/sci/ - Science & Math

>>10334077
In the previous thread I asked for scrap metal from your special stainless steel that doesn't get brittle when super cooled, so that I could attempt to cool it to the bose einstein condensate state of matter, and see if it exhibits the property of being impenetrable.
I've determined that unless I make a lot more money than I do, I cannot make a freezer that is lower than 365 degrees Fahrenheit (absolute zero is 100 degrees cooler) without having hundreds of thousands of dollars to spend.
So instead of sending me a scrap piece of metal from the ship to experiment on, can you do it for me and tell me what happens?

>>10334623
*negative 365 degrees Fahrenheit.

Since someone's gonna eventually bash NASA in this thread, NASA's actually doing some pretty cool stuff. They aren't publicizing it too much, because the normies would freak if they found out. I'm sure you can figure out that magic word you need to search for in this document:
https://www.nasa.gov/sites/default/files/atoms/files/fy19_nasa_budget_estimates.pdf
Since a certain experiment was successful, you might be rather intrigued by the call for a flight demonstration in this document. Might make for an interesting payload on the starship. Just keep it on the down low, we can't let the normies find out. Do not say the magic word.

>>10334678
you can shut down any retard who says "NASA is a shit" by simply pointing out that the sole reason SpaceX exists and thrives is because of NASA

>>10334712
NASA is shit because our dear representatives are cucking them on every turn. They designed the space shuttle for the engineers and held NASA back countless times. The progress they've made with those distractions are truly something.

SpaceX is a good example of what NASA money can do when engineers are left to the work.

>>10334712
So NASA is just a purse, that is oh so much better..

The guy who's seen the Raptor being shipped off to McGregor says it's 3 times the size of a M1D and has more complicated plumbing.

>>10334772
So he's lying or didn't know what he was seeing. Raptors and Merlins are almost identical size.

>>10334785
He saw them being loaded onto a truck side by side.

Going off of the spotter's observations, a little more on Raptor:

-Nozzle was matte like M1D and approximately 50-100% wider at the base.
-Powerpack seems about 25-50% wider than M1D at its widest point.
-Plumbing is visibly more complex with lots of mirror-shiny piping and finishes along the powerpack.
-Rough guess but - with nozzles flat on a level surface - Raptor looks to be 0.5-0.75 meters taller than M1D.
-They eyeballed Raptor around 3X the overall volume of M1D.
-Sitting side by side, the gist is that Raptor looked "waaay larger" than M1D.

>>10334772
>>10334806
Why can't I hold all these sources?

>>10334806
That would make it bigger than Saturn 5's f1. That would also mean that only a maximum of 4 raptors would fit on the BFR, which would mean landing manuveurs are impossible. Its bullshit, plain and simple.

>>10334822
I think your really underestimating the size of the F-1s...

>>10334861

>>10334077

Look lads, its been great, a fantastic joke and all, trolling some tards and poking fun, but seriously, what playground is going to receive this toy?

>>10334678
Please give me a clue about that, I don't know what to look for.

>>10334721
It still hurts

>>10334861
The Merlin is 1.30m and the raptors cant be much bigger because even with 1.30m its going to be tough to fit 31 engines on a 9m diameter rocket.

>>10334907
it was destined to fail anyway, hydrogen + SSTO is a shitty combination

>>10334907
Lel that was a fucking joke.

>>10334806
>Nozzle was matte like M1D and approximately 50-100% wider at the base.

Maybe a vacuum one? sea level will be 1.3m afaik, similar to Merlin

>>10334955
They said they aren't making vacuum raptors.

>>10334931
There's pretty solid evidence that the base of the 'Super Heavy' booster will skirt out and be wider than 9m, so I'm pretty sure SpaceX have realised this already.

>>10334948
>>10334950
>t. George Bush/McDonnell Douglas

>>10334955
>>10334956
There's the whole theory about the duel bell compensating nozzle, but that's pure speculation and based off the hopper's frankenengines.

>>10334957
No, there isn't. If they say the rocket's diameter is 9m they mean the bottom part that is the widest.

See the pic, the bottom is a bit wider than the rest and will be 9m.

Why the fuck haven't we got aerospike engines yet?

>>10334958
Hydrogen fuelled SSTOs are a huge fucking meme.

>>10334967
and a spaceplane on top of that.. triple fucking meme

>>10334967
>t. Rockwell

>>10334971
It's still a joke friend, if it had any promise to it one of the many launch startups would be at least exploring the concept, guess what? They aren't because it's shit.

>>10334970
Also aerospike, quadruple meme.

>>10334961
>BFR 2017

Very retro

>>10334960
That would have been for ultra deep throttle capability, not for compensating for altitude.

>>10334962
You try keeping a long spiky thing non-meted inbetween a bunch of combustion.

>>10334992
*melted

>>10334977
no, it's because traditional rockets are tried and tested. the development time/cost into space planes is what's holding them back

>>10335018
>Bro just carry up tonnes and tonnes of extra weight so you can land like a fucking plane rather than using your existing engines to retro burn and land

Durrrrr, spaceplanes are fucking retard tier.

>>10335022
>bro just use a fully expendable rocket to send 2 guys to a big floating cylinder in the sky durrr

>>10335022
SSTOs are the way forward gramps

>>10334992
There's a truncated version that works just as well

>>10335022
Spaceplanes are the future.
We just need air breathing engines that can get us to orbit. Much easier than rockets.

A bit more money into scramjets and we'll have it in 10 years tops.

>>10335023
>Strawmanning expendable rockets onto me

Ok bro

>>10335024
Yes they are, SSTO boosters that do retro burns to land back on the pad. Spaceplanes are a fucking meme.

>Bro send this massively expensive spaceplane up with the same launch cost or more than a rocket but it's payload is like a few tonnes because you are carrying all this plane shit lmao

>>10335023
God the Soyuz is such an ugly rocket

>>10335032
But it's a plane.

Who'd ride in a tincan if he had the option to ride on a luxurious jet liner?

>>10335031
>Using your fancy new scram jet engines to send a fucking plane into orbit rather than attaching them to a rocket and massively increasing your payload

Fucking

Why

Also, how are your scram jet engines working above the karman line? Oh they don't? Throw it in the bin.

>>10334077
You double nigger I already made a thread

>>10335034
It's an old icbm with some mods. Why would you make your icbms pretty?

>>10335038
This is the only appeal of a spaceplane

>But it looks kewl

>>10335039
Scramjets throw the plane to near orbital with perigee in the atmosphere. Few m/s from the RCS is then needed to circularize. If that fails no problem just reenter. Much safer and better than rockets which are essentially tightly packed tnt.

>>10335038
What if the jetliner is the tincan when compared to the luxurious rocket ship?

>>10335047
Wow so it got you to into a barely orbit, congratulations, now you only need a few km/s delta v to do anything useful except there is no payload component because you expended all the capacity to get all that dead plane weight into orbit where it does fuck all.

>Muh TNT

What is powering your scram jet? Oh yeah, liquid fuel just like a rocket, you just get to shave down the oxygen component.

>>10335034
Russia doesn't care about form factor at all. Never has.

>>10335051
Reread the comment.

>>10335051
I mean there's always the Skylon method where you use a hybrid rocket/turbo-ramjet that uses air breathing to reach hypersonic speeds and then closes it's cycle to reach orbit. Like the SABER engine in KSP.

