How to space elevator mod (brainstorm)

[beabop]

Hey kerbal engineers! I've heard that a space elevator is impossible in KSP, because parts over 2.25km away in thick enough atmosphere instasplode, and an elevator ribbon must go all the way to the surface, through the atmosphere. But... if Squad implemented Futurama's ship drives (they move the universe around your ship) to make Krakensbane, then why can't we do something equally ridiculous to fake a space elevator? Let's brainstorm how it could work!

Parts list:

• Cable. Runs from an anchor to another anchor or ends in space. Length could be a tweakable, effecting mass and cost. Ideal material, doesn't taper. Launched as a spool, deployed from a menu when in the proper orbit. (It unrolls both up and down.) Any given elevator cable would have multiple instances, each a view of the entire gigameter long structure. Elevator state could be saved in a master cable part; the views would refer to it. Spins with the planet.
  
• Anchor. Attaches to the surface of a planet or an asteroid. Has a special attachment node for a cable.
  
• Climber wheels. They consume electricity and climb at a throttleable rate. Menu options to turn them on or off and to detach or attach them from cables (like docking).
  

The key to making it work: the elevator cable would mostly exist outside of KSP, in mod code. The mod would give KSP 2.25km views of the full elevator whenever in physics range and would move anchors and climbers around on custom rails for the tracking station/map. Since force is transmitted through our parts, we can implement anchors and climber wheels as engines!

Tracking station craft. The cable is strung between these outside of KSP, and forces are exerted on them to keep them on that cable.

• Ground anchor. A craft containing an anchor, on a planet's surface.
  
• Anchor station. A space station (or asteroid) beyond stationary orbit.
  
• Climbers. Any craft with a climber wheel part.
  
• Cable end. Marks the end of a cable without a counterweight.
  

Half of the fun of KSP is spectacular failures, and for a space elevator, they could be spectacular indeed. In Red Mars, the cut elevator cable screams in through the thin Martian atmosphere and obliterates everything on the equator, even creating diamonds where it hits! People in the anchor space station and upper elevator cars go flying off into space. I imagine some players might want to sabotage their space elevators to see what happens. Afaik, real world engineers still don't agree on what would happen, so our bar for realism is the low one set by KSP's stock aerodynamics model. ;-)

Potato version:

• Simplified cable model - a straight line from ground anchor to space anchor.
  
• Cable can only be deployed within a couple degrees solid angle of an equatorial ground anchor from a stationary orbit. The in-space anchor would jump to directly above the ground anchor when you change focus.
  
• Cable deploys instantly. Another cable part (a view) is spawned and attached to the ground anchor.
  
• Cable has two states. If there isn't enough of a counterweight, it falls to the planet when you change focus and everybody onboard dies anti-climactically (just like with atmospheric first stages). If there is enough of a counterweight (long enough cable and/or a massive enough space station or asteroid anchored to the space end), then it hangs perfectly vertically.
  
• Climbers climb when on rails at whatever rate they were last throttled at. If going at different speeds, they will go right through each other. They will stop in a neat line if they reach an anchor, or climb right off a cable that ends without one, entering their own orbit.
  
• When the cable is cut, everybody below the cut point dies anti-climactically. Everything above the cut point flies off into space, with cable parts despawned.
  
• Forces applied to the anchor will not move the cable.
  

Polished version:

• Cable is simulated in segments. Now fails correctly when cut.
  
• Cable can be deployed with a greater margin. Anchor or cable end will migrate to stable point (above the anchor) realistically
  
• Cable unspools at a certain rate, consuming power.
  
• Cut cable segments not attached to an anchor or a climber despawn.
  
• Within physics range, cable is still perfectly straight, but now can be at a non-vertical angle. Can exert a force (through spool or anchor) on attached craft.
  
• Attaching a rocket and moving the cable end/anchor station will now move the cable realistically.
  

Ideal version:

• Separate tracking station icon for space elevator climber.
  
• Space elevator cable rendered in tracking station.
  
• Loosen/eliminate deployment restrictions, but simulate the consequences of deploying far from the anchor or not in a stationary orbit. I.e. you're never gonna anchor that sucker.
  
