Our burn completed successfully.
LRO's orbit passes over the Moon's north and south poles and is described as "inertially frozen." That means that it is unchanging in orientation with respect to the stars. The Moon rotates below, once each month, the Sun will circle it once a year, and Earth will circle it once a month, but the stars will remain fixed in LRO's sky.
I think the easiest way to picture this is:
Whenever the Moon is in the constellation Gemini, we see LRO orbiting the lunar disk counter-clockwise. When the Moon is at the opposite side of its orbit (180 degrees away in the sky, in the constellation Sagittarius), again we see LRO orbiting the lunar disk, but clockwise.
90 degrees to the east of Gemini is the constellation Virgo. When the Moon is there, LRO's orbit passes from south to north across the middle of the lunar disk as we see it. During half of LRO's 113-minute orbit, we can't see it from Earth because it's blocked by the Moon.
On the opposite side of the sky from Virgo is Pisces. When the Moon is there, LRO passes from north to south across the middle of the Moon's disk.
In between those four locations, you can interpolate where LRO's path would cross in front of or behind the Moon.
Friday, June 26, 2009
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