>>10334888

>>10335066
You re read mine, your scram jet spaceplane is a junk meme.

>>10335067
Again, what is the point of strapping that to a plane? You take a fucking huge mass penalty for the dubious benefit of being able to land on a runway, woop de doo.

>>10335076
>dubious benefit of being able to do safe and easy landings anywhere instead of doing suicide burns onto a tiny ship in the ocean.

>>10335081
>implying fast low drag/low lift planes are safe and easy to land
Or even take off, as the Concord shows.

>>10335081
>Safe and easy landings anywhere
>Implying space missions are just yolo bro land wherever you want rather than carefully planned orbital insertions with pre defined landing sites
>Implying future rockets won't be landing on the launch pad
>Implying a suicide burn is not as safe or safer than an aerobrake followed by a ridiculously high speed landing into a packed as fuck international airport

Seriously did you idiots learn nothing from the shuttle? Even if it all goes off without a hitch you could loft many, many times the payload without all the meme plane shit.

>But muh planes look kewl

>>10335090
What does a burning tyre have to do with drag you idiot

>>10335091
For vertical landing you need fuel and legs. The weight penalty without a doubt is bigger for vertical landing. See the Space Shuttle weight vs. BFS weight. They weigh approx the same, however the Space Shuttle didn't need any fuel for landing manuveurs.

>>10335090
Just make the wings retractable so it can have enough subsonic lift.

Or go Harrier style.

Plenty of solutions that don't involve dangerous vtol rockets.

>>10335099
>what does burning tyre
Are you retarded?

>>10335102
You should maybe look up what caused the Concorde crash you fucking idiot.

>>10335099
The shuttle had a joke of a payload, needed massive solid fuel boosters and blew up on re entry when the tiniest part of the lifting body and heatshield was compromised, great design.

>>10335100
>Bro just make these critical structural components that have to withstand re entry heat and pressures without the tiniest failure retractable lol

Official /sci/ approved list of aerospace memes:

- hydrogen
- SSTO
- spaceplanes
- aerospikes
- space elevators
- skyhooks
- colonization of Venus

Thanks for listening.

>>10335108
High take-off speed complications.

>>10335100
>Harrier style spaceplane

That's the biggest meme I have ever heard. They can barely make a few tonnes of plane VTOL without huge engineering and it's still unreliable and dangerous and you think you can just make a few hundred tonnes of spaceplane VTOL? Fucking hilarious.

>>10335115
add solid rockets to the list

>>10335112
The Shuttle had a payload capacity that was sufficient for every mission it was designed for. Had they wanted a bigger payload capacity, they would have made the first stage bigger and more powerful (and also more expensive). The Shuttle is the second stage, and thus you should compare it only to the BFS, and there the Shuttle wins in any aspect.

>>10335116
No, you fucking idiot, a burning tyre crashed into the engine, my god are you retarded.

>>10335120
>this is what someone actually believes

I swear I will kill myself right there and then.

>>10335120
>there the Shuttle wins in any aspect.

Literally what aspects

>>10335120
>you should compare it only to the BFS, and there the Shuttle wins in any aspect.
>the Shuttle wins in any aspect.
>wins
HAHAHAHAHA oh god


BFS may yet fly or not, but if it does it will BTFO Shuttle in all aspects (payload mass, volume, cost..)

>>10335115
>>10335118
SSTSO (Sub-Orbital) hydrogen spaceplane with aerospikes and solid rockets (not staged) for early thrust boost launched of micro-space elevator (magnetic sled) aimed at skyhook to kick it on Trans Venusian Injection trajectory with inflatable hydrogen balloons to act as dirigible once it aerobrakes using inflatable ablative heatshield tiles also capable of landing vertically like Harrier but with the addition of airbags for the touchdown.

>>10335133
>BTW this is all expendable
>pls gib 9000 girrilion dollars
>t. ULA

>>10335133
This is actually a good idea though

>>10335131
How much payload could the BFS carry if it had two side boosters instead of a gigantic first stage, you brainlet.

>>10335140
much less per $$

>>10335140
>Doesn't specify literally anything about the hypothetical side boosters meaning you can just make up whatever you feel like and claim victory
>Lel u R brainlet

>>10335145
The STS side boosters brainlet.

>>10335146
Nah senpai you are the brainlet here.

>>10335146
>Using expendable boosters instead of a reusable booster

Ok

>>10335126
Do it after you kill him first such stupidity has no right to exist.

>>10335133
>SSTSO (Sub-Orbital) hydrogen spaceplane

You treat this as a joke, but Boeing are actually building one for DARPA, it uses an AR-22 engine which is basically a smaller RS-25 made out of leftover space shuttle parts.

https://en.m.wikipedia.org/wiki/XS-1_(spacecraft)

https://m.youtube.com/watch?v=9AkXp4VSB0k

>>10335164
Looks like thinly veiled sat killer.

>>10335067
Skylon can only get to around 1.5 km/s on air breathing engines.Even F9 with RTLS is throwing the upper stage into a much better position to get into LEO and it does that with very simple engines not the unicorn SABRE

>>10335140
A ton of $ to ATK

>>10335164
It is not a SSTO tough. There is an expendable second stage.

>>10335170
It's apparently designed to fly 'once a day for 10 days', which is a weird requirement unless you consider that the vehicle is being designed for military purposes. The DoD keep going on about using small launches to prevent 'intelligence deniability' via space e.g. China shoots down a US spy satellite using an ASAT weapon, so the US quickly launches some small satellites to temporarily regain coverage in that area.

>>10335047
Scramjets do not exist
Don’t act like they do

>>10335173
Skylon doesnt have a second stage you absolute brainlet.

Skylon definetely has a good shot at actually becoming fully reusable because of how light and at the same time big it is. This means relatively harmless reentry, which means the biggest issue for reusability is not so big.

>>10335200
That makes it even worse you brainlet.You add a ton of complexity to allow for SSTO with airbreathing engines when a reusable booster can get you a better start conditions for propelling into LEO.BFR and Glenn will be long flying and Skylon will be the last 90s SSTO meme forever on paper

more scaffolding

>>10335073
interesting things in this book:
solar electric propulsion
europa clipper
low boom flight demonstrator
DART
hydrazine alternative
they have some in-space robotic assembly and manufacturing bits
this thing is 800 pages long

>>10335200
>>10335234
This conversation is kind of pointless because Reaction Engines doesn't even have enough funding or resources to build Skylon, their barely scraping along on investment from Boeing, ESA and UKSA. They plan to test their Sabre engine in 2020 but that's it, it seems like Boeing will swoop in if the testing goes well and Sabre will end up powering a Boeing vehicle.

>>10335259
If they get SABRE working you will see numerous Skylon clones within years.

>>10335234
Hello brainlet, like most shillboys you have no clue about anything. Skylon can launch and land on any runway, no launch pad assembly needed. Plus, its only one stage, so you dont have to put together two stages that landed on different spots first, which is a costly and difficult process. Third, because of how big it is (83metres, similiar to a whole New Glenn rocket) while at the same being very light (53 tons, 30 tons less than BFS or Space Shuttle) it will experience only very low reentry-heat and thus it will almost avoid the heat shield-issue altogether.

