Pendulum Gravity

originally posted by: D8Tee
a reply to: graysquirrel

I've wondered why this approach hasn't been taken.
Not sure why it hasn't been done, rotate the spacecraft to get some simulated gravity.

I don't know all the scientific explanations behind it, but basically humans can only handle rotation to a certain degree without getting sick. The smaller the craft, the faster you need to rotate. You'll never generate a meaningful amount of gravity using this system, the best you can get is about 30% of earths gravity with a giant space station. Beyond that, people get motion sick, dizzy, etc...

my two cents..


in my opinion
Atrificial gravity aboard space ship like in Space Odyssey is totally not going to work. Imagine yourself inside donut shaped tube in zero g. Tube all over sudden begins to rotate under your feet and all around you. You will continue to hang in zero g no matter how fast the tube rotates. And if you accidentally run into tube's wall while it's spinning, you might seriously hurt yourself.
))))

I can see space ship where two habitats rotate around common center. Will work but rotation rate has to be ever increasing to maintain constant 'g'. Or increasing rotation and then slow down phase to maintain constant 'g'. This set up should include allowing each 'habitat' cabin to flip around in opposite direction giving additional supplemental momentum to the whole structure. It would also be beneficial for the sake of the crew who won't have to walk on the 'ceiling' during slowing down phase))

Curious if the following artificial gravity concept would work..

What If from my space ship I drop a weight on tether toward Earth? These two would balance two new orbits for each where net orbit for each is a third orbit, common for two orbits. As a result my ship can remain in original orbit while having much higher speed. This should create some 'g'. Retracting or releasing the tether with weight can regulate balance between velocity and number for g.

Abstract

Previous papers have examined the physical differences between natural and artificial gravity, through mathematical derivation and computer simulation. Taking those differences as given, this paper examines: the role of gravity in architectural design; the extensions of architectural theory necessary to accommodate the peculiarities of artificial gravity; and the appropriateness of space colony architecture as illustrated in the “Stanford Torus”, “Bernal Sphere”, and similar proposals. In terrestrial gravity, there are three principal directions – up, down, and horizontal – and three basic architectural elements – ceiling, floor, and wall. In artificial gravity, due to inertial effects of relative motion in a rotating environment, east and west (prograde and retrograde) emerge as gravitationally distinct. Thus, there are not only three, but at least five principal directions: up, down, east, west, and axial. The grammar of architecture for artificial gravity should accommodate this fact. To be meaningful, architecture should have formal properties that are similar to other aspects of the environment. The goal is not to fool people into thinking they’re still on Earth, but rather, to help them orient themselves to the realities of their rotating environment.

Copyright © 1995 by Theodore W. Hall. Published by the American Institute of Aeronautics and Astronautics, Inc., and the Space Studies Institute, with permission.

* Postdoctoral research fellow, Department of Architecture, Chinese University of Hong Kong. Research completed while doctoral candidate in architecture, College of Architecture and Urban Planning, University of Michigan.

www.artificial-gravity.com...


Further reading....

history.nasa.gov...

originally posted by: Kashai

Hi Kashai

in that video he says 'gravity' for an astronaut would feel like nausia..Yes, but it is an ill side effect. Astronaut first of all would feel like 'falling' in free fall. That sensation would definitely freak me out.

I use my imagination to 'test' some ideas. I picture myself inside a donut shaped space vessel. At this moment nothing is rotating and I am in a mid air in zero g inside that structure. Now the donut begins to rotate. Slowly. I can see the wall I am facing started to move. I am still in mid air in zero g. Rotation speeds up and the wall in front of me is moving really fast now. Question, in this scenario, when I supposed to feel any g?



cheers)

a reply to: greenreflections

Question, in this scenario, when I supposed to feel any g? At what donut's rotation speed?

No particular speed. But unless you grab something on the hull you won't feel anything. You'll just hang there as the hull rotates around you.

