Artificial gravity questions and a link?

[hansolo0]

I have q's on artificial gravity in space ...<br /><br />Why isn't more effort being done into some kind of rotating module for the ISS? I would think that would solve a lot of the gravity and reduced muscles mass problems, etc calcium loss. How hard would it be to do this? Wasn't there going to be a centrifuge add on to ISS and isn't it cancelled, what happened, etc?<br /><br />Let's say you had a spinning cylinder of some kind in space, and it was rotating fast enough for you to feel one G while standing inside it. The inside diameter is 20 feet, lets say . If you bounce a ball or jump straight up, would you /it appear to move backward in the air on the way 'down' to an observer a few feet behind you or stay the same distance in front of them since you are all moving 'forward' relative to each other? If you jumped or bounced the ball hard enough would you stick to the 'ceiling'? What about if you were in a rotating donut shape if you were standing on the inside of the outer edge? <br /><br /><br />Interesting link to nuclear space travel article related to gravity problem solution + faster travel:<br />http://www.spacedaily.com/reports/Could_NASA_Get_To_Pluto_Faster_Space_Expert_Says_Yes_By_Thinking_Nuclear.html<br /><br /><br /><br />

 

[spacester]

Please see the links and discussion here:<br /><br />http://uplink.space.com/showthreaded.php?Cat=&Board=sciastro&Number=365123&page=&view=&sb=&o=&vc=1<br /><br />http://uplink.space.com/showthreaded.php?Cat=&Board=sciastro&Number=365640&page=&view=&sb=&o=&vc=1 <br /><br />There is more, but the first 3 links in the first one will answer a LOT of questions.<br /><br />Oh, and I would re-iterate to all that the term 'spin-gravity' seems to me much more appropriate than 'artificial gravity.' <div class="Discussion_UserSignature"> </div>

 

[hansolo0]

I skimmed through the articles and posts , and maybe missed it but I didn't see any answers. I'm just looking for some simple answers to these questions without having to search through a lot of posts and/or reading. Thanks for the links though.

 

[spacester]

Um, well it would appear that you need to acquire a better grasp of Physics before you will find the answers you seek, and I 'm not prepared to take on that task.<br /><br />Perhaps if you narrowed the questions down a bit?<br /><br />Although if you are looking for answers without expending any effort yourself, I don't feel like playing that game either. <div class="Discussion_UserSignature"> </div>

 

[search]

I hope this will help answer your question.<br /><br />From:<br />http://www.ksc.nasa.gov/nasadirect/archives/KSCDirect/archives/launch/sts110/iss-qa.htm<br /><br />David from Boca Raton, FL<br />Why hasn't there been any tests for artificial gravity on the ISS or the shuttle? why can't you spin the space crafts even a little, similar to the Moon's rotation and gravity?<br />I think it's a good question and that David has been watching James Bond movies. That can happen. Well, we are going to have a thing on the Space Station called the CAM, or Centrifuge Module. And the CAM is going to be a circular disk about four feet in diameter and maybe about three feet in height. The purpose of the CAM is to artificially produce gravity. This will be rotated and I think it will be positioned on top of the Japanese module. And the CAM will be rotating because the main purpose of the Space Station is to perform all sorts of research experiments. There are things that we can do in space better than we can do on Earth, and there are things we can do on the Space Station that we just can't do on Earth. And medical, life science, computer, the list is really endless of the different types of research we can do in space. But there are certain experiments that we want to do in space in a microgravity environment, or what people call zero-G, but at the same time we want to perform these experiments in a gravity environment to compare the results. And this CAM, or the Centrifuge Module, that will be rotating on the Space Station, will allow us to do that. And that's going to go up on the UF-7 flight in the year 2006.<br /><br />Bryant from Avon, Indiana<br />Why not rotate the space station while in orbit if it would make artificial gravity? After all, isn't bone and muscle loss due to zero-g one of the biggest problems for people in space?<br />Good question, it is a problem in spa

