Stoke Space Aims To Build Rapidly Reusable Rocket With a Completely Novel Design (arstechnica.com) 62
Andy Lapsa and Tom Feldman, former Blue Origin engineers and the founders of Stoke Space, are working to develop the first fully recyclable space rocket -- one that features a reusable first and second stage. Here's an excerpt from Ars Technica's exclusive report, written by Eric Berger: In the 20 months since its initial seed round of funding, Stoke has built a second-stage engine, a prototype for the second stage, turbopumps, and manufacturing facilities. It also increased its headcount to 72 people and finalized the overall design for the rocket, which has a lift capacity of 1.65 metric tons to low-Earth orbit, in fully reusable mode. Last month, the company started to test-fire its upper-stage engines at a facility in Moses Lake, Washington. The images and video show an intriguing-looking ring with 15 discrete thrusters firing for several seconds. The circular structure is 13 feet in diameter, and this novel-looking design is Stoke's answer to one of the biggest challenges of getting a second stage back from orbit.
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. "What you're seeing in the photos of the test is a high-performance upper-stage engine that can operate within atmosphere at deep throttle to support vertical landing but then also perform at a higher ISP than some variants of the RL 10 engine in space," Lapsa said.
Another significant second-stage problem is protecting the whole vehicle from the super-heated atmosphere during reentry. NASA's Space Shuttle accomplished this with brittle thermal tiles, but these required 30,000 employee hours to inspect, test, and refurbish between flights. SpaceX is using a different type of ceramic tile, designed to be more reusable, for Starship. Given Stoke's background in rocket engines, Lapsa said it made the most sense to try a regeneratively cooled heat shield. The vehicle's ductile metallic outer layer will be lined with small cavities to flow propellant through the material to keep it cool during reentry. The second stage, therefore, will return to Earth somewhat like a space capsule -- base first, with the regeneratively cooled heat shield.
Stoke Space has a very long road ahead of it to reach space. Engine tests are an important step, but they're only the first step of many. Next up for the company is "hop" tests with a full-scale version of the second stage at the Moses Lake facility in central Washington. This prototype won't have a fairing as it would during launch, but it will still stand 19 feet tall. Initially, the tests will be low-altitude, probably measured in hundreds of feet. If there's an engineering need to go higher, the company will consider that, Lapsa said. But for now, the goal is to prove the capability to control the rocket during ascent and descent and make a soft landing. This is a shockingly difficult guidance, navigation, and control problem, especially with a novel system of distributed thrusters. "This is kind of a final proof point of this architecture," Lapsa said. "It is new. It's different. It's weird. It's original. There were a lot of questions that we had about how this thing is going to work. But we've already mitigated a lot of risk." If Stoke can manage to land the upper stage, it can move ahead with the first stage and start to turn the yet-unnamed rocket into an orbital vehicle. It sounds easy, but it's not...
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. "What you're seeing in the photos of the test is a high-performance upper-stage engine that can operate within atmosphere at deep throttle to support vertical landing but then also perform at a higher ISP than some variants of the RL 10 engine in space," Lapsa said.
Another significant second-stage problem is protecting the whole vehicle from the super-heated atmosphere during reentry. NASA's Space Shuttle accomplished this with brittle thermal tiles, but these required 30,000 employee hours to inspect, test, and refurbish between flights. SpaceX is using a different type of ceramic tile, designed to be more reusable, for Starship. Given Stoke's background in rocket engines, Lapsa said it made the most sense to try a regeneratively cooled heat shield. The vehicle's ductile metallic outer layer will be lined with small cavities to flow propellant through the material to keep it cool during reentry. The second stage, therefore, will return to Earth somewhat like a space capsule -- base first, with the regeneratively cooled heat shield.
Stoke Space has a very long road ahead of it to reach space. Engine tests are an important step, but they're only the first step of many. Next up for the company is "hop" tests with a full-scale version of the second stage at the Moses Lake facility in central Washington. This prototype won't have a fairing as it would during launch, but it will still stand 19 feet tall. Initially, the tests will be low-altitude, probably measured in hundreds of feet. If there's an engineering need to go higher, the company will consider that, Lapsa said. But for now, the goal is to prove the capability to control the rocket during ascent and descent and make a soft landing. This is a shockingly difficult guidance, navigation, and control problem, especially with a novel system of distributed thrusters. "This is kind of a final proof point of this architecture," Lapsa said. "It is new. It's different. It's weird. It's original. There were a lot of questions that we had about how this thing is going to work. But we've already mitigated a lot of risk." If Stoke can manage to land the upper stage, it can move ahead with the first stage and start to turn the yet-unnamed rocket into an orbital vehicle. It sounds easy, but it's not...
