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Another problem with longer flights



 
 
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  #21  
Old January 29th 09, 08:25 PM posted to sci.space.policy
Rick Jones[_3_]
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Posts: 587
Default Another problem with longer flights

Fred J. McCall wrote:
Reel in the weight, maneuver, reel it back out, and respin.


I think you left-out (perhaps it was implicit?) "unspin" there -
either before "reel in the weight" or perhaps during - otherwise,
conservation of angular momentum means the who thing starts spinning
faster as the weight is pulled-in right?

:And what happens if you can't keep the line taught.


Then you have much bigger problems, since that would mean that the
basic laws of physics had broken down.


Or elastisity in the tether?

rick jones
--
portable adj, code that compiles under more than one compiler
these opinions are mine, all mine; HP might not want them anyway...
feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...
  #22  
Old January 29th 09, 09:12 PM posted to sci.space.policy
jacob navia[_2_]
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Posts: 145
Default Another problem with longer flights

Martha Adams wrote:
I don't see a need for robotic exploration today. It's a side branch, a
dead end. Looking at space requires some *reason* to look at space, and
when we have people there, then everything changes and we have the
reason.



The reason is obvious. It is called

SCIENCE.

Science has emerged as the central activity of mankind. It has taken us
from an agricultural society, the fruit of the neolithicum revolution,
to a space faring society, the fruit of science and her daughter:
technology.

Investigating the solar system with robots can bring us immense
scientific knowledge:

o If we find living beings elsewhere we will at last have a crucial
COMPARISON point. What is specific to life in this planet? What is
universal to life as such?

There are serious hints of living beings in Mars, and there are good
conditions for life in Europa, and Enceladus, around Saturn. There
could be good conditions too in the Uranus or Neptune systems, we know
nothing about those.

o Comparing wheather systems from oither planets to our own increases
our understanding of how whether works in general.

o Exploring the solar system will give us a first view of where it is
possible to go, where we can find enough natural resources to
establish new settlements. We know now, that Europa has an ocean below
the ice. This means that we could establish a submarine settlement in
there (if there is no life or if the life there is not incompatible
with ours). The same in Enceladus.

For long trips (Jupiter, Saturn) we need to build big spaceships, able
to survive unscathed in space for years and years. This technology will
arrive slowly, and will arrive by developing practical applications now.

Pie in the sky dreams of going to Mars NOW will only lead to failures.
We just do not have the technology now, and it will take much more
time to develop it as we thought it would.


But we can have the pleasure of exploring another planet without the
inconvenience and costs associated with going there. We can send robots
and explore from here until we have the technology to go there.


--
jacob navia
jacob at jacob point remcomp point fr
logiciels/informatique
http://www.cs.virginia.edu/~lcc-win32
  #23  
Old January 29th 09, 10:44 PM posted to sci.space.policy
Pat Flannery
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Posts: 18,465
Default Another problem with longer flights



jacob navia wrote:

There are serious hints of living beings in Mars,


If by "beings" you mean bacteria...

We know now, that Europa has an ocean below
the ice. This means that we could establish a submarine settlement in
there (if there is no life or if the life there is not incompatible
with ours). The same in Enceladus.


The water pressure might be pretty high, as some estimates put the ice
cover as being many miles thick.

Pat
  #24  
Old January 29th 09, 10:51 PM posted to sci.space.policy
Rick Jones[_3_]
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Posts: 587
Default Another problem with longer flights

Pat Flannery wrote:
The water pressure might be pretty high, as some estimates put the
ice cover as being many miles thick.


That presumes Europa started thawed and then froze right - with the
ice expanding inwards as well as outwards? Otherwise, since water
expands when it freezes, if it started frozen and had its core thawed
by tidal (?) forces there might not be as much pressure.

rick jones
--
I don't interest myself in "why." I think more often in terms of
"when," sometimes "where;" always "how much." - Joubert
these opinions are mine, all mine; HP might not want them anyway...
feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...
  #25  
Old January 29th 09, 10:59 PM posted to sci.space.policy
jacob navia[_2_]
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Posts: 145
Default Another problem with longer flights

Pat Flannery wrote:


jacob navia wrote:

There are serious hints of living beings in Mars,


If by "beings" you mean bacteria...


If there are bacteria, there is surely something that eats those
bacteria.

Then, there are surely others that eat the bacterial eaters.

The bacteria could be at the base of a food chain.

We know now, that Europa has an ocean below
the ice. This means that we could establish a submarine settlement in
there (if there is no life or if the life there is not incompatible
with ours). The same in Enceladus.


The water pressure might be pretty high, as some estimates put the ice
cover as being many miles thick.

