It all sounds very unpleasant, but most of the nasty stuff described in TFA is the result of living in zero gravity. That is a solved problem: build a rotating space station to create artificial gravity. It probably “just” requires a trillion dollars. But if we collectively wanted it, we could have it.

The two problems called out here that wouldn’t be solved with that are the smell (not dangerous, live with it) and the radiation (very nasty indeed).

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m4rtink 2 days ago | parent | next [-]

You can do very low cost rotating gravity if you don't mind some of the downsides. Eq. you can basically split your craft to 2 pieces of ~same weight, connect them with cables and have them rotate around the shared center of mass in the middle.

This scales from two tiny one-person capsules up big habitats, until you end up hitting structural limits of available materials for the cables.

Might be less practical than a full rotating ring, but should be much cheaper & more flexible - you can just winch the cables in and out to regulate gravity or switch back to a combined zero gravity configuration.

The main issue being moving stuff between the two sections - but if you put cargo, fuel, power supply, etc in one section & living space in the other, it should be fine. Or you can have some crawlers going back and forth via the cables.

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joak 2 days ago | parent | prev | next [-]

Radiation is also a solvable problem: water is a very effective shield for all type of space radiations. 10 cm of would block harmful solar radiation. 3m would block cosmic rays and bring radiation to Earth levels.

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bobajeff 2 days ago | parent [-]

Okay so if I'm understanding right you'd to need have a big constantly rotating satellite with 10cm of water insulation spanning the satellite's surface area with no gaps. That's difficult but at least it's a solution.

	▲	m4rtink a day ago \| parent \| next [-]
		Also one more note about shielding in general - at least in the Solar system, you need to work with two types of radiation regimes: 1) The roughly constant stream of radiation from the Sun & deep space. That drives your shielding baseline & the areas where people spend the most time in should be shielded. One concept I liked (in the manga/anime Planetes) was a big rotating habitat having de-spun zero-G "capsule hotel" in the inner core of the station where people would go to sleep & which provided the best shielding possible, both from radiation and possibly also orbital debris, etc. 2) Solar flares and coronal mass ejections that can release basically a cloud of bunch radiation it roughly random direction from the Sun at roughly random times (related to the cycle of solar activity). Those are short but potentially very intensive events that might effectively kill un-shielded people outside (eq. doing EVA work) and still be dangerous even with shielding of the regular type. But by these evens being quite short, you can have a small area with very heavy shielding (sometimes called a "storm shelter") where people would wait out the radiation storm in safety. This might even be the same as the "sleeping area" mentioned above.
	▲	m4rtink 2 days ago \| parent \| prev [-]
		Just a note about shielding & alternative spin gravity concepts: If you just spin two masses connected by cables, the shielded area can possibly be much smaller, reducing shielding weight or enabling better shielding for the same mass. Also you could more easily add living space & shielding incrementally, as long as you keep the two cable connected masses roughly balanced. With a ring type station/habitat, you need the whole thing (or at least most of it) complete before you get any benefits.

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lazide 2 days ago | parent | prev [-]

If by ‘solved’ you mean ‘never attempted except in scifi’, then sure.

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libraryofbabel a day ago | parent [-]

I mean, sure, but this isn't "sci-fi" in the sense of a fusion ion engine or something. I don't think there are really any big engineering unknowns here, and building a rotating space station is certainly less technically complex than sending humans to Mars, and maybe even less than going back to the moon. We already know a lot about space stations from the ISS; it's just very expensive to build all the bits of a rotating station and to lift them into orbit.

	▲	lazide a day ago \| parent [-]
		Per the Russians anyway, the stability of the station isn’t what we expect. It would NOT work the way it naively seems like it would.