FT-Airless bodies

I was watching the luna eclipse, and it raised some points in my mind-

Would beam weapons have any range modifiers firing from a airless body?,
as
opposed to firing through a atmosphere with it`s attendent difusion
effects?

How much of a modifier would have to be used on SML`s/missiles to
represent
the power used to climb out of a gravity well, which would be smaller on
a
airless body as opposed to out of a larger gravity well for a atmosphere
planet, and how much would have to be used to overcome the atmosphere
it`self (or would the atmophere be a neglible compair to the gravity
well?).

What would be the requirements for fighters climbing out of a small
gravity
well, on a airless body?

These may seam to be pointless questions, but they are for a senario I`m
going to be running, with a brown dwarf star with only one planetary
body
orbiting it, which is going to be a captired airless moon. This system
is
going to be placed between the NAC and ESU, and have been turned into a
resuply base for forces that operate in the area. The ESU are giong to
have
to take out this base, or it will allow raiding/flank attacks while they
advance. The NAC will have some ships based here, with some static
defences,
and a lot of fighters.

The base will be called MIDWAY 2 (the idea was raised from a comment
about
the original midway was just a lump of rock that allowed american planes
to
use as a unsinkable runway in the middle of nowhere).

BIF
"yorkshire born,yorkshire bred,
strong in arms, thick in head"