>>10335196
>Scramjets do not exist
https://www.isro.gov.in/launchers/isro%E2%80%99s-scramjet-engine-technology-demonstrator-successfully-flight-tested

>>10335246
Any mEMe drive testing?

>>10335284
>If they get SABRE working

Yep any day now...

>>10335413
They demonstrated their precooler to Boeing, Rolls Royce, Darpa, and the DoD, who are all investing in this engine. Just because they don't produce CGIs every couple of weeks doesn't mean they aren't making progress.

>>10335437
>A precooler

Wow it's fucking nothing.

>>10335442
It's the piece of technology to reach Mach 5 with a jet, brainlet. If they get this done, everything else should be relatively easy.

>>10335450
>Literal paper engine

>>10335023
PYOTR GET BACK FROM ROCKET YOU ARE DRUNK

>>10335450
>Mach 5

Wow it's fucking nothing

>>10335451
It literally is being fired at a test stand in the US.

>>10335458
That's the speed Falcon 9 first stage reaches, brainlet.

>>10335472
>They made a precooler
>If this works they will be able to finish it
>It is being fired at a test stand

Kek get your story straight

>>10335458
Only 20 machs to go. Don't forget the magic materials that can take the heat though.

>>10335485
Wow, a shillboy knowing nothing about rocketry, what a surprise.

>>10335472
>That's the speed Falcon 9 first stage reaches, brainlet
>The super magic high tech engine that can't even make orbit

Lmao

>>10335484
>30 threads in
>still can't identify plebbitors by their posting style

>>10335500
Another shillboy not understanding basics of rocketry. Jet engine mode = Mach 5 = similar to what Falcon 9 1st stage does. Rocket engine mode = Mach 25 = similiar to what Falcon 9 2nd stage does.

Now kys.

>>10335244
Didn't they work using cranes? Why do they need that for?

>>10335505
Lel OK buddy, cute paper engine. I'm sure it'll fly one day.

>>10334987
How does changing the bell geometry effect throttle-ability? Isn't the primary limiting factor in throttle-ability turbo-pump stall and combustion instability within the combustion chamber?
Please educate me if I'm mistaken.

>>10335507
The crane rent got too expensive.

>>10335196
>Scramjets do not exist

>>10335507
Elevated work platforms (boom lifts, scissor lifts ect.) have a large footprint making it near impossible for more than 2 to work close to each other. With scaffolding you can have 5+ guys on each layer instead of 4 guys total working from two lifts.

What motivates this guy to shit up dozens of threads? And why are anons still replying to him?

This is a demonstration.

>>10335535
top kek shillbois btfo lmao

>>10335535
>demonstration
the absolute state of muskfags
>>10335539
this

>>10335535
>>10335539
>>10335545
delusional shitposter stop shitting up the threads lol

Demonstration is over.
If there are any questions send them over the formal channels.

>>10335535
>>10335539
>>10335545
>>10335549
>>10335551
>That one samefag that has no clue about rocketry but shits up every space thread with his SpaceX bullshit.

>>10334678
what is this referring to?

>>10335287
Lol no

>>10335570
Schizo /x/ bullshit by the look of the post, just ignore it.

>>10335570
>>10335583
I suspected there was something about BFR in there but after searching "spacex" and checking all 90 results all it has is dragon capsule contracts, the falcon heavy launch, the 2016 cato investigation and spacex hiring their vacuum chamber for fairing testing.

>>10335458
>Wow it's fucking nothing
A conventional air breathing turbine at mach 5 would be nothing less than revolutionary. Conventional turbines aren't really capable of exceeding 2.8; you need a ramjet for that.

>>10335649
It could revolutionize many more aspects to have such an extremely capable heat exchanger.

>>10335595
my guess is it's the quantum computing thing mentioned, since he says it's a "magic" word and the word "quantum" is colloquially used as a synonym for "magic".

>>10335699
"Quantum" is the new "Nano" people think it's going to be some magic wand when in reality it'll be another incremental improvement.

>>10335710
Incremental improvements aren't bad. there have been very few technologies that weren't slowly introduced through incrementally better applications

>>10335833
I'm all for any improvement, I just get annoyed when researchers produce a pair of meshing gears on the nano scale and you get dickheads saying we are going to be injecting robots to repair bones in 10 years.
I would rather people be realistic about technological development instead of hyping shit up and acting like everything is going to lead to a major revolution in a decade.

The biggest revolution of the past century has been the electronic computer and even that with plenty of DoD funding took 30 years to be useful in labs and another 20 to be useful to the average person.

>>10335346
it's 800 pages dude

>>10334077
i'm a spacex fan but i'll be surprised if this hunk of crap flies the first time

>>10335845
nanotechnology will probably be revolutionary in some areas in 60-80 years, but even then will require a long time to refine. this type of technology is orders of magnitudes more complex than previous techs have been at the time of their development

>>10334077
So the fuel tank is a composite one or a more conventional li-al one?

>>10334962
The diffusion of the plumb cannot be regulated by a pressured fuel injection system in the exhaust? instead of using that surface effect that clearly is very material demanding?

more scaffolding

>>10336204
stainless steel, and you're looking at it
this is an early photo, before they wrapped it in foil

>>10336228
>"so uh, Jim, are we, you know, rocket scientists now?"

>>10336255
It's not wrapped in foil, they just polished it.

https://www.youtube.com/watch?v=GTJmlXSCD0A

>>10336268
>rocket *surgeons* Bill. Rocket *surgeons*.

>>10336352
they wrapped it in foil, it's not polished
the upper half is polished and it came that way from wherever they bought it, but the bottom is wrapped in foil

>>10336368
I hope the foil blows away next.

>>10336389
I doubt it will, I don't know how they've fastened it on there but it hasn't come off yet

>>10336362
Rocket construction workers.

>>10336228
Kek did they just toss the cone into the tent and be like

>Nah its fucked forget about it

>>10336400
>I don't know how they've fastened it on there but it hasn't come off yet
I hope somebody said that just before the nose cone collapsed.

>>10336537
no, nobody said that
also it didn't collapse, it fell over

>>10335246
>>10334888
>>10335570
>>10335595
>>10335583
dammit, the magic word was nuclear. NASA is investigating a way to do ground testing for a nuclear thermal rocket. The document also recommends doing a flight test of the kilopower nuclear power reactor if it was successful, which it was. Don't talk about the rocket much, the normies will freak out about a rocket engine that belches radioactive exhaust. But hey, that's why they're investigating an exhaust capture system.

>>10336647
it won't belch radioactive exhaust if you build it properly, SLAM only shed reactor bits because they built it wrong as a joke

>Chemical propellants

lmao, humanity will go extinct on this rock never to have made kit beyond its only satellite..

>>10336656
they also have research into high-power hall effect thrusters
last year they got up to 100 kW

have we seen them building a new nosecone yet? i havent been keeping track lately.

>>10336756
no

>>10336536
Took them less than a month to build. Repairs would probably be harder than building another one.

>>10336791
>Repairs would probably be harder than building another one.
expendable_rockets.jpg

Remind me again, what's the economics of reusability again?

>>10336791
I'm pretty sure they only built it for the photoshoot anyway, they'll build another one eventually

This seems to have became an Aerospace General Thread, so I'll drop my question here.