• Hooking the other end of the cable becomes its own challenge. A "cable end" craft would be necessary, which you would steer to the anchor or vis versa. What might the specifics look like? It would be cool if this problem could be solved in all sorts of ways - e.g. move the anchor, move the anchor station in its orbit, grab the cable with a crane, attach a ton of ducted fans to the cable end, etc.
  
• A cut cable can destroy KSC buildings and landed craft if it hits near them fast enough - and if it survives coming through the atmosphere.
  
• Cable segments that fly off into space or survive reaching the ground become cable debris.
  
• Within physics range, a cable could wiggle and wobble if not pulled taught. Most commonly when being first deployed.
  
• Cables would be simulated well enough to make skyhooks.
  

Realistic version:

• Real materials. E.g. steel, Kevlar, carbon nanotube. The cable spool would be heavy.
  
• Cable can snap from too much weight/stress.
  
• Cable taper. Realistic materials would have it. Some materials need to be absurdly wide to support their own weight past a certain length.
  
• Dampers now must be installed manually along the cable. I hope you calculated your vibrational modes correctly...
  

Mods that would be nice to integrate:

• KSP Interstellar. With the stock mod, your climbers could only be powered by solar panels. With KSP Interstellar's wireless power transmission, you have another option. Change needed: climbers preferentially consume Megawatts.
  
• Flight Manager for Reusable Stages. Would let you pilot each climber and the anchor station to rescue Kerbals from a cut cable catastrophe. Change needed: Are there any? Afaik, not if cable state is stored well in the save files.
  
• ISRU mods. Change needed: A Cable Extruder part lets you make cable out of space-mined materials using one of several community-defined, minable resources.
  
• Extraplanetary launchpads or Kerbin-Side. It would be nice if locations other than right next to KSC's launchpad were practical. Change needed: make a planetary anchor a special EPL that only works for climbers and attaches them to the cable. Or, add a crane to move climbers from launchpads they're anchored right next to.
  
• FAR/NEAR. To simulate a cut cable accurately in atmosphere, if possible. Change needed: ?
  

What do you all think? Could this work? I would love it if we could work out a specification then create a mod from it. I am a coder, an amateur cartoonist, and an amateur 3D modeler, so I would love to help any community effort we could get going. But I've never modded a game nor do I know Unity, so I'd rather not take the lead on something this ambitious.

TL;DR: Simulate space elevator in mod code to get around the 2.25 km physics range. Attach special parts to it.

Edited November 29, 2014 by beabop

[beabop]

[Reserved.]

[Nuke]

i wonder if you couldnt do one with kerbal konstructs. have a base station model places somewhere on the surface, it will be static geometry and shouldn't become kraken food. just put a launch platform at the space end and spawn craft there. while i have a feeling that such large models will be glitchy, its worth a dry run. you might also try to stick a tank to a launch clamp and hack the ship file to put the tank way up into geo, and you might build a car to climb the thing as part of the design.

but i have the feeling you would need some kind of procedural generation of the cable mesh. so that nearby geometry has some detail and far away geometry doesnt have any tearing. you might get large polygons whos verts may get culled because they are all off screen, which would make the thing look like a big glitch.

though i do like the installation mission, which would invlolve moving a class e asteroid into geosync orbit, attaching a spool to it with a really big claw, and reeling down to a ground station. this mission might unlock a static elevator model. you could probibly build the elevator car itself with parts, and the cable would be all capsule colliders all the way up. but i have the feeling operating such vehicles would be long and boring affairs.

[artwhaley]

You might look at the mods that create laser beams. If you could change the texture, you've got a cable, and you just need a plug-in to move things up and down.

[Helix935]

You might look at the mods that create laser beams. If you could change the texture, you've got a cable, and you just need a plug-in to move things up and down.

make an insanely long kas cable

[Nuke]

i built this out of my way out of date parts pack, it seems to stay on the rail but it cant climb on wheel power alone (though breaks appear to work). i tried it on a launch clamp and it wouldnt stay on.

Edited November 29, 2014 by Nuke

[cicatrix]

You've got to think around the 2.3 km physics bubble. I'm pretty sure that you can't build a craft bigger than this.

[Abdu]

You've got to think around the 2.3 km physics bubble. I'm pretty sure that you can't build a craft bigger than this.

but is there a way to make the bubble bigger ?

