Artificial Gravity in Space

Kristian Dolghier, BASIS Phoenix

Mentor: Ms. Cooper, kelsey.cooper@basised.com, BASIS Phoenix

When astronauts go into space, there are many health complications that follow. The absence of gravity causes the astronauts to lose bone density, muscle mass, and eyesight. This is why astronauts must exercise for two hours every day on the international space station. If humans will want to go mars in the future, they must travel in space for seven months which will make these problems detrimental for their health. Although exercise can stave it off for a short time period, it may be different for long term travel. My goal is to build a rotating disk which will generate a force equal to gravity here on earth. This disk will have to rotated at a high speed and will be very large to remain stable. The structure will be similar to a car tire, just significantly thinner. This project will cost billions of dollars to research, construct, and transport into space. With the funding of the United states, i will be able to finance this project. This technology will be needed if we will colonize other planets in our solar system or beyond.

Idea

Ever since the first long term periods in space, astronauts have noticed that their eyesight has deteriorated. Many have complained that they cannot see close up and had trouble focusing their eyes. Scientists believe this is because in the absence of gravity the eye flattens out. The eye flattens out because the fluids in our body tend to equally disperse in the absence of gravity. As a result, there is more pressure on the optic nerve on the eye which makes the eye more flat. This flattening causes the focal length to change which makes astronauts have trouble seeing up close and far.

One of the more well known problems is the weakening of bone and muscles. The inherent reason we have muscles is to combat gravity. Simply standing, or holding your neck up strengthens your muscles against the pull of gravity. Therefore, when there is not gravity, astronauts muscles deteriorate and weaken significantly. Currently, NASA's solution to this to make the astronauts exercise for two hours every day. NASA employs a treadmill and a weight machine. This is efficient in strengthening back, arm and leg muscles, but will not exercise every muscle causing some muscle atrophy. The weakening of bone has very significant consequences. As our bones weaken, they can be more easily broken and will cause troubles for astronauts in the short run. All of these problems can be alleviated by making artificial gravity in space. While exercise machines mitigate the damage, artificial gravity prevents them. With artificial gravity in use, there will be no bone loss, no muscle loss, and no deteriorated eyesight. Stone, M. (2015)

There is only one feasible way to construct artificial gravity in space: using centripetal force. In order to make a uniform force, there must be a large circular shape which is made to rotate around a certain point. After it is accelerates to a certain speed, the force on the inside will be equal to the force of gravity. This force is due to Newton's first law of motion which states that objects in motion will have the same speed and same direction unless another force interferes. This is why when a car stops you are pushed forward; your body wants to keep on going but is stopped by the seat belt. This same concept can be applied to the circle, as your body keeps on wanting to go in one direction. This force is called centripetal acceleration. See diagram 1

The rotating circle would be enclosed with a barrier to absorb and deflect space rocks from hitting it. This barrier may also be used as a solar panel as it is stationary. On the inside there would be a rotating circle which is attached to the main bearing by five carbon fiber trellis. I believe that carbon fiber is the best material to use as it is very strong, and very light which will make it cheaper to transport. The inner circle and the trellis will be made up of carbon fiber. The outside will be made of a metal alloy to absorb the space debris. An optional addition is to cover the outside with solar panels in order to get electricity. The inner circle would be sped up using gaseous oxygen. I believe gaseous oxygen is a good alternative as it is less volatile than conventional propellants. After the circle has been accelerated to its prime velocity, the astronauts will be able to get in. There will be an arm on the outside which is non moving, but can be accelerated. After the astronauts get in, it can be accelerated to the speed of the circle, and be locked into a doorway on the inner circle.. On the inside of the inner circle there would be no windows as it would be very disorienting and a structural weakness. Instead, there will be screens which can show the outside view or data. The one problem that remains is that the force applied to the head and to the feet is different which will result in less blood flowing to the brain. There are two possible solutions to this problem. The more expensive, but practical solution to this is to make the structure very large. This will result in a small difference between the force acting on the head and on the feet. The main problem with this solution is that the entire project will be significantly more expensive. In the long run, this will be a better solution as this can act as a habitat for people without the people needing to take extra equipment to not pass out. Also, the entire circle will be able to travel at a significantly smaller speed which would make it more stable and less prone to damage. The second solution is less expensive to implement, but will have more problems. The second option is to have a smaller circle which is rotating at a higher speed. However, having a smaller circle will create a greater difference in the force applied from the feet to the head. This will result in people fainting from the loss of blood to the head. A remedy for this is for everyone to have suits on which constricts the lower body allowing more blood to go to the head. This concept is similar to the suits that fighter pilots must have to stay conscious when they are experiencing several g forces . The second problem with the smaller circle is that it must rotate at a much higher speed than the bigger one. This can make it more unstable and wear down the bearing it is attached to. The smaller circle is more economical, and is a good first step when it comes to artificial gravity. Eventually humanity will progress to a point where this standard on every ship, but at this point a smaller artificial gravity ring will be better.

