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[PS] Liquid Water on Mars! Really for Real This Time (Probably)



 
 
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  #11  
Old August 3rd 18, 12:15 PM posted to sci.space.science
Niels J°rgen Kruse[_2_]
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Posts: 14
Default [PS] Liquid Water on Mars! Really for Real This Time (Probably)

Jeff Findley wrote:

You're right. I got the two mixed up. Kuiper belt is closer in and
according to Wikipedia it should contain an estimated "100,000 KBOs over
100 km (62 mi) in diameter". You start with some small ones (easier to
move in a "reasonable" timescale) then work your way up in size as the
reliability and size goes up on the tugs.


I would think you would look for objects that are about to have a close
encounter and nudge them so one drops in and one is flung out.

--
Mvh./Regards, Niels J°rgen Kruse, Vanl°se, Denmark

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  #12  
Old August 8th 18, 04:54 PM posted to sci.space.science
Jeff Findley[_6_]
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Posts: 1,618
Default [PS] Liquid Water on Mars! Really for Real This Time (Probably)

In article ,
says...

Jeff Findley wrote:

You're right. I got the two mixed up. Kuiper belt is closer in and
according to Wikipedia it should contain an estimated "100,000 KBOs over
100 km (62 mi) in diameter". You start with some small ones (easier to
move in a "reasonable" timescale) then work your way up in size as the
reliability and size goes up on the tugs.


I would think you would look for objects that are about to have a close
encounter and nudge them so one drops in and one is flung out.


Well, yes, the actual implementation might be far more complex than
"nuclear tugs to move Kuiper belt objects".

One possible argument against flinging one object in while flinging
another out would be loss of potentially useful mass from the solar
system. The mass we have is the mass we have to work with. Making
everything as mass efficient as possible would be the goal. Of course,
you'd have to run the numbers on all this. It could very well be that
flinging one mass out saves so much mass on the one directed inward that
it's worth the cost. But with highly efficient nuclear engines, I kind
of doubt that.

Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.

  #13  
Old August 9th 18, 01:59 AM posted to sci.space.science
Alain Fournier[_3_]
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Posts: 337
Default [PS] Liquid Water on Mars! Really for Real This Time (Probably)

Le Aug/8/2018 ├* 11:54 AM, Jeff Findley a ├ęcrit┬*:
In article ,
says...

Jeff Findley wrote:

You're right. I got the two mixed up. Kuiper belt is closer in and
according to Wikipedia it should contain an estimated "100,000 KBOs over
100 km (62 mi) in diameter". You start with some small ones (easier to
move in a "reasonable" timescale) then work your way up in size as the
reliability and size goes up on the tugs.


I would think you would look for objects that are about to have a close
encounter and nudge them so one drops in and one is flung out.


Well, yes, the actual implementation might be far more complex than
"nuclear tugs to move Kuiper belt objects".

One possible argument against flinging one object in while flinging
another out would be loss of potentially useful mass from the solar
system. The mass we have is the mass we have to work with. Making
everything as mass efficient as possible would be the goal. Of course,
you'd have to run the numbers on all this. It could very well be that
flinging one mass out saves so much mass on the one directed inward that
it's worth the cost. But with highly efficient nuclear engines, I kind
of doubt that.


It doesn't have to be one object flung out and the other drops in. Many
scenarios are possible. I think the most likely scenario would be one
object is flung into a slightly more energetic (meaning kind of higher)
orbit, the other one goes near Neptune and from there to Mars. Even the
one going to a more energetic orbit, might be in an orbit that makes it
easier to go to Mars. That orbit might be more eccentric. It is easier
to bring down an object in an eccentric orbit than a circular one. Well
that last sentence is an over simplification, but I think it gives the
right idea.

Even without using a planet, it doesn't have to be one flung out the
other drops in. If one object gets into a more energetic orbit the other
must go into a less energetic orbit because of conversation of energy.
But the more energetic orbit doesn't have to bring the object further
away from the sun. The one with the more energetic orbit could be on a
hyperbolic path that crosses Mars. It would therefore slam into Mars
quite hard, but I don't that would be very important. Once you accept
having objects from the Kuiper belt slamming into Mars, a few more km/s
wont do much difference.


Alain Fournier

  #14  
Old August 9th 18, 12:12 PM posted to sci.space.science
Alain Fournier[_3_]
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Posts: 337
Default [PS] Liquid Water on Mars! Really for Real This Time (Probably)

On Aug/8/2018 at 8:59 PM, Alain Fournier wrote :
Le Aug/8/2018 ├* 11:54 AM, Jeff Findley a ├ęcrit┬*:
In article ,
says...

Jeff Findley wrote:

You're right.┬* I got the two mixed up.┬* Kuiper belt is closer in and
according to Wikipedia it should contain an estimated "100,000 KBOs
over
100 km (62 mi) in diameter".┬* You start with some small ones (easier to
move in a "reasonable" timescale) then work your way up in size as the
reliability and size goes up on the tugs.

I would think you would look for objects that are about to have a close
encounter and nudge them so one drops in and one is flung out.


Well, yes, the actual implementation might be far more complex than
"nuclear tugs to move Kuiper belt objects".

One possible argument against flinging one object in while flinging
another out would be loss of potentially useful mass from the solar
system.┬* The mass we have is the mass we have to work with.┬* Making
everything as mass efficient as possible would be the goal.┬* Of course,
you'd have to run the numbers on all this.┬* It could very well be that
flinging one mass out saves so much mass on the one directed inward that
it's worth the cost.┬* But with highly efficient nuclear engines, I kind
of doubt that.