I suppose that, after a long while, the air within the hull might start moving (through friction with the rotating hull) and you'd start being moved by the air and, after a long while you would end up against the hull. But that would take a long time and maybe wouldn't happen at all.

a reply to: Phage

No particular speed. But unless you grab something on the hull you won't feel anything. You'll just hang there as the hull rotates around you.

yup..grab something like a handle..ok. Once your body matches the speed of what ever you grabbed, you find yourself in zero g again.
Better solution may be is to put some sort of a shelf attached to tube's inner wall which I can jump on, a platform.
To sustain some g value, the tube has to be in a state of continues acceleration. Or acceleration and slowing down sequence. This might work. Although, there will be brief transition period in between sequences with zero g. And another problem is that In this scenario, 'g's for astronauts are not uniform and continuous. So, this might work but do we need to put space ship occupants through this?))) They would feel like inside house hold dryer machine.

Air confined to rotating tube more likely would form mini vortex-like patterns all around inside volume. I don't think this is some how a contributing factor toward artificial gravity like in Kashai's video. Space Odyssey style gravity is good example of how human senses fool logic when it comes to gravity.



cheers)

a reply to: greenreflections

Once your body matches the speed of what ever you grabbed, you find yourself in zero g again.

Nope. Unless you some how shed the velocity you acquire when you grab hull, angular momentum will keep you pressed against the hull. Inertia makes your body want to go in a straight line. Trouble is, there is a hull in the way.

To sustain some g value, the tube has to be in a state of continues acceleration.

There is acceleration. Acceleration is a change in velocity. Velocity is a vector quantity composed of direction and magnitude (speed). Because your direction is constantly changing (because there is a hull in the way), you are constantly accelerating, even if the magnitude of your velocity is not.

a reply to: Phage

You'd still get dizzy would you not?
I've been on the gravitron ride at the carnival, made me dizzy.

a reply to: Phage

Nope. Unless you some how shed the velocity you acquire when you grab hull, angular momentum will keep you pressed against the hull. Inertia makes your body want to go in a straight line. Trouble is, there is a hull in the way.

so, as long as I am attached to the wall, I will be fine? Other wise the floor would slip from under my feet coz I have inertia too, you know.
This rotating hull is a fantasy.
This sort of artificial gravity based on rotating hull will never work in reality. Even if you manage to get on your feet gs will never be uniform, you will roll and bounce off that wall and then pressed against the wall again looking for a handle to grab.

If you have a washer/dryer machine at home, stand by and imagine rotating 'hull' and picture yourself inside.



Much better solution would be to drop a weight on tether from my space ship toward Earth. It will work as an anchor allowing my ship to go faster never leaving current orbit. This will generate some g.


cheers)

originally posted by: D8Tee
a reply to: Phage

You'd still get dizzy would you not?
I've been on the gravitron ride at the carnival, made me dizzy.

I believe you.

In my opinion, centripetal force in means of artificial gravity is very undesirable for human beings. For some bio lab experiments on board ISS micro gravity is created based on rotation and that is ok, but hardly fit to accommodate occupants with gravity effect.

a reply to: greenreflections


Learning to acquire a tolerance for that is actually very possible.

One of the techniques the Air Force uses to test pilot recruits is to place them on a field 100 ft. away from a finishing line.


The applicant is supposed to spin 12 times while in place

and then try to walk a strait line to the finish point. Its a lot of fun as long as it is done safely. Like the field has to be walked prior to beginning to remove any potential hazards that a person can fall on also its better to do on a sandy beach.

Some people are naturals at this but with practice and again an emphasis upon safety (protective gear like if you were mountain biking) it is possible to get used to it.

Astronauts as well as pilots (which most if not all astronauts are) get all kinds of training in this regards...

a reply to: greenreflections

Other wise the floor would slip from under my feet coz I have inertia too, you know

Yes. I know. That inertia provides the angular momentum which keeps you pressed against the hull. You gain that momentum when you grab the hull.

Much better solution would be to drop a weight on tether from my space ship toward Earth.

Drop it, how?

It will work as an anchor allowing my ship to go faster never leaving current orbit.