 

[spacester]

The CAM has been cancelled, right?<br /><br />The first actual new work on this subject that I have seen in the last 5 (25?) years is from Sorensen at Marshall (1.02 MB pdf) , with the notable exception of Ted Hall of course. <div class="Discussion_UserSignature"> </div>

 

[search]

Yes you are absolutely right<br />http://en.wikipedia.org/wiki/Centrifuge_Accommodations_Module<br /><br />http://www.astronautix.com/flights/sts138.htm

 

[hansolo0]

Really all I wanted was some simple answers to " What happens when you bounce a ball?" and so forth in the examples I mention above. Does anyone on these boards know? <br /><br /> I think at least one good reason why they haven't done more on the ISS is because they don't have the time/money. Those links did say the centrifuge was cancelled because of cost overruns and shuttle problems. So was the CRV. I kow the ISS is for research in microgravity, but it is also how to overcome it. Not only muscle and bone loss, but being able to do everyday things like sleeping , eating , showering, etc, like we do now (and take for granted).

 

[rfoshaug]

Thanks for those links to previous threads, spacester!<br /><br />And thanks for the formulae:<br /><blockquote><font class="small">In reply to:</font><hr /><p><br />Here's the formula:<br />G = [R * [(pi*rpm) / 30]^2] / 9.81<br />OR<br />R = (9.81 * G) / [(pi*rpm) / 30]^2<br />Where:<br />G = Decimal fraction of Earth gravity<br />R = Radius from center of rotation in meters<br />pi = 3.14159<br />rpm = revolutions per minute<br /><p><hr /></p></p></blockquote><br /><br />With this, it's quite easy to calculate how big a wheel you need for a certain G-force and rotational speed.<br /><br />However, calculating just how sick the astronauts would be due to the rotation, is a totally different matter.<br /><br /><img src="/images/icons/wink.gif" /> <div class="Discussion_UserSignature"> <p><font color="#ff9900">----------------------------------</font></p><p><font color="#ff9900">My minds have many opinions</font></p> </div>

 

[spacester]

You're welcome and thanks for the acknowledgment.<br /><br />Yes, it is easy to calculate. That's why I get so frustrated that seemingly I'm the only one here to actually do so.<br /><br />It actually gets easier if you assume 3 rpm: <br /><br />R=100 m gives you 1 gee<br />R=38 m gives you 0.38 gee<br />R=16 m gives you 0.16 gee. <br />So those are the radii which would simulate, respectively, Earth, Mars, and Moon. <br /> <div class="Discussion_UserSignature"> </div>

 

[elguapoguano]

I read a study somewhere (sorry I can provide a link). That said the most a person could tolerate without having nausiating effects is 2.5 RPM with 2 RPM being the desired figure to shoot for. I'm quoting from memory so bare with me. You could get to 80% earth gravity with a 60 meter diameter structure at 2 RPM's <div class="Discussion_UserSignature"> <font color="#ff0000"><u><em>Don't let your sig line incite a gay thread ;>)</em></u></font> </div>

 

[spacester]

