Design Tips

Considerations for the Design of Orbital Hotels

In the future there will be orbiting locations that can be reached from the surface of the Earth by means being developed today. Even at $200,000 for a seat on suborbital flight, it looks like it will be a very big business, so much so that many of the richest people on Earth are investing millions in the prospect.

While many orbital hotels have been proposed so far, none have been Designed with the features that I here propose.

Free Fall or Artificial Gravity?

The fights taken to train prospective space tourists are flown in planes call "vomit comets" because the experience can often lead to throwing up in the least suspecting people, even experienced pilots. While, I don't know for sure, I suspect that if the stomach is full the effect is less, considering my experience on cruise ships and my 240 flying reconnaissance missions in Vietnam.

The rule for flight crews was no drinking 24 hours before a flight, and if you did you found out why that is a rule. Smoking is not an issue anymore, thankfully.

However, we read that trained and experienced astronauts have issues with weightlessness and the contents of their stomachs. Prolonged flights have lessened this we are assured, but if you are just spending a 24 hour period or two in space, it would not be enough to acclimatise yourself, and while weightlessness is fun, it would be a comfort to have a place to go where you can have an environment at one G, or the weight you would have on Earth.

Currently proposed Designs do not include artificial gravity, but I would, and so therefore, to expand the population that might consider an orbital flight, a haven of artificial gravity must be included. My proposal deals mostly with considerations of artificial gravity. With artificial gravity you have the option of both free floating in the central hub and full 1 G simulated gravity at the perimeter.

It is accomplished by rotating the craft, I will call for now an Orbitel, a Hotel in Orbit.

The craft would be cylindrical for simplicity. Its dimensions would be its radius or diameter and its height. Small radius hotels would have to spin faster than large radius hotels because the perimeter, the gravitational "habitable zone" where the rooms and facilities would be further from the center of the craft.

Once the rotation is established, inertia would maintain the rotational speed, save for the movement of the inhabitants which, over time, due to conservation of energy would degrade the spin. Rotational speed would then be maintained on a instant by instant basis.

The Orbitel would be spun by rockets, but I propose that those would be ion propulsion rockets, even though they have only a slight thrust. The required thrust would be accomplished by many thrusters. They would be powered by solar generated electricity which would ionize large mass atoms and magnetically accelerate them to achieve the thrust. It would be a cross between an arc light and an TV electron gun.

Those details will not be dealt with further in this essay.

There are a plethora of engineers who claim to be well versed in ion propulsion. Though I have not seen any in current operation that use magnetic acceleration. I am not familiar enough to Design these but proposals in the 1950's placed the propulsion of ion engines at less than that of the propulsion of liquid fueled rockets. It would not be enough to achieve orbit from the surface of the earth, but should suffice for our needs. As they typically require a vacuum to work, it would not suffice for flight, let alone suborbital flight. Putting the spin on an orbiting space craft should just be a matter of scaling up the number of thrusters to meet the challenge. Quick control of the thrust is available by varying the accelerator voltage.

We consider for this discussion something that rotates easily and can easily synchronize counter rotation of solar arrays to maintain the satellite's power having the solar arrays always pointing at the sun. Selection of orbit, like a polar orbit oriented along the Earth's orbital path could ensure that.

As occupants move in the same direction as the rotation they gain relative rotational velocity and feel heavier. Moving in the opposite direction creates the opposite effect.

As you move toward the center of the cylinder your weight also decreases. So for the purposes of enjoying weightlessness a central hub would be provided where the guests can float free.

To get to the hub, we can imagine ladders or elevators, but using parabolic ramps, rotating inward in the opposite direction as the Orbitel's rotation from the outer area to the inner hub would allow people to feel the effect of both moving against the rotation and moving toward the inner hub. The weightlessness would come to them gradually.

I propose that it would be rather fun to run up such a ramp, aware that one would likely bounce off the opposite wall of the inner hub, so it would therefore require thick padding.

If these ramps are two or four on even in number, the downward ramp at the opposite end would allow guests to run up into zero G only to be caught by the downward ramp on the opposite side. If they hadn't properly oriented themselves an accident would likely happen, so I would suggest that the number of ramps be an odd number.

And swimming pools with glass bottoms, hanging out into space from the outer perimeter, with the earth and stars visible in the water would be a wonderful thing. However if the craft stopped rotating, that water would have to be confined.

Orbitels will go up, and will serve guests, and as time goes by they will reach higher and higher orbits, and finally occupy the Lagrange points between the Moon and the Earth, ahead of the Moon on its orbit and behind the Moon on its orbit and one beyond the moon. Objects placed at these point will remain in their relative positions. It is the dream of many of us to see this happen, and to see an extraterrestrial economy that could support it.

Dean W. Johnson is a technical recruiter and website developer. He has over 30 years experience in the computer industry and has worked through many paradigm shifts, from Mainframes through Minicomputers through PCs and on to networked and internetworked computer systems. He has worked in both software and hardware. He has lived in a paperless world for more than 12 years. He now recruits for the IT industry and webmasters several websites.

posted by sablm @ 7:30 PM