Stoke Space

[sevenperforce]

Yep, looks like that'll do it. That's what we're going for, right there.

[sevenperforce]

Christmas lights!

https://www.linkedin.com/posts/stoke-space_our-lights-are-hung-with-care-happy-holidays-activity-7012084589292654592-VSWK?utm_source=share&utm_medium=member_desktop

[sevenperforce]

Actively cooled heat shield?

Check.

 

[tater]

52 minutes ago, sevenperforce said:

Actively cooled heat shield?

Check.

The more they show, the more Phil Bono vies I get.

NICE.

[tater]

Very much worth the watch. 
 

 

[magnemoe]

Excellent Everyday Astronaut video as usual. Does anybody has specks on this. Expected payload to orbit and dimensions, Outside of the video and this. 

I say its shorter than expected more so as upper stage uses hydrogen.  First stage also looks short. 
Now its nothing stopping them making an larger rocket later. 

[tater]

This is likely very much in the rtls f9 payload range I would bet, maybe o the low end of that. Same dia, but methalox stage 1 and hydrolox S 2 buys some margin.

This is by far the most interesting vehicle after Starship, and only then because timing (SS very soon).

This vehicle is just awesome if it works.

[magnemoe]

13 minutes ago, tater said:

This is likely very much in the rtls f9 payload range I would bet, maybe o the low end of that. Same dia, but methalox stage 1 and hydrolox S 2 buys some margin.

This is by far the most interesting vehicle after Starship, and only then because timing (SS very soon).

This vehicle is just awesome if it works.

Disagree, cargo bay is around 2 m^3 but truncated at the front, I say less than a ton. But this and starship should scare the pants of anybody launching payloads for profit. 
You have an realistic full reuse plan or your out. 
Its there airplanes was 100 years ago but the future is more obvious. 
 

[tater]

Looks like ~1/10 of F9 while fully reusable. 
 

my bad. S1 is really short, but the fluffy H2 likely drives the S 2 capability.

[AckSed]

The way this heatshield/aerospike operates is elegant. First off, the upper-stage rocket itself is powered by an expander bleed cycle: liquid H2 flows through the combustion chambers and nozzles to cool them, absorbing heat and expanding along the way. Some of it is tapped to run through the O2 and H2 turbopumps, but instead of returning the lower-pressure gaseous H2 to the chambers, it's dumped overboard. In this design, the vent for this is in the centre of the heatshield. Truncated aerospikes need what's called base-bleed to maintain the 'spike'... and what a coincidence, here's some waste gas that feeds through the centre to do so.

Once it's up above atmosphere, the bleed gas also provides something for the exhaust from the combustion chamber to push against. If you've seen this video from inside a SpaceX F9 fairing, note that the rocket exhaust of the second stage exits the nozzle in a sideways sheet (really a half-sphere, but). I may be wrong, but intuition says the bleed gas also expands sideways, crashes into the expanded gas from the aerospike combustion, and half the collision would impact the heatshield and give it a bit of extra push.

In reentry mode, the bleed gas might even push the shockwave a bit further out, reducing the heat load. Of course if it ever increases, the heat will just push the LH2 around the heatshield faster, expelling more relatively cool gas in front and reducing the heat load once more. And the heatshield is canted to give the same lift and control authority as a ballistic capsule without moving the centre of gravity too far from the central axis. *shakes head* Genius. Though you have to make triply sure you don't run out of hydrogen. But LH2's heat capacity makes it the finest method of cooling bar none, so it works out.

Barely a single wasted part.

They're even packing the avionics and turbomachinery behind the heatshield. Now this gives me pause: cryogenic LH2 has a habit of condensing out liquid oxygen from the atmosphere, and if that drips straight onto your electronics or insulation, you have Problems. I didn't gather whether the LO2 tank was on the bottom or on the top. However it does make for a bottom-heavy design - ideal for a stable ballistic reentry.

Best part was, they didn't even plan to make an aerospike.

