The High Frontier

In a message dated 11/3/00 8:53:25 AM Eastern Standard Time, mikecombs@...
writes:

<< To me, the advantages of attaching a habitat to an asteroid would
have more to do with easy availability of resources than any concerns
about the axis of spin. In fact, I trot this scenario out whenever a
Mars advocate tells me than an advantage of a Mars settlement over an
orbital one is that the orbital settlement would have no locally
available resources. >>

One particular habitat I have in mind is the martian moon Deimos, it has an
orbital period of 30 hours, 17 minutes, and the orbital Inclination is 1.79
degrees which I believe is relative to the plane of Mars' equator. Mars
itself tilts at an angle of 25.19 degrees. The orbital radius of Deimos is
23,460 km and the radius of Mars is 3,396 km. Putting the orbital radius and
Mars' planetary radius together you can make a right triangle where the
angles are proportional to the sides opposite The hypotenuse opposite the 90
degree angle at the center of Mars is 23,705 km.

90 / 23,705 = x / 3,396

Solve for x:

x = 90 * 3,396 / 23,705 = 12.9 degrees. The entire diameter of Mars as seen
from Deimos would then be 25.8 degrees or half that 12.9 degrees which we
compare to Mars' axial tilt of 25.19 degrees. As a rough guess I'd say that
Mars would eclipse Deimos once every 30 hours and 17 minutes for about half a
martian year. We could either have an orbital habitat whose day/night cycle
is 30 hours and 17 minutes arranging for the eclipses to happen at night or
we could have a 24 hour day/night cycle and put up with some inconveniant
eclipses in the middle of the day and perhaps extend the daylight hours to
compensate. Since Deimos traverses a full 360 degrees of its orbit every 30
hours and 17 minutes, a Martian eclipse would last no longer than 2 hours and
7 minutes. This orbit is also convieniantly close to a Martian stationary
orbit and a good location to manufacture Solar Power Satellites for
deployment into that orbit. For a large influx of settlers heading toward
Mars the economics of Solar Power satellites would make sense and would
compare favorably to them bringing their own nuclear reactors to power their
settlements. As settlements on the Martian surface grows, so too would the
orbital settlement on Deimos. Since Mars generates a lot of public interest,
it seems that Matian orbit might be a good place to built the first orbital
colony. The colony would be of Island One size or smaller, either a Bernal
Sphere, a torus, or a small cylinder such as Island Three - Model One.
Cylinders have maximum area at 1 g while bernal sphere force some people to
cling to a slanted landscape at less than 1 g. A torus is better suited
towards an office building type environment where people live in apartments.
If you want a cathedral like structure that simulates the outdoors, you would
go with a sphere or a cylinder. At best a torus looks like the inside of a
greenhouse.

Tom Kalbfus