Orion needs shaped charge nukes and precise control over yields. Just using little bit analogues won't work well.
Let's do rocket engineering from the beginning
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Orion needs shaped charge nukes and precise control over yields. Just using little bit analogues won't work well.
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And something like that would be way beyond the capabilities of this society ... which they wouldn't have any use for.
The most expensive WWII project wasn't the atomic bomb. It was the B-29 ... and there was a backup plan involving the use of modified British bombers capable of carrying something that big.
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And now for the next part:
You've got reliable orbital manned and unmanned spacecraft. What do you do next?
You've got reliable orbital manned and unmanned spacecraft. What do you do next?
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Explore the clearly artificial moon orbiting the nearest gas giant.
Neepa
Always pondering story possibilities
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- Germany
While I'm only an turbojet mechanic in training there is one problem that has so far not been discussed.
How the fuck do you achive the pressures and gigantic mass-flows to feed the engines?
The fuel and oxidiser pressure at the injector valves has to be atleast equal or greater than the combustion pressure.
First of all how do you want to build the necessary turbopumps, which are driven by a gas turbine and hence "turbo"pump, with 1925 metallurgy and manufacturing capabilities? You need super tight tolerances to make the divided pump stages as gas tight as possible as they are most likely driven by one gas turbine over one common shaft. Also the turbine has to survive and cannot afford to just "make it" over the whole run time of the stage. It cannot afford to gradually loose power as its eroding away since the pressure and flow has to stay as even as possible to ensure stable combustion.
And this is were good old Hydrogen Peroxide comes into play. Wernher von Braun and his team had quite severe problems to feed the engines they were designing. The V2 in the end used a Hydrogen peroxide-Manganese dioxide gas-generator fed turbine to drive the pumps. The work of Helmuth Walther for the Kriegsmarine on his Walther drive was nearly essential to make the V2 leave the ground. Which was also used in the A and B versions of the ME163 rocket interceptor.
And I'm sure the turbojet efforts helped with the pumps too.
Alternatively you could pressurerize the tanks which could be done in two ways. Firstly by using an inert gas under pressure stored in its own little tank or by using a gas generator to pressurerize them.
Now whatever you use as a propellant and oxidiser has to be non-reacting with whatever you're pressurizing the tanks with. And following the outline of OP it might not be Helium since its arguable if this imaginary earth even has acces to oil or natural gas. Which is where we passively collect our Helium from today.
With the abilities outlined so far I cannot see/imagine how they will overcome the basic challenge of feeding their rocket engines.
It will be a very long and rocky road ahead with key technologies/components missing entirely.
How the fuck do you achive the pressures and gigantic mass-flows to feed the engines?
The fuel and oxidiser pressure at the injector valves has to be atleast equal or greater than the combustion pressure.
First of all how do you want to build the necessary turbopumps, which are driven by a gas turbine and hence "turbo"pump, with 1925 metallurgy and manufacturing capabilities? You need super tight tolerances to make the divided pump stages as gas tight as possible as they are most likely driven by one gas turbine over one common shaft. Also the turbine has to survive and cannot afford to just "make it" over the whole run time of the stage. It cannot afford to gradually loose power as its eroding away since the pressure and flow has to stay as even as possible to ensure stable combustion.
And this is were good old Hydrogen Peroxide comes into play. Wernher von Braun and his team had quite severe problems to feed the engines they were designing. The V2 in the end used a Hydrogen peroxide-Manganese dioxide gas-generator fed turbine to drive the pumps. The work of Helmuth Walther for the Kriegsmarine on his Walther drive was nearly essential to make the V2 leave the ground. Which was also used in the A and B versions of the ME163 rocket interceptor.
And I'm sure the turbojet efforts helped with the pumps too.
Alternatively you could pressurerize the tanks which could be done in two ways. Firstly by using an inert gas under pressure stored in its own little tank or by using a gas generator to pressurerize them.
Now whatever you use as a propellant and oxidiser has to be non-reacting with whatever you're pressurizing the tanks with. And following the outline of OP it might not be Helium since its arguable if this imaginary earth even has acces to oil or natural gas. Which is where we passively collect our Helium from today.
With the abilities outlined so far I cannot see/imagine how they will overcome the basic challenge of feeding their rocket engines.
It will be a very long and rocky road ahead with key technologies/components missing entirely.
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It's not quite as hard as you think. With chamber temperatures and pressures not much higher than an automoblile engines you can build rocket motors capable of getting things into orbit.
Hell, you can do it with with an 8-stage black power rocket. The devil, however, is in the details.
BTW: I've designed steam systems meant to operate with inlet pressures and temperatures past the critical point of water: 705F, 3200psia. The limit is what the materials you have access to can handle. The motors used by the Saturn V didn't have chamber pressures anywhere near that.
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That's no moon!
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To elaborate ...
