[WIP] PSI Antigravity

[Kashaar]

Hello, everyone!

I've been playing Kerbal for a while, and recently decided that while real-life is kicking my ass, I need a creative side-project to mellow out a little. So this Sunday I started learning C# to make an add-on for Kerbal pace Program! Since at the time in my Kerbal career I was struggling with making a reusable skycrane lifter, I figured I'd make something to assist with that. I had just finished reading Peter F. Hamilton's Void trilogy, and the Regrav drive technology in that universe which seems to work best at low altitudes and badly in space seemed like a decent point of departure. I shall call it:

Pyrron Spacefaring, Inc. - Antigravity

I managed to create a working prototype in game as a proof of concept, which I'm demonstrating here:

In that video, the antigravity force applied is constant. It is always applied in a direction away from the current SOI's center of gravity, so as you can see in orbit, it has the same effect as a radial burn - moving the Pe down and Ap up 90° from where the craft is located in its orbit. This is just a first proof of concept, so those big colorful arrows are just visual debugging tools that won't be in the final add-on

Now, my intention with this isn't to be a free propulsion device... I want it to be useful, but not overpowered to the point of cheating. It should fill a niche, and add interesting gameplay complexity. So I got some help from a friend (who is actually an aerospace engineer) coming up with a formula to make the antigravity force dynamic: it now scales with distance from the current planet's sea level, decreasing the higher you go. I thought about making it independent from the planet's radius and depend just on local gravity alone, but that turned out to be inconvenient to model in a way that makes it useful on more than one planet. (I'll probably revisit this later though, maybe scale it so higher gravities require more resources, or something like that.)

Here's a chart of what it could look like on different planets:

The AG factors mentioned are AG strength and attenuation, and can be set per part. The different graphs show the effect of the same factors on different bodies. The vertical axis shows the difference between AG strength and gravity at that altitude. At 0 m/s² is the equilibrium point, where AG force and gravity cancel each other out.

My current "development plan" is to keep working on it whenever I need a break from writing my thesis, so updates are probably going to be intermittent. The to-do list looks like this right now:

• Design: Figure out a working model for resource use
  
• Coding: Implement resource use
  
• Coding: Create UI elements for relevant readouts and interaction (probably right-click and action groups only at first)
  
• Design: Decide whether to use surface height or sea level as reference point for AG strength
  
• Coding: Create smoother establishing of equilibrium point (right now the vessel goes up and down a lot before settling there)
  
• Design: Come up with interesting variations for parts
  
• Art: Conceptualize and create 3D model for basic inline part
  
• Coding: Ensure that using multiple parts works as intended, and general QA.
  
• Initial release
  

There is, of course, lots of room for expansion, not only but especially in the art department. I've worked with 3D art before, so it'll be fun to revisit some old skills and see how rusty they've become Radial parts and thruster-like bottom caps are also things I'm considering, but I prefer to start small and expand if this turns out to be successful and fun.

So... what do you all think?

Edited December 11, 2013 by Kashaar

[KvickFlygarn87]

Hmm, looks nice. What will it be used for?

[Kashaar]

Hmm, looks nice. What will it be used for?

I'm planning for this to be useful in surface missions, landers and skycranes and so on, where you might want to need to hover for extended amounts of time, and doing so using main thrusters would be wasteful and inconvenient.

[KerbMav]

Hmm, looks nice. What will it be used for?

And OP wrote about skycranes, so basically it could be used for base assembly - he seems to want to limit its usability at high altitudes, so maybe not for orbital skycranes or dropships.

[Kashaar]

*images snipped*

And OP wrote about skycranes, so basically it could be used for base assembly - he seems to want to limit its usability at high altitudes, so maybe not for orbital skycranes or dropships.

Yeah, pretty much. The same formula could easily be adjusted to allow higher orbital hovering, but I think that's not the niche this add-on should fill. Getting out of a gravity well is much more fun with proper thrusters, anyway!

[Tommygun]

We had something like this before and it was very useful for moving and placing large buildings or structures that where otherwise impossible to move.

It would be nice to have something like this again, but if you want to limit it I can understand. But what if you had two versions with one rescaled to be too large for a ship, but could be placed on a building for moving it with a different part file and lifting abilities.

[wasmic]

So, will this mod have a "stabilize radar altitude" function? That way, we could make hoverRovers that always hover a set distance (like a few meters) above the ground. The function shouldn't allow it to be done more than 100 meters above the ground, though, as that would make airplanes useless.

[pantheis]

So, will this mod have a "stabilize radar altitude" function? That way, we could make hoverRovers that always hover a set distance (like a few meters) above the ground. The function shouldn't allow it to be done more than 100 meters above the ground, though, as that would make airplanes useless.

This, really this. I would love a hover rover that I can tell to stay a certain distance above the ground.

[Railgunner2160]

Interesting!! I forsee great uses for this in building large vessels that I've had a tough time try to balance using conventional thrusters. Looking forward to building exploration craft that can land on the surface in their entirety!!!

Use the antigrav for surface navigation and the main engines for maneuvers and space operations, along with providing power to make the escape from a planet's gravity well. That's the idea in my head anyway!!!!

[Kashaar]

This, really this. I would love a hover rover that I can tell to stay a certain distance above the ground.

I'm working on a stabilizer function right now. Currently the AG power is fixed, which leads to some funny oscillation effects... but doesn't make this very useable. More work is needed!

In other news, resource consumption is in, and increases proportionally with planetary and vessel mass.

[Tetriswizard]

This seems like a great idea. Hopefully you get somewhere decent with this.