I've been designing my own liquid bi-propellant rocket engine (N2O + Propane) and I've been struggling with designing a regenerative cooling system that is both light enough for flight and simple enough that a bunch of college freshmen can wrap their heads around it.

I've looked into using copper pipes which are bent into the shape of a chamber and nozzle, but that seems to be both incredibly fragile and incredibly difficult to manufacture.

My colleagues suggested designing the cooling chambers to be directly in the walls of the chamber and nozzle and just having the part 3D printed, but that kind of technology is not quite available for cheap around these parts yet.

Any recommendations?

>>10336795
Not having to repair at all.

>>10336817
the F1 did the pipe thing
it's lighter but more expensive than the channel method that everybody is using nowadays

>>10336817
>I've looked into using copper pipes which are bent into the shape of a chamber and nozzle, but that seems to be both incredibly fragile and incredibly difficult to manufacture.
Get a decent plumber/gas guy to show you how to pipe bend. A couple of little tricks are to fill the pipe with sand or salt and to twist the pipe as you bend it, stops it squishing. I've self taught it, it's not that hard. You need to accept not insanely tight tolerances and work around that.

>>10336820
No, that's expendable rockets. Reusability requires fixing sometimes.

>>10336836
Thank you.

Tight tolerances are not my concern for this engine, but designs that are resistant to loose tolerances are preferred.

One major problem that I and my collages (who are designing an engine separate from my personal project) have encountered with pipes (that run lengthwise from the top of the chamber down to the nozzle exit) is that the pipes would have to be squished together at and around the throat such that they will all fit within the limited circumference, and squishing the pipes precisely enough such that they will all fit together when assembled was a huge headache.

Now, having the pipes run from one side of the engine to the other (widthwise) would solve this issue, but I have never seen an engine that does this.

Maybe I'm overthinking this...

>>10336907
Myb 3D print it

New sheperd feels kinda memey. Does anyone have any ideas on New Glen timeline. It feels like bezos is behind. If the BFR project as a whole takes off even with like 2 years worth of set backs it seems apparent that new glen program is slow albeit well funded. So my question would be if Blue Origin is playing the long game how come they don't seem concerned with the pace of the BFR. The whole point of the design is that musk wants a fucking fleet of them some time by 2030.
Won't Blue Origin be seriously behind. I mean they got a great engine but is that all they are?
New Armstrong on the horizon? It just feels a tad goofy. Not as good as the continued push from NASA to continue the SLS when they'd probably do better with backing either horse and pulling their equipment around new capsules for those crafts

Also Blue Origin commercial market is more or less banking that they can beat the FH, and that their is a market for them post bfr. They are pretty much gambling on failure.

>>10336907
>but designs that are resistant to loose tolerances are preferred.
You should be able to do it with some practice and using a form of some kind. I would suggest you try it out for yourself a bit first, you are not me after all and I have no direct knowledge of how precise you want this and how well you'd take to it, you may decide it's not for you or stupid or something.

>One major problem that I and my collages (who are designing an engine separate from my personal project) have encountered with pipes (that run lengthwise from the top of the chamber down to the nozzle exit) is that the pipes would have to be squished together at and around the throat such that they will all fit within the limited circumference, and squishing the pipes precisely enough such that they will all fit together when assembled was a huge headache.
So if I've understood this correctly you want continuous cooling pipes (contacting each other) and a continuous interface (in contact with all of the chamber). If that's the case separate the two problems: a continuous interface would at its simplest be two cylinders I guess separated by water; the pipes are really just there to divide that water up, so you can either do other bits of flat metal to divide stuff up, or you can do a loose pipe system with every other pipe "missed" and a sheet wrapped around the outside and inside and welded to the pipes (this could have the benefit of having better thermal distribution too as every other pipe is taking cold coolant in or taking warmed coolant out; cool and warm are adjacent). If that doesn't make sense I may try and draw a little picture or something, I found it harder to describe than expected..

>>10337054
>So if I've understood this correctly you want continuous cooling pipes (contacting each other) and a continuous interface (in contact with all of the chamber).

Yes, imagine the walls of the chamber and nozzle are pipes that run lengthwise like in the picture. These pipes pump cold fuel through them, absorbing the heat that the chamber and nozzle walls will be feeling thus keeping them cool enough to be useful structurally.

For the rest of your post, perhaps a picture would be better, its hard for me to follow your train of thought on this.

>>10337157
Damn that's a big boi

>>10337054
Nah it is more complex.Channel spacing and surface finish is determined by thermal transfer and mechanical properties of metal.In general you attempt to minimise pressure loss over the channels but that is counteracting thermal transfer and thermal transfer is mostly related to thickness of liner wall that is determined by mechanical rigidity of the material. Various copper alloys are used

>>10337162
Not sure if this is clearer. Make a helix with a gap between turns equal to pipe diameter. Sandwich that helix between two sheets of metal (one inside, one outside). The gap is now another enclosed helix i.e. another pipe. The negative/positive shape doesn't have to be a helix, there are a number of different solutions but I felt this is most straightforward way to explain. It may not be feasible for you, but shouldn't be too much different to smooshing pipes together but without having to worry about a precise pipe to pipe interface. You can make the inside wall on a form and then use it as a form for pipes, so you get a precise pipe to chamber interface.

Fixing the sheet to the pipes may be problematic, but you may not need to have a perfect seal between consecutive turns, although you probably want a decent enough sheet to pipe interface for decent heat transfer. Copper is decent at compression welding though, and you can use compression + heat. You could also try box section depending on what exact positive/negative shape you settle on, and that could simplify some aspects of machining. If you fix everything together well enough, it'll also be very strong and rigid. I think this gets rid of your major problems.

If you want precisely fitting together pipes machined it's just a total pain as far as I can think of anything. You have to set up some rollers and heat it up and all that jazz, like you'd need to build a little machine for it. Some places will make custom shapes for you using is it wound metal forming? I don't think it'd be easy though, and probably pretty expensive.

>>10337249
What is the cooling media? Is it going to be traditional refrigeration with Delta p and a compressor or just some bigass HXRs and a pump?

>>10337243
>In general you attempt to minimise pressure loss over the channels but that is counteracting thermal transfer and thermal transfer is mostly related to thickness of liner wall that is determined by mechanical rigidity of the material.
I think you've told me a number of things there. Pressure loss will be down to increased resistance, so a smaller pipe diameter/longer pipe line will have more contact (because more turns) with whatever it's cooling, but also more contact of the fluid to the walls, so more drag/resistance. You mean thickness of liner allows larger pipe diameter? Is that what you're trying to relate? There's also channel size/speed of flow, larger channel = lower flow = better heat transfer but also less drag because slower. and less surface area to volume

It depends what level of sophistication you want it the end. There are ways to increase the rigidity fairly simply if need be, but I don't think that should really be an issue desu with how stuff has to connect whatever approach is taken so long as you give it a passing thought.

>>10337270
You need to ask the other guy, he's saying the fuel is cooling the chamber but no details beyond that.

I'm merely saying what comes to top of mind that works with pretty basic manufacturing by hand while avoiding stuff that worries too much about tolerances..

>>10337249
Nice idea and nice drawing!

The pipe coil can be tightened and the gaps brazed together so that the inner wall isn't needed.

