(Obvious idea is obvious.)
walkplate (n.): A walkway for magnetic boots (q.v.). Since starship hulls in the modern era are manufactured from a variety of light composites very few of which are significantly ferromagnetic, such walkplates are necessary to enable crewers on EVA to remain attached to the ship.
While early examples of walkplates were simply bolted to the hull, recent designs – preferring to maintain clean lines for the sake of elegance – embed a thin mesh of iron-alloy within the outermost layers of the hull structure, sufficient to be gripped by heel and toe electromagnets. Embedded v-tag transmitters and/or hull markings provide guidance as to which parts of the hull can safely be walked upon.
– A Star Traveler’s Dictionary
How do you deal with integrated walkplate that got vaporized with a segment of armor that ablated from laser hit? In case of bolt-on you just build a bridge of spare or relocated segments, but with mesh, not so much.
Nothing stopping you fastening plates over the top of the hole in an emergency. There’s also nothing stopping you using other methods, like temporary cable handrails or cold gas thrusters, depending on what you have to hand. This isn’t an essential facility after all, just a convenience.
I’d have gone for flux-pinning boots. Not only are they intrinsically cooler, but you can skate and glide as well as step… a useful feature if you were trying to get around on a really, really big ship like a Leviathan or big habitat.
Pretty certain you could inductively power a magnetic grid in the hull, so it wouldn’t necessarily require an active, co-operating ship (useful for civilian rescue purposes) but in a military context having the ability for your own crew to trot around on your hull but everyone else to be catapulted away might be quite a useful one…
Are safety tethers also used as a backup?
When going for a walk out in the black, certainly; belt-and-braces protection against unexpected accelerations, and all that.
People generally feel less need when orbiting quietly or in dock, though, especially since there’s usually plenty of traffic around to catch you if your mag-boots and MMU both fail.
I’m assuming that the rings the tethers attach to are recessed into the hull, to help maintain the clean lines. It also occurs to me that, rather than being simply a higher-tech equivalent of the tethers and hooks that NASA currently uses, they might well be closer in design to the mechanical tentacles that you’ve mentioned microgravity robots using, with small utility spiders at their ends. Which would also make them useful for grabbing errant tools before they drifted too far, or even performing certain repair tasks that require a sophont, but are in awkward-to-reach spots.