Re: zero-fuel satellite maneuvers

Forrest Bishop (
Sun, 01 Nov 1998 04:38:56 -0800

David Cary wrote:

> This idea is probably already implicit in
> but I thought I'd like to make explicit a simple example.

Actually, an analysis of all the below occupies several pages of "TheInterworld Rapid Transit System", including the computer-generated graphs.If you would like, I could send a draft.

> For simplicity, this entire article is from the point of view of a
> non-rotating observer above Earth's North pole.

> Say we have a ring of (at least 3) identical satellites orbiting Earth.

It can be done with two, I used three and four in my analyses.

> . It seems obvious that by
> slowly increasing the number and/or velocity of the particles, this ring
> can push itself out to any arbitrary distance from the earth, perhaps even
> beyond the moon.


> ... Unlike the bicycle rim, though, these
> satellites can only "push" each other apart; they cannot "pull" each other
> together or provide any force out of the plane. (Does this necessarily mean
> this system is unstable ?

Yes it is, necesitating active control.

> If a satellite get bumped by a meteroid, will the
> particle beam push it even further out of their desired orbit ?).

Yes, over a portion of the orbit, then it can act somewhat to restore the original orbit.

> When we view the system of satellites as a solid ring, then we can see that
> the central problem in moving the satellites from a (beam turned off)
> stable orbit in LEO to a (beam turned off) stable orbit in geosync orbit is
> really just increasing the angular momentum of this wheel "eastward".

Um, the angular momentum has to come from somewhere. If by "beam turnedoff" you mean that all the exchange particles are back onboard the satellites, their orbits can not raised or lowered.

> (Perhaps counterintutively, increasing angular momentum actually causes
> this wheel to spin *slower* in RPM, although faster in linear velocity.).

You've lost me here.

> to keep the main satellite pointed the right way, until torque rockets
> [What is the correct term for these ?]

Momentum wheels andReaction Control System (RCS), though there may be other terms in use.

> So far, this discussion has applied to particles of any size and shape --
> from individual atoms

Atoms tend to disperse, it does not seem possible to generate an atomic beamthat can maintain decent collimation over large distances, which is why I invented
mesoparticle beams.

> to small chunks of various ices to small autonomous
> vehicles to manned craft, and to particles of almost any speed -- from the
> very fast "straight-line" path pictured above (far above escape velocity in
> both directions), to the medium-speed transition (the speed at which a
> satellite throws a particle "out" in a straight line away from earth, such
> that the particle falls back to earth and intersects the satellite orbit
> just at the instant the next satellite arrives -- pushing *both* satellites
> directly towards the earth), to very slow speeds that take many revolutions
> around Earth between throw and catch -- the orbit of the particle is almost
> exactly the same circle as the satellites themselves.
> There are 3 ways [or are there more ?] to reduce the accuracy necessary to
> catch "nearly all" of the particles:
> (a) increase the size of the "catcher's mitt"
> (b) increase the size of the particle, and design things so that a small
> "catcher" can sucessively grab on to even the fringe of a near-miss
> particle.
> (c) make the particle smart, so it can correct mid-route (via
> micro-thrusters, magnetic field interaction, or light sails) and give fine
> adjustments to a coarse throw.

(d) Decrease the distance between satellites (increase their number).

> Forrest Bishop already covered (c) at
> so let me mention a interesting combination of (a) and (b). Perhaps one
> could make the reciever, rather than a large disk covering the entire
> expected particle reception area, just a long narrow bar oriented in one
> direction, longer than any expected trajectory error in that direction.
> Then the "particles" would be long, narrow threads or strings or loops,
> longer than any expected trajectory error, "polarized" in the opposite
> direction. (Perhaps a "particle" could be folded/wadded/wound up at launch,
> as long as it was fully extended in the appropriate direction by the time
> it landed at the reciever). It seems natural to stabilize the "particles"
> in that direction via gyroscopic action, giving yet another way (in
> addition to the one given above) to transfer torque from one satellite to
> another.

Well, this is covered in "South Pole Accelerator", at IASE site.

> (side view)
> spinning circles or multi-armed wheels as "particles"
> designed to have enough friction to grip and wrap around the
> reciever pole rather than being slick enough to bounce off.
> How can we keep these long, stringy "particles" from getting all tangled up
> with each other on the reciever pole ?

It does make a mess, there is also a problem with unequal mass distribution. In"South Pole Accelerator", the collector and bolos are all wadded up and shipped
to a handling facility together. I looked at various Rube Goldberg gizmos back in 1981, none were very appealing

> What's a good way to scrape the "particles" off the catcher and feed them
> into the device that throws them to the next catcher ?

Little collector robots run up and down the arm? Melt the wires? Secondary arms

that fold up when full?

The problem with unguided projectiles lies in the demands placed on the launchers
and receivers. These are large and few in number pieces of capital equipment. The
risk of damage from incoming is probably enough to justify Smart Pellets.


Forrest Bishop
Interworld Productions, LLC
Institute of Atomic-Scale Engineering