Re:Not this again... (Score:5, Informative)
Re: (Score:3)
He never said Musk was a conman :) Just that he inspired them.
And yes, the SLS is just a job/political clout provider program.
Re: Not this again... (Score:2)
Re: (Score:2)
The best evidence that Musk is a conman is the fact that he appointed himself "chief engineer" at SpaceX and isn't actually, you know, an engineer.
"I wont even go into Tesla; because it has been such a massive game changed in the auto industry, that no one can reasonably argue they have made the most meaningful disruption since Apple released the iPhone."
Cars that crash into things on their own are certainly a game changer!
Re: (Score:2)
There's plenty to be said about Tesla. But drivers not reading/listening to instructions and being retarded on the "Auto Driving" (Yes, they marketed that completely wrong), should by now really not be one of those things..
Re: (Score:2)
The best evidence that Musk is a conman is the fact that he appointed himself "chief engineer" at SpaceX and isn't actually, you know, an engineer.
That statement is a bit of a minefield. You're just screaming for a "what's an engineer thread". Then we the whole: "You're not an engineer unless you have a B.S. in engineering like me, an Electrical Engineer" and then "Electrical Engineers aren't real engineers, you're only a real engineer if you have a B.S. in a physical engineering field like me, a mechanical engineer!", "Only people with Civil engineering degrees are real engineers", "Wait, do you just have the degree, or are you a licensed civil engin
Re: (Score:2)
No it's actually pretty easy to avoid this minefield. Whatever your company creates, you should only be the "chief engineer" if you have technical expertise in that subject that lets you make meaningful contributions. A mere BS in physics ain't going to cut it.
Re: (Score:2)
No it's actually pretty easy to avoid this minefield. Whatever your company creates, you should only be the "chief engineer" if you have technical expertise in that subject that lets you make meaningful contributions. A mere BS in physics ain't going to cut it.
If only expertise in a subject were really that clear cut. An important reality that university usually makes clear is that you do all of your own learning. The purpose of a degree isn't really supposed to be just a professional certificate for hiring purposes, and you can keep on learning afterwards without getting another degree. Plus there's the question of whether you even need an engineering degree to manage engineers and know what they're talking about. Frankly, with over-rigid thinking like that, you
Re: (Score:2)
We're not talking about "engineer" -- we're talking about "chief engineer" to a company that makes rockets. I can understand why Musk does it -- he's a profound narcissist. What I don't understand is what motivates his fanboys.
Re: (Score:2)
We're not talking about "engineer" -- we're talking about "chief engineer" to a company that makes rockets. I can understand why Musk does it -- he's a profound narcissist. What I don't understand is what motivates his fanboys.
If you're implying that I'm a Musk fanboy, think again. This is not even specifically about Musk, it's about the fact that "engineer" or even "chief engineer" as a job title is simply not as exclusive as you think it is. To the point where probably the majority of people with that title do not hold an engineering degree. There's nothing remarkable or unusual about Musk calling himself chief engineer.
Re: (Score:2)
The Elon Musk haters are looking more and more stupid by the day though.
The SpaceX haters are definitely looking more and more stupid by the day. It's a bit of a different story for those who think that Elon Musk personally is a very flawed human being but are capable of separating their opinion of him from their opinion of a ground-breaking space company. There are definitely some concerns about his personality affecting the company, of course. Little (and not so little) things around the edges, mostly to do with employee relations. Ego-based firings are part of it, some sexua
Re: Not this again... (Score:2)
Usually those senators have many constituents that are employees of those companies, and it's those votes they're chasing. Same reason we make way more HMMWVs and Abrams tanks than the Army asks for or even wants. Same reason prison guard unions heavily lobby for criminalization of marijuana. Same reason why the steel workers union heavily lobbies for steel tariffs.
This is what happens when you ask politicians to create jobs, or when progressives argue that the responsibility of a business is solely to crea
First? (Score:3)
working to develop the first fully recyclable space rocket
What about those other companies that have been developing a fully recyclable space rocket for some time now? How come this one should be called 'first'?
