Space Elevators and Mass Driver Runways

[Guest]

I don't think either of these would be fun, certainly not if they were just building/base upgrades. 

It would be very cool though if KSP2 provided sufficient parts and physics that we could build them. Which is highly unlikely IMO.

Edited September 8, 2019 by Guest

[GoldForest]

5 hours ago, Dragon01 said:

Space elevators are very unlikely to happen. It's more than just nanotubes, nevermind that making nanotubes of arbitrary length is a huge challenge in itself. A space elevator may never be practical, in fact, due to reusable rockets getting cheaper all the time. Before we get to the point where we could make nanotubes of sufficient length, we might start building everything in space, and reusable orbital ships would be so cheap that passenger transport would not justify investing in an elevator.

Claiming that they are "near future" is utter malarkey. They're about as far a future as you can get. They also certainly don't compare to mass drivers, which are already used on a small scale (on the other hand, they aren't so hot of an idea, though they do have their uses).

Well, we all have our opinions and I respect yours. I feel we could have a working space elevator with a decade or three. I feel they are indeed very possible, just not probable in less than a decade. 

I do agree there are more problems than just the nanotubes, but the nanotubes are the biggest concern I feel. 

Other problems, wind restraints at the various levels of the elevator. Storms and earthquakes, it would need to be a less active area of Earth. Material, the ground structure, although would only be a mile or two high and supported by nanotube cables, would still need to stand up to high winds and stresses. Political problems would plague it certainly. A space elevator would have to be put in a neutral territory or in international waters and have a multi-national team governing it. 

So, yes, lots of problems to iron out, but a decade to three decades isnt a far fetch in my opinion. 

3 hours ago, DStaal said:

Space elevators are physically possible in real life - but currently require unobtanium to build on Earth, though the material strength requirements is within what is known possible.  Mass drivers are current tech (at a smaller scale) - but not really useful on Earth.  They would be great on the Moon however.

My biggest problem with a space elevator on Kerbol in KSP is that the Mun would interfere - While KEO itself is within Mun's orbit, your counterweight would be getting very close to Mun's SOI, and I'm not sure such a device would be stable if we were using N-Body physics.  There's also the materials issues above.

Mass drivers for colonies make perfect sense, especially for smaller airless worlds.

Why does it need unobtainium? You could build it out of steel and titanium and other super strong metals just fine. Nanotubes are unobtainable, just difficult. 

Mun wouldn't interfere... it would deck the space elevator every orbit. 

Ksp system = 1/10th sizes, right?

Mun orbit = 12,000,000 meters

Space elevator orbit = 144,000,000 / 10 = 14,400,000.

But the irl space elevator height comes within 1/4th to 1/3rd give or take of the irl moon's orbit. So if we use that...

Space elevator orbit 1/4th scale = 3,000,000 meters. 

1/3rd scale = 4,000,000 meters

So it will be fine.

[DStaal]

11 minutes ago, GoldForest said:

Why does it need unobtainium? You could build it out of steel and titanium and other super strong metals just fine. Nanotubes are unobtainable, just difficult. 

Steel and titanium are not strong enough.  Nanotubes are - but we don't know how to make them at macrosopic lengths.  Therefore, unobtainium. 

12 minutes ago, GoldForest said:

Space elevator orbit = 144,000,000 / 10 = 14,400,000.

Space elevator orbit is Geosync.

[GoldForest]

16 minutes ago, DStaal said:

Steel and titanium are not strong enough.  Nanotubes are - but we don't know how to make them at macrosopic lengths.  Therefore, unobtainium. 

Space elevator orbit is Geosync.

Oh, right. Doy lol. Totally forgot. And I'm the one that copied the info XD.

Well in that case the height of the counter weight is about 3.3 times that of the geo station, so

2,863.33 (keo) * 3.3 = 9,448.989 km

Edited September 8, 2019 by GoldForest

[Guest]

From a gameplay perspective a space elevator would just make all the Mun and Minmus infrastructure useless.

