In our design for a hotel we have addressed a number of issues.
The first question is where to locate the hotel.
We want to have the hotel in a location that is easy to toss to.
A geo-stationary orbit would always be at a fixed location relative to
our launch site, which would be nice. We could toss to it in less
than 6 hours.
Most of current station thinking assumes zero gravity. This was
not always so. Early space experts assumed there would be some
kind of artificial gravity. Some desgines, like Von Braun's wheel,
generated their own artificial gravity. As tether enthusiasts
we like the idea of 2 hotels connected by a 20 km tether and rotating
fast enough to generate 1/6th G. These hotels can winch out thin long tethers
to catch and toss payloads. The tourist space-ship will rendezvous
with the end of the long tether. Hermann Oberth [Oberth1957, page 83] had a
design similar to this. His design had an 8 km long tether and rotated
29 times per hour to get one-g at the living quarters at the ends.
At the center of mass between the 2 hotels we can
have a zero-gravity play area. Each hotel will have an
elivator to climb the 10 km to the zero-gravity area. Tourists will be
able to play here with the comfort of knowing they can take a fast
elivator ride back to a place with gravity if they start to feel sick.
Even with our lower launch cost of about $30/lb, we would
still like to recycle CO2, persperation, human waste, etc.
The natural way to do this is by growing food in space.
Growing food seems to be much easier with some gravity.
Farming does a number of things that all can help reduce the cost of
operating a hotel in space. It removes CO2 from the air, it releases
oxygen, and it provides food. If you have 1/6 G it should not be
that hard to farm.
In Anguilla, where one of the authors lives, there is a hotel that grows
most of its own vegitables in a green house. Taking a tour of this greenhouse
is something many of the guests enjoy doing.
A space farm should be even more interesting to tourists.
Level of Gravity
A low gravity, say 1/6 of a G, can make a lot of things easier.
Growing food, going to the bathroom, washing your hands,
thermal control, burping, exercising, etc.
Being able to set something down and not lose it as it
drifts away can make life much easier. Many cheap
products from Earth that could not work in zero gravity
will work just fine in 1/6th Gravity. For example,
an electric fork-lift, a common ballpoint pen, and a kitchen sink
would all work just fine at 1/6th G but not at zero-G.
A higher gravity would not make all that much difference to
many things, but it would increase the stress on the hotels
and the tether between the hotels. Human muscle loss would
be reduced by higher gravity, but we expect most tourist
visits to be short, like 1 week.
We like 1/6th G because it may help tourists to start thinking about
what it will be like to visit the Moon on their next trip.
Further in the future, we expect to take tourists to the Moon.
Catch and Toss
Each hotel will be able to winch out a tether to catch or toss a payload.
The two big hotels will provide both plenty of rotational inertia and
plenty of orbital inertia.
When a payload comes from the LEO tether to the GEO tether it has to
syncronize with the end of the GEO tether for the catch.
This does not have to all be done by the payload as the GEO tether
can help by adjusting the rate of its spin so it is at the
right angle at the right time. To adjust the rate of spin it
can real-in/let-out the ends from the center of mass.
Number of Rooms
If there are 14 launches every day with 10 tourists on each and they
each stay for 7 days, then we need to be able to hold 980 tourists
at any given time. This is 490 rooms at double occupancy.
If we estimate 40% more people for staff living in 1/2 sized rooms
it is like 20% extra space for staff or 588 rooms. So we can
round up to 600 rooms. With a hotel at each end of
the GEO tether, each hotel needs 300 rooms.
If they are 15 rooms per floor they would need 20 floors each.
Once we are growing food and producing oxygen in space, it would not
cost very much much to
support someone for additional week. If people were paying
$50,000 for the first week and $20,000 per week after that, the additional
weeks should have a higher profit margin.
So it would be wise to design the hotel so that more rooms could be added.
Energy Generation and Storage
Each hotel can have solar arrays to collect energy. At GEO the hotel would be
in sunlight almost all the time. It would be possible for each hotel to
have a winch so the whole hotel could climb the tether when it had extra
energy and lower itself to generate power when it needed to. This would
impact the rotational period, but it could be an easy way to store a
huge amount of power.
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