Comments on: Nanotechnology and Nuclear Reactions

By: Eric Drexler

Eric Drexler — Tue, 12 May 2009 02:04:16 +0000

@ Phillip -- A problem with any tight integration would be that the structures in sails are extremely thin compared to those that would stop even an alpha particle (~0.1 micron v. >10 microns). BTW, there’s an interesting but little known (and probably impractical) propulsion concept that would make direct use of asymmetrically escaping fission fragments as exhaust. From the abstract of 1977 paper [pdf]:

A space propulsion concept is proposed and analyzed which consists of a thin sheet coated on one side with fissionable materials, so that nuclear power is converted directly into propulsive power. Thrust is available both from ejected fission fragments and from thermal radiation.

“Thin” here means “very thick” in the present context.

By: Jeffrey Soreff

Jeffrey Soreff — Thu, 07 May 2009 01:41:49 +0000

Basically agreed but

- nanotech is an enabling technology for cheap isotope separation for weakly radioactive isotopes, notably U235.

- if fission-free ICF fusion can be made to work, then the high power density available from nanotech would be a natural match for the pulsed power sources needed.

By: History of the University of Pittsburgh » Molecular nanotechnology

History of the University of Pittsburgh » Molecular nanotechnology — Wed, 06 May 2009 20:50:38 +0000

[...] Nanotechnology and Nuclear Reactions [...]

By: Phillip Huggan

Phillip Huggan — Tue, 05 May 2009 23:40:22 +0000

They will go nicely together as space probes. Eric, I bet if you try hard enough you can figure out a way to integrate radioactive isotopes as a heat source in your solar sail designs.

By: Anthony

Anthony — Tue, 05 May 2009 14:13:42 +0000

Thank you – this is one of the succinct arguments against cold fusion that I’ve seen. It’s been difficult for me to quantify, to explain to non-technical, interested, friends and aquaintances why I’m so skeptical.

By: Nanotechnology and Nuclear Reactions | Nano Broadcast

Nanotechnology and Nuclear Reactions | Nano Broadcast — Tue, 05 May 2009 06:28:12 +0000

[...] Nanotechnology and Nuclear Reactions [...]

By: Chris Phoenix

Chris Phoenix — Tue, 05 May 2009 02:48:33 +0000

I did a similar calculation once based on Heisenberg: even assuming (which is not the case) that you could get two nuclei aimed *exactly* at each other one nanometer away from the collision point, the minimal uncertainty in their position by the time they reached the collision point would be many times the capture radius.

One place where *advanced* molecular manufacturing will make a big difference is in Big Physics, perhaps including conventional fusion R&D. If construction of complicated physics equipment gets down to $1/kg, and blueprint-to-device takes days instead of years, we could build as many Tokamaks (or whatever) as we want, and spend less time optimizing each design. Thus, research cycles should go a lot faster.

Similar arguments can be made for aerospace technologies. If you can build and test a rocket a day for not much more than the cost of fuel, you can develop an advanced aerospace capability (including testing advanced propulsion concepts) very quickly. The country with the least oppressive regulatory regime (among the countries that have molecular manufacturing) will win that race.

Chris