# 2001 artificial gravity - how realistic? **URL:** \ **Category:** Factual Questions\ **Created:** [July 2, 2012, 3:42am UTC](https://boards.straightdope.com/t/2001-artificial-gravity-how-realistic/626966 "2012-07-02T03:42:49Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![randomplanck](https://avatars.discourse-cdn.com/v4/letter/r/2acd7d/32.png) [@randomplanck](https://boards.straightdope.com/u/randomplanck)\ **Post date:** [July 2, 2012, 3:42am UTC](https://boards.straightdope.com/t/2001-artificial-gravity-how-realistic/626966/1 "2012-07-02T03:42:49Z")
The artifical gravity created in 2001 by the rotating spaceship - is that accurate? Bogus? ---
**Author:** ![astro](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@astro](https://boards.straightdope.com/u/astro)\ **Post date:** [July 2, 2012, 3:54am UTC](https://boards.straightdope.com/t/2001-artificial-gravity-how-realistic/626966/2 "2012-07-02T03:54:14Z")
Here > **[Science Fiction Archives](https://www.popsci.com/category/science-fiction/)** > > See the latest Science Fiction stories from Popular Science. See news, trends, tips, reviews and more at Popular Science. > [@](#): > > The first thing we notice is that the space station is really big, and in the artificial gravity business, size does matter. The radius of the rotating station is large enough that any difference in rotation rate between the feet and head of an inhabitant will be negligible, and thus they will experience the sensation of gravity evenly throughout their bodies. It’s no accident that the living areas (where we see all the windows) are on the outside rim. If you were to move along one of the spokes towards the center of the station (to make repairs, for example) then your centripetal acceleration would gradually decrease, along with your experience of artificial gravity. When you arrived at the center you would feel weightless. > > We can see this expressed mathematically in the equation for centripetal acceleration: > > ac = v2/r = ω2r > > where v is the tangential speed, and ω is the angular speed of the rotating station. Because angular speed is the same everywhere along the radius, we can see from the right-hand term that as r approaches zero so does the centripetal acceleration ---
**Author:** ![Trinopus](https://avatars.discourse-cdn.com/v4/letter/t/2bfe46/32.png) [@Trinopus](https://boards.straightdope.com/u/Trinopus)\ **Post date:** [July 2, 2012, 5:06am UTC](https://boards.straightdope.com/t/2001-artificial-gravity-how-realistic/626966/3 "2012-07-02T05:06:53Z")
Ever been inside one of those big rotating drums they have at county fairs and other amusement parks? Rotation _definitely_ imitates gravity! ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [July 2, 2012, 5:51am UTC](https://boards.straightdope.com/t/2001-artificial-gravity-how-realistic/626966/4 "2012-07-02T05:51:40Z")
The large rotating space station in _2001_ would provide perfectly respectable gravity for its inhabitants. However the artificial gravity inside the spaceship _Discovery_ is a little more problematic. The carousel on that ship spins once every ten seconds, apparently, giving artificial gravity equal to that of the Moon; the low gravity itself is not really a problem, but the 6RPM rotation rate might be. At that speed the astronauts might feel dizzy and suffer some strange effects from Coriolis force. But as dedicated astronauts they might be expected to accept this sort of discomfort. ---
**Author:** ![coremelt](https://avatars.discourse-cdn.com/v4/letter/c/4491bb/32.png) [@coremelt](https://boards.straightdope.com/u/coremelt)\ **Post date:** [July 2, 2012, 6:05am UTC](https://boards.straightdope.com/t/2001-artificial-gravity-how-realistic/626966/5 "2012-07-02T06:05:27Z")
so whats the smallest diameter space station you would need to spin to avoid unpleasant Coriolis effects? The pop sci article calculates that the 2001 space station is huge, 980 meters across. More realistically could a 30 meter diameter station achieve a realistic 1 g gravity? That would make a 1.6 meter height person approx 10 percent of the height of the rotation radius. Would you feel the difference in gravity between your feet and head with a 30 meter diameter station? ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [July 2, 2012, 9:22am UTC](https://boards.straightdope.com/t/2001-artificial-gravity-how-realistic/626966/6 "2012-07-02T09:22:36Z")
A comfortable rotation of 3 RPM would require a space station about 100 in radius, or 656 feet in diameter, assuming 1 gee of artificial gravity. But a space station rotating to give lunar gravity would be much smaller - about 112 feet in diameter. Still large, but maybe a bit easier to build. ---
**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\ **Post date:** [July 2, 2012, 10:54am UTC](https://boards.straightdope.com/t/2001-artificial-gravity-how-realistic/626966/7 "2012-07-02T10:54:45Z")
A more practically realized system would be two modules at either end of a tether. It could be two modules that are essentially equal in nature, or one inhabited module and one more massive but uninhibited one that traveled in a smaller circle and experienced less gravity. ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [July 2, 2012, 11:41am UTC](https://boards.straightdope.com/t/2001-artificial-gravity-how-realistic/626966/8 "2012-07-02T11:41:42Z")