Although I see one problem with this unfortunately, this way will not cool the chamber and nozzle evenly compared the the previous method. This may result in hot-spots that will compromise the engine. Sadly, I don't know enough about heat transfer (yet) to quantify this.

Again, nice drawing!


>>10337270
For rocket engines the cooling medium is their fuel or oxidizer that is carried with the rocket.

For the case of this engine, it would be either be N2O or Propane whichever is found to have better cooling properties.

>>10337293
>>10337243
Also with a compression weld, the thickness would reduce in those areas. It would still be thicker, but not as thick as one might expect.

>>10337302
>Although I see one problem with this unfortunately, this way will not cool the chamber and nozzle evenly compared the the previous method. This may result in hot-spots that will compromise the engine. Sadly, I don't know enough about heat transfer (yet) to quantify this.
Tune the channel size between the positive and negative shape, larger channel on the thicker areas = lower flow rate = longer time for heat transfer. This may be impractical, but would hopefully even it out, maybe not enough. There are also materials with high lateral heat transfer (graphite and graphene sheets), but they're fucking expensive so eh.

>>10337302
Btw, I like the idea of N2O as an oxidizer.

>>10337308
>Tune the channel size between the positive and negative shape...
Interesting idea, could work. I may pass this idea with my colleagues (especially the ones who know heat transfer) and see what they think.

>>10337318
Thanks! I chose it because while it doesn't have as much energy as Liquid Oxygen, it won't straight up kill you if you handle it wrong. Perfect for freshmen.

Plus its fun to say "It runs on Propane and Laughing Gas"

>>10335453
AYYE BLYAT

>>10334981
They are the true meme company, truly ahead of their time.

>>10335115

>>10337442
I can't tell if this is shooped or not

NASA presents the lunar rover by IKEA

I really hate the bureaucratic shitfest that is NASA, looks like DM-1 is taking a March to the right...

>>10337660
>BFR crew shows up
>Haha look at this IKEA garbage
>Kicks rover over and bullies it
>One dude rips out transponder gear and takes it to comfy tunnel home as a prize

>>10337447

>>10334875
Give it an R2D2 paint job and you could drop it into a Disney park.

>>10336352
The bottom is wrapped in foil

>>10338351
>MuH sHiNY 50'S RoCKeTs

>>10335284
>Plus, its only one stage, so you dont have to put together two stages that landed on different spots first, which is a costly and difficult process.
>implying you always have to reassemble the exact same two stages together
With enough extra big dumb booster stages, you just stack your upper stage with the next available booster, and the newly recovered boosters go into the refurb pipeline for a couple of days, plus shipment time if it landed on an offshore platform.

>>10335437
Meanwhile, SpaceX is about to "demonstrate" their second generation launch system. Better hurry!

>>10335458
>Mach 5
It's FIVE BLADES motherfucker. Fuck going to four blades.

>>10337660
>>10337970
>>weird radio blipping noise
>>"was that you steve? Steve?"
>>Steve's gone
>>Some pebbles fall off a boulder
>>"BLIP BLIPP BLIPP" echoes over the radio getting louder
>>"Guys I think we need to get out of here"
>>Something moves just out of the corner of vision then it happens
>>"BLIIIIIIIIIIIIIIIIIIIIIIIIIIIIIPPPPPPPPPPPPPP"
>>out of the corners thousands of Puffer robots emerge and start attacking one of the crew swarming over them
>>they fold onto him and spin wheels wildly eating away at the suit
>>screams and blips can be heard over the radio,
>>"GET TO THE ROVER!"
>>"But they got Tim!"
>>There's no sign of Tim now, only a pile of pulsating puffers which has started to take on a red hue
>>"It's too late for Tim, GET TO THE ROVER!"
>>The crew run as fast as they can in the low gravity with the puffers in hot pursuit
>>They stop. It's too late. Where the rover used to be there's now a roughly rover shaped mound of writhing puffers surrounded various debris
With BFR, we could land millions of these robots

>>10338442
>go into the refurb pipeline for a couple of days
Haha, funny joke. Also they can't even fix the tinfoil hat, what makes you think they're going to fix the fucking rockets?

>>10337034
>Also Blue Origin commercial market is more or less banking that they can beat the FH
...when even FH is barely flying due to low demand for heavy lift. Jeff who?

>>10338450
Why do you seem to think that the this bumpy wobbly runt will be their mass-production vehicle? It's just to test the rockets and the going up and down. It's not even the same height. It's probably even better that be wobbly and bumpy, it makes them test with lower tolerances than a production unit.

>>10338484
>It's probably even better that be wobbly and bumpy, it makes them test with lower tolerances than a production unit.
Then it's probably even better they take the dings out of the hat and stick it back on in a couple of days.

>>10338484
BO's in bed with oldspace so they'll be fine. Question is whether they'll be independent company or absorbed by the big guys after that whole divorce thing. From the point of view of Boeing and so on buying out a company that already did decent chunk of R&D on something desired is conventional practice and much faster than reinventing the wheel.

>>10338446

>>10337157
a literal fucking water tower

>>10338487
If it was carbon fiber they would have to completely trash it.

>>10338503
I'm still waiting for them to add the cement mixer crew capsule.

>>10336647
Block II starship with closed cycle gas core NTP when?

http://www.projectrho.com/public_html/rocket/enginelist.php#ntrgasclosed

>>10338507
Luckily with stainless steel they can chuck it into a recycling center.

>>10338503
achually it's a LNG tank with fins wrapped in tinfoil

>>10338531
You aren't thinking big enough. They can sell it for ten times the price as an art piece.

say bfr works out how many people will fit inside? how much will it cost to go to leo? how much to mars?

>>10338575
If it works I'm retiring somewhere I can get a neat view of Saturn's rings.

>>10338529
Bro, just hold out for NASA actually flight testing an NTR, any NTR. NASA's being investigated by a watchdog group for why it's taking so long to develop nuclear anything. Cause that watchdog says we need nukes for ISRU, which private companies want to do. So yeah we got kilopower, but it's the simplest damn reactor we could build. NASA's still not great at this nuclear thing, but they can fucking do it. A private company would have to be absolutely batshit insane to even think about building a nuclear rocket for ground launch. It would not fly with the NRC. I don't think the NRC has ever approved a nuclear reactor that moves, much less one that could dirty bomb any major US city while making a good sized crater (dat delta V) in the process. NRC approval for new reactor designs is an expensive and long process.

>>10338529
>increase delta v <2x
>increase price >100x
Doesn't sound that good.

>>10338618
Tyranny of the rocket equation
NTP is not worth it for a disposable rocket, and anything reusable needs to either end up aerocaptured, with the obvious problems arising from that, or you need to use a bunch of dV to brake at your target, so it's only really worth it for missions to airless rocks

>>10338646
>tyranny of the
Overused meme and not applicable in this case. NTR has use in a situation where one is limited to low flight rate flagship launch configuration with little certainty in big orbital assembly or refueling.
Essentially the situation NASA expected to find itself in for its early Mars missions hence neat increase of payload for the Saturn V or similar vehicle using a more radical upper stage.
But in a situation where the upper stage is refueled easily and cheaply introducing NTR will be massively counter productive on the things that matter - cost, schedule, flight rate, politics.
If the nuke hysteria wasn't so ingrained in popular culture NERVA could have found its place in the SLS program.

exciting

>>10338865
>better performance than hydrazine
>not toxic
But what will we do about the jerbs of people who have to unload the hydrazine after vehicle return?

