Stoke Space

[tater]

 

[Spaceception]

Is this where Rocketdyne was in 2006 with their integrated powerhead?

[Kartoffelkuchen]

38 minutes ago, Spaceception said:

Is this where Rocketdyne was in 2006 with their integrated powerhead?

I loosely follow this thread and their updates, but the speed they're moving at sure is looking impressive. Getting the powerhead of such an engine to work probably has to be the most difficult task. I'm stoked for what's to come!

Edited January 31 by Kartoffelkuchen
Almost let the opportunity to use "stoked" pass by

[Spaceception]

Going to read this later, but I suspect there will be a lot of new details

https://spacedventure-marketing.s3.amazonaws.com/Stoke+Independent+Investment+Guide.pdf

 

Edited February 15 by Spaceception

[tater]

Quote

Milestones Upcoming
• 1H24: Full-flow staged combustion
Methalox engine hotfire for Nova 1st stage

• 2024: Completion of environmental
assessment and groundbreaking for pad
construction at Cape Canaveral LC-14

• 2025: First commercial orbital flight of
Nova launch vehicle

 

 

[Spaceception]

1st half, and they've made progress on both preburners, so they might have a good shot at it. Curious how quickly they can restore the pad and get it ready for launch.

The document on page 19 also shows reusable/expendable figures for Nova (making a table here)

Reused	LEO	3,000 kg
Reused	SSO	2,000 kg
Expended	LEO	7,000 kg
Expended	SSO	5,500 kg
Expended	GTO	2,500 kg
Expended	TLI	1,500 kg

 

Is it a little outdated though? I thought LEO reused was upgraded to 5mT, not 3 (and before that it was something like 1.5 I believe). I bet they're planning on making their 'expended' figures functionally reusable with orbital refueling either way though. Loiter in orbit for a little bit to get the tanks filled just enough for landing, then return for reflight.

Even without that, Nova is right around Delta II's capability.

Edited February 15 by Spaceception

[Spaceception]

Second stage development is coming along well. I wonder how far along it is to being ready for orbit.

[Spaceception]

Second stage is testing

What do you think they're naming the 1st and 2nd stage engines? After other novae, like Persei, or Delphini?

[Spaceception]

https://www.nasaspaceflight.com/2024/03/stoke-stage-2/

I don't know if we knew this before, but they mentioned Nova would be 30.5m tall, 12m taller than New Shepard.

[darthgently]

46 minutes ago, Spaceception said:

https://www.nasaspaceflight.com/2024/03/stoke-stage-2/

I don't know if we knew this before, but they mentioned Nova would be 30.5m tall, 12m taller than New Shepard.

That is much larger than I imagined.  In fact, I pictured it being about 20m at most

[AckSed]

30.5m tall, 3.7m wide... any other rockets that are comparable? The expendable, hypergolic Long March 2D has roughly the same payload and diameter, but 10.5m taller.

[Exoscientist]

 I’m a little annoyed with Stoke Space they didn’t credit Phil Bono who came up with the idea of using a plug nozzle for thermal shielding during reentry:

https://twitter.com/rgregoryclark/status/1677672260159561729

 By not crediting Bono they are missing a key aspect of his proposal: Bono wanted to actually use the altitude compensating effect of the aerospike/aeroplug.

 Stoke Space is ignoring that aspect of his proposal. But by ignoring that they are missing a key advantage of this type of nozzle: the aerospike/aeroplug is even more effective for first stages. Their plan is to use standard, fixed bell nozzles on the first stage with full-flow staged combustion engines:

https://www.stokespace.com/rocket/

 But actually altitude compensating nozzles such as the aerospike, among many other different kinds and types, can get even better performance than staged combustion engines and are far cheaper. Remember SpaceX with billions of dollars at its disposal still hasn’t gotten the Raptor to operate reliably.

 Since Stoke is already using a multi thruster plug nozzle for its upper stage, Stoke could be making concurrently a multi thruster plug nozzle for the first stage, except dense propellant rather than the hydrolox used on the upper stage.

 In fact since dense propellants are easier to work with than hydrolox, the first stage could even have been ready earlier than the upper stage.

