Stoke Space

[magnemoe]

On 9/12/2023 at 7:54 PM, tater said:

Think it's 1 engine, multiple combustion chambers (with throttles).

Saw some there  its not two sets of turbo pumps for lower trust then landing, limit how low you can throttle an turbopump. 

[tater]

 

[AckSed]

That was far more chaotic than I anticipated.

[magnemoe]

10 minutes ago, AckSed said:

That was far more chaotic than I anticipated.

Agree, looks like they are flaring a lot but is that hydrogen? Now if you can not get the rating on turbo pump low enough or change flow fast enough one option if to flare the exec, but that is something you would only do the last couple of seconds before landing. Also you would not run all the combustion chambers at touchdown I think as they also have trust ranges. 

[AckSed]

I mean I sort of expected the flaring about the base. that's where the hydrogen vents from the expander cycle, but the flares from the side were a surprise.

[RyanRising]

On 9/14/2023 at 2:36 PM, AckSed said:

I mean I sort of expected the flaring about the base. that's where the hydrogen vents from the expander cycle, but the flares from the side were a surprise.

I think those are roll control thrusters! 

On 9/9/2023 at 6:15 AM, magnemoe said:

Shuttle and SLS is insulated on the outside, could you insulate the inside instead? Benefit is that you have no risk of damaging the fragile insulation while handling. But then you needed to make it pretty hydrogen tight. should be doable I think. It will be a bit heavier than on outside like on the shuttle tank but if would be reusable. 

Yep! Saturn’s S-IVB was a notable use of internal insulation, so it’s definitely doable.

[JoeSchmuckatelli]

On 9/14/2023 at 1:58 PM, AckSed said:

That was far more chaotic than I anticipated.

I'm surprised your comment didn’t get more traction.  I finally got to watch the video... 

Steampunk rocket. 

[darthgently]

I am wondering if the height above the surface had been double or so that the combined plume may have been more coherent.  There seemed to be a lot of surface interaction

[tater]

 

Woot!

[StrandedonEarth]

Looked like a bit of a hard landing there, complete with wenbounce. But well done

[JoeSchmuckatelli]

7 hours ago, StrandedonEarth said:

Looked like a bit of a hard landing there, complete with wenbounce. But well done

Yeah - from what I hear that is not easy to do. ( SX makes it look easy.) 

So is Stoke the second to propulsively land something large? 

[darthgently]

16 minutes ago, JoeSchmuckatelli said:

Yeah - from what I hear that is not easy to do. ( SX makes it look easy.) 

So is Stoke the second to propulsively land something large? 

Now, now, we need to give BO their due.  New Shepard is impressive in this regard and was before SpaceX iirc.  Or maybe you don't consider that "large" and I could see that

[StrandedonEarth]

41 minutes ago, darthgently said:

Now, now, we need to give BO their due.  New Shepard is impressive in this regard and was before SpaceX iirc.  Or maybe you don't consider that "large" and I could see that

Need a size comparison between StokeStage, New Shepard, and DC-X...

 

[magnemoe]

Next is an higher jump, then try to jump first stage. I wonder if they will do an jump with second stage at top of first and land both before going orbital? Main value will probably longer flight time for first and second stage. 

[tater]

1 hour ago, StrandedonEarth said:

Need a size comparison between StokeStage, New Shepard, and DC-X...

NS is about 16m tall, and the widest part is around 3.7m (same as F9). DC-X was about 3m on a side, ~12m tall. Hard to tell on the Stoke vehicle. The widest part might actually be bigger than F9/NS at 4m? Not nearly as tall as it will be with the fairing which I would guess would make it similar to DC-X?

So for largish stuff (vs Masten): DC-X,  then Falcon testbeds (grasshopper, then F9R), then NS, then Stoke?

2 hours ago, darthgently said:

New Shepard is impressive in this regard and was before SpaceX iirc.

Operational landing, yes. Not hop testing like this stoke flight. SpaceX did that at McGreggor a few years before NS flew.

[sevenperforce]

On 9/14/2023 at 8:36 AM, magnemoe said:

On 9/12/2023 at 1:54 PM, tater said:

Think it's 1 engine, multiple combustion chambers (with throttles).

Saw some there  its not two sets of turbo pumps for lower trust then landing, limit how low you can throttle an turbopump. 

There are valves between the turbopumps and the individual thrust chambers to allow differential throttling of the individual chambers.

On 9/16/2023 at 5:04 PM, RyanRising said:

On 9/9/2023 at 9:15 AM, magnemoe said:

Shuttle and SLS is insulated on the outside, could you insulate the inside instead? Benefit is that you have no risk of damaging the fragile insulation while handling. But then you needed to make it pretty hydrogen tight. should be doable I think. It will be a bit heavier than on outside like on the shuttle tank but if would be reusable. 

Yep! Saturn’s S-IVB was a notable use of internal insulation, so it’s definitely doable.

One issue with internal insulation is the threat of debris ingestion by the engine. Fortunately they have the best kind of engine for that. Expander cycle engines are very robust; during testing the RL-10 was fed chunks of insulation mixed with the propellant flow and it just chewed it up and spat it out like nothing.

1 hour ago, tater said:

2 hours ago, StrandedonEarth said:

Need a size comparison between StokeStage, New Shepard, and DC-X...

