On Wed, 16 Mar 2022 14:31:44 -0700, Trolidan7
<
Trolidan7@eternal-september.org> wrote:
On 3/16/22 6:52 AM, dlzc wrote:
Dear Trolidan7:
On Tuesday, March 15, 2022 at 1:21:39 PM UTC-7, Trolidan7 wrote:
...
Since they are both tidally locked to each other a cable
might have a possibly somewhat static place to anchor a cable
to on both near sides.
This is the idea of an Orbital Tower. It is a proposed technology for
cheaply launching blobs of stuff from Earth. It has also been proposed
for, and would work better on, Mars.
Due to the slow rotations, Mercury and Venus would be very unlikely
candidates for this technique.
Due to their enormous sizes, the four larger planets would be quite
high on the scale of impossibility.
An Orbital Tower between Charon and Pluto, anchored by Pluto just
might be within the range of allowed Physics and nearly sane
engineering but it would, except for the singularly stupid idea of
taking a drive from planet to moon be an idiotic venture and
completely useless.
...
Could this be used in some way to slingshot ice to Mercury
or the Earth's moon? If so how?
No.
Pluto's orbit and the P-C-co-orbit are tilted such that aiming a
sling-shot at Mercury or the Moon would only be possible for very
brief windows. At all other times, the shot would miss by very many
miles, metres and kilometres. One could always add engines to correct
the trajectories and allow for wider and more windows but that sort of
thinking leads to "why-bother-with-Pluto?".
We've observed nearly superfluid liquid nitrogen oceans
flowing over Pluto's surface. No water-ice.
Cool. I wonder whether Pluto ever gets cold enough for everything but
helium to solidify?
What will mass loss due to "ice removal" do to the
dynamics of this stable system... except break your cable?
Probably damned all unless the strip-mining is done on a truly
planetary scale, which, having witnessed Man's effect on the Earth,
would be entirely within the bounds of commercial policy.
Planets, even teenty ones like Pluto and Charon, are bloody *huge*
critters.
Even were one [or one company] to strip-mine on a planetary scale,
one could always use both objects as sources of mass, thus ensuring
that any orbital perturbations would be minimal and easily dampened.
It's only rocket science, after all and humans are good at that one.
What metal will hold up and not become brittle at liquid nitrogen >>temperatures?
Why metal? Ices seem to hold up well under Plutonian temperatures as
is evidenced by Pluto, Eris, Sedna, Charon and a vast array of other
blobs of stuff out there. Engineer the "cable" [really it would be a
bridge or tunnel, but that's the kind of semantics lawyers dream of
litigating upon] with sheaths of ices on overlapping joints every few
miles and you could account for orbital variances.
We'd probably have to produce it and ship
it from closer in...
Or take it from the comets circling Sol in that far distant cloudy
zone. Which choice would obviate the need for Pluto, Charon and the
bridge. If we're going to send comets inwards, we may as well send
them all the way in.
Mercury and the Moon are unable to retain enough atmosphere,
to keep the water. Spend they money on making mobile space
habitats in the Goldilocks zone.
Build a MIR and a SkyLab. Add bits to them until they become
city-farms in orbit. Make more of these. Make some really, really
huge. Make more of these, too.
Gently move many city-farms into high Earth orbit, into Earth-Luna
transit orbits, into [admitted unstable but that's moot when the
location of everything is optional and temporary] Lunar orbits, Mars
orbits, Venusian and Hermian orbits [the former for volatiles to sell
to the growing populations elsewhere and the latter for non-volatiles]
and orbits around the larger of the asteroids.
Eventually, some habitats drift outwards. With protection in the form
of thick mud, plastics, ceramics or even plumbing some may even become commercial empires around the Jovian moons, the Trojans, the Uranian
and Neptunian systems and all of the little rocks and ice-blocks
falling around Sol in this warm zone.
After a while, some inhabited "Worlds" would drift into the Oort
Cloud to make a living dropping iceblobs into the warmer reaches of
the System.
The Cloud of comets is about two lightyears deep. That is a
fantastically large volume and an interesting number. There are stars
not much more than 4 LYs from Sol. [Note: this is not a fixed fact.
Within 40,000 years there will be stars closer than 4 LYs. At times in
the not-too distant future, there will be nothing for more than five.
Stars move.] It is not beyond the rules of physics that those stars,
too, would have ghostly clouds haunted by ices. It is not beyond the
limits of human psychology [or the psychologies of whatever passes for
human in the Worlds Of Ice] to imagine some of those regions being
slowly infested by human Worlds. Peoples who bear no loyalty nor
allegiance to Sol.
