I can't count how many science fictions stories I have read where someone is strapping on magnetic boots to walk in or on a space ship without gravity. How realistic of a solution is this? Just for reasons of mass I assume pretty much everything currently in space is Non-ferrous which also means non-magnetic.
Assuming for some reason (not sure why) you actually wanted to walk in/on a space ship/station without gravity would magnetic boots or something else be the best way to go?
This turns out to be a pre-space-age thing. It's not really needed, most of the time it's perfectly fine to float around. On Skylab they provided an elaborate system of triangular grid floors and special shoes with triangular cleats to lock into them. The crew hated them and hardly ever used them.
When body positioning is important (like for flying the robot arm), various types of foot restraints can be used, mostly simple straps. If you are riding the robot arm, there were also foot restraints.
EVA folks also use tethers to secure themselves to work points.
But for just moving around, in or out of a space vehicle? Use your hands and/or push off with your feet (not recommended on EVA). Walking is highly inefficient in free fall.
As long as we use ultra-light materials in space, it isn't realistic. But even if we assume the space ship to be built of iron or steel:
You'd want the boots to simulate earth gravity towards your spacecraft while you are on an EVA to facilitate movement etc.
First, if you'd want that, you probably would line the whole suit with magnetic fibres so that the entire suit is being pulled towards the spaceship to simulate gravity on your whole body. The boots alone would just mean that your feet get pulled down while your body won't. I doubt that this would really help with working in a 0G envionment when just your feet get pulled down. Would feel a lot like in a water tank with weights around your ankles.
Second, to be viable this suit would not disengage and reengage like a magnetic lock that is visible in several movies everytime you try to lift your foot. It would simply be an always on like earth gravity - which you might have guessed by now - is also always on and would cause your suit to accelerate with 9.81 m/s² towards the spaceship. On the plus side, this would almost negate the requirement of training every day on a spaceship to combat muscle atrophy.
INSIDE a station, the easiest way to simulate gravity would be to rotate it. No need for anything magnetic around you to give you "gravity". Also inside you'd have the problem that you'd need one plane to be your "anchor". Otherwise you'd lift a foot and it would suddenly get pulled to the wall because that happens to be made of steel just like the "floor".
There's a few things that work and don't work with magnetic boots. Firstly, you're partly correct, ferrous metals have higher densities than non-ferrous and keeping mass low is important, so for using them along the entire length/surface area of a craft or station is infeasible, at least with current restrictions in reaching orbit. The soft counter to that is using small quantities of ferrous metals in specific areas (think a thin tightrope-style line across broad sections of exterior to simplify spacewalks, or contextual strips around workstations) This would greatly improve mobility on spacewalks and help with workstation anchorage, but even having magnetic boots brings us to problem 2. Even using standard non-energized magnets (think your neodymium, hobby magnets, or really anything that sticks to your fridge) would likely be a bulky measure, assuming you get ones weak enough to stick along to but not so strong they tire out walkers who have to lift their feet. Electromagnets could contextualize and form as active anchors you turn on and off, but those would require power sources. Maybe not a big deal in bulky spacesuits in spacewalks, but in-station shoes would at least have to be plugged in every few hours. Plus, the push-grab-lever approach of most zero-g movement is simply more efficient than walking. One good push could get you all the way through a long hallway in a space station, but walking along it could take more time and effort. While magnetic boots are good for some situations, it's probably better we either use centrifuges or find some way to generate artificial gravity wells.
it could screw around with all the electronics, and would require the ship to have an outer layer that is ferromagnetic,
but beyond that, it would need a constant source of energy (assuming they're electromagnets) which could be a big issue if that energy runs out
but if you can get around that then I would think they would be rather useful
