Optimal mobility technique for non-Earth-like terrestrial planets?

[MKI]

We all know about how Apollo astronauts ended up "hopping" on the lunar surface to get around. However, I was thinking they were also wearing bulky heavy space-suits, and had other basic problems with mobility.

Lets assume a human was under a pressurized dome, or wearing a near non-existent space-suit. What would be the optimal "mobility technique" for getting around on a body such as the Moon, or Mars, or any other terrestrial planet in our Solar System?

Has any research been done on such problems? In the near term humans would still be in their bulky space-suits, but to ignore the problem of the suit's design, what would be the optimal way to move if all restrictions were removed besides the different gravity?

 

 

 

 

Edited January 6, 2022 by MKI
updated title

[cubinator]

For how to leap through the air in an environment where we can move all over, I'd look to our cousins the monkeys.

For worlds as large as the Moon, I think walking and hopping will be effective. You might even be able to get up to running speed and keep yourself there without much effort.

[sevenperforce]

1 hour ago, cubinator said:

For how to leap through the air in an environment where we can move all over, I'd look to our cousins the monkeys.

For worlds as large as the Moon, I think walking and hopping will be effective. You might even be able to get up to running speed and keep yourself there without much effort.

I imagine the challenge is changing direction at speed.

You need friction to change direction. Low gravity means low normal force, and since friction is proportional to the normal force, you have much less of an ability to change direction.

[cubinator]

53 minutes ago, sevenperforce said:

I imagine the challenge is changing direction at speed.

You need friction to change direction. Low gravity means low normal force, and since friction is proportional to the normal force, you have much less of an ability to change direction.

Indeed. So if you're going somewhere in a straight path you're good to go. But if you want to turn you might want some posts to grab onto with your hands - maybe even to carry around something like a ski pole to stop yourself. Of course, on Titan moving around can be a lot more fun.

[Spacescifi]

1 hour ago, sevenperforce said:

I imagine the challenge is changing direction at speed.

You need friction to change direction. Low gravity means low normal force, and since friction is proportional to the normal force, you have much less of an ability to change direction.

Cool... so a more physics accurate Krypton would have Kryptonians running and stopping on a dime as it were.

Cars driving on Krypton would have shorter stopping distance.

 

Only place where inertia really could have more say would be in the air in sea.... but more the air.

[sevenperforce]

2 hours ago, Spacescifi said:

Cool... so a more physics accurate Krypton would have Kryptonians running and stopping on a dime as it were.

Cars driving on Krypton would have shorter stopping distance.

Only place where inertia really could have more say would be in the air in sea.... but more the air.

Unless Kryptonians are substantially denser than humans, yes.

I don't believe they are. Superman is supposed to be about 225 lbs. So it would be much easier for Kryptonians to stop on a dime on Krypton than it would on Earth.

Of course, that means that if Kryptonians ever came to Earth, it would take them a long time to acclimate because they'd be slipping and sliding and falling over every time they tried to move faster than a snail's pace.

As for air and sea, friction in a fluid is independent of gravity, and so inertia would be unchanged. Buoyancy might be a little different, though, but I can't remember. It might be the same.

Powered flight based on aerodynamic lift would be impossible. You'd need legit antigrav (or zeppelins) for any sort of aerial vehicle.

[MKI]

So regardless of what you end up doing = lower gravity = slippy slidy.

 

I remember listening to a science podcast about how "off world sports" would be vastly more interesting since basically everyone would be doing superhuman feats bahaha. I guess that not only means I could finally dunk, but I could probably dunk from the midcourt line ;D

 

 

[JoeSchmuckatelli]

4 minutes ago, MKI said:

So regardless of what you end up doing = lower gravity = slippy slidy.

 

I remember listening to a science podcast about how "off world sports" would be vastly more interesting since basically everyone would be doing superhuman feats bahaha. I guess that not only means I could finally dunk, but I could probably dunk from the midcourt line ;D

 

 

I honestly think it matters how much atmospheric pressure there is and whether it is toxic, or outside survivable temperatures.  If you had a planet with an atmosphere that had similar pressure to Earth, but oddly no O2 (or not enough) and wasn't toxic to skin, I'd think you could get away with only wearing an oxygen tank and a face shield.

Where you have little atmosphere - the suit is required not only for breathing, but also pressure and radiation protection.

Here's what they're thinking about for Mars:

The Advanced Spacesuit Tech For NASA's Mars Mission Looks Futuristic (screenrant.com)

[Piscator]

Walking and running in low gravity might be more problematic than you think, as it involves quite a lot of controlled falling. When we're making a step, we rely on gravity to pull us forward and downward. This means that in lunar gravity your usual walking cycle might actually be up to six times slower than on Earth. Even without a heavy spacesuit, hopping might be your most practical way to get around.  It might also be some kind of power shuffle or ninja running. I will be very interested in seeing people getting actual experience in shirtsleeve low-g locomotion.

[kerbiloid]

The natives do that this way

Spoiler

 

And handrails to push yourself along the corridors.

[jimmymcgoochie]

Am I the only one thinking that on low-gravity moons etc. it would be easier to get around on all fours? Greater surface area to contact the ground = more friction, wider and lower stance improves centre of mass so turning would also be easier… or is the idea of galloping around with a gait almost like a cheetah infeasible?

[MKI]

58 minutes ago, jimmymcgoochie said:

is the idea of galloping around with a gait almost like a cheetah infeasible?

