Stoke Space

[StrandedonEarth]

The problem is the imprecision of the wording. If they said “full mission duration “ or “full planned test duration”, it would save these arguments.

[tater]

19 minutes ago, StrandedonEarth said:

The problem is the imprecision of the wording. If they said “full mission duration “ or “full planned test duration”, it would save these arguments.

Their statements are fine, they know what they are doing better than randos with axes to grind.

[JoeSchmuckatelli]

1 hour ago, tater said:

randos with axes to grind

Aka 'the internet' 

[sevenperforce]

On 6/18/2024 at 1:07 PM, darthgently said:

Yep. Has there ever been a rocket engine test officially tagged a "partial duration test" for example? 

Indeed. A "partial duration" test would be a weird and confusing way of describing a test fire.

Language is descriptive, not prescriptive. But that doesn't mean anything goes. We use language because it is useful for communicating; if a particular use of language fails to communicate, then that use should be deprecated. 

Reminded of this....

Spoiler

If a usage of language is sufficient to communicate the desired information within readily available context, then that is a good use of language. "The rocket engine completed a full-duration test" could mean that the engine completed a test fire equal to the duration of a launch, but it could also mean that the engine completed the full planned duration of the test. That's where you have to look to context. If this claim is accompanied by a video of a 15-second static fire, then context has provided you with all of the necessary supporting information.

On 6/18/2024 at 1:07 PM, darthgently said:

And a "launch duration test" ™️ still doesn't test fuel icing and slosh, ambient pressure changes with altitude, and bird strikes.  For full safety we really need to be doing full bird strike tests of all rocket engines.  Until then every one of them is a ticking timebomb

On 6/18/2024 at 3:44 PM, Exoscientist said:

 If Blue Origin continually referred to their little suborbital hops by New Shepard  as “flights to orbit”, it would then be accepted in the rest of the industry they are flights to orbit. You just have to keep repeating it.

I had a dream last night that I had the chance of getting a seat on a New Shepard launch with Bezos on board, but one of my wife's high school friends ended up taking my place. Bezos had pulled a Musk and decided to launch New Shepard out of the top of a barn for "rule of cool" rather than from the existing launch mount, and the engine clipped the struts of the barn, causing the launch escape system to trigger while still in the building. I simultaneously mourned the loss of my wife's friend and rapidly shorted Amazon stock, making tons of money in the process.

This anecdote has nothing to do with the terms used by SpaceX or Stoke, of course.

On 6/18/2024 at 5:16 PM, magnemoe said:

Agree, now an rocket engine burning for minutes would get kind of dull to watch. Also starting the engine is harder than running it. 
Still why call it full duration burns if its not?

I suppose that we could say there is a difference between a "full duration test fire" and a "full duration test burn". A "test fire" can be any length, while a "test burn" suggests the length of an ascent burn.

"Full duration test" is therefore ambiguous and so reference to a full duration test should be accompanied by additional context clues.

On 6/18/2024 at 8:33 PM, JoeSchmuckatelli said:

I've always assumed that phrase meant 'duration the rocket would be lit during a launch' - so, like, a little over 2 minutes for a Falcon. 

Doesn't that allow them to make sure the engine won't eat itself before stage separation? 

For modern engines that use regenerative cooling, the thermal conditions are really quite extreme. Within a few seconds of startup, the system will reach steady-state operation: all of the heat going into the engine and all of the heat coming out of the engine is in equilibrium. As a rule, rocket engine failures don't happen slowly or gradually; if something is going to go then it goes fast. So achieving complete startup and getting 10 seconds or so of a burn is pretty good evidence that the engine won't eat itself.

[tater]

4 minutes ago, sevenperforce said:

If a usage of language is sufficient to communicate the desired information within readily available context, then that is a good use of language. "The rocket engine completed a full-duration test" could mean that the engine completed a test fire equal to the duration of a launch, but it could also mean that the engine completed the full planned duration of the test. That's where you have to look to context. If this claim is accompanied by a video of a 15-second static fire, then context has provided you with all of the necessary supporting information.

Well said.

4 minutes ago, sevenperforce said:

For modern engines that use regenerative cooling, the thermal conditions are really quite extreme. Within a few seconds of startup, the system will reach steady-state operation: all of the heat going into the engine and all of the heat coming out of the engine is in equilibrium. As a rule, rocket engine failures don't happen slowly or gradually; if something is going to go then it goes fast. So achieving complete startup and getting 10 seconds or so of a burn is pretty good evidence that the engine won't eat itself.

Musk actually addressed elements of this in the recent tour video with Dodd. What you learn from tests vs flying, and what they are interested in characterizing needs flight testing.

