[X] My Assistant

[Phil Stooke]

Typically the first polar mission is intended to stay in sunlight, but a future version would go into the shadow - the Astrobotic site especially is clear about that..

This ability to see into shadow opens other possibilities. Kaguya should be able to image the Lunar Prospector impact site somewhere near the foot of the crater wall on the north side of Shoemaker crater. Would there be anything to see at that resolution? Hard to say, but it would be interesting to look.

Phil

[djellison]

Guessing here:

CODE

[b]Projectile Descriptors[/b]
[indent]  Projectile Diameter  2  meters   Projectile Density  1000  kg/m[sup]3[/sup] [/indent]  
[b]Impact Conditions[/b]
[indent]  Impact Velocity  1.69  km/sec   Impact Angle  10  degrees [/indent]  
[b]Target Descriptors[/b]
   Target Density  1500  kg/m[sup]3[/sup]   Acceleration of Gravity  1.6  m/sec[sup]2[/sup]   Target Type  loose sand

Using the Pi-scaled transient crater, the final crater is a Simple crater with a rim-to-rim diameter of 0.167 x 10² meters.

So 16m?

I got the velocity by using Orbiter, and putting myself into a 40km x 0.007km orbit - and seing what my speed was at 0.007km altitide (wierd seing a shadow just under the vehicle at orbital velocity) - 1.69k/sec was the speed.

Doug

[Phil Stooke]

... so the crater is barely resolvable - I think you'd have to say unresolvable. More likely to be seen would be the ejecta deposit - if it might be visible under these unusual circumstances. I think this site would be less well illuminated that the interior of Shackleton, being further from likely sources of reflected light.

Phil

[Paolo]

The Shackleton article is on today's "Science" and Science Express has a new one "Long-Lived Volcanism on the Lunar Farside Revealed by SELENE Terrain Camera"

[dvandorn]

I have obviously only read the abstract linked in the previous post, but I'll take a moment to remind y'all that crater counts can be misleading. On lunar mare surfaces specifically, regoliths containing a higher-than-normal admixture of basaltic glass beads tend to have a higher erasure rate of smaller craters, leaving older surfaces *appearing* younger when age is measured only by crater counts.

On the nearside, most of these types of terrain are darker than the normal mare regoliths due to admixture of black volcanic glasses (assumed to have been formed in fire fountain eruptions), though some areas are tinted other colors based on impurities and slight constituent alterations in the glasses' source magmas. Some glasses are red, some are orange, some are purplish, some are green. But a vast preponderance of the devitrified fire fountain glass beads seems to be a deep black.

I would be interested in knowing which areas are being observed by Kaguya, and what the relative colors and albedo of the regoliths are. For example, there is a very dark patch of mare floor fill in Tsiolkovsky, with what appears to be a small cinder cone or dome-shaped vent sitting in the middle of the dark patch. Sure looks to have fewer small craters than the adjacent lighter mare floor, too. But it seems possible (if not likely) that this patch in the Tsiolkovsky floor is roughly the same age as the adjacent mare surface, and (like the dark soils along the Serentitatis basin's east rim) have fewer smaller craters because the soil is "softer" and retains craters of that size range for shorter timeframes.

I'll be really interested in seeing the types of mare surfaces they were looking at when the authors came to their conclusion in re surface ages. I don't insist they have to be wrong, I'd enjoy it if they're right; I'm just bringing up one of the ways in which lunar geologists have been proven wrong about crater-count-derived surface ages in the past.

-the other Doug

[dvandorn]

Found and took a detail of the piece of Tsiolkovsky's floor that I referenced. It was taken using a Hasselblad with a 250mm lens (I believe) from Apollo 17's CSM. It's not from the SIM bay panoramic or mapping cameras.



Actually, the more I look at this detail, it appears to me that the cone-shaped strucure is related to central peak materials and the scarp that borders the darkened regolith patch may have been the source of the fire fountains (if that is indeed what is causing the darkening). Hard to be sure, of course.

-the other Doug

[charborob]

Jaxa has released a fantastic 3d flyover of the Moon's Alpine valley here.

Go to the Japanese Gallery here and click on the 2008/11/10 link for images from various angles. You can also download the movie.

[Guest_Zvezdichko_*]

http://www.jaxa.jp/projects/sat/selene/manager_e.html some updates

http://jp.youtube.com/JAXASELENE - Youtube site.

[Phil Stooke]

Yes... Kaguya will impact next summer some time, on the nearside. And before that, the small RStar subsatellite will impact on the farside in mid-February. Also next year we get LCROSS, of course, so my lunar site maps will need updating. I wish I knew where to put MIP... still no news. And now we learn MoonLITE will proceed to a detailed study, with the chance for more sites to plot on the map. It's enough to bring a smile to the face of a cartographer.

Phil

[Guest_Zvezdichko_*]

By the way, did AMIE succeed in mapping the whole surface? If i recall correctly it didn't, but we had some good maps of the poles.

[Phil Stooke]

Here's a link to a map of coverage:

http://www.unmannedspaceflight.com/index.p...mp;#entry110426


Yes, nearly full coverage was obtained, with resolutions varying from about 250 m at the north pole to 30 m at the south pole because of the elliptical orbit. The higher resolution coverage is concentrated in the south.

Phil

[Guest_Zvezdichko_*]

That's cool!

I do hope that some day ALL images of Kaguya will be released and when I saw all images I mean Raw data.

[kenny]

I got the velocity by using Orbiter, and putting myself into a 40km x 0.007km orbit - and seing what my speed was at 0.007km altitide (wierd seing a shadow just under the vehicle at orbital velocity).

When Apollo 17 was in its descent orbit, and after the LM had undocked, it filmed the CSM below it passing over the landing site. The shadow of the CSM is visible crossing a hill to the right (west) of the orbital track. Quite startling to see, as you say. But I imagine it is explained by perfectly parallel rays of solar illumination and no atmposhere to diffract or diffuse.

[ugordan]

When Apollo 17 was in its descent orbit, and after the LM had undocked, it filmed the CSM below it passing over the landing site. The shadow of the CSM is visible crossing a hill to the right (west) of the orbital track. Quite startling to see, as you say. But I imagine it is explained by perfectly parallel rays of solar illumination and no atmposhere to diffract or diffuse.

Where can one see this footage? Somehow I'm not convinced CSM shadow was visible at all from such an altitude. Solar rays are not parallel because at 1 AU the Sun subtends about 30 arc minutes in diameter. Any shadow will have a diffuse component (umbra/penumbra) and casting the shadow far enough will diffuse it to non-existence. Think about it this way - from several kilometers altitude the CSM cannot eclipse the entire Sun, it can merely transit the disc.

LM shadow likewise started to become visible only in the last phase of the descent.

[dvandorn]

Here is a detail of the image Kenny is talking about:



There is indeed a black dot in a position where you would expect the CSM shadow to be cast. I've often wondered, as well, if this is indeed a shadow. Sure looks like one.

-the other Doug