Arguing that the future of humanity lies in space, I am writing a series of posts that describe what life in space would really be like, as opposed to what we typically see in science fiction.
In my last post I got our heroine from the surface of earth and onto (into) a space station. This space station is on a low orbit directly over the equator. This is the cheapest route into space and, for the most part, business interests will be looking for the cheapest route.
This means that this station will become the New York of space civilization. It will be the port through which almost all cargo and passengers pass. This, in turn, means that what will start as a small service station will probably grow into a community.
But what will this community be like?
I find it tempting to think of the original hub being built, then other businesses coming around and planting their own stations next to the original hub – like new buildings going up in a new city. However, this scenario is not going to work.
We have our initial hub. Now, somebody else comes along who wants to build his own station next to this hub – a hotel, for example, or a laboratory. He plants his hotel one mile away to the south (right) of our hub.
The way orbits work, a station that is 1 mile to the south of our original station will, 45 minutes later, be one mile to the north of our station. I will be 1 mile to the south 45 minutes after that. It will continue this oscillation from north to south every 90 minutes. The problem is that, in order to get from the right side to the left side it will have to go through our initial hub.
If, instead, this second station is higher than our hub, then it will also be slower, and fall steadily behind the hub over time. If it is slightly below our hub, then it will slowly pull ahead of our hub.
The only way to keep our stations fixed relative to each other is to connect them. It should not take a lot of work – a simple structure joining one section to another keeping them the same distance apart.
However, this will raise another problem, if you will pardon the pun. A low-orbiting station will slowly lose altitude as friction with the thin but still very real atmosphere slows the space station down. In order to keep our station in orbit, we are going to have to spend some fuel and push it into a higher orbit.
This, in turn, will require that the station be put together in a way that can stand the stresses of this maneuver without either going into a spin or falling apart. Our station will likely be something very near to symmetric with counter-balancing parts added at nearly the same time.
These two factors combined suggest that our low earth orbiting station is going to have to be a single unit somehow tied together, it is going to have to be engineered for balance, and it is going to have to be expandable. This is not to say that the initial station will have these qualities. However, if it does not, then it will soon find itself eclipsed by a competing station that recognizes these values.
The reboosting events will be significant station-wide events. Things will need to be set up so that, for a few minutes every couple of months, the whole station feels 'gravity' as the engines fire up and the station moves to a higher orbit. It would be like having Los Angeles intentionally trigger a magnitude 5 earthquake once every two months.
One more feature that our station will need is for a way in which its occupants can counter the effects of weightlessness on muscle and bone mass. If bones and muscles are not used, they start to atrophy. Several astronauts have come back from trips in space with their bones and muscles having aged significantly. Even though these individuals return to normal with exercise back on Earth, the daily fight against gravity itself seems essential for our health.
So, our one-piece, expandable, well-planned space station is going to have to include a component that spins. The easiest way to do this is to put two pods on opposite ends of a tunnel – like a baton used in a marching band – and set the habitat to spinning.
This itself will be a complicated piece of machinery.
First, after we set this construction spinning any change in the mass distribution (the more people move around) will introduce wobbles and other problems. Also, a spinning device such as this would act like a top on a table. The law of the conservation of angular momentum suggests that the speed of rotation for such an object speeds up if mass goes from the outer pod to the center, and slows down as mass moves from the center to the outside. If the balance is not maintained, the spinning part of the station will wobble.
A complex computerized system with counter-weights would be useful in getting keeping this spin stabilized.
Finally, we would have to deal with the fact if a portion of the station is set to spinning that this will create a gyroscope. Forces acting on gyroscopes produce unexpected results – which explains why a top can stay balanced on its point as long as it is spinning quickly enough, and lean all the way over on its side on the tip of a rod without falling off.
If we are going to promote an desire for living in space in our children or grand children, this is the type of world we should be describing. This also tells about the types of space activity we should be promoting. Where the government should be putting its money is in a one-piece but expandable station in an equatorial orbit, built all in one piece and expandable.
This is the type that would have the most use (and value) in the years to come.
No comments:
Post a Comment