Project Orion: A discussion of Science and Science Fiction

[intelliCom]

2 minutes ago, sevenperforce said:

It could still be balanced if Orion was (a) prone to blowing itself up if launch in-atmo, (b) very heavy, (c) very expensive, (d) unthrottleable other than altering pulse frequency, and (e) produced actual thrust pulses so great that they would overwhelm the gee-limits of most in-game parts.

Why introduce an engine you can't even use yet? Just for the sake of making the tech tree more akin to if we didn't have the test ban treaty? KSP introduced the Nerva at the end of the tech tree, so nuclear power in general- nuclear reactors, nuclear pulse propulsion- shouldn't exist before this point.

Also, having the pulses being too strong for the ship itself is just counter-intuitive. Orion might need a small debuff to be balanced alongside all the new engines, but there's no good reason to put it earlier than NERVA in the tech tree.

[sevenperforce]

4 hours ago, intelliCom said:

Why introduce an engine you can't even use yet? Just for the sake of making the tech tree more akin to if we didn't have the test ban treaty? KSP introduced the Nerva at the end of the tech tree, so nuclear power in general- nuclear reactors, nuclear pulse propulsion- shouldn't exist before this point.

I don't think they should have it in the game at all. I'm just saying, if they were going to, that's how you could balance it.

4 hours ago, intelliCom said:

Also, having the pulses being too strong for the ship itself is just counter-intuitive. Orion might need a small debuff to be balanced alongside all the new engines, but there's no good reason to put it earlier than NERVA in the tech tree.

It's not completely out of the question to make the pulses super strong. There are parts with reasonably high gee-limits, after all. It would just limit utility to a handful of use cases.

But I would agree with putting it past NERVA in the tech tree, for sure.

NERVA first, then Orion, then ions.

Kerbal needs some small low-thrust, high-specific-impulse solid fueled kick motors too, to help balance probes.

[kerbiloid]

5 hours ago, intelliCom said:

Why introduce an engine you can't even use yet?

Any engine was originally never used yet.

Also, is it Spaceflight & Science or KSP Questions part of the forum?

The game logic differs from the real world one.

6 hours ago, Strawberry said:

You cant use Orion in atmosphere

You can't use ше at low altitudes.
But you can do it in thin air, where the shockwaves and secondary radiation are negligible.

So, lift it up to 50..60 km where the conditions don't differ from vacuum until you reach 8 km/s speed, and start nuking.

6 hours ago, Strawberry said:

even ignoring the environmental effects

They are absolutely negligible for low-kiloton yield at hight altitude, with pure-uranium charges, several times per year.

6 hours ago, Strawberry said:

You cannot transport a nuke of this size to space no matter

What's the difference between 1 000 t of nuke and 1 000 t of sand?

6 hours ago, Strawberry said:

in the hypothetical you were to transport a multi gigaton nuke to space for some reason, you will need to construct it, while this is far far from easy

In kitchen - yes. But the nuke connstructors were sure that's not a big deal, and there is no visible reason why not.

Anyway, I took the Sundial as a reference point for the ship mass, so I can't see why do you focus on the Sundial details when the talk is about Orion.

6 hours ago, Strawberry said:

I should've mentioned that I was referring to theoretical efficiency instead of deuterium instead of efficiency in practice, using the fuel in a more efficient manner would give it a greater energy to mass ratio

The liquid deuterium is the worst possible fusion fuel in sense of energy-to-mass ratio.

The combat version of that 82 t Ivy Mike charge (aka EC-16/TX-16) was weighting 19 t, yield ~10 Mt so its ratio was 0.5 Mt/t.
This is by order of magnitude worse than was achieved by the LiD bombs.

Even if take the deuterium spatial density in LiD, it's 2/8*820 ~= 200 kg/m³, when the liquid deuterium is ~220.
And the litium is weighting definitely much less than required heavy metals.

As the theoretical upper limit of the yield-to-mass ratio is ~80 kt/kg for D,DT and ~50 kt/kg for LiD, this also means that deuterium is at least twice worse in sense of energy-per-voulme.

