Re: A good altitude for Ortillery? Math and astrophysics guys help out

You aren't taking into account a "forced" orbit.

If I can match accelerations with the accel on
the ground I can pick a point over the planets 
surface, match angular velocity with it, and thrust 
in such a direction that my ship apparently hovers 
over it from whatever height I want as long as I am 
outside the atmosphere.

Think of it this way,  By cancelling part of the
planetary gravity by thrusting away from the planet
I can change the "geosynchronous distance" to whatever
I want it to be.  Now, with a 1 G accel over Earth I
must thrust with the nose pointed away from the planet
so can't fire weapons at the planet.  However, with a
2 G accel my direction changing thrusters would be
enough to cancel gravity and maintain station.

There is a Niven story where this is reversed.	He
gets in orbit around the planet and thrusts directly
toward the planet.  He thus maintains his speed while
decreasing the circle travelled so his speed with 
respect to a point on the ground goes way up.

Roger