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This topic is inspired by Terraformer's recent posts about rotation as a way of simulating gravity.
This topic is offered for NewMars members who might find link to ongoing research about the effects of constant rotation on the human mind. To my knowledge, the only experiments performed with humans have been of very short duration.
Examples would be riding on playground merry-go-round equipment, or riding on a similar attraction at a fair.
In thinking back, I don't recall being uncomfortable in either of these situations, but I ** also ** knew they were of short duration.
It is possible to set up a simulation of a rotating habitat at almost any location on Earth.
A business might be built around such a facility, so that patrons support the enterprise by paying for the privilege of "traveling" for a week or longer on one of these devices.
The test would be all the more realistic if the full complement of shipboard services (and constraints) were included.
For example, I think that RobertDyck's vision of a rotating habitat for 1060 people is unlikely to succeed in the Real Universe, for any length of time more than an hour or two as an entertainment.
Never-the-less, there may be a market for such an experience.
We have members who reside in Europe and members who reside in the US, as well as Canada and Mexico
Test facilities could be built and operated in any of these locations.
China is a logical place for such a facility, because China is very likely to be sending Taikonauts to Mars and other Solar System destinations.
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This post is reserved for an index to posts that may be contributed by NewMars members over time.
This topic is intended to lead to Real Universe achievement.
Identification of suitable sites for rotation facilities would be welcome.
Identification of related market opportunities would be welcome.
Design of facilities to approximate the features needed for space deployment may inspire some members.
Identification of funding sources would be welcome.
Index: Terraformer #16 http://newmars.com/forums/viewtopic.php … 78#p229178
Link to report of study of rotation
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In the years after the 1960's and well into the 70's, entrepreneurs were willing to pay the extravagant costs of revolving restaurants on hotels or tall towers, such as the Seattle Space Needle and the similar one in Toronto.
I asked Google if any are left, and it reported there are a few still hanging on, but apparently there will be no more. Only a small number actually pay for themselves.
That said, here is one:
Perched 844 feet above the Las Vegas Strip and rotating a full 360 degrees every 80 minutes, Top of the World offers the ultimate in a romantic dinner date. The restaurant offers steaks, seafood and specialty dishes with a French accent and is world renowned for its cuisine. Sharing the same location at the top of the Stratosphere Hotel is the 107 SkyLounge where you can enjoy one of the designer cocktails such as “Lemon in the Coconut” (coconut vodka, lemon juice, honey) as you gaze at the Las Vegas skyline by night.
Assuming the two restaurants I visited adhered to the same standard, I can report that 80 minutes per revolution is most definitely tolerable.
A rotation every 20 seconds as RobertDyck suggests would seem to me quite a different experience.
And the rotation every 15 seconds as GW Johnson suggests would ** really ** be pushing the envelope.
Never-the-less, there is absolutely NO physical reason why a restaurant featuring either of these rotation rates could not be built for those hardy souls who are willing to try anything once.
A hotel featuring this rotation rate would be another order-of-magnitude more challenging, but I see no physical reason it could not be done.
A rotating stool could be set up at home, so the adventurous could experience life at this rotation for themselves.
Even less expensive would be a video designed to deliver images of a landscape rotating at one of these rates.
It just occurred to me that the rotating stool would be a useful test, because some humans might discover their bodies cannot tolerate it.
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Following up on the rotating stool idea ...
I checked with Amazon, and they carry a photographer's platform for large objects (such as a statue) that weight up to 170 pounds.
Unfortunately, the RPM is 1, and the rate is fixed.
This suggests to me there is a business opportunity for an entrepreneur who can make a rotating platform with a variable rate that can hold up to 300 pounds (with an "extra" version for a heavier person). The rate needs to be variable so the experimenter can experience 3 RPM (RobertDyck) or 4 RPM (GW Johnson) or 5 RPM (Stanley Kubrick/Arthur C Clarke), or even the stately 1 RPM of the Stanford Torus.
The price on Amazon for the 175 pound platform was/is $139.
The price would probably be greater for a version designed to hold a human safely.
Alternatively, the platform could be rented.
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The limiting factor for restaurants would be the view. They're intended for looking out, which means you'll get dizzy from the eye ear mismatch.