>>10338937
HAZMAT jeorbes are in high demand

>blatant jeorbs congress bait

In the meantime, enjoy the new Apollo 11 doc trailer
https://www.youtube.com/watch?v=3Co8Z8BQgWc
They scanned never before seen footage at 8k

>>10338981
I absolutely love the crawler
look at the size of that absolute unit

>>10334623
Looooool bro u just need a styrofoam chest and a bunch of liquid nitrogen, which is cheap.

>>10338618
>>10338646
Nuclear is for use in space
Make a yuge nuclear interplanetary craft that the planetcraft dock to get true effectiveness out of it

>>10339024
if you're restricting nuclear to space (as is perfectly reasonable) then you might as well throw it out for Mars missions because of how much dV you can save by doing an aerocapture instead of an orbital insertion burn

>>10339035
Time though, nuclear lets you burn more, slashing travel time massively, and potentially removing the transfer requirement
Saving delta v is for cargo runs, not manned

>>10339196
you have more delta v with NTP
you need more delta v with NTP because you can't just use the atmosphere to slow you down, you need to do a capture burn instead
conventional will be faster to Mars because of this

>>10339207
I have a feeling that the needed deltaV gained from not aerobraking isn't as big as you think it is.

Using NTR over Chemical effectively doubles the Isp (and thus can double the deltaV for a given mass ratio)

DeltaV from Earth Low Orbit to Mars Low Orbit with aerobraking is estimated to be 4.3 km/s

DeltaV for the same trip but without aerobraking is roughly 5.7 km/s

A 1.337x increase in DeltaV, not as bad as you implied.

>>10339196
It's roughly doubled isp but with increased dry mass. Aint gonna make a dent especially if you do propulsive capture. Elliptic orbit refueling does the energetic transfer without all the hassle.

>>10339257
4.3km/s is slow. You need to burn more to reduce it to 3-4 months time and then naturally the price of capture grows...

>>10338599
>what are nuclear submarines

>>10339458
The DoD forced that one through because of the strateigic necessity
Space nuclear is not as nessesary in their eyes, and thus gets red tape hell

>>10336656
You watch too much sci-fi.

>>10338446

>>10338529
Nuclear propulsion is a bad idea for space traveling, reactors are heavy and the thermal transference is not good from the moderator material to the propulsion gas, so at the end you will get low ejection temperatures, actually chemical rockets achieve better efficiency.

So at the end you probably will need for even more mass and an even larger space ship than one powered by chemical propulsion.

Ion propulsion is the way to go, powered with a nuclear reactor.

>>10339257
Aerobraking is huge
It also enables fast transfers because you don’t need fuel to decelerate

>>10339941
Ion is useless for anything close

>>10339981
>Mars
>close

>>10339987
Ion can’t use the oberth effect
Andspiralling out of Leo is shit

>>10339993
Alright, then a combination of ion and chemical (specially hypergolic)

But nuclear is a meme.

>>10339993
I think nuclear would be workable using electrolysis over chemical elements that would have a very violent thermal reaction when combines, then use that energy to heat up a propeller, but that design of injecting gas into the reactor wouldn't work.

>>10339458
meant to say a private reactor that moves.

hmmmm

>>10340197
OH NO NO NO NO NO NO NO

>>10338575
They should just stick to a crew of two and there would be volume for unlimited fucking consumables in an emergency.

>>10340229
the Europa Clipper team is incredibly salty about SLS

>>10340197
>2023 will be here before you know it! What do you mean 2025 is too late? 2027 will be BTFO the most optimistic commercial timeline by years!!

>>10340197
HAHAHAHAHAHAHA! For all those not in the know, the Europa Clipper was required by congressional mandate to use the SLS(which NASA is required to construct also under a congressional mandate). This is the only NASA science mission to have a launch vehicle specified by congress. Typically the mission planners make this decision. It basically got funded to give the SLS something to do.
>>10340257
BRUTAL! They're basically giving congress the middle finger.

are all spacecrafts built this way? thing looks like shit.

>>10340526
good thing it's not a spacecraft

>>10340537
does it go into space?

>>10340574
nope, it's an engine and avionics testbed

>>10340635
isn't it currently vertical on pad 39A right now?

More fairing video from spacex
https://twitter.com/SpaceX/status/1090400806703001600

>>10340640
Dunno why they keep trying to catch the fairings with Mr. Steven, it'd be so much easier if it was done autonomously.

>>10340640
Fug so close

>>10335120
Fuck you

>>10335140
>How much payload could the Shuttle carry if it wasn't a stupid piece of shit?

>>10335512
Raptor has full-flow turbopumps for each propellant, so it's really good for operating across a large range of rpms without stalling. More importantly, the biggest instability issue for a throttling rocket engine is the flow separation that starts to occur if you drop your combustion chamber pressure (throttle down) while at the ambient pressure conditions the bell was optimized for. If at 100% thrust your engine is close to ideally expanded, at lower throttle it will be under-expanded and at very low throttle it will become grossly under-expanded. The nozzles we saw on those placeholder Raptors were exactly as big as we expected them to be given the chamber pressure figures and expansion ratio figures we were told Raptor would have. By doing a little figuring and math we found that the nozzle size at the kink in the curve would correspond to a much lower expansion ratio at full throttle, but an almost ideally expanded size at around 20% throttle. This would make sense because Raptor (in a group of three landing engines) will need to be able to throttle down to less than 30% during landing burns to produce the G loads seen in several simulations SpaceX released.

So you're not mistaken, however the first problem you mention is solved by the nature of the power-head cycle of Raptor and the second is solved by the double-nozzle shape.

>>10339941
>actually chemical rockets achieve better efficiency
No, only with heavier chemicals like water or CO2, whereas with NTP you obviously are going to use either methane (~650 Isp) or hydrogen (~1000 Isp).
The real use for NTP is for rapid propellant production using minimal power, because unlike chemical propellants which must be built with chemistry in reactions that require lots and lots of energy, refilling a vehicle using nuclear thermal engines can be as easy as compressing and storing the required amount of CO2 or melting and storing the required amount of water, since any sufficiently inert volatile can be used for providing thrust if run through a nuclear thermal rocket that is designed to handle it. Sure in the context of using carbon dioxide as NTR propellant the efficiency is lower than in a chemical engine, however that doesn't really matter if you're using this vehicle for long hops across the surface or even orbital launches around low gravity worlds like Mars and the seven big moons of the solar system (Mercury not included because no atmosphere to use to slow back down from orbit like Mars has).

>>10337034

Biezos can afford to fail several times over. Even after his wife takes half his money. He has a net worth measured in the hundreds of billions.

>>10340712
Look senpai, I think NTR is a great idea, loads of potential. But the fact is that it will never be allowed for use, just look at the morons in congress.

>>10340719
When the LAIMO's get put on display you can bet all those silly rules will go right out the window.

>>10340719
NASA's investigating building one. At least the test stand for one. Those morons in congress will actually be for it because it means more govbux for their districts(contractors). There's a test stand at Stennis that's not seeing much use now that some parts of the SLS were delayed(less govbux!)... Keep quiet about it though or the normies will freak out.