Pat


Most literature I have read put the ice cover as a very thin layer
of ice, since there was some dark liquid oozing out of the cracks in
many photographs sent by the Galileo spacecraft. An impact crater in the
ice hints also to a thin layer.

In any case we would not know anything about Europa if the robot
Galileo wouldn't have been there in the first place.

In any case we need to explore more with robots first. Imagine
sending people only to find out that they can't establish anything
there... What a waste of time!

You just confirm what I am arguing :-)

--
jacob navia
jacob at jacob point remcomp point fr
logiciels/informatique
http://www.cs.virginia.edu/~lcc-win32
  #26  
Old January 30th 09, 01:39 AM posted to sci.space.policy
Jonathan
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Posts: 215
Default Another problem .... This Research is Suspicious!


"Martha Adams" wrote in message news:YMmgl.664

One reason why this is good to do, is many people are talking about space
travel, and a very few of them are actually saying something. But they all
miss a point: that *travel* is a brief temporary condition of getting
somewhere. Then when you have arrived, what do you do? Terran-centered
thinkers say, "Go back." That's bad thinking in a space context: the sensible
thing to do, once you're arrived, is *stay there.*



So, just one week into the new administration, out comes research
showing rather convincingly that a manned mission to Mars is, for the
foreseeable future...a pipe-dream!

Huh. Funny about that!

Of course, the entire premise of the 'Vision' revolved around a manned
mission to Mars. It's the core justification for the new moon shot.
And just like that....poof... the rug is yanked quickly, cleanly and with
scientific precision, right out from under the Signature Goal of NASA.

Just as President Bush did the same to the goals he inherited.
From the X-33, to Space Solar Power, Sert, spaceports and such
which were summarily deep-sixed with the arrival of Bush.

So now another new era is upon us!

Which will revolve around the issues of climate change, energy etc.
Instead of a military driven cold-war race to the Moon with
the Chinese...the true goal of the now vanquished 'Vision'.

I'm not going to say 'I told you so', not going to say
that since day one I came here I've been telling y'all
the moon and mars are mirages for military motives.
And as such they'll never survive. I'm not going to tell
you any of these simple facts~ It wouldn't be prudent.

All I want to say is....IT'S ABOUT TIME!

About time...everyone came to their senses and
started dreaming about things that ...are...possible
practical and urgently needed.

It's not every day the agency devoted to our future
gets a chance to wipe the slate clean and reinvent itself
.....from scratch.

'bout time!


Jonathan

s







Titeotwawki -- mha [sci.space.policy 2009 Jan 29]






  #27  
Old January 30th 09, 01:49 AM posted to sci.space.policy
Jonathan
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Posts: 215
Default Another problem with longer flights


"jacob navia" wrote in message
...

In any case we need to explore more with robots first. Imagine
sending people only to find out that they can't establish anything
there... What a waste of time!

You just confirm what I am arguing :-)




This research certainly means the debate between robots and humans
as explorers has ended. The winner is obvious.






--
jacob navia
jacob at jacob point remcomp point fr
logiciels/informatique
http://www.cs.virginia.edu/~lcc-win32



  #28  
Old January 30th 09, 03:06 AM posted to sci.space.policy
[email protected]
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Posts: 2
Default Another problem with longer flights

On Jan 30, 1:45*am, Fred J. McCall wrote:
jacob navia wrote:
:Fred J. McCall wrote:

: jacob navia wrote:
:
: :Fred J. McCall wrote:
: :
: : No "huge, rotating, ship, [sic]" is required. *A much smaller ship, a
: : rope, and a counterweight will achieve the same end.
: :
: :
: :
: :Science fiction. You need shielding, and a lot of it. If not, you will
: :arrive with a life expectancy of a few years. Read about radiation
: :dangers in space. That is why I said "shielded".
: :
:
: You don't need hundreds of meters of shielding, you silly ******.
:
:
:Obviously Mr McCall is unable to put forward
:any argumentation, and just throws insults around. That is
:quite typical for him.
:

Obviously Mr Navia is unable to understand that a lousy couple feet of
water (the 'massive shielding' he himself called out) doesn't require
a huge ship. *The huge ship was required because Mr Navia was too
stupid to imagine any way to get 'artificial gravity' other than a
huge ship spinning on its axis.

snip

:
: :But obviously you haven't researched this problem.
:
: Obviously you're too bloody stupid to be in this conversation.
:
:Yeah *sure. The best way to disguise your lack of any arguments.
:

As usual, Mr Navia fails to engage his brain in the least.

:
:"Just send people there". If they die, doesn't matter since Mr McCall
:is not going to be part of those that get killed.
:

Mr Navia now compounds his stupidity with outright lies, since I've
made no such statement as he quotes above. *Mr Navia imagines that
because HE is too stupid to think of things that everyone else must
be, too.

