A rotating wheel or many rotating wheels should make up the space station while spinning on their axis to simulate Earths gravity at 9.807 m/s2. This way, many negative affects of space could be prevented. Keeping the citizens on board healthy and with proper bone density and connectivity, while also preventing bird leg syndrome.

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Yes, vision loss has been experienced by 20% of astronauts. This is thought to be caused by increased intracranial pressure caused by shifts in bodily fluids from the lower extremities to the upper part of the body, due to micro-gravity. The artificial gravity generated by the rotation of the wheel (where everyone would live their lives in Asgardia) would help to prevent vision loss do to micro-gravity in orbit by supplying a downward force on the body and stopping/limiting the fluid shifts.

There is not any question about people needing gravity when living in space for long periods of time, e.g., many years. There are many questions about how much is necessary. That cannot be answered on Earth, only by going to Mars or trying various g levels in orbit. There is no scientific / experimental data showing that people must have 1 g. Mars has 0.4 g and many people think that will be okay, but without firm evidence. If it were my decision, I would start a rotating station at 0.4 g to help answer the issue for Mars enthusiasts. The g level could later be increased as necessary. I think it is very important to answer the questions about 0.4 g before people are put on Mars on one-way travels.

In regards to the Mars gravity, wouldn't a 2-tiered rotating station accomplish both objectives at the same time? For example, following the single wheel station theory, a smaller ring located closer to the center of rotation would rotate at the same speed as the outer ring in regards to rpm, and not a predetermined speed, but being closer to the axis of rotation it would actually experience a smaller g-force from the centrifugal effect. Granted being closer to the axis of rotation would also mean a greater difference in force between your feet and your head, but I believe if both rings were large enough the percentage of difference would be so minimal you wouldn't be able to notice it without equipment.

The wheel idea is one of the best ideas out there about generating gravity. The situation is that the material for making those stations have an issue: The forces of being rotating constantly make the needs of stronger materials and this, al most all times, make material heavier and launching to the space those heavy materials means a lot of money. I think that the first situation for the artificial gravity is the materials for the "ship".

For a start, you don't lift the material into space, you take it from up there. Weight becomes less of an issue. Making these materials in space both simultainously avoids the need to waste energy then figthing Earth's gravity, and using the infinite resources of the solar system, there's less requirement to compromise on functionality in order to achieve an affordable solution.

Centrafugal force is the easiest way to achieve "artifical gravity" - but nothing says the entire structure must spin. It's possible to have a static toroidial structure with an internal spinning section(s), for example.

However, a giant toroid should be reasonably strong. The forces required to smash this should be much greater than required to achieve 1G centrafugely. Even if this toroid had hollow spindles that connect to a central, stationary spire, a fluid bearing system could prevent vibrations whilst reducing friction to the spinning and non-spinning parts - like a giant roller bearing, it could spread the forces over a larger surface area...

the issue with taking the materials from "up there" is that we would need a mining, refining, AND manufacturing station already in space to allow for the processing and refining of raw materials, which would actually cost the Asgardian project more money to get established then what the multiple launch costs would be to fly interlocking sections of a station up there in the first place.

And not to dismiss the toroidal structure at all, merely personal curiosity, but would it be plausible to use a fluid bearing system that is not only under pressure, but stress of expansion in a vacuum? it seems a solid and sealed system would be more practicle.

How are you going to control this wheel? People moving from one part of the wheel to another, liquids, gases and so on - mass center will change it's position constantly. As a result we'll get an object that needs tons of fuel every minute to stabilize itself. Just roughly calculations: 100 000 people x 75 kgs = 7 500 tons. Also they carry some clothes, equipment and/or gadgets - around 8 000 tons of mass that is constantly moving from one part of the wheel to another. Maximum force in this case will be 8 000 000 kg x g = 77 600 000 N. That is aproximately 77 600 kW. We need huge amount of energy to stabilize this.

Let's say we develop traditional triple axis magnit stabilizer. Our system is close to ideal, so we need to produce 80 000 kW just to stabilize the habitat. Else we need some energy for life: gas and water recycling, food production and so on. So let's say 100 mW of energy.

How are we going to get this energy? ISS is using Solar Array Wing: that gives 32,8 kW from 298 sq. meters. So we need more then 908 000 square meters of solar pannels. That is around 150 footbal fields. And we are not going just to be another ISS, we want to build a nation there: we need plants, farms? and so on. So we need several times more energy.

Probably we should first develop a huge space nuclear reactor? And perform a test launch of it?

The problem of Artificial Gravity is almost certainly one of the first things we need to solve. We know lots about living in zero g and the damage it causes, we also know a fair bit about living at 1g and the health benefits gained. Anything in between....zilch! So, we don't know what the optimum cost effective gravity for a healthy Space Colony is. I propose that Asgardians design a small scale experiment that can be launched into space containing small vertebrates (say mice?) with an appropriate life support, that can be used to analyse this problem. Each "habitat" could be located on the end of an adjustable tether and rotated to achieve the desired simulated g force. I would suggest that it should be placed close to the International Space Station for ease of monitoring and resupply.

Volia

I can agree with the nuclear reactor being a main contributor to the power grid, and have even found studies showing that the CO2 emissions from the reactor can be recycled into a fuel source as well, allowing for less wasted material. As far as the mass of people and personal effects moving around the wheel though, I would think that the distribution around the wheel, along with the mass of people/mass of station ratio would keep the center of mass fairly constant, unless there was ever cause to congregate 100,000 people in one area at one time, and short of mass evacuation, I don't see that happening. I am not trying to debunk your math at all, merely stating my view on the subject, so please correct me and explain if I am wrong.

On another note. Beyond just generating the power needed to accommodate a station this size, does anyone know how large the reserve batteries would have to be to hold the excess/reserve energy generated?

Another use for the CO2 emissions could be to provide an atmosphere for the station, I made mention to this in my post to "Asgardia: A Self sustaining Atmosphere" under the Biological Sciences Forum, as well as a link to a NASA site describing how they would do that.

pwmmal,

Does nuclear reactor produce CO2?

Volia,

http://www.world-nuclear.org/nuclear-basics/greenhouse-gas-emissions-avoided.aspx

I apologize for posting links to third party sites, but they can sum it up better than I. Even though nuclear power produces far lower amounts of CO2 than most other fuel sources, there is still enough to be considered emissions, which can then be recycled.

pwmmal,

I'm sorry, but can you share the link where is written - how does nuclear reactor produce CO2? Normally nuclear energy produce heat, that is used to warm water to steam that is used to run the electric generator.

P.S.: I'm not a nuclear engineer, just a space one.

I don't know what nuclear reactors have to do with artificial gravity. In space we will have sunlight 24/7, so I don't see why we would use nuclear reactors unless we place our habitat outside the orbit of Mars.

Artificial gravity can be induced by spinning the habitat. The inside rim of a wheel or cylinder would experience the maximum of gravity. If the habitat spins too often, residents will feel the Coriolis effect, which causes trajectories to curve in unintuitive ways. The quirks of Coriolis effects may cause longterm psychological problems, such as head aches, involuntary clumsiness, etc.

A full-sized cylinder with a diameter of six kilometers and earthlike gravity at the rim would spin about once every 32 minutes. Coriolis effects would be unnoticeable.