QUESTION:
After reading about terraforming Mars on NASA's web pages, I was wondering
if NASA ever investigated the possibility of terraforming the Moon?
Obviously if it could even be done it would require different techniques
than on Mars. Perhaps some sort of manufactured heavy gas could be used to
trap in the atmosphere in order to compensate for the Moon's low gravity.
Also, if there was not enough oxygen, nitrogen, carbon, etc. embedded in
the rocks and soil, it might require shipping in the material from another
source such as a comet. This would obviously make the endeavor a lot more
expensive to say the least.

So, the main questions seem to boil down to:
1) Is there a mix of gasses that would provide breathable air that would be
heavy enough to stay on the Moon?
2) Are the elements needed for 1) available on/in the moon?
3) Can biological or technological means be used to produce the atmosphere
for 1) from the raw materials identified in 2)?

ANSWER from Bruce Jakosky on January 5, 2000:
Those are certainly the right questions to be asking. In addition, there is
one fundamental difference between the needs in terraforming the Moon versus
terraforming Mars--the Moon is at the same distance from the Sun as the
Earth, and would not require any greenhouse warming. Thus, the question is
simply one of making a breathable, sustainable atmosphere. Unfortunately,
the Moon's gravity is light enough that it cannot hold any gases for
substantial periods of time. This can be seen in the fact that the Moon
does not have a substantial atmosphere today. The atmosphere that it does
have is a transient one, existing in a dynamic state between supply of gases
to the atmosphere from the interior or from impacts and loss to space or to
the polar regions.

As for availability of gases, there certainly are resources on the Moon that
could be tapped into. Unfortunately, again, they would rapidly become
depleted as they would have to be continuously mined to replace gases lost
to space.

Unfortunately, it does not seem to be feasible to consider terraforming the
Moon.