Re:First? (Score:5, Informative)
Re: (Score:2)
SpaceX has done the same already: first develop a second stage that can land and be reused, then develop a first stage that can land and be reused, then integrate them in a fully reusable rocket. So the word 'first' is out of place. I'm not saying SpaceX was first, but Stoke Space certainly isn't.
Re: (Score:2)
SpaceX does not re-use its second stage.
Re: (Score:3)
Who gets to claim the title "first" depends on who actually launches their rocket and completely recovers it first.
SpaceX has been working on their fully-recoverable Starship for a lot longer than Stoke has been working on theirs; whether Stoke can catch up to SpaceX, let alone overtake them, remains to be seen.
Re: (Score:2)
I did. I was responding to parent, who was blithely ignoring Starship.
Re: (Score:2)
Starship has not completed an orbital test, and its first stage- Super Heavy, hasn't even lifted off the ground, much less landed.
i.e., the following:
SpaceX has done the same already: first develop a second stage that can land and be reused, then develop a first stage that can land and be reused, then integrate them in a fully reusable rocket.
Is patently false.
Why do they get mentioned? They're not the first.
They are another contender for first, for sure, but the bigger question is, when talking about one contender, why is it you feel compelled to make sure we know about the other contender?
Re: (Score:2)
Neither of them have completed, therefor neither is first.
Both aim to be first.
It is appropriate to use the following verbiage to describe both parties:
They are both working on the first fully reusable rocket.
Re: (Score:2)
Re: (Score:2)
One day it will be. If these guys are first, they will have the first. If SpaceX is first (seems most likely to me) then they will be first.
Right now, first is open for grabs, as there are no fully reusable rockets.
Re: (Score:2)
I understand that, but it is not.
It is. It is intended to be. Like I said.
Right now, first is open for grabs, as there are no fully reusable rockets.
That was the intent of my first post. Like I said.
Re: (Score:2)
It is. It is intended to be. Like I said.
Intended to be does not matter.
It is not.
This distinction is important, because it means the title of first is no one's, and the status of "developing the first" is anyone working on one.
That was the intent of my first post. Like I said.
And I'm explaining why.
This article is about one such company.
Why does this one get to be called first? Because they all are developing the what they hope will be the first reusable rocket.
Whichever of them succeeds shall be the first to have done so.
Your complaint is odd, is all. It did not say the first to develop,
Re: (Score:2)
I think you're a bit backwards on SpaceX.
The Falcon 9 booster (first stage) is reusable. The second stage is not, and they abandoned any attempt to make it so in favor of developing Starship.
The Dragon capsules can be re-used, but those are the payload, not the second stage.
If you're instead thinking of Starship (which at present is not even a usable system, much less reusable), I think its more accurate to say both stages are being developed simultaneously, with second stage style prototypes being actuall
Re: (Score:2)
First stage reusability is comparatively simple. The main purpose of it is to get altitude, so you just need to fall back down and have enough fuel for a suicide burn at the landing. Second stage boosters are what get you up to orbital velocity. The space shuttle de-orbited by doing a dozen large wide "s-turns" in the upper atmosphere, gradually shedding velocity by carefully cooking their belly of thermal tiles. Musk's starship looks like it's going to just try a similar idea without the banking turns,
Re: (Score:2)
Umm.... technically the Shuttle began a deorbit by firing its OMS thrusters...
Re: (Score:2)
Those only accounted for a small fraction of their orbital velocity. Just enough to sink down into a higher density of atmosphere that the shuttle could being the process of de-orbiting without having to wait a long time.
Not mine, but a good explanation;
Re: (Score:2)
Just above the "Hop Tests Next" section:
Given Stoke's background in rocket engines, Lapsa said it made the most sense to try a regeneratively cooled heat shield. The vehicle's ductile metallic outer layer will be lined with small cavities to flow propellant through the material to keep it cool during reentry. The second stage, therefore, will return to Earth somewhat like a space capsule—base first, with the regeneratively cooled heat shield.
A couple paragraphs above that they say
And during reentry, with a smaller number of smaller thrusters firing, it's easier to protect the nozzles.
So it sounds to me like they plan to come in engines-first like a Falcon 9 booster, only with a regenerative heat shield around the engines to handle the much higher reentry temperatures, and the engines firing to protect their nozzles.
