# How to go out for a walk in microgravity?

Suppose that humanity has spread out through space. Humans are exploring all kinds of environments, including some with gravity much weaker than our Moon's:

Bases are built on such places, and they get populated.

Regular walking in such gravity ranges becomes impractical. Kerbal Space Program has a body with a surface gravity of $0.049m/s^2$ (which is close to Phobos's), and the wiki has this to say about it:

It is very impractical to walk on Gilly; each step will launch a Kerbal several meters into the air. A Kerbal can jump over 200 meters on this moon and will usually take more than 4 minutes to return to the surface. This makes jetpacks a necessity to move around the moon practically.

I find the constant use of jetpacks on a daily basis awesome but wasteful. You would also be in trouble once you ran out of fuel.

I also know that magnetic shoes could be a solution while inside a building, but I'd like my space civilization to walk outdoors too.

What would be a practical solution if people wanted to go for a low gravity hike?

I am aware of Alternative for magnetic boots, but I am open to alternatives that do not involve gripping boots. I think that if someone depended on gripping for that, stepping on a loose rock would be quite troublesome.

• Not saying I mind the question, but realistically, even if there are any reasons to colonize such a place and even if this is done without creating some kind of gravity because think long term, there are still zero reasons to go out on a hike. Being on a space walk isn't fun, it sucks. Btw what about ropes/cables along certain paths, e.g. to get to important equipment? – Raditz_35 Apr 10 '18 at 17:54
• @Raditz_35 there are (...) zero reasons to go out on a hike let's say they are doing it for science (gathering rocks and stuff). Being on a space walk isn't fun, it sucks. YMMV what about ropes/cables along certain paths, e.g. to get to important equipment? Could be part of an answer ;) – Renan Apr 10 '18 at 18:05
• What if you went for a bike ride? – bendl Apr 10 '18 at 19:26
• I'm adding this as a comment instead of as an answer because I just know the powers that be would shoot it down; "you're not answering the question". Anyway, my answer goes in a somewhat different direction. Why go for a hike at all? Why not fly to where you're going? At low enough gravity with wings, a jet pack, etc. even some powerful jumps, you might be able to fly/float wherever you're going. After all you wouldn't be hiking for the exercise, you'd do that indoors on a treadmill in a controlled environment. – Len Apr 10 '18 at 19:43
• @bendl that would not end well, especially on Atlas. Also you might be throwing dust and rocks at a very high speeds towards whatever and whomever is behind you. – Renan Apr 10 '18 at 19:47

Cross country ski.

The vector forces entailed in cross country skiing are well suited for a low gravity environment. Rather than pushing downwards as with walking or running, one moves by shifting the weight and pushing off forward against the back ski. This was developed for snow but works on sand or other reasonably flat surfaces. The mineral surfaces of the listed small bodies should work just fine as ski substrates.

Plus if you have a hill you could set up awesome low grav jumps.

• It's better than walking but I feel like it would still launch you in the air at least a little – bendl Apr 10 '18 at 19:24
• I was going to say that climbing hills would be a pain, but then I remembered my own central point in the question: microgravity. This could actually work quite well. – Renan Apr 10 '18 at 19:52
• I think micro gravity exerts too little force for this to be practical. Your acceleration would be tiny and probably wouldn't even be able to overcome the friction of your ski against the ground. So basically you wouldn't move at all, or you would move extremely slowly. Of course this all depends on how micro the micro gravity is. But it is certainly a problem to consider. – Tyler S. Loeper Apr 16 '18 at 17:16
• @Tyler Sigi: my acceleration might be tiny, but it is because I am puny not because of low gravity. It is the same force exerted by my leg, whether on Ceres or Earth. My efforts do not depend on gravity. Also I would think that frictional losses through the ski would be much less in low gravity. – Willk Apr 17 '18 at 1:50
• @Willk Apr. That is a good point to make then, which wasn't too obvious to me. Propulsion will be from pushing with your legs. The propulsion from gravity, which I think is a much more significant factor on Earth, will probably be negligible in microgravity. – Tyler S. Loeper Apr 25 '18 at 17:11

If you really wanted to go out for a walk on your low gravity rock, and often, then your colony might want to invest in setting down some railing. Possibly everywhere. When you go outside you have a cord attached to you, and the other end you attach to the rail. You can use a simple clip. When you walk the clip slides and slides along with you. The tether prevents you from flying away.

