Comments on Next Big Future: Fuel scooping variable Minimag Orion proposal

Back when Andrews first published on MiniMag orion...

2009-02-26T14:43:00.000-08:00

Back when Andrews first published on MiniMag orion, I immediately did a calculation on the fuel pellet trail idea and then realized that it is easier to produce a neutral particle beam of fuel. We would arrange things so the beam velocity is always zero wrt the ship meaning we have to launch fuel beams waaay before we launch the ship. However, it is easier to collect such a beam than to collect pellets, you simply follow the beam.
Beam current would be very high, I cannot remember the numbers but it was Meg-amps or so and requires that the beam is then neutralized. The advantage of such is that such a beam can be aimed toward various destinations easier than a pellet launcher. Such a neutral beam device could also be used to support several missions at once by magnetically steering the beam and pulsing it.
The beam device would be built in solar orbit to support missions to outer planets and to inter-stellar missions. Thus it would be available for multiple missions.
The advantage of this is that although the actual energy expenditure may be higher than carrying the fuel, it means the ships engines can be smaller because it does not have to carry the fuel.
A similar calculation can be done for a Xenon based electric thruster getting to .1c where power is provided by a nuke reactor and we simply scale up the NASA Deep Space 1 thruster. We use a neutral Xe beam. It looked reasonable except for the large amount of expensive Xenon. However, i have just heard of a "helicon" thruster using nitrogen gas.............

Tom,

I had not worked out the catching of t...

2007-09-07T22:53:00.000-07:00

Tom,

I had not worked out the catching of the pellets. Either the pellets are slower and the craft overtakes them and catches/scooops or they are faster. With potentially far faster pellets from lorentz propulsion, slamming into the pusher plate makes sense.

And if the target mass is designed so the collisio...

2007-09-03T23:44:00.000-07:00

And if the target mass is designed so the collision triggers fusion, that would seem to get you an even bigger boost.

If I read what you intend correctly, you plan to "...

2007-09-03T23:28:00.000-07:00

If I read what you intend correctly, you plan to "catch" the pellets?

Once you hit 1% of C (perhaps before), why not just let them slam into a target mass a bit behind the ship, and use the resulting explosion to propel the ship? The faster you're going, the less mass the target has to have.

Or is that actually what you had in mind?

Updated my article with lorentz propulsion to acce...

2007-08-30T23:37:00.000-07:00

Updated my article with lorentz propulsion to accelerate tiny ships to 1-10% of lightspeed as a mean to get pellets up to speed.

interesting post, but your pellet catcher will exp...

2007-08-30T15:13:00.000-07:00

interesting post, but your pellet catcher will expend a lot of energy. You will need to accelerate the pellets from their current velocity to the velocity of the ship when they intercept one another. The faster you go the more energy the pellet catcher will need. Now i am not saying that the idea isn't a good one, but it may not be as efficient as one would like it to be.