Re: Um, eh? (Orbital Mechanics for Dummies)

----- Original Message -----
> Okay, I'm an idiot. Let's start by assuming I know very little.
>
> I'm in orbit (ignore drag). I launch a Thor Javelin by applying thrust
> directly towards planetary centre of mass. What will happen to my
> projectile? With thrust applied, it should move away from the
> satellite.... and then what?
>
> PS - won't gravity play into the picture? I understood orbit was
> achieved by balancing gravity with centripetal (or was that
> centrifugal... never get those two straight) force?

The situation is basically the same as if you drop a bomb out of an
airplane
(ignore drag). Gravity pulls the bomb down, but does nothing to slow
down
the bomb. It keeps moving forward at the same speed as the plane, until
it
hits the earth. This means that a bomb released directly over the target
will hit the ground much further on. To hit, you must release the bomb
well
before the target.

The situatoin with a satellite is basically the same. It moves at high
speed, and applying downward thrust to a missile will not do anything
stop
the forward motion. The missile will keep the forward speed and most
likely
miss the planet completely, entering an orbit of its own (depends on the
original orbit and the thrust applied).

Greetings