Plan

The first part in building the artificial gravity machine is to calculate what size everything will be. For the bigger version, the diameter will be a football length (109.5meters). Under that diameter, the circle must spin at 23.2 meters per second. This is relatively slow compared to the size of it. The average height for people in north america is 1.755 meters. Therefore the force they would feel at their head is 9.53 meters per second squared. This is very similar to the force at their feet which allows them to stand up and live in the habitat without problems.

The smaller version the radius will be 40 meters which is a less than half the bigger one. As a result, the machine must spin at 14 meters per second to achieve an acceleration of 9.8 meter per second squared. Although This is a smaller speed, relative to the size of the machine this will seem to be going significantly faster and become possibly unstable. The acceleration at their head will be 9.01 meters per second squared. This may seem small, but that difference is 8.03 percent which is significant and might have consequences. Ideally, the machine will be big enough that the force is almost the same, but we do not currently have the technology.

Transportation will involve many trips to space using non reusable rockets. The carbon fiber will be made in factories on earth and will be formed into small pieces. Carbon fiber is very resistant to difference in temperatures so it will be a good insulating material for the astronauts. Carbon fiber is also very light so it will be cheaper to send it into space. In space each part will be combined like a giant puzzle. The arm, and the outer covering will be made up of steel. Each piece of steel must be put into space in sections and then welded in space. This will be time consuming, but is the only way to do it.

One of my first milestones is a decision on the size of the machine. This will factor in available funds and the most efficient way to create artificial gravity. After deciding the final design i will build a small replica and see if it is stable at the speed it will be rotating. After deciding on a design i will begin finding a factory to build the carbon fiber structure. After i have gotten several tons of materials i will decide at what time to launch it. The first design will be moored to the international space station and will be a testing ground. After it has been built, it be tested with a lower gravity setting to iron out any fluctuations and design flaws. After testing, it will be able to hold humans in space.

There are many risks when building a structure in space. Some of these risks are calculated and cannot be avoided. The first risk can occur during the cargoes travel into space. Although it is rare, space shuttles can explode and it will lose all of its cargo. Currently there is no option which lowers this risk completely. I will most likely be contracting with the united states who have recently begun using SpaceX rockets. SpaceX has had a few accidents in the past few years, but by the time i am ready to send the cargo into space they will hopefully be more reliable. This risk cannot be avoided, and will be calculated into the cost. Another major problem that can occur involves building the structure in space. Each part will be connected using machines that are guided by humans. This allows there to be some error in building it. Unless there is no humans involved in building the machine there will always be a risk of breaking something. Carbon fiber is very resistant to cracks, but can still be torn. The last risk is whether the design will work in space. I can make a design on earth, but gravity will affect the results. One of the biggest problems i foresee is the structure coming loose and flying off into space or into earth. I will propel it using gaseous oxygen, so i hope that there will be enough to correct any movement and keep it stable. The design may be structurally sound, but it can still fall out of orbit if it's inertia is not properly calculated.

I estimate that research and development will take two years. Following this, the construction for the building materials will take one year. Within two years, every part of the main machine will be deployed. After a years, the key parts will be connected together. After this, it will take one year to set up a breathable environment. It will be tested for a month to make it safe. The astronauts will then be able to live there. In total, this will take approximately eight years to research and build. I will use the existing infrastructure to expedite the process. Each part of the plan will be overseen by the head supervisor. He will get data from the leader of each individual part. He will make sure they are on track and not spending excessive money. Each leader will be self sufficient with a set amount of money to spend. It will be their job to hire people and find the necessary materials. Each leader will also be checked by an independent who will make sure they are on track. If i do sign a contract with NASA then each leader will have have some of NASA at their disposal.

Currently i have made a three dimensional of what i imagine the design would be. However, i am limited by the detail in the program i have made it in. i have used TinkerCad to construct the preliminary design of it. I cannot put in tiny details such as rivets or the trellises connecting the outer circle to the bearing. With funding from the THINK program i will be able to construct a real life representation of my design. I will be able to custom order the carbon fiber parts and test out the validity of my idea.

