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SMART-1 impact, September 2006
Phil Stooke
post Mar 26 2006, 03:54 PM
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This map shows the target locations from the report just referred to. The original point may have been a statement of the nominal perilune rather than the actual impact point, misquoted in the press.

I'm just plotting coordinates on the old LAC chart. The points might be a bit off because of improved selenodetic control since the 60s.

Phil


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dvandorn
post Mar 26 2006, 03:57 PM
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So, like, they're gonna crash it into, like, Lake Excellent, dude?

Excellent!!!! ((insert bad air guitar riff here))

-the Other S. Doug, Esq.


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Phil Stooke
post Mar 26 2006, 04:37 PM
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I prefer a Mr Burns-style "Eeeeexcellent!"

Phil


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RNeuhaus
post Mar 26 2006, 05:22 PM
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QUOTE (Phil Stooke @ Mar 26 2006, 10:54 AM) *
This map shows the target locations from the report just referred to. The original point may have been a statement of the nominal perilune rather than the actual impact point, misquoted in the press.

I'm just plotting coordinates on the old LAC chart. The points might be a bit off because of improved selenodetic control since the 60s.

Phil


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Shall anyone let us know the impact location in the Moon longitudinal and latitud's coordinates. I am not able to ubicate the Lacus Excelentia, forgive me, into an excellent lake!

Rodolfo
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helvick
post Mar 26 2006, 05:35 PM
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QUOTE (RNeuhaus @ Mar 26 2006, 05:22 PM) *
Shall anyone let us know the impact location in the Moon longitudinal and latitud's coordinates. I am not able to ubicate the Lacus Excelentia, forgive me, into an excellent lake!

Can't give you lat\lon but this puts it in context, Clausius is on the upper left. Looking at the whole moon it is slightly above and to the left of Tycho (the bright crater with very prominent ejecta rays in the southern hemisphere).
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elakdawalla
post Jun 23 2006, 09:03 PM
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ESA press release today:
SMART-1 manoeuvres prepare for mission end

Looks like they're getting ready for the ending. I was wondering if anybody who knows more about lunar geography than I do could take a look at the unfortunately rather low-quality illustration of the impact site in that story and tell me if it looks like the same location as the one posted here previously.

--Emily


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Rakhir
post Jun 23 2006, 09:19 PM
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Final operational report for the SMART-1 mission.

http://sci.esa.int/science-e/www/object/in...fobjectid=39395
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garybeau
post Jun 25 2006, 10:42 PM
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QUOTE (elakdawalla @ Jun 23 2006, 05:03 PM) *



That was an interesting article. The following paragraph got my attention.

QUOTE
The off-loading consists of braking a set of spinning wheels inside the spacecraft, which has the effect of transferring angular momentum from the wheels to the spacecraft and hence changing its velocity.


I thought all you could do with reaction wheels is change spin and orientation, I didn't realize you
could change velocity as well. Does that only work while in a gravity field or can that work in free space
also?
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Bob Shaw
post Jun 25 2006, 11:29 PM
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QUOTE (garybeau @ Jun 25 2006, 11:42 PM) *
I thought all you could do with reaction wheels is change spin and orientation, I didn't realize you
could change velocity as well. Does that only work while in a gravity field or can that work in free space
also?


Gary:

I read that, and pondered also. I think the key was in the concurrent mention of attitude-control jet firings - I have the impression that they were 'hanging' the vehicle on the reaction wheels and firing the jets to create a force applied in the appropriate direction (the RCS jets wouldn't be balanced through the vehicle CG the way that the ion drive would be). It's all down to vectors... ...and the article could have been clearer!

Bob Shaw


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edstrick
post Jun 29 2006, 02:29 AM
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It's "nice" but not always "necessary" to have balanced attitude control jets, with two jets on opposite sides of a spacecraft's center-of-gravity firing in perfect opposition to rotate the spacecraft without any change in velocity. For a spacecraft doing fine attitude and translational maneuvers in close proximity to another spacecraft, like an Apollo rendezvouis and docking, yes, it's necessary, but often, it's not.