Edit: Full-flow staged combustion on their first stage engines. They don't lack for ambition! However, knowing something can be done does make it easier to attract investment and talent, and if you have the metallurgy to withstand it, the stress on the turbopumps is lessened. I do note that Rocket Lab has switched to ox-rich staged combustion for Neutron for this very reason.

Finally, I have to ask: does it scale? Could this make a Falcon 9 or Neutron-class launcher?

Edited February 5, 2023 by AckSed

[tater]

 

Also, per previous back and forth just above:

 

[tater]

F9 loses ~20% for ASDS landing of booster, and ~40% of RTLS of booster. Dunno what the rule of thumb will be for RTLS of both booster AND stage 2, but obviously it will take above a 40% hit in payload. Looking at claims about SS payload vs expended, maybe ~75% loss for full reuse? That implies ~6t for a reusable F9.

Wonder how that compares to the Stoke vehicle.

[tater]

 

 

 

[tater]

 

[AckSed]

Ugly, and looks like it was welded in a couple of days. I love it.

[tater]

 

[sevenperforce]

18 hours ago, tater said:

 

Any clue which part of the rocket is which? What are we looking at? Presumably this is the second stage, but is this just one tank or both tanks? And is the aft end on the left or the right?

[tater]

38 minutes ago, sevenperforce said:

Any clue which part of the rocket is which? What are we looking at? Presumably this is the second stage, but is this just one tank or both tanks? And is the aft end on the left or the right?

Stage 2.

Looks to me like flight (hop) article.

The "tab" visible at the bottom (left side) I would assume is related to where they will attach some legs, it looks like trilateral symmetry to me based on not seeing more tabs (as their renders show).

[Beccab]

2 minutes ago, tater said:

Stage 2.

Looks to me like flight (hop) article.

The "tab" visible at the bottom (left side) I would assume is related to where they will attach some legs, it looks like trilateral symmetry to me based on not seeing more tabs (as their renders show).

It may also end up just as a test tank like MK1, (RIP), but it's also much smaller than Starship, so who knows. Maybe it will really fly

[tater]

5 minutes ago, Beccab said:

It may also end up just as a test tank like MK1, (RIP), but it's also much smaller than Starship, so who knows. Maybe it will really fly

True, but I thought he said in that interview that a hop was coming soon.

There's a sheet of paper in front of that stage 2 in the interview (past 7 min) that says it's the hopper.

Quickly skipping through. At ~34 min he says the test stand can also do hold down tests on the actual stage.

[tater]

LOL, I skipped past the very beginning in my rush. At just after 6 min in he says the hardware they are looking at is the hopper.

[magnemoe]

1 minute ago, tater said:

LOL, I skipped past the very beginning in my rush. At just after 6 min in he says the hardware they are looking at is the hopper.

Who makes perfect sense and you want the landings to work. 

[sevenperforce]

1 hour ago, tater said:

2 hours ago, sevenperforce said:

Any clue which part of the rocket is which? What are we looking at? Presumably this is the second stage, but is this just one tank or both tanks? And is the aft end on the left or the right?

Stage 2.

Well yes, I assumed THAT. 

1 hour ago, tater said:

The "tab" visible at the bottom (left side) I would assume is related to where they will attach some legs, it looks like trilateral symmetry to me based on not seeing more tabs (as their renders show).

Okay, yeah, that tracks. That would make the flat thing over on the right the PAF.

[tater]

8 minutes ago, sevenperforce said:

Well yes, I assumed THAT. 

I meant the whole stage 2, so both tanks, sorry, wasn't clear.

 

7 minutes ago, sevenperforce said:

Okay, yeah, that tracks. That would make the flat thing over on the right the PAF.

Yep, I wasn't even looking at that end, lol.

Not seeing the heat shield from this angle, though... maybe they will do hot fires, then install it? (easier to work on engines minus everything being buried under that metal).

And playing the Dodd interview back skipping around made it pretty clear it was as I remembered—they were standing next to the hopper doing the interview.

[tater]

Also, um, the hashtag from stoke on the tweet, #wenhop