NS is about 16m tall, and the widest part is around 3.7m (same as F9). DC-X was about 3m on a side, ~12m tall. Hard to tell on the Stoke vehicle. The widest part might actually be bigger than F9/NS at 4m? Not nearly as tall as it will be with the fairing which I would guess would make it similar to DC-X?

So for largish stuff (vs Masten): DC-X,  then Falcon testbeds (grasshopper, then F9R), then NS, then Stoke?

This is what I'm getting:

 

[tater]

Looks like corner to corner diagonally DC-X was 4.1m, so the flat sides a little under 3m.

[Spaceception]

3 hours ago, darthgently said:

Now, now, we need to give BO their due.  New Shepard is impressive in this regard and was before SpaceX iirc.  Or maybe you don't consider that "large" and I could see that

They managed their first landing within a month of SpaceX's. So it was impressive that they beat them there, but it wasn't by much.

I really look forward to seeing Stoke's first full launch. There's a lot of players working on small lift vehicles before making their way to medium lift. SpaceX was (one of) the first, but there's also Rocket Lab, Relativity, Firefly, and (not really) Blue Origin who are doing the same. So I hope Stoke has similar plans, though I'll admit I haven't seen the EDA video about it, so they could've mentioned something.

[darthgently]

44 minutes ago, sevenperforce said:

. Expander cycle engines are very robust; during testing the RL-10 was fed chunks of insulation mixed with the propellant flow and it just chewed it up and spat it out like nothing.

So the turbopump doubles as a macerator?  Nice

Edited September 18, 2023 by darthgently

[tater]

57 minutes ago, Spaceception said:

They managed their first landing within a month of SpaceX's. So it was impressive that they beat them there, but it wasn't by much.

First operational landing from "space" though just a suborbital hop. Grasshopper and F9R flew low altitude hops and landed long before NS did. So those were closer to what Stoke has just done.

No idea if BO did low alt hop testing on NS.

[magnemoe]

2 hours ago, sevenperforce said:

There are valves between the turbopumps and the individual thrust chambers to allow differential throttling of the individual chambers.

One issue with internal insulation is the threat of debris ingestion by the engine. Fortunately they have the best kind of engine for that. Expander cycle engines are very robust; during testing the RL-10 was fed chunks of insulation mixed with the propellant flow and it just chewed it up and spat it out like nothing.

This is what I'm getting:

 

Here is Stoke space first and second stage.

Not that much larger than New Shepard. Has first stage no fins at all? only the small rakes on the side.
Did not find cargo capacity googling but guess that is kind of work in progress. 

Edited September 18, 2023 by magnemoe

[Spaceception]

1 hour ago, magnemoe said:

Did not find cargo capacity googling but guess that is kind of work in progress. 

As of late last year, 1.65 tonnes, fully reused. Not bad https://arstechnica.com/science/2022/10/stoke-space-aims-to-build-rapidly-reusable-rocket-with-a-completely-novel-design/ Which is pretty high for most small lift vehicles. Falcon 1 was about 670 kg max, Electron does 300 kg, Firefly Alpha can do just over a ton, 1,030 kg, and Terran 1 can do just short of 1.5 tonnes, 1,470 kg.

[tater]

1 hour ago, magnemoe said:

Not that much larger than New Shepard

Stage 2 alone is about 2/3 the height of the whole New Shepard stack.

 

[sevenperforce]

31 minutes ago, magnemoe said:

Here is Stoke space first and second stage.

Not that much larger than New Shepard. Has first stage no fins at all? only the small rakes on the side.

I think the first stage is more of just an artistic render. 

1 hour ago, tater said:

2 hours ago, Spaceception said:

They managed their first landing within a month of SpaceX's. So it was impressive that they beat them there, but it wasn't by much.

First operational landing from "space" though just a suborbital hop. Grasshopper and F9R flew low altitude hops and landed long before NS did. So those were closer to what Stoke has just done.

No idea if BO did low alt hop testing on NS.

I think there's a substantial qualitative difference between the types of test hops we're looking at here. I'd break it up into four categories:

• Bunny Hop. Short hop of less than 25 meters and minimal translation, basically only testing hover and low-speed maneuverability. 
  • First three flights of Starhopper.
  • First two flights of Grasshopper.
  • This flight of Stoke Hopper.
• Full Hop. Longer-duration hop with greater translation and/or meaningful velocities.
  • Initial flight of Blue Origin Goddard vehicle.
  • First two flights of DC-X.
  • Fourth flight of Starhopper
  • SN5-6.
  • Third and subsequent flights of Grasshopper.
  • First two flights of F9R Dev1.
• Giant Leap. Involves the use of aerodynamic controls, engine restarts, and/or flightlike maneuvering with a completed OML.
  • Last three flights of F9R Dev1.
  • Third and subsequent flights of DC-X.
  • SN8, SN10, SN11, and SN15.
  • New Shepard test campaign (presumed; no public information).
• Suborbital Flight. Launches propulsively, exceeds the Karman Line, restarts engine(s), lands propulsively.
  • Operational Falcon 9 flights.
  • Operational New Shephard flights.

Each of these successive steps requires an entirely new set of control features, systems, and experience that make it significant.

[tater]

5 minutes ago, sevenperforce said:

I think there's a substantial qualitative difference between the types of test hops we're looking at here. I'd break it up into four categories:

Excellent analysis.