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Comment Re:Comparison, please (Score 3, Interesting) 132

The Neumann thruster is all about saving launch capacity. Most of the ion thrusters we have now work with e.g. Xenon gas; you have to loft their fuel, and your engine mass budget has to include the material handling for the propellant; tanks, valves, etc.

The idea of the neumann thruster is that your reaction mass comes from a simple sold puck which is gradually ionized; so you immediately win on a bunch of hardware you don't have to lift.

And then, you can use as reaction mass the sorts of stuff which is already up there in orbit. Got some excess second stage, which you've lofted to orbit at ruinous cost? Instead of dropping it back into the atmosphere to burn up, melt it into a puck at the focus of some mirrors, and then use it as reaction mass for a few years.

Space junk turned into valuable fuel. Big win. .... IF it works.

Comment Re:Hedge (Score 2) 238

why would they then turn around and be hypocrites by ruining the very reason they're moving intro infrastucture to begin with?

Run like a reformer. Rule like an incumbent.

Not saying that's what they've got in mind, but that's why you'd betray the principles you espoused while trying to gain power.

Comment Re:3D printers suck (Score 1) 129

1) You can't get something CNC for that.

2) Harbor freight (1.5K mill linked to below) doesn't sell tools, they sell tool _kits_. If you're not prepared to disassemble, align, and otherwise fix all the stuff they busted, you're screwed. I'm a half-owner of one, I know.

3) Tool pathing is still expensive / highly skilled. At your price point, you can't just turn a 3D model into a path that a mill can make.

4) Design constraints are different for the two. You can't mill internal voids.

None of which is to say I think the current batch of filament deposition printers are adequate... I've got one of them too, at our Hackerspace in Gainesville. Once they get the plastic printers sufficiently precise that they can turn out e.g. kitchen appliance replacement parts, we'll have gotten somewhere serious.

But your combo requires a bunch of skill to operate, and skill-less object production is kind of the point.

Comment Re:Hmmm... Makerbot? (Score 1) 120

Makerbot's got way worse resolution, and is a bloody bear to calibrate.

The newer version appears to be better than the one we bought and built, but so far all the depositional printers I've messed with seem good for building other printer parts and little toys.

This laser-based one has far better precision and resolution.

Comment Means other than chemical... (Score 1) 542

The author of the original article is presumedly no dummy, and I agree with his analysis as far as it goes. But he makes no attempt to discuss travel powered by something other than chemical rockets you bring along.

VASIMIR is one alternative, which will indeed gain efficiencies from Moore's law (extremely rapid adjustments to optmiize magnetic field?).

The juice to run that can come from nukes or solar...

Chemical fuels are a barrier to chemical propulsion, that's all.

Comment Sadly, no progress since last year? (Score 2) 386

They were saying, in July 2009, http://gigaom.com/cleantech/the-solar-biofuel-hybrid-joule-biotechnologies-launches/ that they were going to build a pilot plant in 2010, and have the initial commercial-scale plant up in 2012.

All through 2010, their press releases talk about awards and management, funding and P.R. I would have expected "Pilot plant ground broken", "Pilot plant going online", "Pilot plant now giving free diesel to all plant employees, outside customers can pay $1.00 per gallon at plant filling station...".

What a work bennie that would be!

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