Think about it, resources distribution permiting, it will make sense to launch every deep space mission from Minmus or Mun and so it would make sense to build a colony there as soon as possible to be able to set up a launch site or even a orbital shipyard; a space elevator totally negates that.

Edited September 8, 2019 by Guest

[GoldForest]

18 minutes ago, Master39 said:

From a gameplay perspective a space elevator would just make all the Mun and Minmus infrastructure useless.

Think about it, resources distribution permiting, it will make sense to launch every deep space mission from Minmus or Mun and so it would make sense to build a colony there as soon as possible to be able to set up a launch site or even a orbital shipyard; a space elevator totally negates that.

That's why it would be very end game, to make interstellar travel easier from Kerbin. Once you're out and about, it wouldn't matter if you launched from the mun or the space elevator.

Edited September 8, 2019 by GoldForest

[Ender65535]

I think we agrees that building space elevator is an engineering problem, not a science one. The problem here is gameplay. We can now just build ships directly on LKO, which effectively teleport the ships from KSC to orbit, and kills the utility of a working space elevator.

 

A mass drive, or some kind of first stage launch assist would be more appropriate for rockets instead of spaceplanes. The idea is go get some deltaV on the ground relatively cheap. Having this dV vertical would be more efficient in atmosphere (because drag). There is actually some working on this idea:

http://www.arcaspace.com/docs/ARCA_LAS_White_Paper_May_1_2019_Issue_1.pdf

 

Quote

ARCA created an electric, water based rocket that works as first stage, or booster for launch vehicles, allowing the reduction of polluting propellant with around 25%, or boost the payload capability with around 30% pollution free. But LAS isn't only clean is unprecedently safe and cost effective.

 

Yes, you read it right, a water rocket, not different from the ones you have played with as a kid. This ultimate water, however, carries thousands tons of water, and throws another thousand ton payload a few kilometers up into the air with a ~389 m/s dV. It has a laughable isp of ~50, but who cares? water is cheap, the power to pressurize while on ground is (relatively) cheap, and if the water tank can be recycled, that would be a (almost) free first stage.

Edited September 8, 2019 by Ender65535

[Incarnation of Chaos]

13 hours ago, GoldForest said:

Like I said in an earlier comment, the distances that mass drivers would stretch our vast. Upwards of 5 to 25 to possibly hundreds or even thousands of miles. The longer the stretch, the slower the acceleration could be, but it would severely hinder launch capability the slower you accelerate. 

Also, I don't think you understand that Mass Drivers are not meant to do all the work. Mass Drivers serve to HELP the spacecraft accelerate up to speeds able to break the atmosphere. The SSTO would still need to do a lot of work once it left the ramp, including maintaining escape velocity as well as the aforementioned circulation. Mass Drivers aren't there to put things into orbit, they're there to help things escape the atmosphere, that's it. The shuttle still has to do most of the work. 
 

I never mentioned anything about the mass driver putting things into orbit on its own.
 

 

Then you wasted literally billions of dollars to accomplish the same thing extra fuel mass could for MUCH cheaper; this is silly when you have reusable rockets that can do pretty much anything this would for a fraction of the cost. Railgun/Mass driver launches are only useful in two cases; you're on a moon with no atmosphere, or you don't have enough runway to reach takeoff speeds to begin with. The former is a compelling prospect and would likely be economical, the latter doesn't require vast stretches of launcher but the craft isn't going to space. If you're going to space there's no way around it; you're going to be carrying a boatload of fuel.

11 hours ago, GoldForest said:

On an unrelated note, Carbon Nanotube CPUs were created by MIT. So... not that far off from space elevators after all. joking.

I read about this; apperently they had to develop the architecture specifically to have enough redundancy to not fail if defects in the CNT's were present in the transistors. Which i found odd because this is already somewhat of a staple in modern uarch design; CPU's would die much quicker without redundant logic, traces etc. to counter the effects of electromigration. regardless it's a hell of an accomplishment, but wasn't due to any increase in our ability to make CNT's.

3 hours ago, GoldForest said:

That's why it would be very end game, to make interstellar travel easier from Kerbin. Once you're out and about, it wouldn't matter if you launched from the mun or the space elevator.