How does an anchor make your ship go faster? But, since you don't understand angular momentum, I guess you can't be expected to understand orbital mechanics.

a reply to: greenreflections


To be clearer the real problem for a trip tp Mars is getting the crew their in a condition where their musculature and skeletal structure will allow them to function "normally", under Martial gravity.

That would be about 38% that of earth.

In relation to modern technology there is really no other way to do this.


Take the issue of generating a warp bubble to travel through space-time, how exactly would this help us with gravity while at warp?

One answer would be absolutely nothing.

See with such circumstances we would still have to deal with generating gravity with Centripetal force unless we otherwise discover an alternative.

Any thoughts?

a reply to: greenreflections

So you've never done centripetal force experiments as a kid?

Like rotating a bucket of water or something more involved: www.youtube.com...

a reply to: moebius


You know as an adult there are times I wished I was a kid again.

In a way but not exactly its like the feeling I had when I was a child and wished to be an adult.

a reply to: Kashai

The topic is addressed by a number of experiments on the ISS, actually. While problematic, freefall is not the greatest problem posed to humans on a 7 month interplanetary voyage.

scholar.google.com... QgQMIGDAA

A reply to Phage:

Here is one of my favorites...

Abstract:
It has always been a desire of mankind to conquest Space. A major step in realizing this dream was the completion of the International Space Station (ISS). Living there for several months confirmed early observations of short-term spaceflights that a loss of gravity affects the health of astronauts. Space medicine tries to understand the mechanism of microgravity-induced health problems and to conceive potent countermeasures. There are four different aspects which make space medicine appealing: i) finding better strategies for adapting astronauts to weightlessness; ii) identification of microgravity-induced diseases (e.g. osteoporosis, muscle atrophy, cardiac problems and others); iii) defining new therapies to conquer these diseases which will benefit astronauts as well as people on Earth in the end; and iv) on top of that, unveiling the mechanisms of weightlessness-dependent molecular and cellular changes is a requirement for improving space medicine. In mammalian cells, microgravity induces apoptosis and alters the cytoskeleton and affects signal transduction pathways, cell differentiation, growth, proliferation, migration and adhesion.

This review focused on gravi-sensitive signal transduction elements and pathways as well as molecular mechanisms in human cells, aiming to understand the cellular changes in altered gravity. Moreover, the latest information on how these changes lead to clinically relevant health problems and current strategies of countermeasures are reviewed.

www.ingentaconnect.com...

One of my favorites.

"Right after I landed, I could feel the weight of my lips and tongue and I had to change how I was talking," Hadfield said in the press conference, which was broadcast on the Canadian Space Agency's website May 16. "I hadn't realized that I learned to talk with a weightless tongue."

Speech is one issue, but other health effects are more pressing for long-term orbiting astronauts. Bone density lessens at a rate of 1 percent a month. Muscle mass shrinks. Eyeball pressure changes, with roughly one-fifth of astronauts reporting vision issues.

Until about June 3, Hadfield will do an intensive battery of testing and recovery at NASA's Johnson Space Center in Houston before pursuing an independent physical rehabilitation program for a few months.

The data gathered during this period is crucial not only to ensure his health, but to add more information ahead of the one-year International Space Station crew missions NASA plans to begin in 2015.

www.space.com...

Physiological effects

Many of the environmental conditions experienced by humans during spaceflight are very different from those in which humans evolved; however, technology is able to shield people from the harshest conditions, such as that offered by a spaceship or spacesuit. The immediate needs for breathable air and drinkable water are addressed by a life support system, a group of devices that allow human beings to survive in outer space.[7] The life support system supplies air, water and food. It must also maintain temperature and pressure within acceptable limits and deal with the body's waste products. Shielding against harmful external influences such as radiation and micro-meteorites is also necessary.
Of course, it is not possible to remove all hazards; the most important factor affecting human physical well-being in space is weightlessness, more accurately defined as Micro-g environment. Living in this type of environment impacts the body in three important ways: loss of proprioception, changes in fluid distribution, and deterioration of the musculoskeletal system.

en.wikipedia.org...