Name: DeWayne T Halfen
Status: Other
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Question:
At what altitude off the surface of the Moon would a satellite be in a sta-
tionary orbit over the Moon?

Replies:
This is a neat question, but one which does not have a simple answer. For
an isolated planet we can work out the read radius of a circular orbit with
a certain period. To be motionless, stationary, the period must be 24 hours
for Earth, while for the Moon the period must be 28 days. The longer the
period the farther away is the orbit from the planet. For an orbit far away
from the Moon our satellite would encounter the gravity of the Earth and
that would alter the orbit and make a stationary orbit unlikely. Because of
the Earth's presence such an orbit is not possible. If it were, you could
use the value of the radius for Earth and multiply it by the one-third power
of the ratio of the Moon to the Earth masses and multiply by the two-thirds
power of the number 28. That should give the value without the presence of
the Earth.

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