The funding will be used differently for an actual machine in space,. At first, the funding will be used to construct a design which will work in space. This will require many designers and even more designs. The design which is both strong, and cost efficient will be picked. I will have a budget, so i will not be able to pick the most expensive or strongest one. After this i will set aside an amount of money to construct the carbon fiber, the technology and the metal covering. The next step is to send it all into space. SpaceX's most powerful rocket is the Falcon Heavy. It will begin to carry out missions in 2017 with a payload of 54 metric tons. Falcon Heavy. (n.d.) The entire structure will take several trips if it utilizes all of the 54 metric tons available. This will cost several million dollars to send. Next, i will have many technicians here on earth operating machines to build the structure in space. Only after the entire structure is built can people live in there. After years of construction it will finally be finished and can contain people. However, now the inside must be built to be conductive to life. This involves installing screens, beds, an oven, etc. this will be a more gradual process as people will bring what they personally need for their self. Other than maintenance and repairs, there should be no more costs. This is how i will spend all of the funding i receive.

Budget

This is the budget for the smaller version of the structure. The radius of it is 40 meters.

Personal

Last summer I went to an engineering program at Yale. There i was asked to make a new technology that would help the medical health of people. My mind immediately turned to physics and I wondered how I could use physics to help people. I looked back at all of the concepts i've learned and thought which one could have an effect on people. One of my favorite concepts in Physics was the concept of centripetal acceleration, because it contradicted what you felt. When you are moving in a circle you feel that you are being pushed towards the outside yet the acceleration is the exact opposite direction. While this puzzled me at first, I grew to understand it. After sitting there and thinking about centripetal acceleration I realized that I had already thought about this in class and I knew exactly what i wanted to do. I had thought of this problem a long time ago and it had come back to me. How could i make artificial gravity in space. My first attempt to solve this is to find out which forces could exert a force on humans. I ruled out magnetism, buoyancy and many other forces which couldn't have an effect. Eventually I was left with one: acceleration. While you could continually accelerate in one direction to make a similar gravity force, this would eventually cause infinite energy so this was not a feasible solution. However there was a similar force which was centripetal acceleration.

The idea that I thought of was a circle in space which was rotated until there was a force which was equal to the force of gravity. I had thought of this idea before this, but i had not written it down. After thinking about it some more i wrote down a few sketches on a piece of paper and solved every problems that i could think of. Later i presented my idea to my group and they gave me more problems with my idea. My group didn't pick my project, but they still gave me valuable insight into my idea. Thanks to my intensive knowledge of physics i have been able to solve any problems i have in that aspect. In order to finish this project i must learn how to construct small scale models and be able to prove that my design can function.

References

Stone, M. (2015). The Biggest Health Risks to Humans in Space. Retrieved December 25, 2016, from https://gizmodo.com/here-are-the-biggest-health-risks-to-humans-in-space-1732733392

Falcon Heavy. (n.d.). Retrieved December 25, 2016, from https://www.spacex.com/falcon-heavy

August 5, 2014 Updated 8/5/2014, & Bregar, B. (n.d.). Price keeping carbon fiber from mass adoption. Retrieved January 01, 2017, from https://www.plasticsnews.com/article/20140805/NEWS/140809971/price-keeping-carbon-fiber-from-mass-adoption

NORTH AMERICAN CARBON STEEL PRICES, STEEL PRICE FORECASTS. (n.d.). Retrieved January 01, 2017, from https://www.meps.co.uk/N.Amer%20Price.htm

Oxygen Element Facts. (n.d.). Retrieved January 01, 2017, from https://www.chemicool.com/elements/oxygen.html

What is the cost per Sq ft for solar panels? (n.d.). Retrieved January 01, 2017, from https://www.quora.com/What-is-the-cost-per-Sq-ft-for-solar-panels

2016 New Arrival Cheap Indoor Big Tv Advertising Screen,Indoor Big Tv Screen,Indoor Advertising Tv Screen - Buy Indoor Big Tv Advertising Screen,Indoor Big Tv Screen,Indoor Advertising Tv Screen Product on Alibaba.com. (n.d.). Retrieved January 01, 2017, from https://www.alibaba.com/product-detail/2016-New-Arrival-Cheap-indoor-big_60426908714.html?s=p

User, S. (n.d.). Costs of a Rail Siding. Retrieved January 01, 2017, from https://www.acwr.com/economic-development/railroads-101/rail-siding-costs

Space Station Teaches NASA Valuable Lessons About Life Support Systems. (2015, October 30). Retrieved January 01, 2017, from https://www.nasa.gov/centers/marshall/news/releases/2015/space-station-teaches-nasa-valuable-lessons-about-life-support-systems.html