I have a question about this proposal of Dr. Winterberg.

To build up these currents, wouldn’t you have to drag a huge nuclear power reactor along, effectively destroying your mass ratio? After all controlled net gain fusion hasn’t been achieved yet.

Isn’t it that unless we achieve net gain fusion, pure fusion rockets remain a fantasy?

In any case, haven’t we already graduated to being able to generate antimatter propulsion? And won’t this be completely free of debris, as well as being much more efficient?

Maybe we could actually send a probe thusly powered… And brake it with magnetic coils.

Somehow the sail concept seems way too fragile. It would greatly multiply the frontal area and increase the likelihood of damage from collisions.

How to avoid damage from dust/pebbles, etc. at .1c may be the stopper problem. You can’t dodge around like the Millenium Falcon, even if you could somehow detect oncoming objects with radar.

I’d like ro read some, if not all, of the essays, but my blackberry cannot handle the black on dark grey format.

Is there any way around this?

Before we launch probes for a closer look we’ll have a good idea about the planets in the target systems. In-space optical instruments will make most of the work of flyby missions quite pointless and only rendevous missions will really produce sufficient data return for the effort expended. Unless flybys are small, cheap and fast in which case we can fire off lots of them.

http://www.niac.usra.edu/files/studies/final_report/320Zubrin.pdf

Zubrin and Dana Andrews were pioneers in looking at magsail possibilities for deceleration, and in this report Zubrin and Martin consider how they could be used for fast missions within the Solar System as well. They go into the details of using these superconducting wire coils for various missions and analyze coil characteristics under various configurations.

Here’s a bit of the report:

“A loop of superconducting cable perhaps tens of kilometers in diameter is stored on a drum attached to a payload spacecraft. When the time comes for operation, the cable is played out and a current is initiated in the loop. This current once initiated, will be maintained indefinitely in the superconductor without further power. The magnetic field created by the current will impart a hoop stress to the loop aiding the deployment and eventually forcing it to a rigid circular shape. The loop operates at low field strengths, typically 0.0001 Tesla, so little structural strengthening is required. The loop can be positioned with its dipole axis at any angle with respect to the plasma wind, with the two extreme cases examined for analytical purposes being the axial configuration, in which the dipole axis is parallel to the wind, and the normal configuration, in which the dipole axis is perpendicular to the wind.”

And so on. Diagrams are furnished in the report.

What is a ‘magnetic breaking coil’?

Are you thinking of ‘braking’ by use of magnetic tethers?

Where does a coil come in?

Good grief. My vote is firmly with Greek mythology!

My vote would be for Commerce, or something along those lines. ;^)

Ultimately large scale trade between systems will require energy beams of some kind powered by solar energy. Electromagnetic accelerator/deccelerator systems could, theoretically, operate with very low overall energy losses because incoming cargo returns energy to the system by regenerative braking. A continuous loop of transport pods could be developed to provide rapid transit between the stars eventually.

But that’s all a long way off. To build such things requires massive efforts in the Oort Clouds of the stars involved and to trek around the Clouds will require Winterberg’s fusion rockets or some such.