On Jun 25, 6:37 pm, (Henry Spencer) wrote:
In article ,

Jeff Findley wrote:
There have been recently discovered lunar orbits that are very stable. I
remember reading a few articles about them within the last year or so...
http://science.nasa.gov/headlines/y2..._highorbit.htm

Beware, however, that all such work is based on current maps of the Moon's
gravity... and there are sizable uncertainties in the farside parts of
those maps. They are based on tracking of spacecraft in low orbit, and we
have *no* such tracking data more than 20-30deg into the farside. There
is some indirect information about the farside's gravity field to be had
from looking at spacecraft orbits before and after a farside pass, but the
data analysis is formidably difficult, and getting sane results tends to
require making arbitrary "regularization" assumptions which probably
aren't exactly true.


Would it be possible to map the farside gravity with something like
the GRACE mission? - two satellites in formation tracking each other.
It sounds like this is information that is sorely needed.

John Halpenny