[Rockhounds] Terraforming Mars might be impossible? for now

[J Bryan Kramer]

I've seen articles on the other methods of altering asteroid orbits. Tho I
don't recall the YORP effect, I'll have to look that up. As for the lack of
a strong magnetic field it is true that Mars would lose any atmosphere that
we created quickly in geologic time, that would me hundreds of thousands or
millions of years. Quite tolerable for humans. The other problems are well
known. Other astronomical bodies, other than the asteroids, have their own
serious drawbacks. The Galilean moons are strongly irradiated with gamma
for example.

I saw an article recently that said that the Mars magnetic field is ten
times stronger than expected but obviously still too weak to be useful. <
https://www.sciencealert.com/magnetic-fields-around-nasa-s-mars-lander-are-10-times-stronger-than-scientists-expected
>

There actually is a company that wants to return metallic type M asteroids
to earth orbit for exploitation. They seem to be fixated on the Platinum
group for some reason.  Those type M asteroids are the differentiated core
fragments of some failed proto-planet in current theory. I think most
asteroids are the mantle fragments with few useful metals. Tho a carbon
rich body would be quite useful as would one with ice. Heinlein's story was
actually all about bringing an asteroid into earth orbit as I recall, so
nothing new there.

I missed the that sf story you refer to Alan, I'll have to see if I can
find it.

BK

“When bad men combine, the good must associate; else they will fall one by
one, an unpitied sacrifice in a contemptible struggle.”
Edmund Burke

J Bryan Krämer       North Florida, USA
photos at: http://pbase.com/photoburner


On Sun, Mar 15, 2020 at 8:07 AM Axel Emmermann <axel.emmermann at telenet.be>
wrote:

> In my book there are a few things wrong with Mars ...
> 1) it doesn't have a strong enough magnetic field to protect the planet
> from
> the solar wind. Any atmosphere that is created by terraforming attempts
> will
> be blown away in a short time period.
> 2) it's to small... its gravity would irreparably weaken bones and muscles
> of people stat spend more than a few years on its surface. Once beyond a
> certain time, "Martians" could no longer return to Earth without grave risk
> to their health.
> 3) It's large enough to have undergone gravitational segregation of the
> chemical elements that made up the planet. This means that there is an iron
> core. That core would have collected most of the siderophile elements. A
> much shorter seismic active history would have separated the lithophile
> elements  into a lighter crust and heavier mantle. The mantle is where the
> important stuff is, if you want to go mining a planet. The REE are there.
> They are also to be found in the planetary crust, provide there is some
> seriously evolved volcanism there... Isn't the Red Planet's seismically
> active period a bit short for that?
> 4) Go a little bit further... just beyond Mars are the asteroids. They are
> so small that there has been no gravitational segregation of their
> elements.
> If you want a financial return from space exploration, the asteroids are
> the
> pace to go. No dust storms there too...
>
> Cheers
> Axel
>
>
> -----Oorspronkelijk bericht-----
> Van: Rockhounds <rockhounds-bounces at rockhounds.drizzle.com> Namens Alan
> Silverstein
> Verzonden: zondag 15 maart 2020 4:44
> Aan: rockhounds at rockhounds.drizzle.com
> Onderwerp: Re: [Rockhounds] Terraforming Mars might be impossible? for now
>
> > It's OK to dream big, but don't forget that it's just a dream at the
> > moment...
>
> Sure.  I put my notion out there -- explore, evacuate, bombard, return
> -- just as a novel out-of-the-box concept to keep in mind.
>
> > I want to hear more about how we harness the sun's energy to
> > accurately move massive bodies 2.7 AU out from the sun's surface...
>
> Not sure if you keep up with various pubs like I do, such as Science News,
> Sky & Telescope, and the Planetary Report...  But I see that we've dreamed
> up quite a few creative ideas for how to modify asteroid orbits (of course
> mainly intended for collision avoidance).  None of them yet proven of
> course, but I think one test mission is in the works?  Anyway, just from
> memory, here's a summary of possibilities that I can recall:
>
> - Nuclear or other explosions, the brute force approach.
>
> - "Laser bees" or other methods using co-orbiting satellies to direct
>   solar energy onto hot-spots that act like low-thrust, long-term rocket
>   engines, blasting reaction mass off the object.
>
> - "Gravity tractors" where a sufficiently massive co-orbiting satellite
>   propels itself, and tugs on the asteroid.
>
> - Directed YORP effect (however you do it) turning the object into a
>   crude solar sail using solar photons.
>
> Of course in all cases, the smaller (less massive) the target, the better.
> Hydrating/oxygenating a whole planet, even a small one like Mars, would
> take
> a lot of raw mass, but possibly this can be done using a large number of
> smaller objects, each of which is easier to shuffle around.  In each case,
> depending on how patient you can be, it doesn't require a lot of oomph to
> redirect the orbit.  Yeah there's the angular momentum problem; people
> don't
> realize it can be harder to hit the sun than to escape the solar system;
> but
> you don't need to fully circularize the orbit (more delta-v), just
> ellipticize it enough to intersect.
> (Beyond that, though, I'm too far removed my undergrad days at Caltech to
> actually do the math, sorry.  :-)
>
> What was that sci-fi story years ago where a protagonist worked backwards
> from the desired result to play billiards with the Kuiper Belt?  One point
> there was that you don't have to massively redirect every single object, if
> you can swing it right, you can do some elegant momentum transfers, where
> one object, say, hits Mars, while another goes farther out, or escapes
> completely.
>
> Cheers,
> Alan Silverstein
>
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