[extropy-chat] The other space program

[Adrian Tymes]

--- Mike Lorrey <mlorrey at yahoo.com> wrote:
> a) envelope size generally get calculated on helium
> density. These
> would be Hydrogen filled cells.

I'd be worried about helium/hydrogen leaking out the
walls.  They do this already, slowly; it's not that
big a concern since the balloons are expected to
return to the ground eventually anyway.  But this
would be a permanent deployment.

> b) they could also be HOT hydrogen filled cells,
> getting lift both from
> atomic mass differences and thermal volume
> differences. With buckyfiber
> envelopes, you could easily engineer an envelope
> with R factors
> approaching a thermos bottle.

I'd also be worried about atomic oxygen leaking in
and reacting.  Heat + fuel (hydrogen) + oxygen = boom,
no?

> c) the envelope also gets lift from its velocity
> through the air and
> its airfoil shape, propelled by microwave powered
> ion/plasma thrusters.

Not as much in the thin atmosphere, though.

> A 747 sized homestead could have an envelope the
> size of an aircraft
> carrier. An aircraft carrier could have an envelope
> a few kilometers large.

Aircraft carriers are already called miniature cities.
They're not nearly as spread out as the real thing,
but they are livable (by certain types of people, at
least) for several months at a time.  And if one
substituted hydroponics (powered by solar cells on the
gasbags) in place of some of the military systems,
resupply wouldn't be as much of an issue.  (It'd still
be needed from time to time...but then, what proper
city doesn't have mail service?)