Implementing a Small Centrifugal Module

If some investigation is done that supports the use of a high rpm/small diameter module to promote health, then the question of cost and schedule becomes important. I think an early economical method might be to reuse an expendable upper stage that would otherwise burn up on reentry.

Depending on what upper stages are available to a station facility on orbit, it may be possible to use one of them to create a multipurpose centrifuge without building a dedicated module for the purpose. Even a twenty odd foot diameter centrifuge would be a volume  hog in any near term space station. I suggest that a used upper stage could be fitted out in a manner similar to the wet lab concepts of back when.

I seem to remember that the wet lab concept was abandoned because of the difficulties of fitting out an ex propellant tank with a lot of complex equipment using valuable astronaut time while in microgravity. If a very simple facility is required, it just may be feasible to fit it out in an economical manner and use that upper stage that was going to burn up otherwise. With the relatively heavy engine and light tanks, it seems possible that spinning the stage end over end would put the spin center at about the intertank region for some vehicles.  A spin coupler to the intertank region could connect the used stage to the microgravity station. Existing   hatches (if any) from the intertank region into the tanks would serve as entry to whatever facilities were placed in the ex tanks that are now heath maintenance facilities.

stage recycle

One of the problems frequently mentioned is the quantity of time required for exercise in microgravity in some scenarios and motivating astronauts to do the full effort specified. Often enough the “I think two hours mandatory exercise a day is a great idea sir.” translates to “Whatever it takes to keep me on flight status, you chairborne @#$%.” One possible solution is to use the high gravity time to do things that are seriously enhanced by the presence of gravity, real or artificial. This is also a shot at compensating for  the head in traction annoyance that I am suggesting for avoiding motion sickness.

Inability to take a shower in microgravity is a complaint sometimes mentioned. A shower at 2 gees with water recirculated would be a daily destination of choice for most space travelers. A good hot shower is a luxury after a hard days work that many people enjoy. That gives about 10-20 minutes a day in a gee field by choice.

A toilet in a 2 gee field would be a simpler device than the zero gee devices and most likely more desirable than the currently available  arraingements. Five to fifteen minutes a day per person, again by choice.

A few minutes in a gee field might help clear out the sinuses to the point that a hot cup of coffee would taste good.  Breakfast after a bathroom and shower break could be the meeting place of choice in the mornings if food can be smelled and tasted properly. Other meals likely would be eaten there for the same reason for a total of an hour or more per day per person. Eating standing up would be an acceptable trade off to people that could retire much of their required exercise time during meals.

An exercise facility would still be required in one of the tanks with possibly half an hour a day or less being acceptable if the participants are already spending a couple of hours a day or so in a gee field of substantial strength.

This is all speculation about an idea that is dependant on controlling motion sickness in a several rpm field for up to an hour at a time, and that the time in that field will produce the health benefits hoped for. If this turns out to be true, big if, then a station or Mars cycler might prefer an arrangement like this to the tether solution as the travelers will be able to transition from microgravity to a gee field and back in a minute or two whenever they feel the need.  They would be able to do the things that are enhanced by microgravity and the things that are enhanced by gravity in the same ship.

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johnhare

johnhare

I do construction for a living and aerospace as an occasional hobby. I am an inventor and a bit of an entrepreneur. I've been self employed since the 1980s and working in concrete since the 1970s. When I grow up, I want to work with rockets and spacecraft. I did a stupid rocket trick a few decades back and decided not to try another hot fire without adult supervision. Haven't located much of that as we are all big kids when working with our passions.
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12 Responses to Implementing a Small Centrifugal Module

  1. gaetano marano says:

    I’ve suggested to build an artificial gravity space station with the used ATVs without burn them in the atmosphere
    .
    http://www.ghostnasa.com/posts2/054atvstation.html

  2. Luke says:

    A question – if you appropriately ‘packaged’ the contents of the toiled holding tank, and then jettisoned it at the right moment, would it re-enter and burn up? Could throwing things off the centrifuge be a viable garbage disposal strategy for LEO?

