NASA formally unveils lunar exploration architecture

George Evans wrote:

I've been reading what Jeff Findley gave me to read among other things. From
the JPL site:

"Objects can settle in an orbit around a Lagrange point. Orbits around the
three collinear points, L1, L2, and L3, are *unstable*. They last but days
before the object will break away. L1 and L2 last about 23 days..."

The amount of thrust required to stay in orbit is miniscule. Objects
orbiting the Sun-Earth L1 point need less than fifty meters per second
of delta-V every *year*.

But the important thing to recognize is that halo orbits do not match
your assumption that "the energy use would be greater the farther away
from the actual point you are." They're not orbits in the classical
sense; they are special case solutions of the 3-body problem. We're
just now starting to get a handle on the math required to deal with the
general n-body problem. The gravitational dynamics of the Solar System
are starting to look a lot more interesting than anyone imagined even
ten years ago.

Alan Anderson wrote:

The amount of thrust required to stay in orbit is miniscule. Objects
orbiting the Sun-Earth L1 point need less than fifty meters per second
of delta-V every *year*.

To put this in perspective: this is about the delta-V delivered
by solar light pressure to a vehicle with a mass/area of about
3 kg/m^2.

Paul

This picture explains everything you need to know
about the new lunar exploration program:
http://www.theonion.com/content/file...-C.article.jpg

in article , Rand Simberg at
h wrote on 9/30/05 9:44 PM:

On Sat, 01 Oct 2005 00:22:55 GMT, in a place far, far away, George
Evans made the phosphor on my monitor glow in
such a way as to indicate that:

From what I have read, L4 and L5 are the ones that can be orbited. In order
to stay in "orbit" around L1 or L2 would require a constant supply of energy
and I'm would assume the energy use would be greater the farther away from
the actual point you are. Therefore there is a great advantage to getting to
L1 and L2 first.

There is no L1 or L2 to get to. They are both regions. Yet another area in
which you proudly demonstrate your ignorance, and that which you'll impart to
your students.

They are points that migrate around within regions. For any given moment in
time, there will be only one point in the vicinity of L1 where forces
exactly balance. Forces can't exactly balance in a region.

George Evans

in article , Rand Simberg at
h wrote on 10/1/05 7:30 AM:

On Sat, 01 Oct 2005 07:38:35 GMT, in a place far, far away, George
Evans made the phosphor on my monitor glow in
such a way as to indicate that:

Correct me if I'm wrong but isn't a Lagrange point indeed a single point
at any given time even though geometrically it might move around slightly
relative to the orbiting body?

You're wrong.

A Lagrange point in the earth-moon system is a vicinity, due to the
complications of the Sun, Venus, Jupiter, and other gravitational
influences.

But, cannot each one of those distant bodies be considered a point.

Yes, but they are in continual motion with respect to each other, so any
gravitational areas of interest that is caused by them is *not* a point.

I'm not disputing that a Lagrange point is in constant motion. My point is
that at any given moment in time the the solution is going to be a single
point. It has to be. There is nothing to cause it not to be.

Yes, there is. Lagrange points only exist in theory in a two-body system.
When there are more bodies acting, it is no longer a point, it's just a
region.

Alan Anderson suggested I google halo orbits, which I did. This is from the
first hit:

"An orbit in which a spacecraft will remain in the vicinity of a Lagrangian
*point*, following a circular or elliptical loop around that *point*..."

Notice that there is a *point* around which the spacecraft orbits. If you
add more distant bodies to the computation it gravitational force vector
will change. That simple means that the forces will balance at a new
*point*. As these distant bodies move, the Lagrange *point* will migrate
slightly.

George Evans

Pat Flannery wrote:

The thing about the space elevator is that if it did work - and it
doesn't seem to break any laws of physics - it would make all other
methods of getting things into space hopelessly obsolete overnight.

