Low gravity transport

Monday, January 21, 2013

Here’s an interesting way to simulate Mars gravity:

http://www.adamnorton.net/i_works_mars_gravity_simulator.html

I’ve been puzzling over this myself recently as I try to finish my first SF novel; it’s set on Vesta, where gravity is approximately 4% of that on Earth. That’s enough to be annoying but not enough to be useful.

Walking relies on gravity, leaning forward to move your legs, so on very low gravity worlds it would be problematic. A bounding run should work, but could be difficult to control.

Wheels would work, but can only put as much power down as the friction between wheel and ground allows. Since the gravity is much lower, the friction will also be much lower, so you won’t be able to accelerate or brake rapidly.

A railway — probably a monorail — seems potentially effective; if the wheels are forced against the rail, there should be enough grip to allow rapid acceleration and deceleration.

Hovercraft seem sensible, since little power would be required to counteract the low weight of the vehicle, and then it can be propelled by ducted fans or similar as though it was in microgravity in free space.

Moving walkways could work, and would likely be a sensible approach for speeds between slow walk and bounding run. If friction between feet and walkway isn’t enough, a railing could pass the force through, even if it would probably be uncomfortable.

More high-tech, some kind of nano-assisted material for soles and tires could help them cling to the ground and at least help with the friction problems.

I’m still trying to think of a sensible solution for movement on these kind of worlds which doesn’t come with a large number of downsides.

One Comment

  1. ken anthony says:

    I wrote a story on an earlier blog of mine. The only time I paid for blogging and the company went out of business taking my story with it. Anyway, I had underground tubes that people drove in both directions through in electric cars. When two opposing cars met they would drive up opposite walls to pass.

    One colony was on some minor moon of jupiter and when I did the math it turned out they had to drive on the roof of the tube. They had surface buggies as well, but the fast walk I had them going at was too much… under escape velocity, but too much to adhere to the surface. I was going to fix that when the company went away.

    I did have an interesting battle with pirates coming out of Ceres heading for mars. The hero successful defended himself by throwing rocks from his Ceres mine using an auger and rock thrower (usually used to empty his cargo at port.) Most crumbled against the hull or bounced off (a foot thick of Bigelow inflatable) but he got a lucky shot in a vulnerable part of the pirate ship. A weapons port (badly refitted to the ship it turns out) the pirates couldn’t use because they intend to grapple and take the heroes ship intact. It decompressed and the three pirates weren’t suited up.

    The ships were modular so sections could be left behind to alter the remaining Delta V. His family retrieved those as they flew by mars later. But if he hadn’t popped the pirates they would have caught up.

    Reaction mass was water heated to steam by nukes. 200 Isp, but could be separated (Hydrogen/LOX) to produce 450 Isp in smaller bursts through separate engines.

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