[amsat-bb] Re: Could we raise orbit thru magnetorque?

[Gregg Wonderly]

Bruce Bostwick wrote:
> That's been my understanding as well.  Magnetorquing by itself can  
> drive rotation but not translation.  Its main benefit is that it  
> saves propellant, weight, and complexity, as well as moving parts and  
> the risk of a hypergolic plumbing assembly exploding and taking out  
> half the spacecraft's systems, by allowing the spacecraft to handle  
> rotation with more reliable torquing coils and get its energy for  
> that from the PV panels.  Changing orbits still requires firing a  
> reaction thruster of some sort.

It seems to me that the issue is that depending on where the magnet is and the 
relative strength of the field as controlled by other electromagnetic factors, 
trying to figure out how to put the magnetic field exactly parallel to the force 
you want to use for translation would be difficult, if not impossible.  It would 
require extremely sensitive innertial detectors and then a dynamic coil control 
system that would be able to vary the field generated fast enough to keep the 
rotation from happening, or to react to the rotation dynamically so that inspite 
of the rotation there is still a desired vector for translation.

Gregg Wonderly
W5GGW