>>10338865
I wonder if it's something from Ignition or actually something new.

You cunts want a photo of the inside of a Saturn V first stage? Got my camera inside one on display at NASA.

>>10340665
Big and heavy is really completely fucking retarded for a second stage and sooner or later they will find out at SpaceX, too.

>>10341130
Fucking yes. What kind of nig are you?? Post it right away

>>10341237
Le literally no.
Retarded is using a shitty expensive ultra high mantainance heat shield for your reusable craft and mount it right next to an orange tank that literaly bombards it with ice spikes trying to break it.

People who aproved flight of the shuttle should go to jail. Civilians died on it. You could easily argue murder or manslaughter on a court of law

>>10341530
You need that ultra expensive heat shield because you are so big and heavy. The Space Shuttle needed to be smaller and then it would have been a good and working design (like the Dreamchaser).

>>10341536
No. You need some heatshield. You dont need it to b expensive and poorly designed. An exanole for a sane alternative is the ground breaking "perspiration cooling" currently in development by revolutianary space company spacex which is already known by achieving incredibly advanced technology with a very short amount of time and money.

>>10341553
Thanks for the ad, but you aren't changing physics. Big and heavy = very hot reentry = forget "reuseability". You also seem to have no clue about the subject and just repeat sentences like an adbot or something.

>>10341553
>the ground breaking
Do you really want to put the adjective "ground breaking" on rocket reentry technology?

>>10341130
>>10341525
>OP will surely deliver.jpg

>>10341571
Did you see Tom's presentation on their first rocket test stands?

>>10341578
No, tell me more about it adbot.

!Rocket Test stands
!Tom Mueller

>>10341581
I forget where it is in this hour long talk, but the test stand couldn't take it and broke the ground lol
https://youtu.be/0xWRhKB3JTM

>>10341237
Any reasons why?

>>10340665
>yfw dry mass is similar

>>10341867
steel is delightfully counterintuitive

>>10341867
lol, no it wont be.

>>10341878
>empty concept rocket is slightly heavier than existing, fully equipped spacecraft
woah really

>>10341889
That concept is based on carbon fiber and does not include any heat shields or interior. The steel version will easily go beyond 120 tons.

>>10341901
>cf
Right.
>no heatshield
Wat?

>>10341565
>Big and heavy = very hot reentry

Wrong, you dumb fuck. Big = less hot reentry. Heat is spreading over larger area.

>>10341901
Why beyond 120?
Not having passive heatshield alone saves 20 tons and there could be mass savings from other places.
I've seen 300 ton numbers thrown around but that's just plain stupid.

>>10341963
300 tons for the whole rocket isn't that ridiculous. Saturn 5 first stage was 130 tons and it wasn't made out of the steel. So they will surely go beyond 150 tons for the first stage and not much below that for the second.

>>10341983
Second stage is a lot lighter than first stage. It may very well turn out that steel is lighter than composite+heat shield construction. Delightfully counterintuitive.

>>10341994
It will absoluetely not turn out that way, that is simple physics. "Active cooling" is essentially an abletive heat shield where you use a constant spray of liquid instead of any material to bleed the heat off. Liquid however, any liquid, is much worse in taking the heat away than any of the usual materials that are used for heat shielding. They will most definetely need several times the amount of liquid compared to a heat shield. The advantage is that you don't need to replace the heat shield, you just refill the tanks. But the absolute giant disadvantage is the gigantic weight penalty.

>>10342017
You are missing the fact that steel is a lot more heat resistant than composite and also reflective. So while your heat shield is liquid, you also need it to withstand significantly less heat energy. Net result may very well be actual weight saving.

>>10342036
Steel is also a very good thermal conductor, which is why we make pots out of them. Everything inside the BFS will get cooked as the BFS will essentially turn into a giant pot if you just let it get hot like that.

>>10342040
Also, as steel gets hot, it loses a lot of structural strength, so I dont know if it still could survive reentry with those temperatures.

>>10342017
>gigantic weight penalty
How much?

>>10342042
It seems BFS on windward side will use a double layer with outer skin composed of steel optimized for heat resistance and inner layer composed of steel optimized for structural strength, with active cooling in between and transpiration cooling spraying outside. It will be one monster of a heat shield.

>>10341948
Mass increases faster than surface area, r3 vs r2, bigger means hotter reentry

>>10339014
no anon, using that method you will get nowhere near absolute zero, and 100 degrees shy of it won't give you a bose einstein condensate.

>>10341948
>Wrong, you dumb fuck. Big = less hot reentry. Heat is spreading over larger area.
this is the level of retardation spacexfags have achieved lmao

>>10342078
Starship might have enough empty space in it
we'll see

>>10342070
Mass of a rocket stage is almost all on the surface. Bigger stage means gentler reentry.

>>10342082

>>10341948
Drag is very small in the upper parts of the atmosphere, which are the crucial ones in deciding how hot your reentry is (essentially, the longer you can stay in the upper parts, the gentler it gets) which is why mass is much more important, because the bigger surface area doesnt help you as much in the upper parts of the atmosphere. See the formula for the ballistic coefficient, m/d*a. Since d will be small in the upper atmoshpere, rising a will not be as effective compared to lowering m. What you really want to do is have m be as low as possible. Also, like somebody else said, mass grows faster than area, so you have a double penalty there.

>>10342119
Mass isn't solid on the way down (mostly empty fuel tanks) so it isn't r^3, and that just happens to be when it matters for re-entry. That didn't work for the shuttle because it had already ditched its external fuel tank.

>spend 4 tons of methane to ditch the heavy heat shield
Sounds like a deal to me.

>>10342169
This is actually a good point that I completely forgot. I was talking about empty weights the whole time. The Falcon 9 booster needs around 3-5% of its total fuel to do the landing manuveur. Since the Starship will also have to save up fuel it will need dozens of tons of fuel additionally to its empty weight, while the Space Shuttle didn't need that fuel as it landed horizontally. Now I don't know how much fuel is needed exactly for the landing, but if it is anything similar to what the Falcon 9 needs, it will be >33 tons of fuel (3% of its 1.1k tons of propellant mass as per wikipedia). So in fact, the Starship will have an even hotter reentry than assumed.

Thanks for pointing that out, Anon.

>>10342203
>Thinks 4 tons are enough to cool a 500m2 surface down from >2000k

Yeah, not even close.

>>10342216
you're thinking about it wrong, it's not designed to cool it down from that temperature, it's to keep it from reaching that temperature in the first place
also you're a brainlet retard but let's not go there

>>10342207
>reserves 1km/s for landing

>>10342224
>it's not designed to cool it down from that temperature, it's to keep it from reaching that temperature in the first place
sometimes I feel spacexfags haven't done any physics beyond 10th grade highschool
and even then they should understand basic things like this

>>10342047
Well, think about it that way. You need to cool down a surface area of 500m2. This means that 1 ton of water over the surface would create a film that is 0,2 centimetres thick. How long do you think that water would last under 2000k? And you need to keep that shield cool for 15-20 minutes, so you can imagine what kind of water masses you would need.

The "water" doesn't simply vanish. Isn't part of the process that the coolant vapor (steam, methane, whatever) will act as an insulator layer or something like that?