Something that would make design tricky on the surface is that at high RPMs, a short radius produces quite a bit of acceleration. A 3m radius at 5 RPM means at the wall there will be a force of 0.08g. At 2m radius, it's about 0.05g. The floor can be angled of course to help keep the acceleration properly downwards. Don't think we could get much smaller than 2m radius for something a person could spend a week in, that's 12.5 sq.m. I suppose some have gone smaller. But for longer term acclimatisation studies we're probably limited to about 5rpm unless we kick the gravity up significantly. If we're willing to put up with 1.5g, a 10m radius at 10rpm gives about 1.1g, so an angled floor could get it to about 1.5g. This should be doable.
It would not be a pricey experiment, so one of the space settlement enthusiast groups could and should do it.
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The skepticism of Terraformer inspired me to try to thing of Earth examples of carnival or similar amusement rides that incorporate rotation.
A ferris wheel is apparently rotating too slowly for a valid test.
However, a merry-go-round apparently turns at a generally accepted speed of 15 RPM.
I don't remember my rides on those as particularly upsetting. In fact, the experience of riding the carved and painted horses, and sharing the excitement of momentarily being ahead in my tier of four horses was what I remember.
It should be possible to rent a merry-go-round for a 3 RPM experiment or a 4 RPM one, or even a 5 if someone wants to venture that far.
What would be different about the experiment is the duration of the test run.
To find out if an individual human an tolerate 3, 4 or 5 RPM for years, it would seem to me as though testing for an hour would be a minimal duration. In that hour, the subject might carry out a large number of experiments.
I found a candidate merry-go-round at Cedar Point:
Cedar Point in Sandusky, Ohio has multiple carousels, including the Midway Carousel, Kiddy Kingdom Carousel, and a carousel in the Merry Go Round Museum.
Midway Carousel
Built in 1912, it's Cedar Point's oldest operating ride
One of the few Daniel Muller carousels still in existenceKiddy Kingdom Carousel
Has been serving riders of all ages since moving to Kiddy Kingdom in 1968Carousel in the Merry Go Round Museum
A 1939-era Allan Herschell carousel that visitors can ride
Runs faster than most amusement park merry-go-rounds
The Merry Go Round Museum is located in Sandusky's former post office building at 301 Jackson St. The museum features hundreds of carousel artifacts, including the centerpiece carousel.What a ride: Sandusky’s new Cedar Point Historical Museum ...
Nov 14, 2024 — Eventually, they may need a bigger space. But for now, the exhibit space -- roughly 70 feet by 14 feet – is perfectly ...
Cleveland.com
Midway Carousel | Cedar Point
The Midway Carousel is an attraction for every generation. Built in 1912 and operating at the park since 1946, it's Cedar Point's ...
Cedar Point
Kiddy Kingdom Carousel | Cedar Point
Being just one of the three carousel's featured at Cedar Point, it has been serving fun to riders of all ages since moving to Kidd...
Cedar Point
\
The platform is a huge 93' in diameter (the largest made by Prior & Church). The eccentric drive creates back-and-forth as well as up-and-down motion of the horses – to simulate a horse race within each row. The horses move at about 14 mph.Ohio Carousels | RoadsideArchitecture.com - RoadArch.com
RoadArch.com
https://www.roadarch.com › carousels
About featured snippets
•
FeedbackMidway Carousel
Cedar Point
https://www.cedarpoint.com › rides-experiences › midwa...
The Midway Carousel at Cedar Point features 60 beautifully painted horses and chariots. The Midway Carousel, a Daniel Muller carousel, is a park classic!
93 feet is a bit over 28 meters, so well short of the diameter of RobertDyck's large ship:
Updated math with more precision. Mars acceleration for the ship, so 38.0% that of Earth gravity. Radius 37.76 metres from centre of rotation to surface of the floor, 3 RPM. One deck. Circumference 237.25 metres. Ring width 19 metres. This allows 2 isles for cabins, corridors 1.5 metres wide, outside cabins have a window, inside cabins do not. Standard cabin size 4x2.4 metres.
Quote above is from Post #1 of Large Ship by RobertDyck.
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Here is a resource to find locations of a variety of systems including carousels...
https://roadarch.com/roadside.html
Here is the page for carousels in Ohio
https://www.roadarch.com/carousels/oh2.html
What I'm thinking about is a collaboration with the Cedar Point park as the host, Sandusky as the site of overnight accommodations and meals, and NASA as a major connection for university participation.
