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Gravity in space

Posted by: Stefan Sigwarth - Sat Aug 21, 2004 11:30 am
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Post    Posted on: Thu Sep 02, 2004 12:47 pm
A station will not only have huge mass, the ISS grosses 200 ton or something, but with induce gravity it will also be stabilised in one dimension by significant gyroscopic forces.

Don't forget, bouncing up and down away from the centre of mass causes turning moments.

However one the ship is massive enough humans moving won't matter as long as they don't leave the ship. If they push off from one wall they must hit the other eventually.

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Post    Posted on: Thu Sep 02, 2004 1:23 pm
It looks like the arguments are following two different ways both correct and leading to identical results. So we may be sure that the results are right and good answers are given.

We should go on to discus small things and movements and compare them to their huge counterparts I think.

...



Dipl.-Volkswirt (bdvb) Augustin (Political Economist)


Last edited by Ekkehard Augustin on Tue Sep 21, 2004 7:23 am, edited 1 time in total.



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Post    Posted on: Tue Sep 21, 2004 5:45 am
I have another question about this topic. If you would have a round large space station which can generate enough 'gravity' which would give it an earth-like feel (9,81) and you would kick off in zero g and spin the station faster and faster until the space station provides enough gravity, would you feel the motion of the vehicle? Like, would you get 'seasick'?


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Post    Posted on: Wed Sep 22, 2004 10:48 am
I'm a little bit puzzled what motion you are considering - the rotation around the center or the movement along the orbit or course?

To feel the motion and to get seasick depends on the distance from the center of the rotation at a certain angular velocity - the larger this distance is the more similar the feeling will be to the feeling on the earthes surface or to the feeling of the movement of a car along a road I suppose. This is due to the circumstance that with growing distance the shape of the arc of a length of one kilometer will become more similar to a straight line.

The movement along an orbit or a course will always be felt but compared to the feeling of the rotation this feeling will increase as you approach to the center of rotation because the velocity of rotation measured by meters or km will decrease at constant angular velocity.



Dipl.-Volkswirt (bdvb) Augustin (POlitical Economist)

EDIT: Relevant aspect: By the natural rotation of earth we are being moved permanently at a velocity of 1666,666... km/h - without getting seasick. The center of rotation is 6378 km away. For artificial gravity this might be possible too if we take into account some arguments of the discussions concerning the space elevator. The angular velocity at earth's surface is 15°/h. This obviously is not appliable in LEO or HEO but it is aplliable in GEO and during interplanetary flights.


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Post    Posted on: Fri Sep 30, 2005 11:06 am
There seems to be a small project which may result in a real vehicle providing artificial gravity in orbit. The article "NASA Grant Energizes Student-Developed Mars Project" ( www.space.com/businesstechnology/techno ... iosat.html ) is reporting about it.

The project is going to be done by students - and so is an example of how students can be given the chance to develop new solutions in practice which gives them the opportunity to apply their own new ideas.

By the way - $200,000: this could have been a WTN XPRIZE also...



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Post    Posted on: Tue Oct 04, 2005 11:05 am
The article "The Space Cycle: New Way to Exercise in Orbit" ( www.space.com/scienceastronomy/051004_space_cycle.html ) is reporting another method of getting artificial gravity. But this would be insufficient if applied stand-alone I think - I have problems to imagine that space tourists will use that tool permanently and with sufficient frequency. Could the biker replaced by something different that is providing another use too? Soemthing that could oput to rotation a larger object?



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Post    Posted on: Tue Oct 04, 2005 11:40 am
Given Newton's laws of motion, wouldn't constant use of the bike generate rotation in the opposite direction? Perhaps you have to turn the bike around periodically and go in the opposite rotation to cancel its affects (might stop you getting giddy as well).

Now this might not have much effect on the ISS which weighs 180 Tons but prolonged use on a smaller ship on its way to Mars might be an issue. Of course you could treat it as an advantage and use it to intentionally spin your spacecraft to create artificial gravity, a bit like satelites which use flywheels to store energy instead of using propellant for station keeping. :)

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Post    Posted on: Tue Feb 06, 2007 12:06 pm
Under www.wissenschaft.de I read an article this morning the contents of which might have a relation to what's under discussion in this thread.

The article is reporting that reseraches want to look for strange matter on the Moon. This kind of matter could cause small quakes on the Moon.

The article mentions that a grain of strange matter only a few hundredth of a millimeter small would weigh several tons.

Talso Chui of the JPL wnats to look for lunar quakes cause by such matter while moving through the Moon.

Unfortunately I didn't recognize any link to Science, New scientist or the like and so can't provide a link.

I am not sure if the weight of strange matter could provide gravity also if there could a way be found to handle strange matter - it also would have to be found and captured somehow. In so far the thought is highly academic - but it completes the list of the theoretically at least considerable sources of "artificial" gravity.

And I seem to remember one problem with strange matter I have read somewhere - there was a source saying that strange matter turns each normal/usual matter into strange matter it gets in contact to. This would mean that it couldn't be made use of that well and it seems to NOT fit into the idea that strange matter sometmes might be moving through the Moon.

Of course I may be understanding it all quite wrong.

What about it all? What about continuing this thread and work out further the question of artificial gravity?



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Post    Posted on: Mon Feb 19, 2007 7:47 pm
In general my thoughts are turning back again and again that not only the muscles and bones simply might require resistance by ground they are pressed on but that the circulation of blood and other fluids of the body requires gravity. But it seems that no substitute for gravity can keep that circulation as it needs to be.

Will it turn out in the long run that a kind of well-adjusted pumps are required?

Regarding artificial gravity by rotation I am wondering this moment if it needs to be avoided thatthe direction the artificial gravity is the body pulling to is too far of 90°.



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Post    Posted on: Mon Feb 19, 2007 8:34 pm
Ekkehard Augustin wrote:
In general my thoughts are turning back again and again that not only the muscles and bones simply might require resistance by ground they are pressed on but that the circulation of blood and other fluids of the body requires gravity. But it seems that no substitute for gravity can keep that circulation as it needs to be.

Will it turn out in the long run that a kind of well-adjusted pumps are required?

Well, considering only artificial gravitation by rotation, you would have adverse effects if you have a 'short' radius. If you have a radius of 1 km, you could have it spinning round with less then 1 rpm. I doubt you'd even notice that the thing is round. Now, i know that with this type of artificial gravity, objects don't fall straight down because of the rotation. The floor has moved since the moment you dropped the object from 1 meter above the 'ground'. Now, off course this happens also with your blood and the drinks you will be drinking. However, our bloodvanesystem (vascular?) is constant under pressure by a pomp, our heart. So, in a sense, only the low or non-pressurized fluids in our bodies will be affected by zero or minimal gravity. I doubt the vanesystem for these non-pressurized fluids in our body could withstand the pressure of an additional (mechanical) pump, so you'd probably want to reinforce those vanes as well. And that's pretty hard i bet. But i doubt that on a rotating space station with a radius of 1 km you would have any adverse effects.

Quote:
Regarding artificial gravity by rotation I am wondering this moment if it needs to be avoided thatthe direction the artificial gravity is the body pulling to is too far of 90°.

I don't quiet understand what you mean by this. Could you elaborate this? Or make a drawing?


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Post    Posted on: Tue Feb 20, 2007 7:59 am
Hello, Stefan,

you already have understood and answered to the issue you ask an explanation for by saying
Quote:
Now, i know that with this type of artificial gravity, objects don't fall straight down because of the rotation. ...
.

Regarding the pumps I have in mind much smaller miniaturized pumps or even pumps that are enhancements of future spacesuits perhaps.

What ideas about something like that?



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