We're going to have orbital construction yards; a SE would be useful for supplying them but i don't really see the point of launching from a SE vs a dedicated orbital con yard.

[GoldForest]

20 minutes ago, Incarnation of Chaos said:

We're going to have orbital construction yards; a SE would be useful for supplying them but i don't really see the point of launching from a SE vs a dedicated orbital con yard.

Resources.

Space elevator connected to the ksc would have unlimited resources.

Orbital Construction Array needs its resources brought to it.

So cheaper to launch from Space Elevator that could carry unlimited resources to and from KSC than to waste money and resources ferrying resources to the OCA to build and then launch the interstellar ships.

[Incarnation of Chaos]

2 hours ago, GoldForest said:

Resources.

Space elevator connected to the ksc would have unlimited resources.

Orbital Construction Array needs its resources brought to it.

So cheaper to launch from Space Elevator that could carry unlimited resources to and from KSC than to waste money and resources ferrying resources to the OCA to build and then launch the interstellar ships.

That's really the only situation i could see an SE being useful in KSP; even then if we have off-rails acceleration and automation there's NERVA tugs and refueling that could be used.

But a SE would make the construction yard a proper port, so i actually like that idea.

[kerbiloid]

A maglev runway to ignite ramjets without turbojets.

A mountain ridge several kilometers high, next to the sea coast.
A maglev on top ~15 km long irl (shorter in game).

A large maglev carriage. We put a standard large SSTO uncrewed spaceplane on it.
The carriage doesn't fly up away, it just levitates and accelerates.

A large lifting body SSTO uncrewed spaceplane. ~300 t launch mass (as the biggest planes), so ~40 t of payload (self-propelled cargo or spaceship).
This is a pure LEO/LKO launch vehicle. It isn't a real spaceship, it's a winged stage. A real ship or a cargo is placed in its payload volume. may stick out or be hidden by doors.
The stageplane reaches LEO/LKO, immediately releases the payload, makes 1-2 turns, deorbits, and lands on the runway beneath the maglev ridge. The payload gets to its destination on its own.

The spaceplane stage is equipped with a hydrolox ramjet (linear nozzle), air scoop, and air processor (from real 1960s projects). Some auxilliary hydrolox orbital engines to deorbit.
On launch it's fueled only with hydrogen. It fills oxygen tanks when flying in atmosphere (real projects).

***

The nearest to the KSC end of the maglev is equipped with heavy elevator, to lift the unfueled spaceplane and cargo up to the ridge, so ~100 t of payload..

***

Between the maglev ridge and the coastline there are a runway, a (thermo)nuclear powerplant, and a coastal hydrogen facility.
The (thermo)nuclear powerplant powers both maglev and hydrogen facility.

A little aside, on the coastline, there is a launching pool for superheavy 2-stage Convair Nexus rockets for ~500 t payloads.
It's a small gulf with a round launchpad surrounded by water. The water absorbs the acoustic pressure.
The Nexuses are fueled with hydrolox from the same hydrogen facility.

Auxilliary launchpad for usual rockets somewhere.

A landing field for stages and capsules of all types.
Nexuses also land here.

***

So, the maglev usage.

In KSC you put cargo in the unfueled stageplange, and lift it up to mountain, to the end of the maglev.
(No need in elevator implementation, just an animated thing like the vessels in SPH, from time to time moving up-down).

On top you put the thing onto the maglev carriage.
(Actually, this is the real game launchpad place. You assemble the carriage + stageplane + payload in SPH and appear it at the maglev end like if you have lifted it from the valley.)

You launch the maglev.
The carriage starts accelerating at 4 g irl (or as many as Kerbal can survive g in game, so the railway can be shorter).

At ~3 Mach the stageplane separates, lifts up, and ignites the ramjet.
So, gets into air at the ranject igbition velocity, and doesn't need a turbojet and fuel for it, so it saves launch mass.