Visitors could be drawn from all over the United States and potentially even further afield.
I would feature RobertDyck's 3 RPM as a major test for all participants.
I would offer GW Johnson's more ambitious 4 RPM as an option, and Stanley Kubrick/Arthur Clarke's 5 RPM as the stretch option.
The test would be for a hour in all cases, except that individuals could bail out at any time.
Those who could tolerate the higher RPM's would automatically jump to the front of the line of candidates to participate in flights to Mars, Venus or wherever else humans might wish to go.
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Contact form submission to Cedar Point, Sandusky, Ohio...
Please forward this inquiry to your planning department. I am a (Junior) moderator for the NewMars.com/forums, which is affiliated with the Mars Society, Dr. Robert Zubrin, Founder (James Burk, Executive Director)
Question: Might the 93 foot diameter carousel be available for scientific research during the off season?
The question arises from debate among forum members about the practicality of artificial gravity produced by rotation at 3 RPM, 4 RPM or 5 RPM.
While the carousel runs faster than those speeds, I'm hoping it can be adjusted to operate for extended periods such as an hour or more.
I'm thinking about pulling in NASA resources to supervise the science, and various Universities in Ohio who might have faculty interested in the problem.
Due to an oversight, there appears to be absolutely NO data on long duration rotation effects on human beings.
The potential audience would include anyone who thinks they might be interested in helping to settle Mars. Those individuals have parents who would (I trust) be willing to fund an overnight stay in Sandusky.
tahanson43206 (Junior) Moderator
NewMars.com/forums
As a followup:
I received a courteous email back from Cedar Point. The organization is rebuilding/maintaining equipment and does not want any other personnel on the property. That is particularly pertinent now, because the next season is just a few weeks away. I am relieved because following through would have been a lot of work. In addition, the risks would have been substantial, because there is no data to support the idea that anyone would pay money to participate in a study of Mars transportation options. All-in-all, I think this courteous email is the best possible outcome.
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This post is reserved for a collection of information that would enable a person (or small group) to build and run a Maypole type of gravity simulator.
What this post is aiming to achieve is the least cost realistic simulator.
The system would include a pole, one or more cables, one or more gondolas to hold a passenger, and electric or other motors to achieve rotation.
Since the visual environment is to be excluded, the gondola would be enclosed, or the participant could wear a virtual reality headset.
The purpose of the exercise it to enable each participant to discover their own individual tolerance for rotation at 3 RPM, 4 RPM or 5 RPM for extended periods.
While many sizes of equipment might be considered, this post will study the 40 meters radius under consideration for the Dual Inline Rotating Habitat Deep Space Exploration Vehicle currently in study.
Note: GW Johnson is preparing a set of spreadsheets for computation of numbers for various sizes of rotation apparatus and rotation rates.
The link below takes you to a collection of images showing rotating carnival rides in many locations.
https://www.google.com/url?sa=i&url=htt … AdAAAAABAE
It is possible one of these existing systems might be adapted for purposes of this study.
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I asked Google to see if it could find information about swing arm amusement rides. It came back with promising results:
what is the typical rotation rate of a swing arm carnival ride?
A typical rotation rate for a swing arm carnival ride, depending on the design and intensity, is around 2-5 revolutions per minute (RPM), with some rides potentially reaching up to 10 RPM at their highest speed.
Key points to consider:
Variable speed:Most swing rides can adjust their rotation speed, starting slow and gradually increasing to a faster rate.
Ride type:
The specific design of the swing ride, including the length of the arms and the number of seats, can affect the rotation rate.Safety considerations:
Operators typically maintain a safe rotation speed to prevent excessive G-forces on riders.
I think this means that if one of these rides is available in a region where a NewMars member resides, it might be possible to set up a useful test. It is possible the operator of such a ride has no way to know what RPM is actually in play, but instruments should be able provide that information.
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I think it may be possible for individual NewMars members to perform experiments to assess their own individual tolerance for various rotation rates. If there is interest this topic might be updated to provide rapid access to particular test results.
The index (post #2) could be enhanced to permit rapid location of results by RPM, arm length or other useful factors.