Rocket motors have operational lifetimes measured in minutes. Pretty much all other motors have vaslly longer design operational lifetimes. A rocket motor can run above the creep limit (but not the melting point) of the materials it's made of. With all other motors, doing that is an engineering "Oh, hell NO!".
EDIT: to give a simile: the perfect race car falls safely apart just after crossing the finish line in first place and the perfect rocket motor falls safely apart just after it's no longer needed.
Rocket motors have operational lifetimes measured in minutes. Pretty much all other motors have vaslly longer design operational lifetimes. A rocket motor can run above the creep limit (but not the melting point) of the materials it's made of. With all other motors, doing that is an engineering "Oh, hell NO!".
EDIT: to give a simile: the perfect race car falls safely apart just after crossing the finish line in first place and the perfect rocket motor falls safely apart just after it's no longer needed.
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Ok, here's what I think an early orbital one would look like when the starting point for tech is 1925-ish and there are no wars:
The mass to low orbit will probably be about the same as the mass of a Mercury capasule for both manned and unmanned launches.
The launch escape system and payload fairings probably have similar masses and are discarded at the same point during the climb to orbit.
The rocket which gets those up there is simple, two-stage or three-stage, and not a rush job.
The oxidizer and fuel tanks are unpressurized, vented, and heavier than they need to be.
H2O2 pressurized by Nitrogen gas powers the turbopumps.
The turbopumps are a lightweight steam turbine design modified to work with steam and hot oxygen driving centrifugal pumps (possibly two-stage if there isn't enough NPSH at the pump inlet for single-stage to work).
The turbine exhaust will be dumped overboard instead of fed to the combustion chamber so the turbine inlet pressure isn't the chamber pressure plus the pressure drop between the turbine inlet and the combustion chamber.
The rocket motors won't be fancy (i.e. no regenerative cooling, no gas generator, no staged combustion, &c).
The chamber pressure will be as low as they can get away with to minimize design complexity and materials headaches.
The oxidizer is probably LOX because something storeable isn't required and they aren't making missiles which can be stuck in storage for years and then still be useable anywhere on short notice.
The fuel is something miscible with water (i.e.: an alcohol, hydrazine, or an alcohol-hydrazine mix) so they don't have to mess with the complexity of a LOX-hydrocarbon-water tri-propellant mix (which has been done before) to keep simple motor designs from melting.
The ignition scheme uses something pyrophoric that the liquid oxygen gets to say "hello" to before any fuel reaches the combustion chambers.
The motors probably don't have throttles but instead are on-off and controlled by more sophisticated versions of the kinds of things you'd find on 90-100 year old HVAC piping drawings.
The mass to low orbit will probably be about the same as the mass of a Mercury capasule for both manned and unmanned launches.
The launch escape system and payload fairings probably have similar masses and are discarded at the same point during the climb to orbit.
The rocket which gets those up there is simple, two-stage or three-stage, and not a rush job.
The oxidizer and fuel tanks are unpressurized, vented, and heavier than they need to be.
H2O2 pressurized by Nitrogen gas powers the turbopumps.
The turbopumps are a lightweight steam turbine design modified to work with steam and hot oxygen driving centrifugal pumps (possibly two-stage if there isn't enough NPSH at the pump inlet for single-stage to work).
The turbine exhaust will be dumped overboard instead of fed to the combustion chamber so the turbine inlet pressure isn't the chamber pressure plus the pressure drop between the turbine inlet and the combustion chamber.
The rocket motors won't be fancy (i.e. no regenerative cooling, no gas generator, no staged combustion, &c).
The chamber pressure will be as low as they can get away with to minimize design complexity and materials headaches.
The oxidizer is probably LOX because something storeable isn't required and they aren't making missiles which can be stuck in storage for years and then still be useable anywhere on short notice.
The fuel is something miscible with water (i.e.: an alcohol, hydrazine, or an alcohol-hydrazine mix) so they don't have to mess with the complexity of a LOX-hydrocarbon-water tri-propellant mix (which has been done before) to keep simple motor designs from melting.
The ignition scheme uses something pyrophoric that the liquid oxygen gets to say "hello" to before any fuel reaches the combustion chambers.
The motors probably don't have throttles but instead are on-off and controlled by more sophisticated versions of the kinds of things you'd find on 90-100 year old HVAC piping drawings.
Let's start with the basics...
I would drink some kind of stimulant instead - mushroom juice or something like that...
The fuel could be methanol, ethanol or some kind of hydrocarbon.
The oxidizer could be nitrogen oxide or nitric acid - these have been used on Earth before. I'll have to look in our books for some kind of stainless steel or titanium alloy that can resist these things.
I would drink some kind of stimulant instead - mushroom juice or something like that...
The fuel could be methanol, ethanol or some kind of hydrocarbon.
The oxidizer could be nitrogen oxide or nitric acid - these have been used on Earth before. I'll have to look in our books for some kind of stainless steel or titanium alloy that can resist these things.