[Nuke]

obviously you cant build something that big out of parts. the car maybe but not the cable itself. static geometry, i dont know, maybe. you can collide with kerbin just fine and its huge. there have been attempts at a railway mod employing static geometry tracks and part based engines/cars, and idk how successful it was. this is the same thing really, but straighter and more vertical. but i dont think that approach was successful.

instead im thinking procedurally generate geometry between the ground station and the anchor asteroid. a moving chain of capsule colliders (each about 1km long) would be spawned along the cable path around the car's position along the cable. there would be several in series, some out of physics range in front of and behind the car. each time you move onto a new segment, the one furthest away from and behind you is moved to end of the segment chain in front of you. thus the physics bubble is maintained. you may only have to deal with 5 or so capsule colliders. this is going to need to be done in code.

the purpose of my test was to see if wheels could drive the thing up, and so far it hasn't been able to do that, and ive tried 3 different designs so far and none of them worked on wheel power alone. the wheels however did work as linear bearings, as did breaking. so you might implement guide bearings as unpowered wheels using existing part modules. i was also able to drive it up the rail with rocket power (which kinda misses the point). you need to provide climbing force some other way. i figure make a linear accelerator part module which simulates a force producing magnetic interaction between the part and the cable. it would produce climbing force while engaged with the cable and sufficiently powered.

i imagine the parts needed would be a clamp on linear bearing assembly, with 4 wheel colliders to engage the cable. to clamp on to the cable it would have an open and close animation. you would have another part with magnetic coils that also clamps on similar to the bearings. these would contain a simple box collider to check whether the thing is connected to a cable (this would be used by the magnetic accelerator module) or not. you could stack them if more force is neccisary to lift your elevator car (the equivalent of adding moar boosters). these parts may be separate or combined into one unit (though you might provide a combination of powered and unpowered units, and additional coil assemblies).

you would also have upper and lower docking stations. the lower station might be placable static geometry (using the static geometry mod of your choice). perhaps in the future you could instal this facility at ksc with building upgrades. the lower station would have ramps and other facilities for attaching cars to the cable. ideally you would make your craft with the root part being one of the bearing assemblies, and the craft would be spawned pre-attached to the cable stub on the static base geometry. the upper station would just be a part that can be permanently attached to an asteroid (is there any in-game welding mod? i thought i saw one) it might feature docking ports to attach to the linear bearings to hold the ship in place at the asteroid station. both sections would have a section of non-procedural cable built into it as part of its geometry, at the end of which a connection point for the procedurally generated cable would be placed.

you might also completely ditch all the hard physics approach and just do a dumb follow the line kinda thing. but where is the fun in that.

Edited November 29, 2014 by Nuke

[*Aqua*]

There was a mod which changed the physics bubble IIRC. But do you really want every craft in, say, 500 km diameter to be calculated? That's a lot of space. If you've got a sat network it will lag out your computer.

[Nuke]

leave the physics bubble as it is, you dont need to interact with the whole cable, just the local segment. the only time you would need to expand the bubble is if you wanted to climb at a rate that is faster than 2.3km per physics frame, you would likely climb at a much slower rate.

Edited November 29, 2014 by Nuke

[kerbiloid]

I think the only way to do this, ignoring the "physical bubble":

1. Clone any engine you want.

2. Set its fuel consumption to zero.

3. Combine this cheated angine with a command pod and SAS. Btw, KSP 0.21 old TARDIS mod is great for lift cabin, though it's a phone box.

4. Imagine you have a cable: it's very-very long and very-very thin (as it would be in real world) and due to this invisible.

5. Start.

6. ...

7. You're at 1000 km altitude!

For better perception you can use Romfarer Lazor System which shows you a thin beam you can treat as a cable highlighting.

As far as I know, all other ways were not successful. You can watch on youtube.

[trekkie_]

yeah it's impossible due to the physics limits. I'm not sure if even breaking an elevator into individual pieces would work.

a space elevator is also just plain impractical, it'd take a while to get to orbit....might as well just do so with engines. I don't think it would do anyone any good to waste time on that.

and since there are things like orbital construction mods and hyperedit, it becomes more for aesthetics than anything else. space elevators are for energy saving reasons for a very expensive problem in the real world. in game, strapping on millions of dollars worth of fuel is as easy as a few clicks.

there are ways to give the illusion of a space elevator, but they're not good illusions. in the end it's just a whole lot of work for an inferior and useless mechanic.

