National Geographic's "Evacuate Earth"

On 6/25/14 7:41 AM, ERandall e.randalln@... [spacesettlers] wrote:

> I suspect the "silliness" of the NatGeo show would still be realistic:
> only some will accept a habitat-based civilization...and many of those
> will only be after a couple/few generations of not experiencing any
> different. An attainable, "holy mission" might be the difference
> between successful endurance of horrendous hardship and complete social
> collapse. It would really depend on how the "holy objective" of the
> mission is "preached." [The actual release from the mission at its end
> is another question.]

That's a fair point. To put it another way, you might not be able to
"sell" the idea of moving into space to most people, without identifying
another planet as the goal.

On the other hand, the silliness in the show extends to technical
issues... such as the giant elongated cylinder, which will end up
tumbling end-over-end, and which will be impossible to turn without
first stopping its spin (and doing THAT will require lots and lots of
propellant).

> On the other hand, in a Traveling O'Neill ("O'Neill-ers" inherit the
> appellation of "Gypsy" from the Roma?), repeated interaction and
> personnel exchange with other outposts could promote a continued sense
> of membership in the whole human civilization and provide the necessary
> "greener grass" that having other states/countries supplied, in
> abundance, over the last few centuries.

Yes, the more I think about this, the more I agree. Of course you might
more cheaply/easily get exchange of people and goods using passenger and
cargo ships designed for that purpose, rather than moving the entire
worldlet. But moving the whole thing has its own advantages.

> On a High Frontier note, have you included provisions for
> station-keeping engines in future release plans? Just a thought.

Well, my thinking has been that when we add rotational stability
(v0.06), the less stable your spin is, the more you have to spend
maintaining it and counteracting wobble. Of course if it's TOO
unstable, than at some point, we're going to say the stabilization
system is overwhelmed and you just start tumbling.

That's not exactly the same thing as station-keeping though, is it? For
one thing, wobble can be canceled out without expending propellant, by
reeling masses in and out around the outside of the station (as
described in the Kalpana One paper).

So for actual station-keeping, i.e. reboosting the orbit after it drifts
or decays... no, I haven't thought about it that much. In LEO, you
could probably use electrodynamic tethers, but outside of the
geomagnetic field, you'd have to use propellant. On the other hand,
most other orbits need much less station-keeping than LEO.

Thanks for raising this interesting issue! I'll give it more thought.

Best,
- Joe