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Lunar modules still in orbit?



 
 
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  #1  
Old November 10th 07, 02:11 AM posted to sci.space.history
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Default Lunar modules still in orbit?

What ever happened to the Lunar Modules once they were no longer
needed for the apollo missions?

Do we have 7 of them in orbit around the moon right now? If not, how
were they jettisoned in a way that ensured they would not stay in some
lunar orbit?

Anyone with thoughts on possibilities? Stan
  #3  
Old November 10th 07, 04:02 AM posted to sci.space.history
OM[_6_]
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Default Lunar modules still in orbit?

On Fri, 09 Nov 2007 21:11:13 -0400, wrote:

What ever happened to the Lunar Modules once they were no longer
needed for the apollo missions?

Do we have 7 of them in orbit around the moon right now? If not, how
were they jettisoned in a way that ensured they would not stay in some
lunar orbit?

Anyone with thoughts on possibilities?


http://en.wikipedia.org/wiki/Apollo_...dules_produced

....This Wiki article - obviously free of any tampering by catamite
Limey schoolpunks - gives the info you need.

OM
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  #4  
Old November 10th 07, 03:16 PM posted to sci.space.history
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Default Lunar modules still in orbit?

On Sat, 10 Nov 2007 03:00:58 GMT, Brian Thorn
wrote:

Lunar orbits are unstable over long-ish durations. They crashed, some
deliberately... to provide seismic data.


Thanks to the wikipedia links 2 others provided, it appears Apollo 11
and 16 LM were left in lunar orbit and eventually crashed into the
moon. My questions:
1. forgetting mascons for the moment, wouldn't the effects of the
earth and sun on a lunar orbit tend, over time, to pull the LM into a
higher orbit around the moon?
2. considering mascons as well as outside gravity effects, wouldn't
the effect of these be only to alter the orbit, but not cause a crash
onto the moon? My limited background suggest to me that the LM would
have to lose a lot of energy in order to lower it's orbit enough to
crash. What would be the process that causes this?
Thanks to all for the help. Stan
  #5  
Old November 10th 07, 03:30 PM posted to sci.space.history
Rand Simberg[_1_]
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Default Lunar modules still in orbit?

On Sat, 10 Nov 2007 10:16:52 -0400, in a place far, far away,
made the phosphor on my monitor glow in such a
way as to indicate that:

On Sat, 10 Nov 2007 03:00:58 GMT, Brian Thorn
wrote:

Lunar orbits are unstable over long-ish durations. They crashed, some
deliberately... to provide seismic data.


Thanks to the wikipedia links 2 others provided, it appears Apollo 11
and 16 LM were left in lunar orbit and eventually crashed into the
moon. My questions:
1. forgetting mascons for the moment, wouldn't the effects of the
earth and sun on a lunar orbit tend, over time, to pull the LM into a
higher orbit around the moon?
2. considering mascons as well as outside gravity effects, wouldn't
the effect of these be only to alter the orbit, but not cause a crash
onto the moon? My limited background suggest to me that the LM would
have to lose a lot of energy in order to lower it's orbit enough to
crash. What would be the process that causes this?


It doesn't have to lose any energy at all (and in fact
doesn't--orbital motion is conservative). All it has to do is
increase the eccentricity to the point at which perilune goes below
the lunar surface (or just a mountain).
  #6  
Old November 10th 07, 04:45 PM posted to sci.space.history
Greg D. Moore \(Strider\)
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Posts: 2,865
Default Lunar modules still in orbit?

wrote in message
...
On Sat, 10 Nov 2007 03:00:58 GMT, Brian Thorn
wrote:

Lunar orbits are unstable over long-ish durations. They crashed, some
deliberately... to provide seismic data.


Thanks to the wikipedia links 2 others provided, it appears Apollo 11
and 16 LM were left in lunar orbit and eventually crashed into the
moon. My questions:
1. forgetting mascons for the moment, wouldn't the effects of the
earth and sun on a lunar orbit tend, over time, to pull the LM into a
higher orbit around the moon?
2. considering mascons as well as outside gravity effects, wouldn't
the effect of these be only to alter the orbit, but not cause a crash
onto the moon? My limited background suggest to me that the LM would
have to lose a lot of energy in order to lower it's orbit enough to
crash. What would be the process that causes this?


The orbit becomes eccentric enough until it crashes into the Moon.

Note the orbits were fairly low to begin with.

On one of the later Apollo missions, the CSM drifter low enough overnight as
to cause alarm at Mission Control when they realized they missed a mountain
by a lot lower margin than they wanted. (It was still 5 miles or more I
believe but still a bit alarming.)


Thanks to all for the help. Stan



  #7  
Old November 11th 07, 02:48 AM posted to sci.space.history
Fevric J Glandules[_2_]
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Posts: 68
Default Lunar modules still in orbit?

On Sat, 10 Nov 2007 10:45:48 -0500, Greg D. Moore \(Strider\) wrote:

On one of the later Apollo missions, the CSM drifter low enough overnight as
to cause alarm at Mission Control when they realized they missed a mountain
by a lot lower margin than they wanted. (It was still 5 miles or more I
believe but still a bit alarming.)


Any idea which one?

--
One way ticket from Mornington Crescent to Tannhauser Gate please.
  #9  
Old November 12th 07, 02:21 AM posted to sci.space.history
Rand Simberg[_1_]
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Posts: 8,311
Default Lunar modules still in orbit?

On Sun, 11 Nov 2007 21:00:21 -0400, in a place far, far away,
made the phosphor on my monitor glow in such a
way as to indicate that:

On Sat, 10 Nov 2007 14:30:16 GMT,
h (Rand
Simberg) wrote:


It doesn't have to lose any energy at all (and in fact
doesn't--orbital motion is conservative). All it has to do is
increase the eccentricity to the point at which perilune goes below
the lunar surface (or just a mountain).


But would this **always** happen if a LM were left in orbit?


It depends on how low an orbit it is. The LM was sufficiently low
that, yes, it would *always* happen over time.

Is this increase in eccentricity something that is guaranteed to
happen? Or happens only depending on resulting geometry?

For example, if a LM was left in orbit where external mass
distributions were in opposition, so to speak, would we find that the
LM would effectively orbit forever then? For example, I'm thinking of
the case when the moon's geometric centre was directly between the LM
and moon's mascons, and the earth and sun.
Now the LM at release should be at it's lowest possible point to the
lunar surface.
And hence from this position the LM could orbit basically forever?

Guess I'm trying to build a case where a LM could basically orbit
forever. Is this possible then?


It is so unlikely as to be impossible, yes.
  #10  
Old November 17th 07, 01:07 PM posted to sci.space.history
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Posts: 62
Default Lunar modules still in orbit?



It doesn't have to lose any energy at all (and in fact
doesn't--orbital motion is conservative). All it has to do is
increase the eccentricity to the point at which perilune goes below
the lunar surface (or just a mountain).


But would this **always** happen if a LM were left in orbit?


It depends on how low an orbit it is. The LM was sufficiently low
that, yes, it would *always* happen over time.


What's the lowest orbitting satellite of the moon right now? Are
there any that are expected to basically orbit the moon forever?


How low can an orbit be around the moon and expect not to crash onto
the moon?


 




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