The carriage continues moving along the maglev, but decelerates at 40 g, so the deceleration distance is much sorter.
Then it accelerates back, decelerates and stops at the maglev end, waiting for next launch.

 

The stageplane is accelerating with the ramjet like any SSTO spaceplane.
It is fueled only with hydrogen, so it saves launch mass.

While it's accelerating burning the stored hydrogen and intake air, it also runs its onboard gas plant.
The gas plant consumes part of the same intake air, freezes it, separates, and stores the oxygen in the oxidizer tank.
So, the stageplane gets heavier while flying.

When there is enough liquid oxygen to burbn the remaining hydrogen, and altitude and velocity are enough high to switch the engine mode, the ramjet switches into rocket mode (like Sabre, Rapier, etc in KSP).
It starts consuming same hydrogen, but now the stored liquid oxygen instead of the intake air.

It reaches the orbit, releases payload, waits for 1-2 turns to come into the deorbit point, makes a retroburn, vents out both oxygen and hydrogen, and lands as a sailplane.

***

So, for heavy payloads you use requsable two-stage Nexus-like VSVL, while for light payloads and spaceships - the maglev-starting winged SSTO HSHL.

[Xd the great]

I feel like someone on this thread will build a orbital VAB far up above the ground on "extended legs".

So, I think space elevatirs sounds fun, but it does not have a big enough niche to justify its existence.

[kerbiloid]

12 minutes ago, Xd the great said:

I feel like someone on this thread will build a orbital VAB far up above the ground on "extended legs".

So, I think space elevatirs sounds fun, but it does not have a big enough niche to justify its existence.

Turtles and elephants...
If stack them, it can work as a space elevator.

[GoldForest]

40 minutes ago, Xd the great said:

I feel like someone on this thread will build a orbital VAB far up above the ground on "extended legs".

So, I think space elevatirs sounds fun, but it does not have a big enough niche to justify its existence.

As said earlier, it would be an unlimited resource launching platform to orbital construction stations. 

[Guest]

50 minutes ago, GoldForest said:

As said earlier, it would be an unlimited resource launching platform to orbital construction stations. 

And that would make for fun gameplay, because...?

[GoldForest]

1 hour ago, Brikoleur said:

And that would make for fun gameplay, because...?

Lets routine flights to restock the station with the orbital construction yard meaning more time getting interplanetary missions under way. 

[Guest]

4 minutes ago, GoldForest said:

Lets routine flights to restock the station with the orbital construction yard meaning more time getting interplanetary missions under way. 

The problem is the routine flights. If there isn't a solution to that that also works on small remote colonies, the late game is going to be a big tedious grind. A space elevator at KSC would be a band-aid over a compound fracture.

[GoldForest]

11 minutes ago, Brikoleur said:

The problem is the routine flights. If there isn't a solution to that that also works on small remote colonies, the late game is going to be a big tedious grind. A space elevator at KSC would be a band-aid over a compound fracture.

Well, an unlimited resource launch platform is way better for launching 10 large scale supply missions to supply 1 interstellar  mission than launching 50 supply missions from ground to supply 1 interstellar mission.

[KerikBalm]

The sources cited in this thread are laughable.

We would need major advances in material science, and then have one heck of an engineering problem to solve.

An orbital ring could be done with current materials.

Id be fine with space elevators for minmus, gilly, maybe even duna... But not kerbin, and not Eve, etc

[Guest]

36 minutes ago, GoldForest said:

Well, an unlimited resource launch platform is way better for launching 10 large scale supply missions to supply 1 interstellar  mission than launching 50 supply missions from ground to supply 1 interstellar mission.

For sure but it won't solve the general milk run problem of continuous supply launches to keep life support -- or even construction -- going on those interplanetary and -stellar colonies. That's the real problem right there, and if there's a solution for that, then we won't need a space elevator.

BTW I think maglev parts would be cool, so we can build our own mass driver. I just don't want it as a ka-ching base upgrade, that would be boring.

Edited September 9, 2019 by Guest

[GoldForest]

26 minutes ago, Brikoleur said:

For sure but it won't solve the general milk run problem of continuous supply launches to keep life support -- or even construction -- going on those interplanetary and -stellar colonies. That's the real problem right there, and if there's a solution for that, then we won't need a space elevator.