So, the only reason to mention the liquid deuterium at all is a historical one.
The fusion reactions were discovered in early 1930s, earlier than spontaneous fission, and the nukes were originally seen as fusionukes, just nobody had an idea neither how to ignite, nor where to take tritium.
So, they were hoping on liquid deuterium and doubted in LiD until its first tests,

6 hours ago, Strawberry said:

I'm pretty sure Sundial intended to do this through something similar to the classical super design

The "classic Super design" included all possible designs in different variants.
It's just a colloquial term for the early idea of a thermonuke.

6 hours ago, Strawberry said:

you generate extremely immense heat and pressure through pure brute forcing it and generating from just a separate nuclear explosion (to an extreme),

I've heard about the electromagnetic force, the weak and strong forces, and even the gravitational one.

But what is "brute force" to be just applied?
Something different from these four ones?

If just put a primary next to the secondary, you will get a cloud of dispersed secondary. Only negligible part of it will have time to react.

If put it inside, the cloud will be spherical.

You anyway have to oppose the overheated fuel expansion, and it's inertial confinement. You need either heavy metal rock inertia, or thick layer of non-reacted fusion fuel.
So, in any case only small part of total mass will react.

6 hours ago, Strawberry said:

if this were to work if you brute force this enough (through say.. a one gigaton explosion), you could get it to far higher efficiencies then normal.

Gigaton? Not teraton? Not petaton? What makes to think so?

6 hours ago, Strawberry said:

This design wouldnt need many of the complexities of normal nukes and thus save a lot on weight

6 hours ago, Strawberry said:

while construction wouldnt be easy

I can neither connect these two theses, nor reailize what are those specific complexities when there have been tested multimegaton charges.

6 hours ago, intelliCom said:

Still, in a gameplay perspective, making Orion engines come first would make Ion feel really out of place.

Ion engines are either low-thrust or low-efficiency. They are for tiny actions.

6 hours ago, intelliCom said:

Considering how the NERVA equivalent was put at the end of the tech tree anyway, Orion should be after that.

Nerva and Orion have absolutely different principles and different range of thrust.

Nerva is 40 tf and 9 km/s of ISPg, Orion is from 100 to many thousands tf and ~100 km/s of ISPg.

Their construction don't follow each other, so they are on independent branches of Tech Tree, just Nerva is simpler to build, that's why it historically appeared sooner.

Orion depends not on nuke reactor progress, but on pneumatics and mechanics for its piston thing. So, it more depends on big combustion engines rather than Nerva.

5 hours ago, sevenperforce said:

(d) unthrottleable other than altering pulse frequency,

Easily and precisely throttlable as irl anyway would be DT-boosted. So, you can throttle it just by limiting the amount of tritium in the boosting gas, total 1.5 g or just 0.783 g, or maybe 0.045 g.

5 hours ago, sevenperforce said:

they would overwhelm the gee-limits of most in-game parts.

In game parts, not irl parts.

Edited September 2, 2022 by kerbiloid

[sevenperforce]

12 minutes ago, kerbiloid said:

5 hours ago, sevenperforce said:

they would overwhelm the gee-limits of most in-game parts.

In game parts, not irl parts.

Yes, that is the point.

[intelliCom]

2 minutes ago, sevenperforce said:

NERVA first, then Orion, then ions.

Kerbal needs some small low-thrust, high-specific-impulse solid fueled kick motors too, to help balance probes.

Ion engines were utilised in space before NERVA (Kiwi in 1959, ) even had a chance to be. See SERT-1 (1964). Space nuclear reactors, on the other hand, were being operated around the same time as ion engines. See SNAP-10A (1965).

16 minutes ago, kerbiloid said:

Any engine was originally never used yet.

Also, is it Spaceflight & Science or KSP Questions part of the forum?

The game logic differs from the real world one.

@sevenperforce and I were discussing Orion's implementation into KSP/KSP2, and where it would be on the tech tree. I still believe that regardless of the test ban treaty's interference, Orion would have been developed after NERVA due to one simple reason; you just didn't have the launch vehicles necessary to haul such a massive engine into orbit. Nova or Sea Dragon would've done it, but those were considered at the same time as NERVA was being developed, so Orion wouldn't have been before NERVA in active use. Sure, it saw earlier research, but its implementation as a usable technology needs infrastructure to support its use, as well as demand. We may see resources being hauled to Earth in the future utilising a high-efficiency, high-thrust engine like Orion, but for now it's just slim pickings under Congress' leash.

