Plasma Spin Sail
Navigational control and renewable energy source
for a plasma sail
by
Stephen Goodfellow  

It was with great interest that I read of Dr. Robert Winglee's idea of creating a plasma sail (Science News, 09/18/99)
Winglee's M2P2 concept would use the solar wind to push on a small imitation of the Earth's magnetosphere and accelerate the spacecraft to overtake the Pioneers and Voyagers and become the first manmade object to leave the solar system. M2P2 would generate a magnetic field and then inject plasma (ionized gas) that would drag the magnetic field lines out and form a plasma bubble 30 to 60 km (18-36 mi) in diameter.

This is just a quick sketch; I would not be surprised if others had not already thought of the following idea. If so, I apologize in advance for being a bore:
This represents the space craft...
This represents the plasma/magnetic generator...
...Which is gyroscopically independent of the space craft
A spin is placed on the plasma/magnetic generator...
...But the spacecraft can remain in fixed positions, so as to maintain radio contact with Earth, etc.
The space craft's magnetic generator is spinning. This causes the slaved magnetic field to spin as well. Due to the spin, the solar wind now hits the magnetic field at different speeds, causing the craft to change its course on a tangent...
By changing the axis of the spinning generator, the direction of the craft can be controlled... 


(Needless to say,  such control will be limited, the craft always leading away from the Sun, much like a skydiver can control the path of his fall, although he will continue to fall to Earth.)
It also occurred to me that if one were to place a cathode and diode on the North/South poles of a modified generator, one could continuously recharge the batteries of the craft, at least as long as it was within the effects of the solar wind...
...the spinning magnetic field would act much the same way as Earth's magnetosphere in that charged particles would follow the magnetic field lines into the North and South poles of the generator, thereby charging its batteries.
It occurs to me that even after the craft leaves the solar heliopause, the speed through interstellar space may be such that trapped ions may continue to charge the space craft batteries in this fashion.

(09/22/99)

| Nature | Home |