 

   Robert Clark

 

 

[tater]

2 minutes ago, Exoscientist said:

 Stoke Space is ignoring that aspect of his proposal. But by ignoring that they are missing a key advantage of this type of nozzle: the aerospike/aeroplug is even more effective for first stages. Their plan is to use standard, fixed bell nozzles on the first stage with full-flow staged combustion engines:

No, they're not doing that at all.

As Lapsa explicitly said in the long interview video, they looked into all those things, but their optimization is different. They need a heat shield as the primary issue, with engines secondary. There's no reason whatsoever to use a plug engine on first stages at all. Once you have a 2 stage, there is no reason to care in the least about a few seconds of I_sp for the first stage. The upper stage only operates in vacuum or near vacuum except for a few seconds landing.

Bono only used the plug because his designs were semi-SSTOs (drop tanks). Had he used TSTO, there's no reason for the plug design.

 

[Exoscientist]

On 3/10/2024 at 5:04 PM, tater said:

No, they're not doing that at all.

As Lapsa explicitly said in the long interview video, they looked into all those things, but their optimization is different. They need a heat shield as the primary issue, with engines secondary. There's no reason whatsoever to use a plug engine on first stages at all. Once you have a 2 stage, there is no reason to care in the least about a few seconds of I_sp for the first stage. The upper stage only operates in vacuum or near vacuum except for a few seconds landing.

Bono only used the plug because his designs were semi-SSTOs (drop tanks). Had he used TSTO, there's no reason for the plug design.

 

 

 My point is he did  use the altitude compensating effects of the plug nozzle to improve performance.  The increase in performance also applies to two-stage vehicles because it increases the performance of the first stage.

 See Bono’s ideas for SSTO discussed here:

One Giant Leap: Philip Bono's ROMBUS.
Updated: May 17, 2023
https://www.spaceflighthistories.com/post/rombus

  In any case, it is considered bad form in academic circles to take credit for something thought up by someone else.  Bono is now long since dead, and his patents have expired.  Undoubtedly though, Stoke Space in seeking funding believed  it more attractive to their prospective funders to pass off Bono’s ideas as their own to get higher estimation of themselves in the eyes of the potential investors. 

    Bob Clark

Edited March 12 by Exoscientist
Typo

[tater]

44 minutes ago, Exoscientist said:

 My point is he did  use the altitude compensating effects of the plug nozzle to improve performance.  The increase in performance also applies to two-stage vehicles because it increases the performance of the first stage.

1. They're not doing it for stage 1, cause it's not worth it.

2. Altitude compensation happens as a result of a plug, no avoiding it.

[tater]

53 minutes ago, Exoscientist said:

  In any case, it is considered bad form in academic circles to take credit for something thought up by someone else.  Bono is now long since dead, and his patents have expired.  Undoubtedly though, Stoke Space in seeking funding believed  it more attractive to their prospective funders to pass off Bono’s ideas as their own to get higher estimation of themselves in the eyes of the potential investors. 

Also, they did nothing of the sort. You can read their patents, you know—they're posted up this very thread, it's not like it takes lots of footwork.

https://patents.google.com/patent/AU2020398126A1/en?oq=AU-2020398126-A1

https://patents.google.com/patent/AU2020394317A1/en?oq=AU-2020394317-

Quote

[0006] The aerospike nozzle has been studied since before 1960. Analytical design methods (e.g., G. Angelino, Approximate Method for Plug Nozzle Design, AIAA Journal, Vol. 2, Issue 10, pp. 1834-1835 (1964)) and modern first-principles design tools (e.g., NASA’s Aerospike Design and Performance Tool (ADAPT) tool, 2008) have been developed, and computational fluid dynamics (CFD) predictive analysis has been performed (e.g., M. Onofri et ai, Plug Nozzles: Summary of Flow Features and Engine Performance, AIAA-2002-0584 (2002)). The aerospike nozzle has also been ground tested in a number of high-profile programs. These include the 25 klbf-thrust aerospike demonstrator developed under the Air Force 02/H2 Advanced Maneuvering Propulsion Technology Program (AFRPL-TR-76-05), the 250 klbf-thrust converted J-2 engine which formed the basis for Rocketdyne’s original space shuttle main engine proposal (AFRPL-TR-67- 280), and the XRS-2200 linear aerospike nozzle developed as part of the X- 33 program, to name a few.

