Artificial Gravity: punctuated gravity using a centrifuge

[nixter]

 Has it been considered that long term, low gravity induced problems could be addressed with punctuated high gravity using a small on-board centrifuge? It may be discovered that being subjected to very high G's for a short time every 24 hours may counter the effects of long-term exposure to micro gravity. One hour in a centrifuge at two G's would strengthen the body against the negative effects of micro-gravity. I know that the idea of on-board centrifuges is nothing new, but has the idea of brief punctuated bursts of high g’s been considered? The experience would probably be unpleasant and space travelers would learn to dislike them because high G’s are generally considered to be stressful and uncomfortable, but if some basic research on the ISS or elsewhere were to show that this works to counteract micro gravity, it might be worth it. I did a search on punctuated high gravity and did not find anything similar but I know that anything I can think of has probably already been thought of by several people, but I presented the idea here just in case it has not.
 Pre-conditioning space travelers in high gravity environments for some time before a mission begins would also probably help in resisting the negative effects of micro-gravity environments. Elon Musks Hyperloop technology could be used to make a very large centrifuge by constructing a large circular track with a ¹/₄ to1 mile diameter, people would live in these modules for long periods of time and the g's would be slowly increased incrementally as the occupants adjusted to the conditions. Athletes would use these as conditioning units for upcoming strenuous events and they would probably give them an advantage that would be eventually be considered unfair because of the results. It would be interesting to see how a human would adjust to the high G conditions after becoming conditioned to them and also interesting to see how they would feel and react when first reintroduced to one G conditions. I read somewhere that mice subjected to high G’s over long periods of time are at first unable to move around freely, but then they adjust and move about as they would under normal gravity. If this is true, humans should be able to adjust to these high gravity conditions also, especially if the process takes place over several weeks or perhaps even longer periods of time.
 

[speedevil]

Has it been considered that long term, low gravity induced problems could be addressed with punctuated high gravity using a small on-board centrifuge? It may be discovered that being subjected to very high G's for a short time every 24 hours may counter the effects of long-term exposure to micro gravity.

This isn't the sort of thing that can be actually tested without testing it in full-up tests.

You can't meaningfully extrapolate between intermittent high and 1G, and intermittent high and 0G meaningfully, when the behaviour you are interested in occurs pretty much only between 0 and 1G.

It's the sort of research that needs done, but the investment needed to do it is huge, and can mostly be hand-waved away as un-needed, given the effects of going from 0G for 6 months to a year to 1G are well known, and the reasonable assumption that Mars would be less bad.
For the return journey, pretty much all that needs to happen performance-wise to the crew is for them not to die.

[Slarty1080]

Why not just let them sleep in a 1g environment? Being fairly still and level they shouldn't suffer quite as many side effects from the rotation.

[guckyfan]

Why not just let them sleep in a 1g environment? Being fairly still and level they shouldn't suffer quite as many side effects from the rotation.

What would this be good for? Lying in bed on earth is used as a reasonable emulation of microgravity for medical tests.

Gravity needs to be used for exercise. Plus toilet facilities would profit a lot from it.

[dglow]

Why not just let them sleep in a 1g environment? Being fairly still and level they shouldn't suffer quite as many side effects from the rotation.

What would this be good for? Lying in bed on earth is used as a reasonable emulation of microgravity for medical tests.

Gravity needs to be used for exercise. Plus toilet facilities would profit a lot from it.

If spending 7-8 hrs/day in a centrifuge mitigated the vision impairment some experience, that alone would make it worthwhile.

[nixter]

This isn't the sort of thing that can be actually tested without testing it in full-up tests.
You can't meaningfully extrapolate between intermittent high and 1G, and intermittent high and 0G meaningfully, when the behaviour you are interested in occurs pretty much only between 0 and 1G.
It's the sort of research that needs done, but the investment needed to do it is huge, and can mostly be hand-waved away as un-needed, given the effects of going from 0G for 6 months to a year to 1G are well known, and the reasonable assumption that Mars would be less bad.
For the return journey, pretty much all that needs to happen performance-wise to the crew is for them not to die.