The nearer stars become "Human" domains, their worlds and rocks and
ice-blocks converted into and consumed by the travelling Worlds of the
Children of Earth.
"Nearer" becomes a relative term over the next few million years.
The galaxy becomes a Human Galaxy. Sort of "Human".
In ten or more millions of years even the vastness of the home galaxy
begins to seem too crowded for some adventurous Habitats and many try
to make the jump across the transfinite gulfs to Andromeda, the LMC,
the SMC and others.
Survival of those seedlings is rare but there are many, many Worlds
and it only takes *one*.
Survival strategies improve over the next few millions of years and
Triangulum is attempted by those who find the new galactic homes too
noisy.
Again, millions die but it only takes one to succeed.
From a couple of space-stations in extremely low orbit around the
Homeworld to a swarm of Human Galaxies in fifty to sixty millions of
years.
It could be done with not much better than Apollo tech.
David A. Smith-
It is not obvious whether there is enough ice at the poles of
the Moon and Mercury even for enclosed environments.
Possibly not but that is what ion engines and comets were invented
for. Dropping comets onto Luna would, no doubt, piss-off the Greenie
tree-huggy types but any of them who volunteered to stand on ground
zero to block the falling rocks would only add to the mass of
volatiles being merged with those worlds so it's all good.
Although the Earth's oceans have almost equal mass to Ceres
there is a lot of gravity well going up from Earth.
Earth is a lousy place to look for volatiles. Absolutely every solid
object in the entire Solar System is smaller and has a lesser gravity
well. Jupiter's Trojans are far better. Not only are those far closer
than are bits of the Saturnian System and so easier to approach, mine
and move but they also avoid the utter sacrilege of tampering with The
Rings.
That was one of Dr. Asimov's few major blunders.
By 'ice' I tend to mean contained volatiles.
Jupiter and Saturn also have gravity wells, and even though
Saturn's rings are made of volatiles, Pluto is 30-50 AUs out
rather than 10AUs.
Planning to mine The Rings is sacrilege, blasphemy and a major faux
pas. The Belters can have their Belts but we Hearth-worlders get the
Jovian Trojans and Saturn is *OFF* *LIMITS*.
I am thinking you would need an entire object the size of Sedna
or Titania to give the Moon an atmosphere with oceans for tens
of millions of years before it would dissipate into space.
Fortunately, there are many Sednas and sub-Sednas and Luna, Mars and
Mercury would not *need* long-term airs. Also fortunately, there are
currently no Greenies there to complain that lobbing mile-wide ice
cubes at the three M's is a desecration that would hurt the little
bunnies.
It is also so that there are, as yet, no little bunnies to hurt.
Though were Humans to wet Mars and to liven up her air it is
theoretically possible that long-dormant Martian life might be
stimulated.
DNA could not last milliards of years but the Areans may not have
been made from such fragile stuff. Still, even if Mars is declared
"Let Well Alone" by Meta-Law, we'd still have many, many places to go
to build chippies and casinos.
Enclosed habitats however would need a lot less than that.
Yep and "enclosed habitats" could be larger, wider, taller and far
better designed and more pleasant to live in than any city on Earth
has ever been.
They could also be more free, more stimulating, cheaper, better and
better paid for the populations than any city on Earth has so far
been.
I kind of doubt that it would be done in the next 10 years
but it is interesting to speculate upon.
We should have started in the 1970's with SkyLabs and MIRs. It is
entirely possible that manned offworld activities are now and will
forever remain impossible outside low Earth orbits. No one has the
skills, expertise or knowledge to do it and the available expendable
wealth is rapidly vanishing.
The Dream Of Stars is dead.
It would probably be a lot easier to do than this:
https://www.youtube.com/watch?v=G-WO-z-QuWI
That is an *idiotic* "plan". Seeding Cythera with "plants" that float
in the airs of that world would be faster, cheaper and easier. Once
the rains started, seeding the surface with fungi, lichens, mosses,
grasses and trees would be easy.
I once worked out that greening Venus could be done in fifty-odd
years or so with little better than Apollo technologies. It would be
the plankton doing much of the work.
It could also be *fun*!
It is a pity that my little Dream Of Stars is utter fantasy and will
never happen.
Ther will be no Martians, no Hermians, no seed of Earth walking the
newly minted soils of Venus and no thirteenth human on the Moon.
J.
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