>>10342234
It seems in your mind everything is simple and clear. I'll ask again. How many tons of water or methane do you expect will be needed?

>>10342243
I think around 50 tons at least.

>>10342228
>what is terminal velocity

>>10342242
The liquid methane/water will probably be heated in the dual layer and ejected as steam. That will also insulate by reflecting and further absorbing heat in addition to protecting the reflective surface.
The interactions are complex but the performance should be spectacular.

They will need a way to vent the shield layer with some inert gas to prevent water freezing or left over methane mixing with atmospheric oxygen once out of the reentry phase.

>>10342272
>prevent left over methane from mixing with atmospheric oxygen
I don't see how your spaceship being on fire is a negative

>>10342272
The steam will be gone within fractions of a seconds. To keep a constant stream of steam going for the whole reentry you would probably need thousands of tons of methane. You guys are deluded. And I am generous here and completely ignore the fact that hot steam is not a good heat shield.

>>10342277
The reentry tail is not the issue but rather the enclosed space where the coolant was pumped.

Some left over methane playing around with atmospheric oxygen after the bulk of the reentry, a random spark, static or left over heat to start a reaction and boom. So either water coolant or inert gas flush.

>>10342280
I've already made this point, they have no answer to it. It seems they're describing what's going on in more complicated ways in the hope that the heat transfer issue goes away.

>>10342309
I'm not an expert and neither are you, so let's wait and see if it ever materializes? fanatics are annoying but you're just as bad

>>10342316
>and neither are you
???

>>10341635
Looks like the story starts at around 14:40

>>10342277
The only thing cooler than a spaceship that looks like a Buck Rogers sci-fi rocket is a Buck Rogers sci-fi rocket ON FIRE

>>10342323
if you knew what you were talking about you wouldn't be shitposting, duh
it's one of the rules of the internet

>>10341635
>>10342325
oops it's at 22:20 holy crap
"Not only did the throat ablate, but the test stand ablated"

>>10342348
it's a good talk, highly recommend

>"Based on research done in the 2010s by German space agency (DLR), a porous thermal protection material called Procelit 170 (P170) – 91% aluminum oxide and 9% silicon oxide – was cooled from a peak heat of ~1750 C (3200 F) to ~25 C (75 F) during wind tunnel testing, demonstrating that an average of 0.065 kg (~2.3 oz) of water per second would be needed to cool a square meter of P170 to the same degree, assuming a heating rate of around 200 kW/m^2"
>Methane has twice the specific heat capacity of steam - so that's about half the mass flow right there, and at least half again as don't need to bring it down to 25°C (600-900°C will likely suffice), and average heat flux is likely half that 200kW (I read 100kW for shuttle today in this thread). So-back-of-envelope call it ~10grams per m2 over 600m2 of windward side surfaces - about 6kg/s of methane. For 10minutes of peak re-entry heating that would be 4 tonnes (space shuttle TPS weighed about 8-9 tonnes). But will likely be less than that. Swapping LH2 for CH4 would be 1 tonne + ~150kg for a 15m3 LH2 tank.

Shameless copy paste from one nice place.

Annoying one schizophrenic and preventing anons from falling for cheap bait is just too attractive to ignore.

>>10342383
amazing, somebody who copied somebody who's pretending to know what they're talking about
saved for future use lmao

>>10341574
>>10341525
Sorry I fell asleep man

>>10342467

>>10342474

>>10342477
Tfw shoving your hand inside a 50 year old unused stage with no idea what's on the other side and blindingly taking photos hoping to God you wont drop your phone.

>>10342383
thanks

>>10342481

>>10342383
The methane bit is so ridiculously retarded. This dude has no fucking clue what he is talking about.

I btw googled the first part. You forgot a bit to copy and paste there:

>Aside from heat flux, it’s also unclear when or how long the cooling system will need to be supplied with water during potential Starship reentries. At worst, the spacecraft would need to supply a constant 50+ kg/s throughout a 5+ minute (600+ second) regime of high-velocity, high-drag reentry conditions. Assuming that Starship will need to rely heavily on aerobraking to maintain efficient interplanetary operations, it might have to perform 2+ active-cooling cycles per reentry, potentially requiring a minimum of 15 tons of water per reentry. Given that SpaceX intends (at least as of September 2018) for Starship to be able to land more than 100 tons on the surface of Mars, 15t of water would cut drastically into payload margins and is thus likely an unfeasibly large mass reserve or any given interplanetary mission.

>The assumptions needed for the above calculations do mean that 30T is an absolute worst-case scenario for a regeneratively-cooled Starship reentry, given that SpaceX may only have to vigorously cool a small fraction of its windward surface and will likely be able to cut more than half of the water needed by allowing Starship’s steel skin to heat quite a lot while still staying well below its melting point (likely around 800C/1500F or higher). This also fails to account for the fact that a regeneratively-cooled stainless steel heat shield would effectively let SpaceX do away with what would otherwise be a massive and heavy ablative heat shield and mounting mechanism. Perhaps the benefits of stainless steel might ultimately mean that carrying around 10-30T of coolant is actually performance-neutral or a minimal burden when all costs and benefits are properly accounted for.

30 tons for the heat shield ayy lmao they might as well use a heatsinking shield at that point.

>>10342493
so you admit that they're comparable in mass
do you agree that the active heat shield has significant positive impacts with regards to reusability?

>>10342502
Look at this retard not knowing what a heat sink is ayy lmao

30 tons just for the liquid is completely ridiculous. Short question: Do you know the weight of the Space Shuttle heat shielding?

>>10342502
he was off by 20 tons, better than you with your retarded napkin calculations and deceptions of "hurr we only need one ton of coolant" while in reality it is highly complicated and prone to failure, not really a mass decrease in heat system and highly dangerous all at the same time

>>10342467
>>10342474
>>10342477
>>10342481
>shoving your hand inside a 50 year old unused stage

>>10342467
>>10342474
>>10342477
>>10342481
>>10342491
Do you perhaps work at NASA Michoud?

>>10342588
I thought Michoud didn't have their S-V anymore. I discovered this a few months ago when checking Google street view. Or maybe it was a S-1B?

>>10342641
Michoud just has a S-1C first stage, which is apparently pic related.

http://www.americanspacecraft.com/pages/booster/sv-mich.html

>>10342682
The web page you linked is dated 2005. I was trying to look for it on Google street view a few months ago, and with the time warp feature you could see that it had been removed a few years back. Of course it could have been moved elsewhere on the property, but it ain't where it was.

>>10337958
>DM-1
Yep, looks like it's been bumped to March, and it may bump the Arabsat FH launch.

>>10342723
oh noooooo

>>10340640
Do they really need to catch it? I doubt exposure to salt water for a few minutes is really going to ruin the fairing beyond repair.

>>10342588
>>10342682
>>10342697
It's the first stage for Apollo 18 on display at Stennis

>>10342277
>I don't see how your spaceship being on fire is a negative
t. ULA

>>10342534
I actually wasn't off, that article just assumes they will have reentry temperatures like the Space Shuttle (which they won't, its going to be hotter, especially for reentries from moon and mars missions, which is the BFR's primarily purpose) and that they can recreate the efficiency of a laboratory experiment out in the wild, which they wont be able to do either.