Zubrin citisism

You're right that I visualized it wrong. I don't know whether
there's a solution for what I was trying to do. I wanted to find a
pair of impulses in the same direction that will cancel each other
out. To have zero net effect on angular momentum, they have to be
on opposite sides of the primary. But if I boost parallel to the
direction of motion, when I get around to the opposite side I'll be
higher, and I can't get back into the original orbit unless I'm at a
point where the two intersect.

To put it another way, I want to have a pair of orbits that
intersect at at two points. I start out in orbit one. When I get
to the first intersection point, I launch a payload such that the
impulse puts me into orbit two. Then when I get to the second
intersection point I launch another payload such that the impulse
puts me back into orbit one.

Of course, I don't really want to launch the payloads in the same
direction: I want to send them to the same destination. But trying
for the same direction was a simpler exercise to find out that I
didn't have it right.

--- In spacesettlers@yahoogroups.com, "Combs, Mike"
>
> From: spacesettlers@yahoogroups.com
> [mailto:spacesettlers@...m] On Behalf Of Dan Wylie-Sears
>
> > Having mentioned the problem, I'll turn right around and say
that
> > it's not as bad as it sounds: for example, suppose you're in a
> > circular orbit, and you launch a payload in the direction you're
> > moving and then half an orbit later you launch one in the same
> > direction (which is now approximately opposite your direction of
> > motion) with the same amount of momentum relative to you. If
> > I've visualized it right, that puts you back into your original
orbit.
>
> Actually, both impulses would have to be on the same side of the
orbit,