I don't feel I'm flexible enough to do this as much anymore, let alone do that in some low gravity configuration.

 

Now if I had some sorta machine/device to help my move around on a low gravity surface, would it still be a car? hmmmm....

[kerbiloid]

1 hour ago, jimmymcgoochie said:

Am I the only one thinking that on low-gravity moons etc. it would be easier to get around on all fours?

At 0.01 g it's no difference on how many.

Probably the climber-like rope roads on the stuck sticks are the only way.

[sevenperforce]

14 hours ago, JoeSchmuckatelli said:

I honestly think it matters how much atmospheric pressure there is and whether it is toxic, or outside survivable temperatures.  If you had a planet with an atmosphere that had similar pressure to Earth, but oddly no O2 (or not enough) and wasn't toxic to skin, I'd think you could get away with only wearing an oxygen tank and a face shield.

Interestingly, people can (over time) acclimate to lower oxygen concentrations. And a pure oxygen environment lowers the pressure without lowering the oxygen concentration.

In theory, someone who was acclimated to life in the Andes mountains could survive in a pure-oxygen environment with the same atmospheric pressure as Mars. Thus all they would need to go outside would be warm clothing and an oxygen mask.

14 hours ago, JoeSchmuckatelli said:

Where you have little atmosphere - the suit is required not only for breathing, but also pressure and radiation protection.

Here's what they're thinking about for Mars:

The Advanced Spacesuit Tech For NASA's Mars Mission Looks Futuristic (screenrant.com)

Hybrid suits are definitely the way to go. But I'm still holding out for an Iron Man suit.

[kerbiloid]

https://www.researchgate.net/figure/Phobos-Hopper-PROP-F-model-courtesy-VNIITransmash_fig1_224991819

[Scotius]

Anatomically, we are not well suited for quadrupedal locomotion - it would be straining. Though on high gravity worlds crawling would be the safest way to move around.

This might have a potential, though:

[kerbiloid]

17 minutes ago, Scotius said:

Anatomically, we are not well suited for quadrupedal locomotion

Why?

Spoiler

[Hyperspace Industries]

It would take some practice, but walking would be about the same (with maybe a few changes like steadying yourself against walls, but practice and experience could make that rare).

Where it gets interesting is running. Andy Weir mentions a lunar running technique called the artemis longstep in his book Artemis. That would allow faster running (with practice).

I personally think moving fast in low g, would involve parkour, and ridiculous (on earth) maneuvers such as turning horizontal to brake by landing on a wall, bouncing off walls, and perhaps even bouncing like a pinball between two walls.

[kerbiloid]

There is a special moon walk methodics already developed in late 1980s.

Spoiler

 

[cubinator]

7 hours ago, sevenperforce said:

In theory, someone who was acclimated to life in the Andes mountains could survive in a pure-oxygen environment with the same atmospheric pressure as Mars. Thus all they would need to go outside would be warm clothing and an oxygen mask.

I think you've dropped an order of magnitude somewhere. Mars' pressure is 0.006 atm, humans need a pressure much greater than that to get enough oxygen while preventing our lungs from bursting from positive pressure. They would still need a pressure suit of some kind.

[Piscator]

It's also an order of magnitude below the Armstrong limit/pressure, which would make prolonged survival a bit tricky.

[K^2]

There has been research into extended stay in increased gravity. Soviets did a centrifuge experiment with ~2G. There wasn't a lot of space to run around, but what footage I've seen doesn't indicate like they'd be doing a lot of running even if there was room.

For lower gravities, though, I'm aware of precisely two data points. Lunar missions and this wonderful bit from Skylab. (Timestamped, but it's a short clip.)

If this is in real time, I'm timing a full circle to be about 7s. And the inner diameter of this track is about 5m, which would mean it's about a fifth of Earth's gravity. That does actually tell us things, as that's not a lot higher than what you'd experience on the Moon, and yet running seems fairly effective, even if it looks like slow motion. So hopping on the moon might have been due to reduced mobility of the suits, and not just the problem of low gravity. That said, I'm sure there's a lower limit in gravity where running just doesn't work anymore.

So with that in mind, I think there are only four viable options. Hopping in very low gravity, running in something closer to Earth's, walking in higher gravity, and if you can't walk, maybe you can crawl. That's not a lot, but with two legs, permutations are limited.

[kerbiloid]

Quote

How much does a military bag weight?

 

Soldiers and Marines in Iraq and Afghanistan routinely carry between 60 and 100 pounds of gear including body armor, weapons and batteries. The heavy loads shouldered over months of duty contribute to the chronic pain suffered by soldiers like Spc.12 мар. 2011 г.

 

[MKI]

On 1/8/2022 at 2:49 AM, K^2 said:

I'm timing a full circle to be about 7s. And the inner diameter of this track is about 5m, which would mean it's about a fifth of Earth's gravity.

First, aren't they in orbit around Earth and just "running up the curved wall?" the whole time? Which I guess would mean your continuously running up a very steep hill that curves toward you. Lot easier than a flat surface, or "downhill" (!!!)

 

 

Edited January 10, 2022 by MKI

[Nuke]

id love to see what a cat does in a lunar ag-dome. 

i imagine walking through your moon garden, tending to your space potatoes, and all of the sudden the space rodent control system is pouncing on your head from across the dome to demand scritches. 

Edited January 8, 2022 by Nuke