Diamondoid Manufacturing

Yesterday we looked at CRN's recommended study of sensing, manipulation, and fabrication tools for working at the nanoscale. There are at least three plausible ways to begin building from the bottom up: nucleic acid, biological self-assembly, and diamondoid. (Others have been suggested as well.) Each of these areas should be studied separately, both for manufacturing potential and for development requirements.

Here is an outline for an exploration of the various steps needed to develop a complete manufacturing system based on diamondoid vacuum mechanosynthesis. This is CRN's proposed study #8: "What will be required to develop diamondoid machine-phase chemical manufacturing and products?"

Subquestion A: How much computer time and human creativity would it take to invent, then simulate and verify a set of diamondoid-building (and/or graphene-building) reactions?

Preliminary answer: Robert Freitas has proposed a $5 million, five-year project to do just that; the project would also simulate the construction of nanodevices using these reactions.

Subquestion B: What will be involved in developing a non-diamondoid manipulation system that can carry out the required manipulations to build the first system?

Preliminary answer: Unknown, but it should be noted that we can now lithographically fabricate features that are smaller than the molecules we can engineer. In other words, we can build pretty much any shape at any size scale.

Subquestion C: How reliably can the operation of diamondoid machine parts be simulated? What would be the cost and development time of a CAD/simulation system capable of extracting mechanical characterization from molecular dynamics simulation of such parts?

Preliminary answer: Unknown, but this is a much easier problem than characterizing proteins: the parts involved are much stiffer, and energetic computations can afford to be much less accurate. Hydrocarbon MM packages have been around for years (e.g. Brenner) and are now appearing in open source software (e.g. NanoHive).

Subquestion D: How many parts and surfaces would be needed to constitute a complete set of low-level structural and functional components? How much human effort would be required to develop them?

Preliminary answer: Unknown. Low-level components include rotational, helical, and flat bearings; conductive and insulating components; molecular interfaces between different surfaces and crystal orientations. Note that Freitas expects to design at least some working components as part of his $5 million proposal.

Subquestion E: What would be the cost and development time of a CAD/simulation/tracking system that could support the design of machines and systems from low-level components?

Preliminary answer: Unknown. Probably comparable to high-end software design tools, or semiconductor design tools circa 1990. It wouldn't have to handle a lot of different parts or physics, at least in early versions where performance can be sacrificed to reduce undesired interactions between parts.

Subquestion F: What would be the cost of developing a design for an integrated, hierarchical manufacturing system to build large products?

Preliminary answer: An architecture for such a design has been worked out. The molecular fabrication in that design is based on a simple robotic-chemistry design by Ralph Merkle. Many fabricators make parts in parallel, and the parts are then combined via convergent assembly. Merkle's design requires perhaps 100 moving parts and half a billion atoms (most of which don't have to be individually specified). Convergent assembly appears to require only simple robotics at several scales. Assembly and fabrication appear to require only simple control software. Much of the engineering, even at nanometer scales, will be more or less familiar to mechanical engineers. Overall engineering difficulty might be comparable to an aerospace project.

Subquestion G: How many of these steps could be accomplished concurrently in a crash program?

Preliminary answer: All of these steps could be started concurrently, with successive refinement. This may not happen due to caution on the part of the funders. However, a funding organization that was willing to fund a crash program could probably do all these steps in parallel.

Subquestion H: How precisely can costs and schedules be estimated?

Preliminary answer: Due to lack of study, very little information is available. For the sub-projects that we can estimate, the cost is consistently under $1 billion, and several appear to cost just a few million. Also, all of them (with the exception of software engineering, which should not be a major fraction of the total cost) appear to be getting easier rapidly. We can't rule out the possibility that the whole thing might cost less than $1 billion; in fact, that appears likely to us, though we don't say it loudly because it sounds too implausible. A project starting five or ten years from now very likely would find the cost greatly reduced. (However, other studies indicate that this is not a sufficient reason to delay; it's simply evidence that if we do delay, a rapidly increasing set of organizations will be able to do it.)

About schedules, again, very little information is available. The argument parallels the cost discussion. The project can be divided cleanly into sub-projects. In the areas where we can make estimates for the sub-projects, the estimates are surprisingly short. We don't see any sub-project that needs to take more than five years. Doing all sub-projects in parallel would require excellent management, visionary funding, and good communication to ensure smooth integration. But this appears feasible, and implies that the whole thing might be done in five years with sufficient effort and skill. (But government bureaucracy is not well suited to do this.)

Provisional conclusion: At a guess, the difficulty and schedule of developing a tabletop kg-scale manufacturing system producing kg-scale nano-featured products may be comparable to the Apollo Program. Or it may be quite a bit easier; we can't know without more engineering investigation. At this point, we can't rule out the possibility that it could be done in five years for less than $1 billion. Note also that work on this may have already started somewhere, and may be quite close to completion.

CRN's initial basic findings (preliminary answers and provisional conclusions) for all thirty studies should be verified as rapidly as possible. Because our understanding points to a crisis, a parallel process of conducting the studies is strongly preferred.

We are actively looking for researchers who have an interest in performing or assisting with this work. Please contact CRN Research Director Chris Phoenix if you would like more information or if you have comments on the proposed studies.

