Astronomical Intelligence

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Seven Threats in HeavenHow to live in space

a product of Newton’s first law of motion – a moving object will keep moving until something stops it, the opposite is true for things that aren’t moving.

When you are riding in a car, you are moving forward at the same speed as the car. When the car turns, it starts to move in a different direction. However your body has its own inertia, its own momentum – it wants to keep going straight, even though the car is going in a different direction. That is why you or other objects in a car slide around when you turn. When you turn left, everything slides right. When you turn right, everything slides left – because the objects are trying to keep moving straight when the car isn’t.

Using this we can create the illusion

of gravity in space. If we build our space city to be a wheel or tube and set it spinning, centrifugal force will push our space citizens into the outside wall of the space city – just like a person is pressed into the door when a car takes a sharp turn. If we set the radius of space city’s wheel shape (basically controlling how ‘sharp’ of a ‘turn’ we are taking) and the speed of the rotation (how fast we are taking said ‘turn’) we can produce an area where the centrifugal force matches Earth gravity.

We’ll say our space city is a long tube spinning in space – more room for the space citizens to live in and use. Two of the seven issues can be solved at the same time at this stage – we need both water and protection from solar/cosmic radiation.

If you add another ‘layer’ to the outside of the space city, and fill it with water you get both. Water is dense, and it acts a fairly good defense against radiation. There are enough molecules of water in a given area that most of the radiation is absorbed or deflected. This radiation could cause genetic defects in humans, damaging the chemical composition of our DNA, but would

Living in space presents both a great opportunity for the human race to expand and a huge hurdle that we haven’t quite made over yet. The International Space Station is a successful example of humans staying in space for extended periods of time, but it does not provide a good model for any kind of permanent colony. It is a test bed, a research facility useful for testing the effects of space on humans and other organisms, but a real space city would need to be very different.

I’ve thought of seven key problems that need to be addressed in order for a sizable population to survive in space, more or less in a self-sustaining way. This is not the beginning and end of living in space, but it is a good start, and lays a foundation for more specific problems to be addressed.

The first factor that needs to be addressed is producing an environment of Earth-like gravity in space. This is not first because it is the most essential component needed for human life, but because it deals with how the space city will need to be shaped and constructed.

True artificial gravity is outside of our modern scientific capacity. We can’t produce a device that creates a gravitational field like Earth’s somewhere else – we are far behind science fiction on that front. However, we do have a way of creating a kind of ‘fake’ gravity – centrifugal force.

If you have ever been on a spinning carnival ride or been in a car that takes a sharp turn, you’ve experienced centrifugal force. It is

The International Space Station passes over the Mediterranian in its orbit around the Earth.

A tube design that could form the skeleton of our example space city.

be fairly undamaging to water.

By compartmentalizing the water storage so that one hole in the outside doesn’t deprive the entire city of water, and adding another layer of say lead to the outside hull of the station, most of the problems with radiation will more or less be solved.

This has the added benefit that irradiating the water will help sterilize it. Purifying water is something that we have a lot of experience in today, and recycling waste into pure water is also something that we are capable of doing so we would be able to make this water supply last.

Two other factors that can be solved in the same way are a supply of food and a way to filter the air on the space city. As humans breathe, we produce carbon dioxide which is toxic to us. Plants can take this carbon dioxide and use it to produce sugars and oxygen, which we can eat and breathe respectively.

Farming facilities using very controlled irrigation, temperature

control, and artificial lamps would be the way to solve both the food and oxygen problems. The diet would probably be somewhat limited, as foods would have to be selected based on space efficiency as well as dietary need – although an apple a day keeps the doctors away, growing apple trees in space would take up a large amount of room, time, and resources for a fairly low yield in food.

Meat would also more than likely not be feasible – it is far more efficient to grow a crop and eat it than grow a crop, feed it to animals, then eat the animals. Protein would come from beans, which would be much better at feeding a sizable population over time.

In order to keep all of this running though, we need electricity. Electricity to circulate the air, move water where it is needed, keep the temperature at a comfortable level, and run the various computers and other technologies needed for humans to survive in space. All of this will require a power source, one that will not run out and can be harnessed to good effect in space.

Fossil fuels are not feasible – they require oxygen to burn, which is oxygen that our space colonists need to breathe. Nuclear energy is a possibility, and being able to jettison spent nuclear material into space neatly solves the issue of radioactive waste. However the facilities needed are heavy, they would cost excessive amounts of money to move and construct in space, and no one

is interested in sending nuclear fuel into the atmosphere, where a malfunction could spread it almost anywhere in the world.

Luckily we don’t need any of these, because we are near the perfect candidate: The sun. Solar power has several problems on Earth. It is only ‘day’ about half the time, on cloudy days solar panels can’t collect energy, and the solar panels in use today aren’t very efficient at turning solar radiation into energy.

Being in space solves two of those three problems. It is never cloudy in space, and even though our space city rotates if you place the solar collectors at the end of the tube, you could create a motor system that kept the collectors pointed at the sun.

One of the bonuses about a spinning wheel is that the outside of the wheel is actually spinning faster than the inside. If you’ve ever been on a merry-go-round, you’ve experienced this. A wheel is a solid disk, and so if it makes one complete rotation the entire wheel makes a complete rotation. However, the outer edges of the wheel move further – the length around a circle goes up if you increase the radius. If you go a longer distance in the same amount of time, you move faster.

What this means is that even though where our citizens live the space city is spinning fairly fast, if the station is big enough it won’t be spinning fast at all at the center. This would let the solar collection panels remain fixed on the sun, and thus always

An array of solar panels collect energy on a sunny day.

An example of using lamps as a replacement for solar energy, which is needed to farm in space where utilizing the sun is not practical.

collecting energy.

As for efficiency, science is always moving forward and there is a lot of research into making solar panels more efficient. At the present moment the best we can do is around 40% efficiency – that is 40% of the energy collected by a solar panel is converted into energy. Even with this, if the collection area is big enough you could power a large space city indefinitely.

Finally, for the space city to function you would need a way to replace parts that can’t be fixed, and to collect resources that aren’t renewable. This is a real problem – the best system we have, the Space Shuttle program, is being retired and there is no official replacement for it. Ideally, the space city would have support from trans-atmospheric aircraft: jets that can fly above the atmosphere, dock with the city, and land on their own power.

There have been attempts at creating this ‘x-craft’ as it is known, but none have been very successful. The attempts have been promising though, and it is not inconceivable for such a craft to exist – with lighter, stronger composite materials being developed it is not a mere dream of science fiction.

This craft would carry people and cargo from the Earth or perhaps a colony on the Moon or Mars, up to the space city, dock and unload, then return to the planet. It would be a supply line and insurance in case of emergency. Although a system like the space shuttle would be sufficient, having a reusable craft would be much better and having it available to take off when it is needed would be much preferable.

With those seven things, we have the basis of what I believe would be a functional space city. This could be placed anywhere, although straying too far from the sun would be a bad idea. With it the human race could endure a cataclysmic event on Earth, and become that much more likely to survive into the future.

And it would be more or less possible today.

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