I was a bit surprised to learn that the space stations of the 1950s were not intended to have even close to 1 g gravity – the idea was to have _some_ artificial gravity, but not to duplicate Earth’s pull. To do that would require a much large drum,with larger strains. The film _2001_ did, in fact, show a much larger wheel than previous films did (such as George Pal’s _Conquest of Space_). But I haven’t crunched the numbers or seen them crunched to calculate the actual gravity. I think in Clarke’s _Rendezvous with Rama_ the rotation of the enormous alien ship did provide about a _g_. As for the _Discovery_, the space ship, that almost certainly didn’t have a full gravity and wasn’y made for it. I think the idea was, as with vo n Braun’s 1950s space station, to give some gravity to make life easier and to give some relief from the zero-g condition, to minimize adverse health effects. An aside – Kubrick showed the Space Wheel partially finished, which is a cute aesthetic touch, like Lucas showing an unfinished Death Star in _Return of the Jedi_. I note that he was careful to show the unfinished segments “in balance” – empty sections on one side corresponded with ones diametrically across the wheel. But NASA engineers were reportedly aghast at the thought of putting an incomplete wheel into rotation. ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [July 2, 2012, 3:11pm UTC](https://boards.straightdope.com/t/2001-artificial-gravity-how-realistic/626966/9 "2012-07-02T15:11:50Z")
The first complete discussion of a space wheel to give artificial gravity is in the 1929 German book [The Problem of Space Travel: The Rocket Motor By Hermann Noordung](http://books.google.com/books?id=te15mpHmmTwC&pg=PR19&dq=rockets,+missiles+and+space+travel+ley&hl=en&sa=X&ei=wLTxT-qpL-fp6wG-vYCvBg&ved=0CD4Q6AEwAg#v=onepage&q=habitat%20wheel&f=false), a pseudonym for Hermann Petočnick . The details, with many illustrations, start on p. 102. He calls it a “habitat wheel.” He assumes a minimum of 30 meters, at which size the gravitation difference between the head and feet would be 1/9, a ratio he thought would be tolerable. larger wheels would make that even less a factor. It’s next to impossible today to figure out how much influence he had. The forward and preface to that edition chew the problem over. There wasn’t an English edition and the book seemed to have limited distribution in Germany. The one place that featured it was the August 1929 issue of Hugo Gernsback’s [Science Wonder Stories](http://cache.gawkerassets.com/assets/images/8/2011/08/medium_1929_-_science_wonder_-_hermann_noordung_space_station_-_frank_r_paul.jpg) with a Frank R. Paul illustration of the space station on the cover. It doesn’t look like 2001. Arthur C. Clarke cited Noordung in his geosyncrynous satellite paper of 1945, but later admitted that he had never seen the original, just the magazine article. Willy Ley discusses him in later editions of _Rockets, Missiles, and Space Travel_ (mine is from 1958), but mostly to point out mistakes. That meant that before we put a man into space many scientists had looked at the problem and did the math and realized the necessary conditions and problems. The important point is that the concept was fully known decades before \*2001 \*appeared. Only the exact details of construction were at issue. ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [July 3, 2012, 3:51am UTC](https://boards.straightdope.com/t/2001-artificial-gravity-how-realistic/626966/10 "2012-07-03T03:51:05Z")
Iirc an interview with Kubrick or Bradbury, he did admit they fudged the Discovery carousel, because they would need a wheel of 300 feet diameter to avoid coriolis induced dizziness of the inner ear. The diameter and math was never stated, although obviously it was nowhere near 300 feet. ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [July 3, 2012, 5:51am UTC](https://boards.straightdope.com/t/2001-artificial-gravity-how-realistic/626966/11 "2012-07-03T05:51:26Z")
One full gravity of artificial acceleration is not really necessary or desirable. Outside the Earth all planets, moons and asteroids which have a solid surface to stand on have lower gravity than found on our world. If we are seriously considering maintaining a human presence in space we are going to have to get used to low gravity environments; it seems likely to me that in general a lower gravity would be more comfortable than that found on our world. ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [July 3, 2012, 5:53am UTC](https://boards.straightdope.com/t/2001-artificial-gravity-how-realistic/626966/12 "2012-07-03T05:53:50Z")
> [@md2000](#): > > Iirc an interview with Kubrick or Bradbury, he did admit they fudged the Discovery carousel, because they would need a wheel of 300 feet diameter to avoid coriolis induced dizziness of the inner ear. The diameter and math was never stated, although obviously it was nowhere near 300 feet. Rather than Bradbury I expect you mean Arthur Clarke. A collaboration between Ray Bradbury and Stan Kubrick would probably have been entertaining, but unfortunately didn’t happen.