There is not much reason to go outside walking, but if it was something frequent that had to be done then this is the easiest and cheapest solution requiring no high tech inventions.

• I would elaborate on this a little bit. Take inspiration from the safety systems on tall things that have to be climbed -- the system is still simple, but extremely secure, and especially if you're worried about falling away from the railing as opposed to along it, extremely good at arresting travel in a given direction. Heck, if you're alright with a little more complexity, you could easily design some fancy double-carabiner that automatically switched across attachment points just by being pushed. IRL this is bad because those attachment points stop falls, but here it would be fine. – Nic Hartley Apr 11 '18 at 2:57

Use ropes and cables. Attach your suit to them so you don't die. They are cheap, easy to install and remove (that far into the future, I'm sure a robot can do that for you before your trip) and easy to store. And if you don't have time and need to go someplace quickly, you can just attach them to your suit and your station . Your suit already comes equipped with that option. The exact implementation and details, another topic for another question.

Go cave exploring.

There are theories that many of the lower gravity moons of the solar system might have very extensive cave systems with very large chambers.

So if you start to become claustrophobic in your habitat, you might want to try putting on a ruggedized space suit and go spelunking. You can explore the larger caves by pushing yourself from wall to wall or swing around with a grappling hook. But you might still want to use a long and thin tether so you find your way back to the habitat before you run out of oxygen.

Main risk: If astronomers find out in a few years that the moon where your story takes place actually has no caves, then your whole story becomes implausbile. But that's a risk you must be willing to take if you write hard science fiction which takes place in our solar system.

• I can think of so many amusing ways to die in that situation, mostly involving accidental use of too much force when something snagged. – Separatrix Apr 11 '18 at 13:29

Set up walking paths equipped with rails.

It could look something like a walker, possibly with straps to hold you down, and tied into a rail system. Each time you take a step the walker and straps will keep you from bouncing away, and instead that energy will be used to push the walker forward.

The walkers wheels would work something like the ones on a roller coaster; you would have wheels on the top and bottom of the rail, so that when you push off the cart wouldn't just fly away with you.

Fundamentally you need to be carrying about 9.8/0.049 = 200x your body weight to feel normal gravity.

So, wear heavy shoes, build special heavy suits for everyone

• You don't feel 1.2~1.5x the gravity of Earth when you walk around carrying a backpack. I think the same holda for any amount of weight on another planet. – Renan Apr 11 '18 at 4:21
• Worthy7, welcome to worldbuilding.SE. Not a bad first answer, though a bit brief. Cheers! When you get a moment, please take our tour and read through our help center to learn more about us. Thanks! – JBH Apr 11 '18 at 4:27
• This would make it very difficult to start moving, stop moving, change directions, etc.; 200x your body weight also means 200x your body mass, 200x your bodily momentum, and so on. Reducing the gravity doesn't reduce the inertia you need to overcome. – ruakh Apr 11 '18 at 6:43
• Like the crosstrainer at the gym then.... – Worthy7 Apr 11 '18 at 8:18
• No matter how much extra mass you add, you won't increase the acceleration. So this still won't really make it feel like you are walking in normal gravity. – Philipp Apr 11 '18 at 11:49

Your question related to staying down in microgravity. Without a gravity field generator or something the answer is to increase the mass.

While this is not ideal from an inertia point of view it will keep you closer to the planet.

You could have concrete boots, a walking frame or jump into a fluid filled hamster ball.

Sort of like the Flintstones car.

• I think it is more like the iron boots in Ocarina of Time. – Renan Apr 11 '18 at 4:22