20 minutes ago, kerbiloid said:

Their construction don't follow each other, so they are on independent branches of Tech Tree, just Nerva is simpler to build, that's why it historically appeared sooner.

Assuming KSP 2 even follows the tech-tree format, I can imagine both stemming from a shared 'Fission Technologies' tech node (nuclear reactors, RTGs, etc.), then Orion needs the latest research into structural and thermal technologies; research more advanced than NERVA. When I said "Orion comes after NERVA", I meant in when the player should be able to use the engine; not that NERVA directly connects to Orion on the tech tree. If it seemed like that, I'm sorry for the confusion.

[kerbiloid]

11 minutes ago, intelliCom said:

I still believe that regardless of the test ban treaty's interference, Orion would have been developed after NERVA due to one simple reason; you just didn't have the launch vehicles necessary to haul such a massive engine into orbit.

The first stage of Saturn V was to be the launch stage of 10 m Orion. It's no need to lift it to LEO by rocket.

12 minutes ago, intelliCom said:

so Orion wouldn't have been before NERVA in active use.

If Nerva was in active use before the Orion-scale orbital operations, which looks doubtful.

Probably they would be complementing each other.

[SunlitZelkova]

13 hours ago, wumpus said:

The point of "battleships" was the construction of thick armor plating.  Building that pusher plate would take relearning some lost skills.  The size of the thing wouldn't matter,  except that you'd presumably make it in Antarctica (or possibly build it on a barge and tow it to a soon-to-be ice free arctic summer).

There would be no need to launch it from Antarctica because the most serious studies had it either being lofted into the upper atmosphere by boosters or assembling it in space first.

1 hour ago, intelliCom said:

I still believe that regardless of the test ban treaty's interference, Orion would have been developed after NERVA due to one simple reason; you just didn't have the launch vehicles necessary to haul such a massive engine into orbit. Nova or Sea Dragon would've done it, but those were considered at the same time as NERVA was being developed, so Orion wouldn't have been before NERVA in active use. Sure, it saw earlier research, but its implementation as a usable technology needs infrastructure to support its use, as well as demand. We may see resources being hauled to Earth in the future utilising a high-efficiency, high-thrust engine like Orion, but for now it's just slim pickings under Congress' leash.

These are Saturn Vs.

Orion after NERVA makes sense to me. Even without the test treaties, the government and science community saw no use for such a massive payload capability.

Assuming KSP is something of a loose fantasy world along the lines of going forward to Mars after the Moon and so on IRL, the tech tree should be based on the premise that NERVA would pop up first for Mars and then later as the goal shifts to the outer planets, Orion development begins.

[intelliCom]

12 minutes ago, SunlitZelkova said:

There would be no need to launch it from Antarctica because the most serious studies had it either being lofted into the upper atmosphere by boosters or assembling it in space first.

These are Saturn Vs.

Orion after NERVA makes sense to me. Even without the test treaties, the government and science community saw no use for such a massive payload capability.

Assuming KSP is something of a loose fantasy world along the lines of going forward to Mars after the Moon and so on IRL, the tech tree should be based on the premise that NERVA would pop up first for Mars and then later as the goal shifts to the outer planets, Orion development begins.

Saturn-V scale parts in KSP were still close to the end of the tech tree; you'd have landed on the Mun way before reaching such a point. But that's fair enough, I've been corrected. Orion was in fact considered for launches on Saturn Vs. Still, the boost-to-orbit part needed three launches; so launching it all at once without using Orion as a second stage would've needed something like Nova or Sea Dragon. Then again, it's not like you have to put it up in one launch. 

At least my demand argument held up, lol.

Edited September 2, 2022 by intelliCom

[kerbiloid]

They made it black & blue rather than just metallic.

Spoiler

It gives +12 to thrust force, and +10% to fire resistance!

Also, due to the rubber pusher plate, the whole thing can be used as a sink plunger, not only as plungers receiving the hits.

Edited September 2, 2022 by kerbiloid

[intelliCom]

4 minutes ago, kerbiloid said:

They made it black & blue rather than just metallic.

It gives +12 to thrust force, and +10% to fire resistance!

Also, due to the rubber pusher plate, the whole thing can be used as a sink plunger, not only as plungers receiving the hits.