 

[Exoscientist]

36 minutes ago, tater said:

1. They're not doing it for stage 1, cause it's not worth it.

2. Altitude compensation happens as a result of a plug, no avoiding it.

 Actually it is worth it. Rather than the expensive and uncertain development of a full-flow staged combustion engine, they could accomplish the same thing far more cheaply by using the same multiple thruster around a central plug technique they are using for the upper stage, except with dense propellants. BUT this time they would actually use the altitude compensating effects of the plug nozzle.

 SpaceX has been developing the FFSC Raptor since 2016, and it is still not reliable enough to be considered an operational engine. It is said the SuperHeavy/Starship development cost has been in the range of $5 to $10 billion. Note then typically for a new launcher development using a new engine, the engine development costs make over half the entire development cost of the rocket. So likely SpaceX has spent billions overs those years since 2016 developing the Raptor.

  Bob Clark

 

[tater]

9 minutes ago, Exoscientist said:

 Actually it is worth it. Rather than the expensive and uncertain development of a full-flow staged combustion engine, they could accomplish the same thing far more cheaply by using the same multiple thruster around a central plug technique they are using for the upper stage, except with dense propellants. BUT this time they would actually use the altitude compensating effects of the plug nozzle.

It's definitionally not worth it—they are not doing it, and no one else has, either. Apparently every single human on Earth designing boosters is just too dumb.

What's the diameter of your notional plug engine booster for Nova, BTW? You realize they face the same constraint that drove Falcon 9 diameter, right?

9 minutes ago, Exoscientist said:

 SpaceX has been developing the FFSC Raptor since 2016, and it is still not reliable enough to be considered an operational engine. It is said the SuperHeavy/Starship development cost has been in the range of $5 to $10 billion. Note then typically for a new launcher development using a new engine, the engine development costs make over half the entire development cost of the rocket. So likely SpaceX has spent billions overs those years since 2016 developing the Raptor.

The total SpaceX spending on Starship includes building an engine factory, 2 launch pads, and a rocket factory that looks capable of making a vehicle larger than SLS on the order of 1 per month. Current engines cost that is at most right now about 1/100th the cost of the RS-25E, possibly substantially lower.

So far exactly zero operational rocket engines exist that are fully reusable with no refurb. So far for booster engines, they fired full duration on a test flight into space, so yeah, I would call those pretty close to operational if not actually operational.

 

Edited March 12 by tater

[Exoscientist]

3 hours ago, tater said:

It's definitionally not worth it—they are not doing it, and no one else has, either. Apparently every single human on Earth designing boosters is just too dumb.

By that argument SpaceX should never have developed reusable boosters. Some such as ULA’s Tory Bruno are still saying its not worth it.

   Bob Clark

[tater]

24 minutes ago, Exoscientist said:

By that argument SpaceX should never have developed reusable boosters. Some such as ULA’s Tory Bruno are still saying its not worth it.

So start a rocket company and make an aerospike. It's not like the people in question—particularly at Stoke who did the math and decided against it—are not aware of aerospikes.

TWR dominates booster design, and it's important to remember "sea level" engines are not best at sea level, they're best at some altitude above sea level—they just actually work at sea level without problems.

To get the same kind of TWR, the engines are heavier, so the trade is that you need to get so much Isp that the heavier engine is worth it.

And this plug engine booster needs to be no more than ~3.7m in diameter, or you can't transport it.

 

[Exoscientist]

10 hours ago, tater said:

Also, they did nothing of the sort. You can read their patents, you know—they're posted up this very thread, it's not like it takes lots of footwork.

https://patents.google.com/patent/AU2020398126A1/en?oq=AU-2020398126-A1

https://patents.google.com/patent/AU2020394317A1/en?oq=AU-2020394317-

 I noticed those Australian patents didn’t mention Bono’s name. I looked at Stoke’s U.S.  patents. They also didn’t mention Bono’s name.  