Rand Simberg wrote:

I disagree. I think that there will continue to be a market for
people and things that want to get to LEO in a hurry. The elevator
would be used for bulk cargo, as slow ships are today.

I agree with Rand Simberg. There have been
proposals to make short versions of the
elevator that contribute only 2 km/s to
the payload and thus replace the last stage
of the rocket launcher. You do not need buckytubes
or any other unobtanium to make such short
elevators -- steel is good enough.

By the way, rotating orbital tethers are
more economical than the elevators.

On Sat, 01 Oct 2005 16:25:01 -0500, in a place far, far away, Pat
Flannery made the phosphor on my monitor glow in
such a way as to indicate that:

The thing about the space elevator is that if it did work - and it
doesn't seem to break any laws of physics - it would make all other
methods of getting things into space hopelessly obsolete overnight.

I disagree. I think that there will continue to be a market for
people and things that want to get to LEO in a hurry. The elevator
would be used for bulk cargo, as slow ships are today.

in article , Brad Guth
at wrote on 10/1/05 8:53 AM:

George Evans;

OK, Brad. You write like a very disturbed person. I think you have gleaned
some interesting pieces of information, but what you do with them is nuts. I
don't have the time or patients to weed through any more.

That's too gosh darn bad because, here I'd thought yourself not being such a
"disturbed person" actually had half a brain that wasn't assimilated by the
status quo. Obviously you'd rather stick with whatever those liars have to say
than with the truth.

You're right, Brad. They got to me. I have been assimilated.

We did walk on the moon! I was intrigued by the recent questioning of the
reality of those missions so I bought a set of NASA videos and watched
footage of astronauts activity. There is no way everything could have been
faked. The final proof for me was the trajectory of dust plumes kicked up by
their boots. The whole plume spays out and collapses back to the surface.
There is no tendency to sort aerodynamically. It all falls back together.
This could only happen in a vacuum.

snip

Even as having once upon a time been an icy proto-moon, it's not such a clean
place to be, unless you think carbon/soot, iron and titanium deposits are
sufficiently clean and of such little color to boot. Besides all of that; how
does one manage to walk upon less than 5 g/cm2 of surface-tension?

NASA was expecting to sink into the surface. That's why the pads were so
large on the LEM. Why did they forget to "pretend" to sink in?

There's simply no hard-science proof whatsoever that we've walked upon the
moon. There's still no interactive scientific instruments upon the surface of
our moon. Four of the missions had absolutely terrific views of Venus, two of
which were extremely close encounters with the Apollo-16 having the best 87e6
km look-see that had to have been offering an extremely bright if not an
anoyingly amount of what 2640 w/m2 was reflecting nearly 2 kw/m2 of solar
energy off the clouds that had to have been absolutely breathtaking and even
somewhat capable of shadow generating in places where solar and earthshine was
sufficiently blocked by the Apollo lander.

Is Venus annoyingly bright in our night sky? In order to see a Venus shadow
an astronaut would have to be at a place where he could see Venus and could
not see any other sunlit surface. Just walking around behind the lander
wouldn't do. Remember, sunlit lunar surfaces are so bright as to be seen in
the day time from earth.

The available reflected illumination that's derived from the .75~.8 albedo is
roughly providing 1.9 kw/m2 worth of an extra illumination resource that
wasn't even all that far away, thus roughly 2e11 m2 * 1.9 kw/m2 = 3.8e11 KJ of
a photon spot-source of illumination energy that would have been quite easily
photographed from the extremely DARK and NASTY lunar surface. Would have been
somewhat difficult of the Apollo-14 and/or Apollo-16 missions to have avoided
getting Venus into several frames of showing us Venus as residing just above
the lunar terrain or even of a few of those frames having included Earth and
Venus, and lo and behold that even though Earth was extremely close and
extremely bluish wouldn't have been offering per similar area nearly as bright
of an object as Venus...

Venus would have been any bigger in their sky than in our sky. Even with a
telephoto lens it would have looked like a bright star.