I'm sorry, I don't think I understand what you're saying. If this is a joke, it's a really strange one.

[kerbiloid]

9 minutes ago, intelliCom said:

I'm sorry, I don't think I understand what you're saying. If this is a joke, it's a really strange one.

I mean the strange color of a thing withstranding the close nuclear explosions (would the color burn?) and the black color of the steel pusher plate, probably rubber or blued.

[intelliCom]

1 hour ago, kerbiloid said:

I mean the strange color of a thing withstranding the close nuclear explosions (would the color burn?) and the black color of the steel pusher plate, probably rubber or blued.

I think you're referring to the high-strength shock absorber, the black zig-zag drum bit. Really does look like rubber, doesn't it? The artists did a good job with that. Let's hope it compresses like one properly in-game.

[kerbiloid]

39 minutes ago, intelliCom said:

I think you're referring to the high-strength shock absorber, the black zig-zag drum bit. Really does look like rubber, doesn't it? The artists did a good job with that. Let's hope it compresses like one properly in-game.

It's a steel plate with water/steam cooling pipes inside.

Those two-stage plungers should retract extend.

Also, they are sometimes described as springs, but actually they should be pneumatic accumulators of energy,

The piston comes into the pressurized cylinder with inert gas, and adiabatically compresses it.

Then the gas starts extending, pushing out the piston, and pushing the cylinder itself forward, towards the upper piston, pushing it inside the upper cylinder, and adiabatically compressing the upper stage inert gas.

Then the second stage inert gas expands, pushes out its piston, and pushes the second stage cylinder (attached to the engine frame) forwards, together with attached ship.

That's how every plunger stage decreases the piston acceleration a hundred times, and while the pusher late jump up at 10 000 g, the engine frame and the ship receive just oscillating 1 g.

Twenty minutes of horse riding in seats - and the acceleration is over, the ship is drifting to Mars.

[magnemoe]

On 8/31/2022 at 2:56 AM, Nuke said:

currently the only means of interstellar travel within the limits of current engineering and technology.  you just need the bucks and the desire to build one. 

nuclear power could have saved us from the current climate crisis, if not for the stupidity of some operators/designs and fear mongering involved from those opposed. 

nukes are ok. if it wasn't for those we would be in ww3 by now.

Orion pulse nuclear works better who larger scale you use it on. However to make something interstellar you would need something tens of km in diameter after that I read. 
Now the same is true for most realistic high performance spaceship engines, they tend to be huge as an minimum scale while orion had designs down to 5 meter I think. 

One major problem ignoring the rule against nukes in space is that you will need to test all this in deep space because of environmental reasons. 
Technological readiness level is low, so stuff will go wrong just look at SLS and Starship there even raptor is pretty mature. 
 

[magnemoe]

On 9/1/2022 at 2:03 AM, SunlitZelkova said:

The most detailed proposals were for Mars or Saturn but some were made for other stars.

I don’t think the lack of battleship experienced shipbuilders is a problem. We have been building cargo ships the size of battleships (some bigger than battleships) for decades.

But not with thick armor, who I don't think is needed. Battleship armor is face hardened so the front is very hard steel while the rear is much more flexible. 
Kind of like traditional katana's are made but with huge slabs of thick steel. 
This is very nice if you want to stop an large incoming shell but not needed to stop the plasma from an nuke. 
Now I kind of think you want an ablative layer below the structural one, at least if you used this long term who makes sense. Kind of artillery barrel lining. 
 

[magnemoe]

On 9/2/2022 at 12:36 AM, intelliCom said:

Still, in a gameplay perspective, making Orion engines come first would make Ion feel really out of place. Considering how the NERVA equivalent was put at the end of the tech tree anyway, Orion should be after that.

I put them on different tech trees who is also true in KSP 1. 
Now one KSP 2 game play restriction on Orion is that the fuel as in nukes is not only expensive compared to hydrogen who you can mine on any icy world, but you need an industry infrastructure to mass produce and on an rocky world. Well its 4 uranium sources, Kerbin, Eve. Dress and Tylo. Pick your poison. 