It doesn't have to be one object flung out and the other drops in. Many
scenarios are possible. I think the most likely scenario would be one
object is flung into a slightly more energetic (meaning kind of higher)
orbit, the other one goes near Neptune and from there to Mars. Even the
one going to a more energetic orbit, might be in an orbit that makes it
easier to go to Mars. That orbit might be more eccentric. It is easier
to bring down an object in an eccentric orbit than a circular one. Well
that last sentence is an over simplification, but I think it gives the
right idea.

Even without using a planet, it doesn't have to be one flung out the
other drops in. If one object gets into a more energetic orbit the other
must go into a less energetic orbit because of conversation of energy.
But the more energetic orbit doesn't have to bring the object further
away from the sun. The one with the more energetic orbit could be on a
hyperbolic path that crosses Mars. It would therefore slam into Mars
quite hard, but I don't that would be very important. Once you accept
having objects from the Kuiper belt slamming into Mars, a few more km/s
wont do much difference.


Oups! That was nonsense. Except for Pluto and a few others of similar
sized Kuiper belt objects passing close to another Kuiper belt object
will only make a very small trajectory change. It isn't worth the
trouble to get a gravity assist from another Kuiper belt object (except
if it is with one with a mass close to Pluto). So I would think that to
move Kuiper belt objects to Mars, you would find one that is going close
to Neptune, nudge its trajectory so Neptune sends it towards Mars,
possibly with a detour by some other planet.


Alain Fournier

  #15  
Old August 9th 18, 03:32 PM posted to sci.space.science
Jeff Findley[_6_]
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Posts: 1,618
Default [PS] Liquid Water on Mars! Really for Real This Time (Probably)

In article , says...

Le Aug/8/2018 Ó 11:54 AM, Jeff Findley a Úcrit*:
In article ,

says...

Jeff Findley wrote:

You're right. I got the two mixed up. Kuiper belt is closer in and
according to Wikipedia it should contain an estimated "100,000 KBOs over
100 km (62 mi) in diameter". You start with some small ones (easier to
move in a "reasonable" timescale) then work your way up in size as the
reliability and size goes up on the tugs.

I would think you would look for objects that are about to have a close
encounter and nudge them so one drops in and one is flung out.


Well, yes, the actual implementation might be far more complex than
"nuclear tugs to move Kuiper belt objects".

One possible argument against flinging one object in while flinging
another out would be loss of potentially useful mass from the solar
system. The mass we have is the mass we have to work with. Making
everything as mass efficient as possible would be the goal. Of course,
you'd have to run the numbers on all this. It could very well be that
flinging one mass out saves so much mass on the one directed inward that
it's worth the cost. But with highly efficient nuclear engines, I kind
of doubt that.


It doesn't have to be one object flung out and the other drops in. Many
scenarios are possible. I think the most likely scenario would be one
object is flung into a slightly more energetic (meaning kind of higher)
orbit, the other one goes near Neptune and from there to Mars. Even the
one going to a more energetic orbit, might be in an orbit that makes it
easier to go to Mars. That orbit might be more eccentric. It is easier
to bring down an object in an eccentric orbit than a circular one. Well
that last sentence is an over simplification, but I think it gives the
right idea.

Even without using a planet, it doesn't have to be one flung out the
other drops in. If one object gets into a more energetic orbit the other
must go into a less energetic orbit because of conversation of energy.
But the more energetic orbit doesn't have to bring the object further
away from the sun. The one with the more energetic orbit could be on a
hyperbolic path that crosses Mars. It would therefore slam into Mars
quite hard, but I don't that would be very important. Once you accept
having objects from the Kuiper belt slamming into Mars, a few more km/s
wont do much difference.



I believe that we're in violent agreement here. Gravity assists (likely
multiple gravity assists from multiple bodies) absolutely would help to
conserve the mass of the body being redirected to Mars. The details of
the actual paths are quite complex and hard to solve so I didn't want to
get into the gory details here.

My only objection was to flinging mass out of the solar system
completely. That, to me anyway, seems shortsighted since engines will
only continue to get better over hundreds (thousands?) of years
(chemical to ion to nuclear fission to nuclear fusion to ???).

Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.

  #16  
Old August 10th 18, 11:49 AM posted to sci.space.science
Fred J. McCall[_3_]
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Posts: 9,679
Default [PS] Liquid Water on Mars! Really for Real This Time (Probably)

Jeff Findley wrote on Wed, 8 Aug 2018
11:54:41 EDT:

In article ,
says...

Jeff Findley wrote:

You're right. I got the two mixed up. Kuiper belt is closer in and
according to Wikipedia it should contain an estimated "100,000 KBOs over
100 km (62 mi) in diameter". You start with some small ones (easier to
move in a "reasonable" timescale) then work your way up in size as the
reliability and size goes up on the tugs.


I would think you would look for objects that are about to have a close
encounter and nudge them so one drops in and one is flung out.


Well, yes, the actual implementation might be far more complex than
"nuclear tugs to move Kuiper belt objects".

One possible argument against flinging one object in while flinging
another out would be loss of potentially useful mass from the solar
system. The mass we have is the mass we have to work with. Making
everything as mass efficient as possible would be the goal. Of course,
you'd have to run the numbers on all this. It could very well be that
flinging one mass out saves so much mass on the one directed inward that
it's worth the cost. But with highly efficient nuclear engines, I kind
of doubt that.


Yes. I would expect that 'flinging out another' would always be more
efficient if you ran it through a nuclear thermal engine to speed it
up in the direction you want to fling it.


--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw

 




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