Quiet?

On Fri, 13 Aug 2010 14:48:01 -0700 (PDT), Hop
wrote:

Well, Rand was about 50% worthwhile posts and 50% idealogical
flamewar.

50% is still about triple the signal to noise ratio of most the
current posters.

Damning with faint praise, I see. I'm not sure if Rand helped or hurt
sci.space more. Probably helped, but his endless debates with Chomko
got old real fast.

Brian

On 8/13/2010 1:48 PM, Hop wrote:

50% is still about triple the signal to noise ratio of most the
current posters.

Yes, but who _doesn't_ want a really good deal on those Chinese-made
replica tennis shoes?

Pat

On 8/13/2010 1:48 PM, Hop wrote:
On Aug 13, 7:14 am, Pat wrote:

He sure went off on me about my BA degree in History/Political Science.

(yawn)

Just for that, I'm going to see if I can get in touch with North
Dakota's members in the House Of Representatives, who can propose a bill
that will move up to the Senate, which can then return to the House
after they modify it...which then can go to a joint House/Senate
Committee for revision...well, let's not get specific, but if things
work the way I intend, inside of five years your testicles and body can
be in two different places at the same time, if the Supreme Court says
that's okay. :-D

Pat

On 8/14/2010 2:46 AM, Pat Flannery wrote:
Just for that, I'm going to see if I can get in touch with North
Dakota's members in the House Of Representatives, who can propose a bill
that will move up to the Senate, which can then return to the House
after they modify it...which then can go to a joint House/Senate
Committee for revision...well, let's not get specific, but if things
work the way I intend, inside of five years your testicles and body can
be in two different places at the same time, if the Supreme Court says
that's okay. :-D

Oh, I almost forgot:
2,000 METERS OF WATER ICE IN GREENLAND!
CAN YOU UNDERSTAND THAT?
_2,000_ METERS!!!!! :-D

Pat

On Aug 14, 4:16 am, Pat Flannery wrote:

2,000 METERS OF WATER ICE IN GREENLAND!

Naw.

Since Zachary Sharp can find dry dirt in the Atacama desert, that
proves our entire planet is drier than a bone.

http://www.geeksaresexy.net/2010/08/...e-red-herring/

On 8/15/2010 8:42 PM, Hop wrote:
On Aug 14, 4:16 am, Pat wrote:

2,000 METERS OF WATER ICE IN GREENLAND!

Naw.

Since Zachary Sharp can find dry dirt in the Atacama desert, that
proves our entire planet is drier than a bone.

http://www.geeksaresexy.net/2010/08/...e-red-herring/

One thing you have to watch out for in that regard is how easy the water
is to get out of the rock; a lot of rocks contain water as part of their
chemical structure, but if its locked up so tight in the form of parts
of the minerals that they are composed of, it can be very energy
intensive to get the water out.
The comet ice is a lot better alternative if you want to extract it for
a lunar base.
I had a thought on this BTW; if the stuff is really two meters thick...
and radar goes right through it and sees the regolith underneath...then
how about imaging the same spot inside of one of the polar craters from
a low orbit satellite with both a tight beam radar and laser altimeter
at once?
If the altitude reading on the radar comes out two meters greater than
the laser shows, then there's your ice.
You might be able to determine what exact type of ice it was by
examining the spectra of the backscatter from the laser.
Since the Moon has no measurable atmosphere to slow a satellite down, it
could fly over the target crater at very low altitude; maybe at only a
few hundred meters if you slowed it down on approach to the target so
its altitude dipped, then sped it up again once it had overflown the
crater so it again climbed above any danger of collision with lunar terrain.

Pat

On Mon, 16 Aug 2010 01:57:34 -0800, Pat Flannery
wrote:

On 8/15/2010 8:42 PM, Hop wrote:
On Aug 14, 4:16 am, Pat wrote:

2,000 METERS OF WATER ICE IN GREENLAND!

Naw.

Since Zachary Sharp can find dry dirt in the Atacama desert, that
proves our entire planet is drier than a bone.

http://www.geeksaresexy.net/2010/08/...e-red-herring/

One thing you have to watch out for in that regard is how easy the water
is to get out of the rock; a lot of rocks contain water as part of their
chemical structure, but if its locked up so tight in the form of parts
of the minerals that they are composed of, it can be very energy
intensive to get the water out.
The comet ice is a lot better alternative if you want to extract it for
a lunar base.
I had a thought on this BTW; if the stuff is really two meters thick...
and radar goes right through it and sees the regolith underneath...then
how about imaging the same spot inside of one of the polar craters from
a low orbit satellite with both a tight beam radar and laser altimeter
at once?
If the altitude reading on the radar comes out two meters greater than
the laser shows, then there's your ice.
You might be able to determine what exact type of ice it was by
examining the spectra of the backscatter from the laser.
Since the Moon has no measurable atmosphere to slow a satellite down, it
could fly over the target crater at very low altitude; maybe at only a
few hundred meters if you slowed it down on approach to the target so
its altitude dipped, then sped it up again once it had overflown the
crater so it again climbed above any danger of collision with lunar terrain.