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Liquid Oxygen was available circa 1900. If you don't need to stuff the rocket in storage on a shelf for gods knows how long under unpredictable conditions where it must reliably work with no testing at a moment's notice there's no good reason to use a different oxidizer because it can set practically any fuel you'd want to use on fire, and the fires will be hot ones.
With LOX the biggest challenge is keeping the motor from melting.
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13th Bee
Worker
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- Tennessee, USA.
That would've been Plan C. Plan B was the Consolidated B-32 Dominator.
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And that was an engineering failure while the B-29 is pretty much the ancestor of every modern jet airliner used today.
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- The Midlands.
LOX was available in experimental quantities back then, true, but it would be a while longer before it was something you could simply buy from a wholesaler. And refrigeration technology was rather primitive in the early days of rocketry, which makes storing it prior to fuelling the rocket a huge hassle; RFNA, by contrast, can be stored at room temperature for quite a while as long as you have a container made of something it can't react with.
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The first quartz clock was made in 1927. Whatever this theoretical does not yet have that they'll need is probably already being researched, or not too far away.
You can do radio without vacuum tubes using spark gap transmitters. But fun fact you can put a communication taillight into orbit without it having any kind of radio on it at all.
Project Echo - Wikipedia
Which would be a good thing to put into orbit to help with communication to parts of the planet that aren't linked by undersea cables. Though without mylar it might not be fesable.
As for the first thing I would put in orbit it would likely be a wave of unmanned science probes and some alien animals to. It is helpful to know if our species is going to die from some wicked strong van allen belts or if being in zero g makes eating or something else impossible for us before we put the named missions up.
mouli
Terrible QM
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- United States
Not sure about feasibility, but that was a nice read. Especially the bits about how they provide targeting reference points for ICBMs, and the next image over is a big stamp marked 'Communications for Peace'
.Echo sounds good, though, a nice practical use. Not to mention that one can probably manage other microwave-reflective substitutes with lesser efficiency (this is the Twenties after all, synthetic fabrics and blends a decade early isn't that unfeasible with the right circumstances).
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- The Midlands.
We might be getting a bit ahead of ourselves here. An instrument package of some kind, or just a camera, with a parachute to return it to the surface afterwards would be a lot more prtactical for a first attempt. Anything involving telemetry or remote guidance is going to have to wait for a few other fields of science to catch up.
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The first photograph taken from outer space was done by a camera mounted on a captured V-2 that wasn't slowed down by either a heat shield or parachute during re-entry in 1946.
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To put the amount of power a Mercury capsule had into perspective: The 12V lead-acid battery my car has is protected by a 100A fuse. The main circuit from the batteries to everything else in a Mercury capsule would not have been capable of delivering enough power to even start my SUV's engine.
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A solar Stirling engine is doable with 19th century tech, and operate in a vaccuum just fine as all they need is a temperature differential.
Stirling engine - Wikipedia
IIRC Jules Verne did a story where a space capsule was launched from a giant gun sunk into the earth that used conventional explosives. The practicality was questionable, but apparently the math worked out.
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It does, barely.
With a small off-the-shelf gunpowder model rocket motor you can get specific impulses of 80-90 seconds.
When Ve = 0.6275 ΔV (i.e. about 80% of the take-off mass is propellant), that's good enough for 1.25-1.41 km/s.
A solar Stirling engine is doable with 19th century tech, and operate in a vaccuum just fine as all they need is a temperature differential.
They actually compare quite favorably with traditional solar panels.Stirling engine - Wikipedia
en.wikipedia.org
IIRC Jules Verne did a story where a space capsule was launched from a giant gun sunk into the earth that used conventional explosives. The practicality was questionable, but apparently the math worked out.
Verne's math on orbital mechanics was right but the space gun itself was wrong. This isn't surprising as he thought that someone using rockets to get to the moon would be thought of by readers as to fanciful and unrealistic so he went with a gun. Even with the guncotton he talked so much about it simply wasn't possible to get the gasses up to the velocity needed. Chemical explosives in guns are largely held back by the speed of sound in the super-heated and pressurized gas they produce. So you get diminishing returns with larger and larger explosive charges till going bigger does nothing. Even electrochemical guns have to deal with this even though they don't have to care about detonation speed like normal guns do.
Though on the other hand the fastest guns in the world currently are using plan old off the shelf gunpowder to accelerate projectiles to orbital speeds. The thing is the gunpowder isn't pushing the projectile but is simply being used as a way to pressurize the worlds fastest airgun. The important difference is that by using hydrogen and going to ridiculous pressures a light gas gun can get to rather ridiculous muzzle velocities. The current record is using a three stage (aka three different pressurization events) light gas gun that got to 11 km/s.
As for the solar sterling engine. It does seem like a reasonable possibility. Depending on the current technology level of electronics in Tramp_stamp's world solar cells might simply not exist and not be possible. Being able to recharge battteries without using fuel cells opens up far more unmanned options for the space program.
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A more pressing concern is how you survive being accelerated to 11km/s by a gun.