stoke Space recently carried out the first test of the full-size 30-thruster version of the innovative engine that the company is producing for its in-development second stage. This will be an integral part of its future Nova rocket, which aims to be a fully reusable medium lifter.

The engine test took place on Feb. 26 and follows the engine’s first test flight on its prototype vehicle, Hopper 2, in September 2023. Although fitted with only 15 chambers for that flight, Hopper 2 flew for 15 seconds, achieved a maximum altitude of 30 feet, traversed to a landing site, and touched down softly.

The article includes a lot of interesting technical details about this upper stage and what engineers are learning about this radical engine design. Worth reading. At present Stoke is the only company other than SpaceX attempting to make its upper stage fully reusable. If successful it will jump ahead of everyone else.

No launch schedule however for its new rocket was revealed in this report, so it might be awhile, if ever, before any of this bears fruit.

Stoke Space raises $100 million in private investment capital

The rocket startup Stoke Space, which is developing a radically new engine concept for its rockets, has now successfully raised $100 million in private investment capital.

This investment more than doubles the company’s total funding, which now sits at $175 million. The company also announced the official name of its first rocket: Nova.

The funding round was led by Industrious Ventures with participation from the University of Michigan, Sparta Group, Long Journey, and others. Existing investors Breakthrough Energy, YCombinator, Point72 Ventures, NFX, MaC Ventures, Toyota Ventures, and In-Q-Tel also participated. This latest funding round is evidence of strong demand for Stoke’s services, its growing success, and the confidence of investors in its future. As part of this round of fundraising Steve Angel, Chairman of the Board, Linde plc, will join Stoke’s Board of Directors. Angel is also the former CEO of Linde and a member of the Board of Directors of GE.

The company says it will use this money to develop the rocket’s first stage engines, which will follow the same ring nozzle design of its upper stage, a prototype of which it successfully test flew on a short hop last month. Under that design, the engine doesn’t have one central nozzle, but instead the thrust is funnelled out of a ring of tiny nozzles that circle the stage’s outer perimeter. The company believes this design will allow it to return its upper stage safely from orbit for re-use.

New rocket startup focusing on new concepts to make upper stage reusable

Capitalism in space: Another new rocket startup, Stoke Space, is working to develop a new innovative reusable design for its upper stages.

Most commonly, a traditional rocket has an upper stage with a single engine. This second-stage rocket engine has a larger nozzle—often bell-shaped—to optimize the flow of engine exhaust in a vacuum. Because all parts of a rocket are designed to be as light as possible, such extended nozzles are often fairly fragile because they’re only exposed above Earth’s atmosphere. So one problem with getting an upper stage back from Earth, especially if you want to use the engine to control and slow its descent, is protecting this large nozzle.

One way to do that is to bury the engine nozzle in a large heat shield, but that would require more structure and mass, and it may not be dynamically stable. Stoke’s answer was using a ring of 30 smaller thrusters. (The tests last month only employed 15 of the 30 thrusters). In a vacuum, the plumes from these nozzles are designed to merge and act as one. And during reentry, with a smaller number of smaller thrusters firing, it’s easier to protect the nozzles.

Will this company succeed? Who knows? It is presently very early in development. However, that its founders are former engineers from SpaceX and Blue Origin is encouraging, especially based on this comment about why the Blue Origin guy, Andy Lapsa, left that company:

“I love Jeff [Bezos]’s vision for space,” Lapsa said in an interview with Ars. “I worked closely with him for a while on different projects, and I’m basically 100 percent on board with the vision. Beyond that, I think I would just say that I will let their history of execution speak for itself, and I thought we could move faster.”

Lapsa apparently was part of the exodus of high level managers and engineers that occurred at Blue Origin after Bezos hired Bob Smith as CEO. All complained of the company’s far-too-cautious management style under Smith.