BTW I think maglev parts would be cool, so we can build our own mass driver. I just don't want it as a ka-ching base upgrade, that would be boring.

Mass driver runway could be upgraded to various size restraints (10 ton ssto, 50 ton ssto, etc.) and need resources gathered from interstellar worlds as to make it a cost for the benefits.

 

[Guest]

21 minutes ago, GoldForest said:

Mass driver runway could be upgraded to various size restraints (10 ton ssto, 50 ton ssto, etc.) and need resources gathered from interstellar worlds as to make it a cost for the benefits.

It would still be a boring and partial Band-Aid solution to a deeper gameplay problem. I am worried about the potential of late game turning into Milk Run Simulator, but eliminating the launch part of the milk runs with building upgrades wouldn't really help, you'd still need to fly the rest of them, which would get really tedious really fast.

Again, I get the impression that Star Theory is aware of the potential problem and has something in mind to fix it, but it is a tough one. I am expecting some form of supply line automation; what exactly that will be, we will see. But a mass driver or space elevator won't do it, while they will trivialise otherwise potentially interesting gameplay aspects. 

(Example? If your mass driver is limited by payload mass, it completely trivialises packaging problems. A moderate-capacity refinery station for example doesn't weigh all that much, but it's pretty hard to package it aerodynamically so it can be launched effectively. Having that just magically appear in orbit by pushing a button because it's within the mass driver's payload capacity would trivialise that challenge. -- And yes, I am aware that in-orbit construction will do the same thing, but at least to get there you will have had to construct the orbital construction station.)

[DStaal]

4 minutes ago, Brikoleur said:

(Example? If your mass driver is limited by payload mass, it completely trivialises packaging problems. A moderate-capacity refinery station for example doesn't weigh all that much, but it's pretty hard to package it aerodynamically so it can be launched effectively. Having that just magically appear in orbit by pushing a button because it's within the mass driver's payload capacity would trivialise that challenge. -- And yes, I am aware that in-orbit construction will do the same thing, but at least to get there you will have had to construct the orbital construction station.)

Two ways to solve that, depending on what a mass driver is to your game:

If it's an alternate mode of launch - packaging falls nicely into the player's lap, as physics will get applied to the payload as it launches.

If it's a method of automating resupply - then you can't launch arbitrary payloads using it, only what the system provides, so only have it allow launches of resources to designated locations.

Mods for both of these approaches have been seen in KSP1 - approach 1 would give you something like Netherdine Mass Driver: Supply the parts to build the mass driver, and leave the rest to the player.  Approach 2 would be something like the mass pipelines in Pathfinder: Full-featured mass driver models, but launches are entirely virtual.

[GoldForest]

17 minutes ago, Brikoleur said:

(Example? If your mass driver is limited by payload mass, it completely trivialises packaging problems. A moderate-capacity refinery station for example doesn't weigh all that much, but it's pretty hard to package it aerodynamically so it can be launched effectively. Having that just magically appear in orbit by pushing a button because it's within the mass driver's payload capacity would trivialise that challenge. -- And yes, I am aware that in-orbit construction will do the same thing, but at least to get there you will have had to construct the orbital construction station.)

Mass driver wouldn't be one click though, you'd still have to actively fly an SSTO up to orbit t dock with the spacecraft or station you are delivering the payload to.

[Guest]

1 hour ago, GoldForest said:

Mass driver wouldn't be one click though, you'd still have to actively fly an SSTO up to orbit t dock with the spacecraft or station you are delivering the payload to.

Then what would be the point of having it at all? If you're in the late game with the kind of tech a mass driver would need, you will already have designed all the lifters you need, the tedious bit will be the routine flying, and the mass driver wouldn't even help with that.

Again, I'm all for having the parts to build one, but having one pre-built for as a building upgrade would be silly -- that would be the gameplay analogue of having a ready-made one-part lifter stage, and I don't think anyone is asking for those.