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Date: 31 Aug 2006 15:55:29
From: canopus56
Subject: Re: Exact Smart-1 crash point
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MA-MA wrote:
> Between this map http://www.lunarrepublic.com/atlas/sections/g1.shtml
> and this http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=3D=
39841
> it is easy to work out the exact point(s) of impact.
> Go west of Clasius about 1 cm. This is north of the center between Clasi=
us
> B and Clasius D. That is the intersection.
For 3 September 2006 at 05:41 UT, some links to ESA sites with the
projected selenographic lat and long of the point of impact (46.3 West,
34.6S, Rukl Chart 62, north of the north end of Lacus Excellentiae):
http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=3D39841
http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=3D39863
The time and point of impact is not fixed due to uncertainities
concerning the altitude of the lunar terrain. There are three potential
impact times with the Moon low in the sky for Northern hemisphere
observers:
http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=3D39878
Nominal -1 3 September 2006 00:36 UT 43.5=B0 W 36.4=B0 S
Nominal 3 September 2006 05:41 UT 46.3=B0 W 36.4=B0 S
Nominal +1 3 September 2006 10:46 UT 49.0=B0 W 36.3=B0 S
Note the following qualifier on the time and place of impact on the ESA
website, listed above:
"During SMART-1's last orbits, the perilune altitude naturally
decreases by about one kilometre per orbit. This means that, if
encountering unknown peaks in the terrain between one and two
kilometres high, SMART-1 may hit ground one orbit or even two orbits
earlier than the nominal impact orbit."
"The best lunar topographic maps currently available are based on data
from the US Clementine mission in 1994. The laser altimeter experiment
(LIDAR) on board provided the spacecraft altitude over a grid with
roughly 1 kilometre intervals. The values in between have been
interpolated by the SMART-1 experts, assuming there are no peaks."
- Canopus56
P=2ES. Goes to show how much we do not know about our closest neighbor.
There may be a "little" one or two _kilometer_ tall mountain in the
way. We are just not sure.
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