:
:And I was pointing to the dangers of lack of gravity. No tested
:technology exists. There are a lot of untested ideas and no spaceship
:with artificial gravity has ever been built.
:
:Pie in the sky.
:

We've known about centripetal force for a long, long time. *Basic
physics.

A pity such simple concepts are beyond the ken of Mr Navia.

--
"Ignorance is preferable to error, and he is less remote from the
*truth who believes nothing than he who believes what is wrong."
* * * * * * * * * * * * * * * *-- Thomas Jefferson


What is your goddam problem.

If you cant deal with the facts fine, if you cant be bothered to do
any real research because it doesnt agree with you, again fine.

But why bother posting your rubbish here abusing people because they
wont automatically agree with you. Especially when even a cursory
glance at the history of this group shows you to be a clueless git for
the majority of the time.

  #29  
Old January 30th 09, 03:58 AM posted to sci.space.policy
Fred J. McCall[_3_]
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Posts: 10,018
Default Another problem with longer flights

wrote:

:On Jan 30, 1:45*am, Fred J. McCall wrote:
: jacob navia wrote:
: :Fred J. McCall wrote:
:
: : jacob navia wrote:
: :
: : :Fred J. McCall wrote:
: : :
: : : No "huge, rotating, ship, [sic]" is required. *A much smaller ship, a
: : : rope, and a counterweight will achieve the same end.
: : :
: : :
: : :
: : :Science fiction. You need shielding, and a lot of it. If not, you will
: : :arrive with a life expectancy of a few years. Read about radiation
: : :dangers in space. That is why I said "shielded".
: : :
: :
: : You don't need hundreds of meters of shielding, you silly ******.
: :
: :
: :Obviously Mr McCall is unable to put forward
: :any argumentation, and just throws insults around. That is
: :quite typical for him.
: :
:
: Obviously Mr Navia is unable to understand that a lousy couple feet of
: water (the 'massive shielding' he himself called out) doesn't require
: a huge ship. *The huge ship was required because Mr Navia was too
: stupid to imagine any way to get 'artificial gravity' other than a
: huge ship spinning on its axis.
:
: snip
:
: :
: : :But obviously you haven't researched this problem.
: :
: : Obviously you're too bloody stupid to be in this conversation.
: :
: :Yeah *sure. The best way to disguise your lack of any arguments.
: :
:
: As usual, Mr Navia fails to engage his brain in the least.
:
: :
: :"Just send people there". If they die, doesn't matter since Mr McCall
: :is not going to be part of those that get killed.
: :
:
: Mr Navia now compounds his stupidity with outright lies, since I've
: made no such statement as he quotes above. *Mr Navia imagines that
: because HE is too stupid to think of things that everyone else must
: be, too.
:
: :
: :And I was pointing to the dangers of lack of gravity. No tested
: :technology exists. There are a lot of untested ideas and no spaceship
: :with artificial gravity has ever been built.
: :
: :Pie in the sky.
: :
:
: We've known about centripetal force for a long, long time. *Basic
: physics.
:
: A pity such simple concepts are beyond the ken of Mr Navia.
:
: --
: "Ignorance is preferable to error, and he is less remote from the
: *truth who believes nothing than he who believes what is wrong."
: * * * * * * * * * * * * * * * *-- Thomas Jefferson
:
:What is your goddam problem.
:

My goddam problem is lackbrained ****wits like you and Navia.

:
:If you cant deal with the facts fine, if you cant be bothered to do
:any real research because it doesnt agree with you, again fine.
:

I probably know more about the issues than either you or Navia

:
:But why bother posting your rubbish here abusing people because they
:wont automatically agree with you. Especially when even a cursory
:glance at the history of this group shows you to be a clueless git for
:the majority of the time.
:

I treat Navia like a ****wit and insult him because he IS a ****wit
and insults people. He gets what he gives. Now so do you.

Get over it.

So just who the **** do you think you are, sonny? Profanity make you
feel all grown up, does it? Shut up and go do your spelling
homework...

--
"He missed an invaluable opportunity to hold his tongue."
-- Andrew Lang
  #30  
Old January 30th 09, 03:57 PM posted to sci.space.policy
Rand Simberg[_1_]
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Posts: 8,311
Default Another problem .... This Research is Suspicious!

On Thu, 29 Jan 2009 19:39:38 -0500, in a place far, far away,
"Jonathan" made the phosphor on my monitor glow in
such a way as to indicate that:

So, just one week into the new administration, out comes research
showing rather convincingly that a manned mission to Mars is, for the
foreseeable future...a pipe-dream!

Huh. Funny about that!

Of course, the entire premise of the 'Vision' revolved around a manned
mission to Mars.


No, it didn't.
 




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