Coasters on Exoplanets?

[Jarrett]

So as many of you know, I'm an engineering nerd. One scenario that's always fascinated me was the idea of humans setting up a colony on another planet somewhere lightyears away in the universe and expanding to other planets. Looking at a list of some of the most earth-like exoplanets out there, there are some that are very similar to earth that happened to be either smaller or larger. Planet size has an effect on gravity, with larger planets pulling with more force.

So my thoughts were in the hypothetical situation that we've developed some amount of civilization on another planet such as Gliese 667c and a park was opened, what kind of considerations would have to be taken into account for the discrepancy in gravity. Obviously they would go down drops faster and lose energy faster ascending hills, but how would that affect ride design? Would the same stuff possible on earth be possible elsewhere and just ride differently?

I know this is kind of a goofy discussion but I'm genuinely curious to see what we all think of this. I could just look up formulas for projectile motion and mess with the gravity constant, but I really want to think about how it would affect ride experience.

 

[GuyWithAStick]

I think on planets with stronger gravity, they require cars with more comfy seats so G Forces won't kill you, stronger track, vertical/near vertical lifts, and strong propulsion.

For weaker gravity, I think free-flying coasters with little to no propulsion would happen.

Sent from my VS840 4G using Tapatalk

 

[BigBad]

Cool question, especially now that we could build a water slide on Mars.

There would be differences, but they wouldn't be as much as you might initially think. The B&M airtime hill would still be parabolic. The directrix and/or focus would be different, but it would still be parabolic; there's nothing special about 9.8 m/s^2.

I think you could make a coaster feel pretty similar. Do any of the programs like FVD++, Newton 2, or NL2 allow you to tweak the gravitational force?

 

[Ben]

Let's face it Jarrett, if they did open coasters on Mars it would just be more coasters for you not to ride...

There would be a big difference in ride experience. A coaster on a planet with weak gravity would suck.

 

[Jarrett]

^ Touché. But at least I know that Mars isn't at all as habitable as earth or any similar exoplanets.

My guess for high gravity would probably be that they would look similar to scale coaster models such as CoasterDynamix. Racing down drops way faster, it would probably have to be spread out way more than an earth coaster.

 

[BigBad]

A coaster on a planet with weak gravity would suck.

I disagree. In some regards, it would make it better.

You like Skyrush, so I'll assume that you like sustained ejector air. To get the necessary curvature on Earth, you have to bend however much get get to -2Gs for -1G of ejector sensation (-1Gs of force gives 0G sensation). The track will bend, eventually pointing down, when you have to flatten out to the next valley.

On the Moon, for example, you would only need the force to be -1.6Gs to counteract the Moon's -0.6G gravitational constant, plus the same -1G sensation. The curvature doesn't have to be as tight. The hill can last longer.

More than that, you don't lose speed as quickly on the way up, allowing the curvature to be even looser, making for an even longer hill and airtime moment. So even if it's -20m/s^2 of acceleration that you want to feel, regardless of planetary gravity, the curvature could still be looser than on Earth.

Drops would be weaker, but we're coaster nuts; we like AIR.

 

[Pokemaniac]

The weaker the gravity, the thinner the atmosphere. That means less air resistance. A coaster on the Moon, for instance, would only be slowed by the friction of the wheels. That means you could build very long coasters with high hills/inversions in succession, as the train would lose its speed very slowly. However, using a drop to attain speed would be a boring affair, so it'd have to make do with launches.

Lunar coaster launches wouldn't need to be much weaker than they are on Earth; after all most of the energy goes into setting the train into motion, and that is dependent on its mass, not its weight. With no air resistance you'd need a smaller amount of force to get the train up to speed, so a launch would be needing less energy to achieve the same acceleration as on Earth.

Support structures would also look rather flimsy by terrestrial standards. Weak gravity means fewer supports to carry the weight of the track and the train. Dynamic forces induced by the trains would possibly be the limiting factor, not the weight of the train.

Accounting for thermal stresses would be a pain in the rear, though. Too much solar heat by day, too cold by night, and next to no atmosphere to slow the temperature transition between the two.

Also, stalling would be a bit of an issue, should it ever occur. With such a weak gravity, it's possible that the friction in the wheels could be stronger than the gravitational force on the train. As such, it might come to a complete stop, and not roll back. This is rare on Earth - it usually results in valleying, but on the Moon it could be a lot more common. Then again, the coasters would probably not be as prone to stalling, since the lack of air resistance would make the trains' motions a lot more predictable for the engineers designing the thing. Also, no wind, which is the main contributing factor for stalling on Earth.