 Just as I thought, there may still be hope because space X has relatively unconventional research and development processes, they may find a way to invest in this type of research to determine whether or not it is viable.  It may be that the gravity environment on Mars is insufficient to support basic human health norms, if that is the case there will need to be some type of artificial gravity used on an ongoing basis to maintain bone health etc. etc.  if human beings are going to be traveling back-and-forth between Mars and earth in a continuous stream of missions, then our low gravity problems will have to be solved.  In the end most of these problems can be boiled down to one element, money. Space missions in general rarely have enough funding to provide truly robust, large space born equipment, one of the exceptions being the ISS. Perhaps with a planned space station between earth and the moon or a moon base, spaceX, utilizing the BFR will be able to assemble a large spaceship capable of having a huge built-in centrifuge like in 2001 a space Odyssey, that would solve the problem nicely.  This type of spaceship would always remain in space traveling between Mars the moon or the earth.  Of course this solution is obvious, but unattainable because of the lack of funding needed.

[guckyfan]

I have a different idea. Just go to Mars and see what happens. Make expensive plans when they are needed.

[Lampyridae]

Has it been considered that long term, low gravity induced problems could be addressed with punctuated high gravity using a small on-board centrifuge?

...
 

Yes, it has been considered. There are many studies on the topic stretching back to the 90s.

1997: (using intermittent standing, walking as a substitute for AG)
https://www.ncbi.nlm.nih.gov/pubmed/11540676

2018: (gender differences in reactions to intermittent short-radius centrifugation)
https://www.frontiersin.org/articles/10.3389/fphys.2018.00716/full

Basically, it works for a lot of things. Until we get some data from actual spaceflight though, we're not 100% sure how effective.

And as mentioned, centrifuge for toilets would also be great. Going to the loo in zero g is a nasty affair.

I'm not sure how this thread is SpaceX related, though. Unless you want to propose a centrifuge to stick inside a BFS perhaps.

[JulesVerneATV]

Immune System Changes During Space Travel Could Affect Aging on Earth

https://www.spacedaily.com/reports/Immune_System_Changes_During_Space_Travel_Could_Affect_Aging_on_Earth_999.html

[InterestedEngineer]

Immune System Changes During Space Travel Could Affect Aging on Earth

https://www.spacedaily.com/reports/Immune_System_Changes_During_Space_Travel_Could_Affect_Aging_on_Earth_999.html

I don't see how they controlled for lack of immune system stimulation.

The space station is a sterile-as-possible monoculture.

Lack of stimulation by new foreign agents is as bad for an immune system as lack of exercise is for muscles.

They have a mechanistic explanation on the change in immune cell shape, but I think they are missing something just as important as the difficulty of exercise in zero-G.

[edzieba]

Immune System Changes During Space Travel Could Affect Aging on Earth

https://www.spacedaily.com/reports/Immune_System_Changes_During_Space_Travel_Could_Affect_Aging_on_Earth_999.html

I don't see how they controlled for lack of immune system stimulation.

It's an in vitro study.

[punder]

I have a different idea. Just go to Mars and see what happens. Make expensive plans when they are needed.

Had this capability been developed 10 or 20 years ago, as Gary Hudson intended, it would have been quite useful. You’re correct—now, the intermediate data points on the g curve will come from surface stays on the Moon and Mars. Even if someone started a well-funded centrifuge program today, it’d be obsolete before its launch.

[StraumliBlight]

Had this capability been developed 10 or 20 years ago, as Gary Hudson intended, it would have been quite useful. You’re correct—now, the intermediate data points on the g curve will come from surface stays on the Moon and Mars. Even if someone started a well-funded centrifuge program today, it’d be obsolete before its launch.

Starlab (launching NET Late 2028) may incorporate a crew centrifuge, as its based on Airbus's modular LOOP concept.

