Are you sure you're not confusing this with Zubrin's "magnetic sail"
concept for accelerating/decelerating against the solar wind?

Tom Merkle


Tom. No, the "dusty plasma sail", as it seems to be called, is not the
same thing as the Zubrin's "magnetic sail", although it is related.
The Dust Sail is an adaptation of Robert Winglee's M2P2
(Mini-Magnetospheric Plasma Propulsion). Since making my earlier post
on this topic, I have at least found one researcher (Robert Sheldon)
that has put some information out on the internet on it within the
last six months. But that is all I have found so far, and I am a
little surprised by this, because the concept seems to be so
fascinating. Here's the links I found:

http://bex.nsstc.uah.edu/RbS/HTML/M2P2/response.html

http://www.batse.msfc.nasa.gov/collo...ons/robert.pdf


I don't understand much about this, but I will try to share what I
think I know about it.

The idea of the dusty plasma sail is to provide the M2P2 with greatly
enhanced thrust through the addition of a light-reflective "dust disk"
so the M2P2 can take advantage of the photon pressure of the sun's
light as well as the thrust provided by the Solar Wind. Supposedly, if
the magnetic field of the M2P2 is made to rotate, at least some the
plasma that is linked to the field will localize in a disk in the
field's equatorial plane. If some sort of opaque dust can be added to
the plasma, then this would provide a photon "sail" that would
encircle the spacecraft in a manner similar to the rings around
Saturn. At least that is my take on it so far. But I am not sure why
the use of plasma is necessary for such a thing, because if a large
enough dust disk could be created by a simple rotating magnetic field
alone, then the thrust to weight ratio would be so satisfactory as to
make the use of the Solar Wind unnecessary, since the whole point of
the use of plasma in the first place is to expand the magnetic field
to better enable it to intercept the Solar Wind.

My impression is that the dust should be non-magnetic but electrically
conductive (such as aluminum) so that the rotating magnetic field
generated by the spacecraft will induce current (or at least
elecrostatic charge) within the dust. But I am not at all certain on
this point, as I think silicon dioxide has been successfully used as
dust in laboratory experiments.

What makes the concept so interesting to me is that I am impressed
with the idea of photon sail that is made purely of reflective dust
that is localized into a disk surrounding the spacecraft, which is
kept in its relative position (while also mechanically linked to the
spacecraft) soley by electric and magnetic fields. One couldn't
possibly build a lighter solar sail.