Asteroid jumping

[san*klass]

Imagining a 21st cen Sol system only (no jump drive) campaign, I am struggling to imagine movement on a very very
low gravity asteroid/planetoid. I understand escape velocity, and note that even for Ceres (the biggest object in the Asteroid Belt), escape velocity is only 0.51 km/s, but how would that translate into vehicular or vacc-suited human movement? I presume that here(at least) a slow heavy ATV would be able to trundle around at 30-40km/h without risking sailing into space every time it hits the crest of a hill?

But I presume that the small asteroids that make up the vast majority of the objects in the Belt would allow far less speed? Presumably their escape velocity would be around or less than 0.01 km/s? So, would they have to be treated as a zero-g environment?

If any knowledgeable people are out there, then I would appreciate the advice.

 

[Lycanorukke]

There's a calculator here where you can compute out the values.

The other bit is that while escape velocity may be ~0.5km/s, orbital velocity is a lower, ~0.35km/s, so even if you dont escape you could still be stuck in orbit. A smaller example is 253 Mathilde - roughly 50km in diameter, resulting in orbital velocity of 0.01 km/s or 42 kph - hit a bump too hard and you will become an artifical satellite. But even lower speeds could result in you flying through the air for a good period of time until you are slowly pulled back down.

And unless you had thrusters to control yourself you could splatter into a ridge, the vehicle could tumble (the counter torque of the spinning wheels causes you to start flipping in the air), or disappear into a crevice.

But it is not entirely zero G. You still have a solid surface to move against as long as you are careful. If you dont have a Lo-Grav skill, maybe Zero-G -1 could substitute.

 

[san*klass]

There's a calculator here where you can compute out the values.

The other bit is that while escape velocity may be ~0.5km/s, orbital velocity is a lower, ~0.35km/s, so even if you dont escape you could still be stuck in orbit. A smaller example is 253 Mathilde - roughly 50km in diameter, resulting in orbital velocity of 0.01 km/s or 42 kph - hit a bump too hard and you will become an artifical satellite. But even lower speeds could result in you flying through the air for a good period of time until you are slowly pulled back down.

And unless you had thrusters to control yourself you could splatter into a ridge, the vehicle could tumble (the counter torque of the spinning wheels causes you to start flipping in the air), or disappear into a crevice.

But it is not entirely zero G. You still have a solid surface to move against as long as you are careful. If you dont have a Lo-Grav skill, maybe Zero-G -1 could substitute.

Many thanks for your logical and practical reply which both makes things harder and simpler simultaneously.

Obviously ATV's in my setting need to be Tracked not Wheeled, for both greater surface area (presumably easier to keep contact with the surface?) and slower overall speeds.

And RCS are a must!

 

[Travellerspud]

wheels that grip the surface (providing a "downward" force that simulates gravity)

some variation on this maybe...

http://spectrum.ieee.org/automaton/...hameleon-gripper-nasa-swarmies-superman-drone

 

[Lycanorukke]

wheels that grip the surface (providing a "downward" force that simulates gravity)

Boost the tech a bit and you could have 'Gecko wheels', where the wheels 'stick' to the asteroid surface using Van der waals force, though this may not work if the asteroid is 'dusty'.

Using current tech, have a superconductive magnet which can stick the vehicle to nickel/iron asteroids. Though its effectiveness may vary a lot dependant on how much metal is in the rock and its distribution. On a snowball it wont work at all.

Or for lower tech add small barbed spikes to the tracks which dig into to terrain so accidental bumps don't send you into orbit. Though again they wouldn't work too well on a slushy asteroid ad there is no solid surface to grab on.

For really low tech - have a 'grip wheel'. In the middle of the vehicle you have a big wheel with big barbed spikes around it. The tracks provide the motive power, and the 'grip wheel' simply rolls along passively but provides a solid grab point to the ground. Of couse when big spikey wheels are involved PCs often get funny ideas....