[Nuke]

you can never actually simulate the full operating conditions of flight on the ground. no g loads, no pressure changes, no engine next to it blowing up.

[Spaceception]

They recently shared a video of the engine hotfiring from another test!

 

[AckSed]

Sexy bright-blue shock cone right there.

[AckSed]

Finding Of No Significant Impact report on Stoke's adoption of SLC-14 is out. Buried inside are some key details, chiefly that the first few flights are going to be expendable, like the first Falcon 9s. It's also going to have a 1st and 2nd-stage stretch:

 

[darthgently]

On 7/3/2024 at 8:03 PM, AckSed said:

Sexy bright-blue shock cone right there.

I call that the plumedongle

[tater]

 

 

[magnemoe]

21 hours ago, AckSed said:

Finding Of No Significant Impact report on Stoke's adoption of SLC-14 is out. Buried inside are some key details, chiefly that the first few flights are going to be expendable, like the first Falcon 9s. It's also going to have a 1st and 2nd-stage stretch:

 

Will they try an water landing of first stage? And perhaps something like starship orbital launch 4 for the second stage? 
Both will be discarded but you get valuable data for future landings.
And Stoke has an benefit here in that they don't need to catch it, just an landing pad and second stage is much lighter than starship so much easier to handle after landing, I say its some chance them might beat Starship for second stage reuse because of this. 
How road transportable is an 12 feet wide, base might be a bit wider and 31 feet long tube? 

[tater]

1 hour ago, magnemoe said:

And Stoke has an benefit here in that they don't need to catch it, just an landing pad and second stage is much lighter than starship so much easier to handle after landing, I say its some chance them might beat Starship for second stage reuse because of this. 

I was just explaining Stoke to a friend who's not a space guy, and I told him flat out I think this little company might well beat SpaceX to full reuse, even with the huge head start Starship has. I think their concept will work, and it's better than tiles.

1 hour ago, magnemoe said:

How road transportable is an 12 feet wide, base might be a bit wider and 31 feet long tube? 

It's the same as Falcon 9, and for exactly the same reason—it's road transportable.

[tater]

 

[tater]

 

 

[tater]

 

[Spaceception]

Block 2 engine, first stage aft section in the background

Compared to the Block 1 engine

And on the vertical test stand

[tater]

 

[tater]

https://www.stokespace.com/nova/

[Minmus Taster]

3 hours ago, tater said:

https://www.stokespace.com/nova/

Can never go wrong by stretching your rocket a bit, interesting how out of place the second stage looks.

[AckSed]

Ooh, that looks shiny. I do wonder: has the boat has been missed here, or are they hanging on to the boat with one hand? 3 tons to LEO is not too shabby for single satellites, but constellations are 'in'... I'm being silly. Obviously, this enables downmass as well, and satellite recovery and refurbishment. If they license Canadaarm, we'll know I'm right.

[tater]

3 hours ago, AckSed said:

If they license Canadaarm, we'll know I'm right.

Just build one, it's not that hard. Buying that would cost more than the rocket.

[magnemoe]

1 hour ago, tater said:

Just build one, it's not that hard. Buying that would cost more than the rocket.

This, unlike on the IIS an recovery arm on an reusable spacecraft who is cheap to launch don't have to be super durable and don't need the Canadaarm advanced features, interface would be install for mission on ground as an example. 
Now it would need more cooling going down as heavier who would make it even heavier, not sure if they thought of recovery. They have thought of refueling them in space for reuse to higher orbits. 

[darthgently]

1 hour ago, tater said:

Just build one, it's not that hard. Buying that would cost more than the rocket.

That’s what China did; they just built it.  The contrast amazes me how shameless China is with technical emulation of success (to the point of blatant, over the line, copy-paste espionage and theft at times) while simultaneously the west often seems too proud and reputation-aware to even legally spin-off/license and emulate success.

Of course I realize it is much more complex than that on both sides with cultural norms, economic pressures and competition, IP, lawyers, etc., it’s just at the 10k ft level I find it ironic.

I mean at some point the biplane manufacturers just started building monoplanes, yet the incredible lag between SpaceX and BO landing boosters and others in the west even considering doing it just doesn’t click (looking hard at ESA and euro space here).   It is curious taken at a glance, that’s all

[tater]

Canadarm is to commercial robot arms as SLS is to commercial launch vehicles.

The arm for Gateway has a contract cost of ~$1B.

Pretty sure Tesla could make one cheaper—even if they had to design and build their own motors. And design it to run autonomously. And mass produce them.