LCROSS Impact coverage E-

Rick Jones wrote:

Derek Lyons wrote:
Rick Jones wrote:

Pat Flannery wrote:
Anyway, the preliminary results are baffling, with no ejecta plume
observed by anyone

Centaur fell down went crumple on solid rock?

Unless we are *very* wrong about lunar and solar system evolution,
there shouldn't be any such thing. On top of explaining how we
missed what would have had to have been enormous and quite visible
areas of bare rock visible elsewhere on the moon.

Well, it is *far* more likely that I'm very wrong but does it have
to have been an "enormous" area of bare rock?

Because if there is bare rock at the LCROSS impact site, there will
also be bare rock across other areas of the moon.

Apart from the engine, at the
time of impact the Centaur is basically "just" a giant beer can right?
Was there orientation control of the Centaur prior to impact? I'm
wondering if it hit "head on" against a large boulder if it would just
crumple up and the nice hard engine bell not have a chance to hit
anything other than crumpled fuel tank.

At the speeds involved - there isn't any 'crumpling', attitude is
irrelevant.

D.
--
Touch-twice life. Eat. Drink. Laugh.

http://derekl1963.livejournal.com/

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL

Rick Jones wrote:
Pat Flannery wrote:
Anyway, the preliminary results are baffling, with no ejecta plume
observed by anyone

Centaur fell down went crumple on solid rock?

That would be something if it just accordioned on impact, and what's
sitting there now is a big flat disc with some RL10's sticking out of
its top. :-D
The only two things I can think of right off the top of my head would be
that it hit solid rock with nothing atop it that could be blown into a
debris cloud, or exactly the reverse... that it hit something so soft
that it went right on through and ended up deep underground, like it had
sunk into the dread deep lunar dust of 1950's science fiction.
I always liked how Korolev got around concerns about the lunar dust when
designing the first Soviet moon lander probes; when concerns arose about
how to best design the probes, and whether the surface was solid or
covered in dust, he sent this statement to the design team: "The surface
of the Moon is solid. - Korolev.", and that was that. :-)
There's a news story on the impact here, showing the "Comet Kohoutek"
of impact flashes: http://spaceflightnow.com/lcross/091009impact/
....I think we got spoiled by Deep Impact and its debris cloud...that was
really something.
Apparently LRO did detect some sort of impact ejecta plume, thought I
haven't seen any details of that yet.


Pat

Derek Lyons wrote:
Unless we are *very* wrong about lunar and solar system evolution,
there shouldn't be any such thing. On top of explaining how we missed
what would have had to have been enormous and quite visible areas of
bare rock visible elsewhere on the moon.

Unless it hit a protruding boulder in the crater; the Apollo landings
showed some boulders that had very little lunar dust atop them:
http://commons.wikimedia.org/wiki/Fi...tt_boulder.jpg

Pat

Rick Jones wrote:

How "hard" is Lunar Basalt?
http://en.wikipedia.org/wiki/Basalt#...Martian_basalt

About as hard as the Earth basalt I'd imagine, and all of that stuff
I've run into in the field is _damn_ hard if you've ever taken a rock
hammer to it.
On the Moh's scale of hardness lunar basalt runs around 8 to 8.5:
http://www.islandone.org/MMSG/aasm/AASM5C.html
with diamond being 10:
http://en.wikipedia.org/wiki/Mohs_sc...neral_hardness

Pat

Damon Hill wrote:
At several thousand MPH, a crumpled ball of paper would be the
equivalent of an armor-piercing round. A couple of tons of metal
is going to make a hell of a bang and throw regolith around.

Since this is probably going to come up at some point along the thread,
the impact velocity of the Centaur stage was 2.5 km/sec (or 2500
meters/sec) = 5592 miles/hr., = 8202 ft./sec.
For comparison purposes, the M1 Abrams tank's 120 mm gun has a muzzle
velocity of 1575 m/sec when firing its depleted uranium projectile.

Pat

rwalker wrote:


Despite no visible plume, NASA seems satisfied with the outcome:

You know the NASA PAO; it could have missed the Moon entirly, and they
would still be saying it was a 'limited success". :-D

Pat

Jorge R. Frank wrote:
Sigh. OK, let me spell it out for you, real slowly.

That's it Jorge, keep insulting the newsgroup member's intelligence; it
reflects well on your NASA career and will certainly encourage people to
buy your books.

Pat

Pat Flannery wrote:

The only two things I can think of right off the top of my head would be
that it hit solid rock with nothing atop it that could be blown into a
debris cloud, or exactly the reverse... that it hit something so soft
that it went right on through and ended up deep underground

You missed the third possibility - that the PAO (once again) waaaay
overhyped what would happen (complete with sexy CGI video), and you
fell for it completely.

D.
--
Touch-twice life. Eat. Drink. Laugh.

http://derekl1963.livejournal.com/

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL

Derek Lyons wrote:

You missed the third possibility - that the PAO (once again) waaaay
overhyped what would happen (complete with sexy CGI video), and you
fell for it completely.

I ran into the PAO's observing guide for the impact last night:
http://lcross.arc.nasa.gov/observation/amateur.htm
You were supposed to be able to see it with a 10-14" Dobsonian.
In actuality, even the Keck and Hale telescopes saw nothing.
Just over-hyping it to TV was bad enough, but getting thousands of
amateur astronomers cranked up into a tizzy about it - only to see nada
- is a really bad tactical move with a quest for more NASA funding going on.

Pat

On Fri, 09 Oct 2009 23:28:05 -0500, Pat Flannery
wrote:

rwalker wrote:


Despite no visible plume, NASA seems satisfied with the outcome:

You know the NASA PAO; it could have missed the Moon entirly, and they
would still be saying it was a 'limited success". :-D

Pat

That thought did cross my mind.