Pat,

I'm not sure I understand the flight profile you're talking about.
Are you talking about something that, for lack of a better term, would
look like the profile that would have been flown in an aborted lunar
landing? (come in low, brake to reduce speed, then tear ass outa
there)

There would be a huge fuel penalty to burn off all that speed, and
then gain it back again.

take care,
Scott

On 8/16/2010 2:01 AM, Scott Stevenson wrote:


I'm not sure I understand the flight profile you're talking about.
Are you talking about something that, for lack of a better term, would
look like the profile that would have been flown in an aborted lunar
landing? (come in low, brake to reduce speed, then tear ass outa
there)

All lunar satellite orbits are long-term unstable due to the twin
problems of the MASCONs and their interactions with the position of the
three-body problem of the Earth-Moon-Sun.
Sooner or, later anything put into lunar orbit ends up either hitting
the Moon or getting tossed out of lunar orbit into solar orbit.
But at least for a few orbits, you can at least aim the probe right for
the initial entry to the lunar gravity field and have it go around in a
fairly predictable manner, as project Apollo did for the CSM while
awaiting the ascent of the LM.
My concept would be to use the Apollo MASCON maps that were generated by
the Lunar Orbiter probes to at least throw the spacecraft into a
predictable trajectory that had its initial perigee at the low point
over one of the lunar poles, and its apogee at a far higher point in a
elliptical orbit.
Figuring the whole works out in regards to MASCONs and Earth-Moon-Sun
gravitational interaction for further orbits would be complex, but at
least in the first dive over the lunar pole you should be able to get it
to pass over the intended imaging point at very low altitude, clearing
any high terrain on the way in, and then only need to add some speed to
it to make sure its perigee didn't make it hit higher terrain on the way
out as it started climbing back towards its orbital apogee.
The radar, not the laser, is the reason for getting it to pass as low as
possible over the target crater. Due to the lower frequency of the radar
on the electromagnetic spectrum than the optical part that the laser
will see, its accuracy will be inherently lower.
For the radar, the lower, the better.


There would be a huge fuel penalty to burn off all that speed, and
then gain it back again.

I'm thinking of several dozen FPS here max; you already are going to
need hydrazine thrusters on it to do the careful fine targeting of the
orbit on the way in to get the perigee at the intended low altitude, so
adding some more fuel to make a little "dip" as needed if terrain
collision becomes a threat on the way in or out from the highly
elliptical orbit shouldn't be much of a problem.
Of course, if you want to keep it simple you don't do the "dip" and let
it follow its natural orbital path from a slightly higher altitude.
Ice depth measurement may be off by a few millimeters due to the higher
altitude at perigee, but things get a lot simpler and more reliable to do.
This could actually be a pretty simple spacecraft to build and launch if
you kept the instrumentation to a minimum on it - it needs a fairly low
powered laser, spectroscope, and tight-beamed radar capable of being
powered for only a few minutes if you only want to do one pass over
either the north or south polar craters; you wouldn't even need solar
arrays for this, as it could be done by battery power.
It could ride along as a separable parasite payload on another lunar
probe, capable of being launched by something like a Delta II.

Pat

On Aug 16, 2:57 am, Pat Flannery wrote:
On 8/15/2010 8:42 PM, Hop wrote:

On Aug 14, 4:16 am, Pat wrote:

2,000 METERS OF WATER ICE IN GREENLAND!

Naw.

Since Zachary Sharp can find dry dirt in the Atacama desert, that
proves our entire planet is drier than a bone.

http://www.geeksaresexy.net/2010/08/...may-be-red-her...

One thing you have to watch out for in that regard is how easy the water
is to get out of the rock; a lot of rocks contain water as part of their
chemical structure, but if its locked up so tight in the form of parts
of the minerals that they are composed of, it can be very energy
intensive to get the water out.
The comet ice is a lot better alternative if you want to extract it for
a lunar base.
I had a thought on this BTW; if the stuff is really two meters thick...
and radar goes right through it and sees the regolith underneath...then
how about imaging the same spot inside of one of the polar craters from
a low orbit satellite with both a tight beam radar and laser altimeter
at once?
If the altitude reading on the radar comes out two meters greater than
the laser shows, then there's your ice.
You might be able to determine what exact type of ice it was by
examining the spectra of the backscatter from the laser.
Since the Moon has no measurable atmosphere to slow a satellite down, it
could fly over the target crater at very low altitude; maybe at only a
few hundred meters if you slowed it down on approach to the target so
its altitude dipped, then sped it up again once it had overflown the
crater so it again climbed above any danger of collision with lunar terrain.

Pat


I don't know enough about radar to know if this would be effective.

Russia and India are planning a joint mission in 2013, about the same
time as China's proposed Change'e lunar landing.
http://www.bbc.co.uk/news/science-environment-10960409
http://www.lpi.usra.edu/meetings/lpsc2010/pdf/1141.pdf

I believe this mission was planned before the Chandrayan-1 discovery.
Hopefully they will change the site to one of the locations suspected
to have thick ice sheets. Although broken line of sight might be a
show stopper for a teleoperated rover.

It's interesting the Indian rover is 15 kilograms. A far cry from the
750 kg Lunokhod rovers of the 1970s! Moore's Law will continue to be a
game changer when it comes to space exploration.

I am hoping for rovers with stereoscopic eyes, arms and dextrous hands
that mimic the motions of their operator. Not only would this be a
very able tool, but it could be a public relations bonanza.
Teleoperated Wall-Es might be something the public could relate to.

The Japanese have been talking about a robotic moon base for years.
Maybe recent discoveries will light a fire under them to actually
start bending metal towards this project.

A few bases scattered over various longitudes that far north would
still be close neighbors. I like to imagine robotic bases selling
power to one another. A Russian/Indian base on the day side of the
terminator could beam power to their Japanese neighbors on the night
side. 14 days later, vice versa. This might be a way to deal with the
14 days of night.