[Spacescifi]

11 minutes ago, magnemoe said:

I put them on different tech trees who is also true in KSP 1. 
Now one KSP 2 game play restriction on Orion is that the fuel as in nukes is not only expensive compared to hydrogen who you can mine on any icy world, but you need an industry infrastructure to mass produce and on an rocky world. Well its 4 uranium sources, Kerbin, Eve. Dress and Tylo. Pick your poison. 

 

Lol... I am presuming the KSP 2 dev team is blissfully unaware of the weaksauce version of Orion that uses pure fusion triggered by high explosives/magnetic fields.

 

Still effective though.

https://toughsf.blogspot.com/2022/03/fusion-without-fissiles-superbombs-and.html?m=1

With this you CAN mine ice for fuel and and still process the hydrogen for fusion fuel.

 

 

Edited September 3, 2022 by Spacescifi

[magnemoe]

4 hours ago, Spacescifi said:

Lol... I am presuming the KSP 2 dev team is blissfully unaware of the weaksauce version of Orion that uses pure fusion triggered by high explosives/magnetic fields.

Still effective though.

https://toughsf.blogspot.com/2022/03/fusion-without-fissiles-superbombs-and.html?m=1

With this you CAN mine ice for fuel and and still process the hydrogen for fusion fuel.

Yes, however with current technology you need to feed the fusion pulses energy, this is not an dealbraker as it just reduce your trust and add mass, its still good. 
Now the crazy thing is that fusion might be easier in space as you are not concerned about the cleanness of you vacuum chamber. 

No I don't think KSP 2 go down this way, I guess its Orion, the huge starship engine, then the expanse engine and / or antimatter. 
We seen some very large reactors, I say metalic hydrogen or antimatter is the only reason for them

[Strawberry]

We do see a Daedalus style inertial confinement engine in several of the trailers, there will definitely be pulse fusion for interstellar purposes (just likely not to be triggered by anything but lasers).

[Spacescifi]

17 minutes ago, magnemoe said:

Yes, however with current technology you need to feed the fusion pulses energy, this is not an dealbraker as it just reduce your trust and add mass, its still good. 
Now the crazy thing is that fusion might be easier in space as you are not concerned about the cleanness of you vacuum chamber. 

No I don't think KSP 2 go down this way, I guess its Orion, the huge starship engine, then the expanse engine and / or antimatter. 
We seen some very large reactors, I say metalic hydrogen or antimatter is the only reason for them

Too bad. Maybe someone will make a mod later.

I find it awesome that IRL allows for more 'cheats' than even a space sim like KSP2 would present.

 

 

[Spacescifi]

I was thinking... if one wants to get the maximum thrust with the least amount of fuel then you need to detonate a sufficient yield bomb, preferably a pure fusion bomb of sufficient yield since it is safer than fission trigged nukes. In addition pure fusion bombs do not require the critical mass that nukes do so their energy can be scaled down to only what is necessary.

The scenario: You have a rich billionaire who has manufactured pure fusion bombs from low to high yields.

You are his engineer. He wants you to design an SSTO that detonates pure fusion bombs inside the throat of the nozzle for thrust.

Right away you tell him, "Sir, that may damage the nozzle."

"You're the engineer, Find a solution. Maybe I dunno, you could make the nozzle thicker or let it secrete oil for ablation between pulse detonations."

"I will see what can be done and get back to you."

 

So what do you think? Can this be done mechanically without any show stoppers?

Potential problems that come to mind is shrapnel from the pure fusion bombs damaging the nozzle, but I think this can be mitigated if the bomb jackets are made of combustible materials that will vaporize upon detonation.

 

Thoughts?

 

This is more or less external pulse propulsion using pure fusion bombs and a rocket nozzle.

Interestingly enough... this may be a scenario where a large and thick nozzle may be just the right kind for the job. It would have to be actively cooled with pipes of coolant running through it and also oil secreated inside the the throat for ablative cooling.

 

Feel free to correct me if I am wrong in any way.

Edited September 10, 2022 by Spacescifi

[wumpus]

Yep.  Maximum thrust.  Now plug that thrust into the rocket equation and see how much delta-v you  get.

[NFUN]

Let's be real. Whether or not it's viable doesn't change that it's insane

[Gargamel]

As the math will quickly show the only viable solution is an Orion drive, it has been merged into the Orion thread. 

[kerbiloid]

Nothing detonates in the nozzle or in the throat. It's a chamber.