I assume the first photo here: https://www.stokespace.com/abo... [stokespace.com] is their second stage - it looks like an elongated reentry capsule that's mostly fuel tanks, so that tracks. Sadly they don't seem
Re: (Score:2)
TFA says they aspire to be the first. So do the others you mention. Which one will achieve it's aspiration and actually BE the first remains to be seen.
They have the right vision (Score:3)
I've read about them elsewhere. They definitely have the right vision: Build a complete rocket (first and second stages) to be re-usable and failure tolerant. If you have a ring of engines, as they do on their second stage, you can lose more than one of them and still recover the stage.
They ultimately dream of a rocket that can make daily trips to space. That's a long ways away, but getting a fully recoverable second stage is an important step.
Re: (Score:1)
Even the Shuttle, that was designed for multiple use, broke down in epic life threatening fashion due to reuse.
Due to the fragile tiles. This isn't using those.
Wake me when it's done (Score:3)
Since rockets are notoriously prone to exploding, all they really do is give "vaporware" a totally new (but fairly exciting) meaning.
Look like my favorite Chinese restaurant kitchen (Score:2)
if I rotate my notebook 180 degrees.
It also doesn't seem like much thrust with these orange flames.
Just compare it with a SpaceX Raptor engine :
https://www.youtube.com/watch?... [youtube.com]
But I guess early investors get free perks like a nice baseball cap or flamethrower.
Re: (Score:2)
Do they mention what propellant their using?
Kerosene (aka traditional jet/rocket fuel when more refined) tends to burn orange, while natural gas (aka methane when more refined) tends to burns more blue.
I don't think the color has much to do with the efficiency of the engine.
As for thrust - they're looking at using several small engines rather than the traditional one big one on the second stage, or Starship's three. Their second stage is also tiny - looks like it'd fit *sideways* in Starship's payload bay.
Re: Look like my favorite Chinese restaurant kitch (Score:2)
Jet fuel burns blue (Score:2)
They use it in kerosine stoves and when burned with enough oxigen, the flames are clear blue.
Was it real? (Score:1)
Re: (Score:2)
I suspect it's due to some combination of
- Not burning methane (which has a bluish flame we've all gotten used to with Starship tests)
- Being the "dirty" flames near ignition, which are generally fuel-rich with lots of backwash from surrounding obstructions, and tend to be far more dramatically photogenic.
Note: I have no idea what fuel they're actually using. Anyone?
There's no Mach diamonds in the photo, so I think it's safe to say that either the engines are not working at steady-state, or the backwash fr
Easy? (Score:2)
It sounds easy, but it's not...
It's literally rocket science.
Re: (Score:2)
It's not rocket science! ...okay, well it IS rocket science, but it's not HARD.
Re: (Score:2)
It sounds easy, but it's not...
It's literally rocket science.
Yeah. Hard ... but not exactly brain surgery.
Read the comments on Ars (Score:4, Informative)
Eric Berger is a great space journalist, but even better is the comments section of his articles. There's a bunch of actual rocket scientists on there vigorously debating the subject at hand.
Re: (Score:2)
Re: (Score:2)
Re: (Score:1)
Re: (Score:2)
Re: (Score:1)
Deep down ole DNB is a good guy. I think he’s had a head injury or some sort of late life mental decline.
Re: (Score:2)
"We used to have those on Slashdot. I remember those days."
No you don't because it's always been mostly arguing about politics and culture. Back then it was mostly antisocial libertarians driving the conversation.
"But then the constant politics posts and social justice activism drove them off"
The fact that Slashdot has not significantly changed in 20+ years despite the rise of competitors is what drives people off.
Recyclable? (Score:2)
Recyclable, not reusable? I think someone had a headline malfunction...
Too many rocket co's? (Score:1)
It seems everybody and their dog are forming rocket co's of late. While competition is good, there's not a big enough demand to accommodate so many companies, especially since it requires expensive start-up and R&D. Outer-space usage is growing, but not that much.
Is it a case that the rich have too much money, throwing it at "cool & trendy toys"? If so, taxem!
They'll still beat Blue Origin to orbit (Score:2)
and I'm not so sure about SLS either.
Slashdot never fails... (Score:2)
I like how this boils down to "Some guys have some plans to do stuff and think they know how they're going to do it".
what? (Score:2)
Why would I trust an private space travel company run by qualified, experienced engineers?! Reputable private space travel companies are run by non-engineer tech bro con artists!