  3. PrairieKirk says:

    For those of you struggling to read the backwards texts in the upper right portion of the graphic, it reads:

    ” gym 1.25 gee with strength and cardio equipment ”

    Thanks John. Interesting ideas.

  4. Jean-Paul says:

    Would not it be possible to use an inflatable room?
    When you inflate the length shrink so you could pack in a standard stage diameter.

  5. Jean-Paul says:

    Follow up:
    As the diameter is now enough to put in the centrifuge apparatus then you can perhaps build in the centrifuge the toilet, shower, coffee machine.

  6. Coop says:

    A reasonable source for the structure, but the interactions with the 0-G part of the station are the hard part, of course, and they worry me a lot. A rotating interface is not even experimental yet (though I must say it’s overdue to start trying!), and the dynamics of the interaction of a big rotating boom with the rest of the station make my head hurt. A complex non-symmetrical thing like the ISS seems like the worst case (especially with the capability to really mess up microgravity experiments); however, something like a Bigelow hab module might work reasonably.

  7. nooneofconsequence says:

    Think of the stability of the object – remember you are spinning a top, and movement within will cause the object to destabilize.

    The mass distribution is not ideal for a stable system.

    Here’s another idea to think about. Two Dragon capsules, each with a cable/winch harness in the trunk, and pre setup animal experiments in each.

    Each arrive at the ISS, assembled into a coupled system from trunk components, joint Rbar departure/ orbital manuever, and on orbit spin-up for days (or more). Spin axis adjusted so that all four panels are sun facing. Coupled system despins, stabilizes, rendezvous with ISS, is disassembled/stowed in respective trunks, and berthed with ISS for access to experimental animals. Note – never are animals removed from cages or entered into ISS – might even be possible to isolate using glove box access or other manipulator for 100% separation. By extending Dragon consumables, might be able to run this for weeks in successive reassembly/berthings.

    Experimental animals returned to Earth on Dragon recovery. 100% reusable system.

    After using it with animals, could run human experiments as well given accumulated experience.

    I think you could do this for a fraction of the cost of the small centrifuge that didn’t make it to the ISS. And it would be more than enough to validate what you need for long duration HSF like BEO missions.

    Biggest challenges are GNC. And consumables.

  8. johnhare john hare says:

    In my opinion, the ISS is the wrong place to consider doing anything in a reasonable time frame. Bigalow or another commercial operator would be a much better option.

    Small animal experiments first would be the right way to start. I don’t see the usefulness of using two Dragon modules to do them. A small animal experiment should be able to fly on a single Falcon 1E or equivilent.

  9. Paul says:

    Don’t forget, you need to test whether you can use a toilet/shower, or eat or drink at 2g. We’d need to do centrifuge experiments on Earth first. (In your last post, you talked about gym + head-restraints, but you’d need to add toilet, shower and kitchen.)

    (Is it side to side head movements that cause problems in high-RPM centrifuges? Would it help for astronauts to simply wear a neck brace when entering the spin-section? To keep your head centred and upright.)

  10. gaetano marano says:

    “The mass distribution is not ideal for a stable system.”

    the system can rotate around its CG instead than around its physical middle

  11. Roderick Reilly says:

    I’m late to this discussion, but here goes:

    I’m intrigued by this concept of intermittent artificial gravity. Question though: will it be sufficient to maintain muscle mass and bone density? Obviously we won’t know unless it’s tried and tested extensively. One more reason to keep ISS going for extended years.

    Might it not be a good idea to supplement centrifuge sessions with extended periods of wearing those cosmonaut “penguin suits?” I’m thinking that a more sophisticated, elegant, and comfortable version of the penguin suit that can be worn for hours at a time comfortably and without it interfering with mission operations and tasks would be a useful adjunct to centrifuge sessions.

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