Comments

[jim moore]

I think that there is another very good reason (that I just realized today) for making MNT out of almost pure carbon. If the electrical conduits (or some of the low friction surfaces) are made with graphite like material (Bucky balls or Bucky tubes or networks of tubes or just sheets of graphite) it introduces a very real vulnerability to some frequencies of EM radiation. The pi bond structure in these molecular systems makes them capable of absorbing energy at potentially a wide range of wavelengths. The diamondiod material that makes up the rest of the nano-weapon should be transparent across most of the EM spectrum but thats good because it will not shield the vulnerable graphite-like material.

If this graphite vulnerability is deliberately built in ( or better yet, is unavoidable) defending against large numbers of very small attackers could be as simple as a low level laser sweep. Because the very small can't have much shielding this type of weakness limits many of the very underhanded attack modes made possible with MNT. Or at least I hope so.

[jim moore]

Couple more thoughts,
If we take the current nano-factory design it should be easy to integrate vulnerabilities into the designs of all of the active nano-blocks. If the blocks are designed to undergo an irreversible chemical change (that causes the nano-block to break) when exposed to a certain intensity and frequency of light we can add a layer of security to the system.

Ideally you may want to have the nano-blocks break only when exposed to a combination of stimuli. The goal should be for the nano-blocks to almost never break during normal operations but break greater than 99% of the time when exposed to its designed in vulnerability.

If people are going to have a super powerful technology it might be a good idea to have some kyrptonite.

[Mike Deering]

Products that disintegrate upon reception of a coded broadcast. This is a very bad idea. Would you want your spaceship built out of this stuff? Or your artificial heart? What about the chain on your kid's swing? Many nanobot systems will be vital personal safety or security mechanisms that would be dangerous to disable.

If you are going to limit this vulnerability to only weapons or bad nanobots then you are going to have to have intelligent monitoring to differentiate them. And if you have intelligent monitoring why not just prohibit the production of bad products in the first place?

By the way, this kind of weakness can be easily designed in, or easily designed out, dependent on the bond architecture you choose. It is not an unavoidable weakness, but if we thought of a good use for it we could do it.

[jim moore]

Mike,
I was thinking more like designing the active nano-blocks to be especially vulnerable to some kind of low power weapon that would not hurt people. Something with more power than a broadcast code but less than a high intensity UV laser.

I am not so sure that small scale carbon nano-systems that have some components that conduct electricity can be made to be invulnerable some type of EM radiation attack.

[Mike Deering]

So you design active nano-blocks to be vulnerable to a low power weapon. What would you use these vulnerable nano-block in? Certainly nothing mission critical, medical, safety, transportation, communication, or security related. Nothing you wouldn't want someone else to be able to easily disable. What does that leave? Toys? What's the point? Is this some kind of new mechanism of centralized control by a totalitarian leadership? Personally, I'm looking forward to the day when products never wear out, break down, become obsolete because you can't upgrade them, or end up in a land fill (recycle their atoms). I understand the need to build in control mechanisms but the extreme miniaturization of nanotechnology allows for very sophisticated, versatile, and intelligently responsive control systems.

Susceptibility to EMP attack is a function of wavelength which is dependent on circuit length. The circuit lengths in nano-circuitry are too short for any practical EMP weapon. Buckyballs and nanotubes are not graphite and do not share the same electrical or structural strength characteristics.

[jim moore]

Ok, my goal here is to provide a layer of security, not a completely secure system. By designing the publicly available active nano-blocks to be vulnerable to a specific frequency of laser light we can insure a good defense against at least some kinds of possible attacks. It would be most effective against small MNT products. Larger systems (such as a spacecraft, or even a space suit ) could easily be shielded against a low power laser. Intermediate sized systems would have some degree of shielding, but the shielding may make the objects easier to detect.

Now I know some people will say military researchers will make their active nano-blocks different, so that they are not vulnerable to the same frequency of light. And I think they will be right, but this design strategy can limit the destructive capabilities of individuals and small groups.

[Chris Phoenix, CRN]

Jim, I think this is a very clever and likely useful idea. A variant would be to build in "fluorescent" tags (maybe actually fluorescent, maybe some mechanism with similar effect) that made the things detectable but not killable.

In fact, now you've got me wondering whether there's some part of the electromagnetic spectrum that could 1) penetrate many materials, at least a little; 2) resonate/interact with nanometer-scale carbon lattice, "touching" either atoms, bonds/molecules, or machine parts; 3) deliver enough energy to be useful either for sensing or for messing with the machinery. Of course it's preferable if it doesn't do indiscriminate damage to other materials (gamma rays meet all the above criteria, but can't be widely used).

I'll email a physicist I know...

Chris

[jim moore]

Chris,
The tag idea is really nifty. Imagine that you have an L shaped array with a place for four different quantum dots. If each of the dots can be one of four different colors you can uniquely identify 256 different blocks (if my math is right).

It could be very neat you could use a low power scanning laser to stimulate the quantum dots in each nano-block potentially giving you very detailed information on the make up of any product of a nano-factory.

[Hector Magnetic1]

I like that kryptonite comment, the nanoblocks should contain some kind of quantum code only known to the creator. So when i feel like disintigrating my out of control robot, i'll just push my universal RMC and boom its grey goo. Of course the control will be powered by my DNA and brain waves.

[prof.zack]

i dont agree with u....