 In academic circles, you write a thesis or research work. You present it as your own work, but it was copied from another author or researcher.  In academic circles, that is commonly ascribed a word beginning with the letter “p”. 

 But suppose that earlier author is long dead and his copyrights expired. Should it still be ascribed the “p” word?

  Bob Clark

[tater]

8 hours ago, Exoscientist said:

 I noticed those Australian patents didn’t mention Bono’s name. I looked at Stoke’s U.S.  patents. They also didn’t mention Bono’s name.  

The patents (US links here):

https://ppubs.uspto.gov/dirsearch-public/print/downloadPdf/20220412709

https://ppubs.uspto.gov/dirsearch-public/print/downloadPdf/20210381469

Have the same wording as the previous links. They mention that the plug/aerospike nozzle was discussed before 1960. The only patent by Bono (submitted by James Webb, NASA) dates to 1967 (there's a second also Webb that I can't find, but it's not the detailed one). A patent filed in 1961 for a plug rocket engine was granted in 1967 as well, not Bono. Nonetheless, it was apparently not a new concept even in 1961. I suppose there could well be scholarly articles regarding plug/aerospikes that are not online, but it seems hard to find references.

Krase, 1959 (w citations from well before)

Edited March 13 by tater

[magnemoe]

17 hours ago, tater said:

So start a rocket company and make an aerospike. It's not like the people in question—particularly at Stoke who did the math and decided against it—are not aware of aerospikes.

TWR dominates booster design, and it's important to remember "sea level" engines are not best at sea level, they're best at some altitude above sea level—they just actually work at sea level without problems.

To get the same kind of TWR, the engines are heavier, so the trade is that you need to get so much Isp that the heavier engine is worth it.

And this plug engine booster needs to be no more than ~3.7m in diameter, or you can't transport it.

This then we talk about reuse who makes sense. Far more for boostback, you want to drop second stage fast so you don't have to spend loads of fuel boosting back to pad. 
For Saturn 5 it made sense to make the first stage tanks larger even if TWR at launch was low as kerosene and aluminum was cheaper. Later you got cheaper solid fuel engines. 
In part funded by having to replace the solid fueled nuclear missiles rockets. 

Now falcon 9 stretches the road transportable rocket to the edge I say. 

[tater]

16 minutes ago, magnemoe said:

Now falcon 9 stretches the road transportable rocket to the edge I say. 

The alternative is to make them someplace where you can then barge them to KSC, or build at KSC. Currently no other options, as there's literally no plausible land for any new facilities for large rockets. I'd imagine that with any success, Stoke gets a facility in FL.

[sevenperforce]

On 3/12/2024 at 1:41 PM, Exoscientist said:

The increase in performance also applies to two-stage vehicles because it increases the performance of the first stage.

 See Bono’s ideas for SSTO discussed here...

Changing a first stage from a standard bell nozzle to an altitude-compensating nozzle does not increase the performance of the first stage. Quite the contrary. Switching to a plug nozzle (or other altitude-compensating nozzle) DECREASES performance at liftoff, which results in lower actual specific impulse, lower takeoff thrust, and greater gravity drag. The slightly-increased specific impulse at altitude is not enough to make up for the loss in thrust at sea level.

The only reason to use altitude-compensating nozzles on a first stage is if you have a sustainer architecture that goes all the way to orbit, where (a) you aren't worried about liftoff thrust because you have separate boosters, and (b) you have enough time for the increased performance at altitude to make up for your laggy performance at sea level.

On 3/12/2024 at 1:41 PM, Exoscientist said:

In any case, it is considered bad form in academic circles to take credit for something thought up by someone else.  Bono is now long since dead, and his patents have expired.  Undoubtedly though, Stoke Space in seeking funding believed  it more attractive to their prospective funders to pass off Bono’s ideas as their own to get higher estimation of themselves in the eyes of the potential investors. 

It's entirely doubted. This is a commercial environment, not an academic one. More importantly, ideas don't launch rockets. Engineering launches rockets. The engineering is the hard part.