[zubenelgenubi]

Topic moved to Advanced Concepts.

[mikelepage]

The reason I don't like the punctuated gravity idea is that it presumes that biomedical problems are the only ones we're solving with spin G.

Constant (or near-constant) spin G of some sort will save money by removing the necessity to redesign for microgravity, every machine or process which deals with any kind of fluid. The initial upfront investment is dwarfed by the ongoing development costs of not doing it. Plus, non-medical human factors issues are going to be the long pole in getting the general public to actually *want* to settle space.

[Lampyridae]

The reason I don't like the punctuated gravity idea is that it presumes that biomedical problems are the only ones we're solving with spin G.

Constant (or near-constant) spin G of some sort will save money by removing the necessity to redesign for microgravity, every machine or process which deals with any kind of fluid. The initial upfront investment is dwarfed by the ongoing development costs of not doing it. Plus, non-medical human factors issues are going to be the long pole in getting the general public to actually *want* to settle space.

Plus, some people just do not cope well with microgravity. Even a short-radius, low rpm centrifuge might be enough to relieve that.

[edzieba]

The reason I don't like the punctuated gravity idea is that it presumes that biomedical problems are the only ones we're solving with spin G.

Constant (or near-constant) spin G of some sort will save money by removing the necessity to redesign for microgravity, every machine or process which deals with any kind of fluid. The initial upfront investment is dwarfed by the ongoing development costs of not doing it. Plus, non-medical human factors issues are going to be the long pole in getting the general public to actually *want* to settle space.

The caveat there is that the rotation or spin system then becomes a critical system element. If the structure has to be spun down or rotation stopped, then those acceleration-dependant systems either need a microgravity-operation fallback mode (that incurs the costs you are trying to avoid), or a redundant microgravity backup system to be carried anyway.

[acksed]

This is a chance to mention a recent favourite finding in space medicine: take a bungee cord to simulate Lunar-gravity, and a 10m-wide, 5m-tall Wall of Death, to make a circular vertical track that would allow the runner to experience Earth-normal G-forces when running:

https://royalsocietypublishing.org/doi/10.1098/rsos.231906

Essentially, the high dynamic loading of the footstrike when a Lunar wall-runner makes contact reconditions the muscles and bones. They compare volunteers who, when confined to bed for 60 days, underwent 48 sessions of jump training over that time and managed to avoid most of the negative consequences.

The preliminary conclusion is that 8-9 laps of the track per day, split into two sessions, should be enough.

'Proper' centrifuges will need working out, but a circular hab with a running track on the wall could be built now.

[Twark_Main]

Again the "proper" effective solution for Mars or the Moon (vs a Starship or space colony) is just to use wearable weights.

And no, despite the prematurely confident objections of certain fiction writers, it doesn't really matter that weights don't perfectly reproduce 1 g exercise. It's "close enough," and at 1/1000th the cost of more....   fanciful approaches.   

Even on space colonies I expect — after humans get over our initial infragravity phobia — it will be common to see designs with something like 25-50% gravity, with the rest "made up for" (on an as-needed basis) by using wearable weights + more traditional exercise regimens similar to current countermeasures.

[Paul451]

Constant (or near-constant) spin G of some sort will save money by removing the necessity to redesign for microgravity, every machine or process which deals with any kind of fluid.

The caveat there is that the rotation or spin system then becomes a critical system element. If the structure has to be spun down or rotation stopped, then those acceleration-dependant systems either need a microgravity-operation fallback mode (that incurs the costs you are trying to avoid), or a redundant microgravity backup system to be carried anyway.

No. During despin, you only need lossy/storage-based short-duration zero-g life-support systems. Similar to what is on a capsule, say 5-7 day maximum duration. During spin, you have your long-term, low-loss, complex recycling/ & processing systems. The complex systems only need to have a shut-down state that is safe in zero-g, they don't need to operate in zero-g.

(And even the stored waste from the short-duration zero-g systems can be transferred into the more complex recycling systems, once back under spin.)