Typical photographic renderings even with the terrific amount of earthshine
factor should have been offering those frames of extremely harsh contrast,
being that there was no atmosphere and supposedly only the surrounding 12%
albedo of the lunar surface as being nearly asphalt/coal or carbon/soot dark
and nasty, which shouldn't have reflected all that much worth of backlighting
as to fill in those extremely harsh solar generated shadows, although in most
instances a little earthshine should have been available.

Shadow fill on the moon should be about half of what it is on earth. Just
step into a shadow on a bright sunny day and observe that light is coming
from terrestrial surfaces and the sky. If you were on the moon you would
only be missing the sky. And as far as the brightness of the lunar surface,
I notice that it is visible against the day time sky clear out to the limb.
So there is a lot of light available to fill a shadow created by the lander.

Therefore... In other words of wisdom, it's so entirely freaking bogus and of
Kodak photon-physics impossible for those sorts of Kodak moments to have been
obtained from the surface of moon, of course that's besides the matter of
hard-scientific fact that we still haven't a viable fly-by-rocket lander
that's even on the books much less in prototype mode. Thus we have NOT walked
upon the moon. Get it fool, or are you still so freaking dumb and dumber that
your dumfounded and clearly heathen bigoted mindset can't reset/reboot because
of the "blue screen of death" is now upon your sorry LLPOF butt for good. You
have been snookered along with the rest of us village idiots, but obviously
you're the real problem or merely still so absolutely dumbfounded that you
can't realize even that much. No wonder innocent Muslims are having to die,
it's because of the worthless brown-nosed scum suckers of the Earth that'll
believe absolutely anything that's wrapped up in pretty paper, especially as
having the pagan NASA stamp of approval to boot and usually there's a
government paycheck that goes along for the ride.

Pinko commie *******. NASA kicked the Soviet Union's ass, and it was sweet
to watch.

snip

George Evans

in article , Pat Flannery at
wrote on 10/1/05 2:25 PM:

George Evans wrote:

Thanks Pat. I figured out how to operate one of these computers and punched
in these codes. What I liked best was the quote from Arthur C. Clarke:

"As its most enthusiastic promoter, I am often asked when I think the first
space elevator might be built. My answer has always been: about 50 years
after everyone has stopped laughing. Maybe I should now revise it to 25
years."

Talking to all these guys on the fringe had gotten me a little wobbly. This
comment re-centered me.

Here's another way-out idea: http://www.jpaerospace.com/
These guys plan to fly a dirigible into orbit. The thing about the space
elevator is that if it did work - and it doesn't seem to break any laws of
physics - it would make all other methods of getting things into space
hopelessly obsolete overnight.

I know. That's why I am interested in any advances in that area. As much as
I like the thunder of a shuttle launch, my conscience tells me it is quite a
crude way to travel. Of course, if an elevator is developed it will take a
lot of those impressive launches to build it.

George Evans

in article , Alan Anderson
at wrote on 10/1/05 3:02 PM:

George Evans wrote:

I've been reading what Jeff Findley gave me to read among other things. From
the JPL site:

"Objects can settle in an orbit around a Lagrange point. Orbits around the
three collinear points, L1, L2, and L3, are *unstable*. They last but days
before the object will break away. L1 and L2 last about 23 days..."

The amount of thrust required to stay in orbit is miniscule. Objects orbiting
the Sun-Earth L1 point need less than fifty meters per second of delta-V every
*year*.

But the important thing to recognize is that halo orbits do not match your
assumption that "the energy use would be greater the farther away from the
actual point you are." They're not orbits in the classical sense; they are
special case solutions of the 3-body problem. We're just now starting to get
a handle on the math required to deal with the general n-body problem. The
gravitational dynamics of the Solar System are starting to look a lot more
interesting than anyone imagined even ten years ago.

Finally, someone who sounds like they know what they're talking about.
Thanks, Alan. I stand corrected about energy usage vs. distance.

George Evans