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A simple test would use a spinning office chair and a clock. Of course, you don't need to even do that if you stand up and spin yourself around; that's what I did to see if 10 rpm might be reasonable lol. But the more useful information is about the distance of ones head from the axis, since coriolis force depends on that as well as on RPM.
Last edited by Terraformer (2025-01-17 10:03:08)
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As I have repeatedly pointed out, there is a vast difference between the spin rate you can tolerate for minutes, versus the spin rate you can tolerate for months-to-years. You can get 100's of rpm on carnival rides. So what? That's only a couple minutes of exposure, not enough time to have any really bad effects (which is EXACTLY why those rides are short !). As far as I know, there is no formal research for the long-term. The long-term limit is anecdotally said to be in the 3-5 rpm range, sort of a consensus of those who thought about this before.
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GW,
As I have repeatedly pointed out, we don't have that data, and the 3-5RPM limit is entirely vibes based, typically from people who don't know what they're talking about. But we *know* people can tolerate 10RPM for at least half an hour. And getting longer term data is well within our means.
Incidentally, the existence of playground roundabouts does tell us one important thing, which is that children at least aren't badly affected by spending half an hour to an hour each day rotating at 20RPM.
2m radius, 6RPM, force of 0.08g on the outside. Need to angle the floor a bit. But it should be enough space for someone to spend a few days inside. A larger one for weeks to months would be maybe 10m radius with signficantly more angled flooring. But again, it's not exactly a pricey experiment to run.
EDIT: just turned slowly in a circle whilst timing myself. 7RPM. It's tolerable enough.
Also, transient high rotation is enough for excercise. We can use a lower gravity for day to day activities, only the gym needs to be spun up to full g. And we actually do have data that says high rotation is not a problem for such stretches of time.
Last edited by Terraformer (2025-01-17 11:17:30)
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For Terraformer re #14
Please show your cards;
And we actually do have data that says high rotation is not a problem for such stretches of time.
I hope you can back up your claim.
It would be solid addition to this topic if you can.
However, in case you cannot find the material you are remembering, no problem.
Let's create it fresh.
The challenge is simple enough. Find evidence to assure the well being of humans who subject themselves to rotation living for months or years at a time.
The means to deliver that confidence appear to me to be of modest expense. Examples of equipment needed are on display in amusement parks all over the world, but equipment to provide living and working space for months or years would be a bit more expensive.
An ordinary railroad train could be pressed into service if the size of the ring is great enough. An example of that is the Stanford Torus, which was created to the mantra of 1 RPM, strenuously advocated by one persuasive and persistent individual. (I am recalling notes from a biography of the event).
However, for smaller circles, such as those advocated by RobertDyck (3 RPM) GW Johnson (4 RPM) and Arthur C Clarke (5 RPM), another approach is needed.
That said, the physical equipment is a small part of the scientific undertaking. The entire enterprise needs to be set up and supervised by an individual trained in the scientific process. Data must be collected in ways that guarantee it can be evaluated later, so that meaningful results can be published.
Most importantly, all that data needs to be presented in a paper that can pass peer review and become part of the repertoire of system planners.
For individual subjects, the first "data point" is whether they can stay with the rotation for some period of time, or if they have to bail out.
For the purposes of the study, since everything measured in human terms is a distribution over a bell shaped curve, it would be helpful to know the bounds of that curve.
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I already linked the study in the original thread. They had people use them for 25 minutes at a time, each day for 50 days. I'm going off data here, not vibes.
https://pmc.ncbi.nlm.nih.gov/articles/PMC7450067/
The reason fairground rides don't last longer than a couple of minutes is that they need a high throughput of people to make money, not because they're hitting some fundamental limit of biology.
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For Terraformer! Thanks for the link in post #16
I've added Post #16 to the index so future NewMars readers can find the post quickly (from the index) (search would work as well)
The research reported in this paper looks like what I was hoping might be done. The work is dated 2020.
