Re: Branson and Bigelow to team up for a space hotel?

There are several advantages of the saucer shape.

1. The scaling of the pressure vessel cylindrical fuel and lox tanks is
such that having several tanks side by side is not heavier than having
a single large tank that stores the same volume. On the way up we need
low drag, on the way down we need high drag. The saucer can have both
by flying edgewise going up and braking on the way down. The capsule
type vehicles also present a disc shaped surface during re-entry,
because a blunt front shape directs heat away from the vehicle body.
Having the fuel and oxidizer in multiple cylindrical tanks side by side
allows us to have more surface area for both drag and lift. Very little
structure needs to be added to the set of tanks to turn them into a
disc.

2. The double delta shape of the shuttle is advantageous for horizontal
gliding landing because it allows the air spilling over the edges of
the front of the wing to turbulate over the main delta wing. This wing
arrangement is good for pitch stability but not very efficient for
subsonic flight. The shape of the spirit bomber is much more fuel
efficient for subsonic flight. This is very close to a saucer shape.
The double delta has a lot of wing area behind the c.g. which makes it
less efficient for lift.

3. The saucer shape is advantageous in space because it can control how
much radiation it absorbes from the sun and earth. It can point
edgewise to minimize absorption or show some area to absorb heat.

4. A saucer is sturdy and convenient to service when sitting on the
ground.

5. For a flight to a space station 400km up you will climb about at a
36 degree angle so the lift the saucer generates comes handy.

6. The saucer can approach the landing zone at a steep angle and land
under power like the DC-X. This makes precision landings easier.

I can weld steel tubes together much cheaper than 10 million dollars.
When I use a pressurized header tank I don't need turbo pumps, I can
just weld together tubes to form regeneratively cooled reusable thrust
chambers. I can make a saucer shaped vehicle that goes to the Bigelow
space station for next to nothing.

The reduced heat load that I computed comes from a factor of 25
reduction in ballistic coefficient and a factor of 2 reduction in
reentry velocity. In planning the system I designed for residual fuel
and lox to be used during reentry.

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