Hey! You did a calc! One less thing for me to beeatch about, oh happy day! <img src="/images/icons/laugh.gif" /> <img src="/images/icons/wink.gif" /><br /><br /><font color="yellow">. . . with 2 RPM being the desired figure to shoot for . . ..</font><br /><br />Yes, that is the Big Question, the question that simply cannot be answered without conducting on-orbit experiments. When I poured over the available literature 4-5 years ago, I found one summarizing paragraph, which was derived from all extant studies. I've been quoting it ever since:<br /><br />"In brief, at 1.0 RPM even highly susceptible subjects were symptom-free, or nearly so. At 3.0 RPM subjects experienced symptoms but were not significantly handicapped. At 5.4 RPM, only subjects with low susceptibility performed well and by the second day were almost free from symptoms. At 10 RPM, however, adaptation presented a challenging but interesting problem. Even pilots without a history of air sickness did not fully adapt in a period of twelve days." <br /><br />Now, that's just a paragraph written by some guy, so who knows? But it's the best thing I could fine. From that, I personally have chosen 3.0 rpm as a design basis, but it could turn out to be way off one way or the other.<br /><br />That's what makes the work by Sorensen so exciting to me. Not only is it the first new thing I've seen in years, but that hardware scheme seems to be ideal for testing at various radii and rpms. Previously I had assumed that we would be more or less stuck with a constant radius.<br /><br />I'm really looking forward to talking about Bigelow at the same time as Spin Gravity. I figure it's just a matter of time. (Perhaps as soon as January 2007, but that's prolly over-optimistic even for me). <br /><br />edit: darn it! I just checked your calc and found an error . . . <div class="Discussion_UserSignature"> </div>

 

[oscar1]

>And yes, if you jumped high enough in a rotating habitat, you would pass through, or near, the axis of rotation and 'fall' to the other side. In truth, you would be following a straight line path and the habitat would be rotating around you.<<br /><br />Does that also happen when there is no real gravitational pull from any direction?<br />

 

[spacester]

FWIW, I concur with all of that. There are a LOT of unknowns, testing done in the past is of limited usefulness esp. the short-arm experiments, and we can expect a wide degree of variation between individuals. <br /><br />In can be said that the inner ear is what this is all about.<br /><br />I only post this to point out that what we are talking about here is of course Coriolis forces, or perhaps more precisely 'The Coriolis Effect' <div class="Discussion_UserSignature"> </div>

 

[spacester]

Thank you, eburacum45! I was looking for that and came up empty.<br /> <div class="Discussion_UserSignature"> </div>

 

[shadu]

I'm new here and i don't know if i answered at the right location so if i did not, sorry .<br /><br />The question i have is why they are still not trying to find out what gravity is. They know what gravity results in but not what it is. if gravity was rotation we'd all be in space because earth's rotation would have thrown us away already.<br /><br />I know rotation can create an artificial gravity but i still think if we found out how the 9.8N force resulted we would be able to recreate it without the need for big and sometimes complicated rotation devices.<br /><br />True the new device might start as a complicated thing but eventualy i think it could be reduced to such a inefectual thing that ships the likes of Star Treck would be possible.

 

[shadu]

Then i'm happy i was mistaken. <br /><br />I don´t hear much about it where i live and you sometimes develop false notions that way. <br /><br />For me i guess after looking at all the options i go for the complicated answer, I mix all of the current theories together because they all fit and help each other. i can´t put words to it yet but i just see them as a related somehow.

 

[kyle_baron]

<font color="yellow"><br />The short answer is: no one knows what gravity is, exactly.....only how it behaves. It is a mystery of the physical world at it's very deepest level. Some scientists think it's caused by a hitherto undetected particle called a graviton</font><br /><br />Why does gravity have to be a something (particle, force, etc.)? Gravity acts as a force between masses, but is it really? It simply could be NOTHING. As stated in the Bible, "The Earth is hung upon nothing". This nothingness (gravity) could simply be the geometry of space, in the presence of matter. Until someone comes up with a better answer, this simple hypothesis IS THE ANSWER. <div class="Discussion_UserSignature"> <p><font size="4"><strong></strong></font></p> </div>

 

[brigandier]

>>"Why does gravity have to be a something (particle, force, etc.)? Gravity acts as a force between masses, but is it really? It simply could be NOTHING. As stated in the Bible, "The Earth is hung upon nothing". This nothingness (gravity) could simply be the geometry of space, in the presence of matter. Until someone comes up with a better answer, this simple hypothesis IS THE ANSWER."<<<br /><br />How can gravity be "nothing"? It's a quantifiable force that affects all matter. When you place a significant mass is placed near another, they attract. It's been observed. So how can that be "nothing"? It's got to be SOMETHING