NPJ Microgravity
. 2020 Aug 26;6:22. doi: 10.1038/s41526-020-00112-w
Improved feasibility of astronaut short-radius artificial gravity through a 50-day incremental, personalized, vestibular acclimation protocol
Kathrine N Bretl 1,✉, Torin K Clark 1PMCID: PMC7450067 PMID: 32885040
AbstractThe “Coriolis” cross-coupled (CC) illusion has historically limited the tolerability of utilizing fast-spin rate, short-radius centrifugation for in-flight artificial gravity. Previous research confirms that humans acclimate to the CC illusion over 10 daily sessions, though the efficacy of additional training is unknown. We investigated human acclimation to the CC illusion over up to 50 daily sessions of personalized, incremental training. During each 25-min session, subjects spun in yaw and performed roll head tilts approximately every 30 s, reporting the presence or absence of the illusion while rating motion sickness every 5 min. Illusion intensity was modulated by altering spin rate based upon subject response, such that the administered stimulus remained near each individual’s instantaneous illusion threshold. Every subject (n = 11) continued to acclimate linearly to the CC illusion during the investigation. Subjects acclimated at an average rate of 1.17 RPM per session (95% CI: 0.63–1.71 RPM per session), with the average tolerable spin rate increasing from 1.4 to 26.2 RPM, corresponding to a reduction in required centrifuge radius from 456.6 to 1.3 m (to produce loading of 1 g at the feet). Subjects reported no more than slight motion sickness throughout their training (mean: 0.92/20, 95% CI: 0.35–1.49/20). We applied survival analysis to determine the probability of individuals reaching various spin rates over a number of training days, providing a tolerability trade parameter for centrifuge design. Results indicate that acclimation to a given, operationally relevant spin rate may be feasible for all subjects if given a sufficient training duration.
Subject terms: Aerospace engineering, Biological sciences
That conclusion is most encouraging!
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For Terraformer after the first read of the report.... Details about accounting for human reporting fallibility are included in the main body of the document...
Here is the conclusion.... I was happy to see that NASA was a funder of this work...
One surprising result (from my perspective) is that the training provided appears to persist from one session to the next, with ordinary 1 G between.
Another (less surprising but still interesting) conclusion was that 1 G centrifuges could be provided on low-G bodies for occasional tuning.
In fact, it appears to me that this system could be installed on the next space station generation. I hope it will be. The centrifuge needs to be mechanically isolated from the rest of the station but that should be possible using physical separation with springs as dampeners.
Acknowledgements
This work was supported by a NASA Space Technology Research Fellowship, grant number 80NSSC17K0085. We thank all of the subjects who participated in the investigation, as well as Carson Brumley, Sebastian Metcalf, Varun Seth, and Marcos Mejia for helping operate test sessions. Preliminary results were presented at the following conferences and scientific meetings: Aerospace Medical Association Scientific Meeting, Dallas, TX, 2018; Human Research Program Investigators’ Workshop, Galveston, TX, 2019.
Author contributionsExperiments were designed and executed by K.N.B. and T.K.C., data analysis was conducted by K.N.B., and data interpretation and manuscript preparation were completed by K.N.B. and T.K.C. Both authors edited and approved the final manuscript.
Data availabilityThe raw minimal datasets for this study have been made publicly available (https://osf.io/zw6xe/). We request citing this paper when using these datasets for further analysis.
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as a follow up to the study found and reported by Terraformer ... See Post #16 for link...
A spreadsheet was provided by GW Johnson to help NewMars members to perform the calculations needed to evaluate various rotation rates and swing arm radii.
Spreadsheet:
http://newmars.com/forums/viewtopic.php … 89#p229289
This post is about design of facilities for rotation acclimatization on Earth.
A flight to Mars in a rotating ship (or in a ship that has a rotating habitat) would involve living in a cabin some of the time, if not most of the time (depending on the vessel). Such a cabin could be emulated on Earth.
The MDRS (Mars Desert Research Station) is an example of an emulation facility designed to reproduce part of the experience of living on Mars and working from a fixed location.
A flight simulator for a rotating vessel might consist of cabins designed to reproduce as closely as possible the life that a passenger or crew member might experience on a rotating vessel. The facility would essentially be a very large merry-go-round, able to spin up slowly so that passengers can acclimate to the target RPM of 5 within a few days. After everyone in a "flight" is ready for continuous operation at 5 RPM, the facility would turn at that rate for as many days as funds are available to support the operation.
Since flight in space would have nothing except sliding stars to see, there would be little need for windows. Their place would be taken by LED panels. Participants would engage in studies and housekeeping and exercise, just as they would do in flight.
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