That, of course, is what killed Mars Climate Orbiter. The spacecraft was assymetrical, with one solar panel, and offloaded solar light pressure which slowly spun up the momentum wheels with weekly attitude thruster firings. The firings also imparted a small velocity change on the spacecraft that needed to be included in trajectory calculations. It was.. in the wrong units (english vs metric) throwing off the trajectory models in a particularly insidious way.
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Guest_AlexBlackwell_*
post Aug 4 2006, 08:12 PM
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SMART-1 towards final impact
European Space Agency
4 August 2006
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rogelio
post Aug 4 2006, 10:59 PM
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Any harm for the Moon?

Nearly 50 years ago, in 1959, the Russian Luna-2 spacecraft was the first man-made object to hit the Moon. Since then many others have done the same, without any noticeable harm, and SMART-1s impact will be softer than that of any man-made impactor up till now.
... The crater made by SMART-1 will be 3 to 10 metres wide and perhaps a metre deep. The Moon already has 100 000 craters that are more than four kilometres wide, and every day several small meteoroids make craters as big as SMART-1s.
Every chemical element present on SMART-1 and in its equipment exists naturally on the Moon. For instance aluminium and iron are very common. Hydrogen, carbon and nitrogen are much scarcer on the Moon, but they arrive naturally onto the surface from the solar wind and from the impacts of icy fragments of comets, which contain many elements. From this point of view, one can think of SMART-1 as an artificial comet. Furthermore, the little hydrazine left in the SMART-1 thrusters will burn immediately at impact.

...Interesting (and a bit silly if not creepy) that ESA took pains to explain that Smart-1s crash would have a minimal impact on the moon. I suppose they know their audience well and presume them to be extraordinarily green and caring about our fragile little satellite...
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ljk4-1
post Aug 4 2006, 11:49 PM
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QUOTE (rogelio @ Aug 4 2006, 06:59 PM) *
...Interesting (and a bit silly if not creepy) that ESA took pains to explain that Smart-1s crash would have a minimal impact on the moon. I suppose they know their audience well and presume them to be extraordinarily green and caring about our fragile little satellite...


Certain Native American groups were upset to learn that Lunar Prospector contained
the ashes of Gene Shoemaker when it crashed on the Moon in 1998, as they consider
our nearest celestial neighbor to be sacred. Muslims also consider the Moon to be
important to their faith.


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"After having some business dealings with men, I am occasionally chagrined,
and feel as if I had done some wrong, and it is hard to forget the ugly circumstance.
I see that such intercourse long continued would make one thoroughly prosaic, hard,
and coarse. But the longest intercourse with Nature, though in her rudest moods, does
not thus harden and make coarse. A hard, sensible man whom we liken to a rock is
indeed much harder than a rock. From hard, coarse, insensible men with whom I have
no sympathy, I go to commune with the rocks, whose hearts are comparatively soft."

- Henry David Thoreau, November 15, 1853

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Guest_DonPMitchell_*
post Aug 6 2006, 06:44 PM
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Guests






James Oberg had an article some time ago about radical-Islamic objection to space exploration. There is a strong embracing of the Apollo hoax theories too. I guess the greens also object to space exploration, but usually on the grounds of using petroleum in rockets. And of course, if there is even a small RTG in a space probe, some people go nuts.

But remember that Muslims have made important contributions to space. Farouk El-Bas, for example, is a highly honored scientist in the US program.

Radicalism isn't about Islam or Christianity or ecology. It is just ambitious people searching for political opportunities. If you are curious about some theory, read The True Believer by the philosopher, Eric Hoffer.

Oh, my personal favorite crank political protest -- some people objected to NASA's Deep Impact mission, claiming that if the orbit of the comet was perturbed, it might collide with the Earth someday. :-)
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tedstryk
post Aug 7 2006, 03:48 PM
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QUOTE (DonPMitchell @ Aug 6 2006, 06:44 PM) *
James Oberg had an article some time ago about radical-Islamic objection to space exploration. There is a strong embracing of the Apollo hoax theories too. I guess the greens also object to space exploration, but usually on the grounds of using petroleum in rockets. And of course, if there is even a small RTG in a space probe, some people go nuts.


I am assuming you mean plutonium biggrin.gif


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