[Eskandare]

i wonder if you couldnt do one with kerbal konstructs. have a base station model places somewhere on the surface, it will be static geometry and shouldn't become kraken food. just put a launch platform at the space end and spawn craft there. while i have a feeling that such large models will be glitchy, its worth a dry run. you might also try to stick a tank to a launch clamp and hack the ship file to put the tank way up into geo, and you might build a car to climb the thing as part of the design.

but i have the feeling you would need some kind of procedural generation of the cable mesh. so that nearby geometry has some detail and far away geometry doesnt have any tearing. you might get large polygons whos verts may get culled because they are all off screen, which would make the thing look like a big glitch.

though i do like the installation mission, which would invlolve moving a class e asteroid into geosync orbit, attaching a spool to it with a really big claw, and reeling down to a ground station. this mission might unlock a static elevator model. you could probibly build the elevator car itself with parts, and the cable would be all capsule colliders all the way up. but i have the feeling operating such vehicles would be long and boring affairs.

It would work with Kerbin Side if the models were separated into segments. The thing is the car would have to be an animation (animation on click) that travels approximately 2868.75 km

Edited December 1, 2014 by Eskandare

[Nuke]

that might work, just spawn your craft on the elevator platform and let it lift to geo.

[Eskandare]

I may add this to my Jool city project. The project is very intense so far. I've got animated traffic lights, animated draw bridge, and working on a rideable animated monorail. I haven't really been able to do any updates on here because I only have time to work a little at a time on the project.

[cicatrix]

The only reason for a space elevator in real-life is money. The delivery cost of 1 kg payload to orbit is only 20$ (leave construction and maintenance costs) when using a space elevator as opposed to 3K-13K using modern rocket lifters. Aside from that - it's rather stupid. It's big, it's unstable, and ridiculously expensive. I don't think we (here, on Earth) would ever build a space elevator even if we have materials strong enough (yeah, yeah, carbon nanotubes... but they exist only in that 'nano' world so far).

As for KSP - you already have an elevator called HyperEdit. You can make a fancy one showing the transition, but it will still work basing not on physical principles inside a physics simulation, but simply as a way to get around the game physics (Hyperedit).

Edited December 2, 2014 by cicatrix

[RainDreamer]

Well, we can cheat. Have 2 end points for the elevator, requiring them to be connected by a straight line of sight through a limited range, like how remote tech work. Go into one end, get teleported to another.

[pizzaoverhead]

What do you all think? Could this work? I would love it if we could work out a specification then create a mod from it. I am a coder, an amateur cartoonist, and an amateur 3D modeler, so I would love to help any community effort we could get going. But I've never modded a game nor do I know Unity, so I'd rather not take the lead on something this ambitious.

Mods for KSP only get made once someone decides to get stuck in and figure out what the challenges involved are. There are hundreds of ideas that sit in quiet threads for years because nobody attempted them. Once an attempt has been made, people are able to rally around it to improve it. A thread is a good start, but there needs to be code too. Most mods are made by people who have never coded before, let alone dealt with Unity. You have the enthusiasm and experience to make this happen, and even if it doesn't work out, you'll at least have scouted out what problems are hiding in the code for the rest of the community to solve. There are several good ideas here you could attempt.

You might look at the mods that create laser beams. If you could change the texture, you've got a cable, and you just need a plug-in to move things up and down.

Simple. Make a magic part that can provide an upwards or downwards force to the craft it's attached to, then draw a line to represent the cable afterwards. You can get fancy with altitude limits and ground stations afterwards.

Here's the info you need if you want to make it happen:

• IDE setup and building a "Hello World" plugin
  
• Example plugins
  
• Community-created API information
  
• A thread to ask quick questions in

[Buzzou]

i built this out of my way out of date parts pack, it seems to stay on the rail but it cant climb on wheel power alone (though breaks appear to work). i tried it on a launch clamp and it wouldnt stay on.

which parts pack is this? there are so few structural girder part mods, and those pics have me intrigued...

[Nuke]

its the half meter parts pack. http://forum.kerbalspaceprogram.com/threads/23122-0-20-Half-Meter-Parts-and-Other-Useless-Junk

hasnt been updated since 0.20, but the girder parts should still all work. i still work on it but the main holdup is that there are a number of new parts that need textures and i havent been feeling creative the last several months years.