Proto-assembler (outdated)

Note: This page is talking about "molecular assemblers" (here "proto-assemblers") in the sense of:
Diamondoid self-replicative nanodevices/nanobots that are monolitic, ultra-compact, and usually mobile in 3D.
For a disambiguation to other meanings see page Molecular assembler (disambiguation)
(wiki-TODO: make this into a template)

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OUTDATED CONCEPT several highly conceptual illustrations of diamondoid molecular assemblers. Common traits: Just one or two manipulators, a gastight hull enclosing everything, full selfreplicativity, very small size ~100nm, more or less optionally some sort of mobility some swimming others here unspecified

Depicted: The (dated) concept of replicating diamondoid molecular assemblers. Here two free floating assemblers are in the process of copying themselves. Screencap from BBC Horizon doku "Nanoutopia" (1995)

Proto-assembler: The basic idea is/was to create a machine with side-lengths of one to a few hundred nanometers which
packages all the functionality to produce useful products and also make copies of itself (directly with diamondoid mechanosynthesis).
This way one would get an exponential rate of replication and can
eventually switch from replication to production of macroscopic goods withinin reasonable amounts of time.

There's a lot of collary falling out from this premise. One thing that everyone immediately jumps at:
What if the switch from replication to production fails and these assembles never stop replication?
Wahaaa panic!! 😱😱😱
See: Grey goo horror fable, Reproduction hexagon & Replication pentagon

The three problems

There are three main problems with molecular assemblers.

• their inefficiency
• the difficulty in reaching them
• their undesirability

Inefficiency

For a proto-assembler inefficiency can be an excusable issue
so long that inefficiency is not impacting feasibility.

For more on the several inefficiency issues of molecular assembles see page:
Molecular assemblers as advanced productive nanosystem (outdated)

It turned out that packaging all the functionality into such a small package is a rather unbalanced and inefficient approach for in-vacuum gem-gum technology. This can be seen in the nanofactory cross section image where it is visible that the bottommost assembly levels (there arranged as stacked coplanar layers) take the largest portion of the stack. In the small package of an assembler the bottommost layers would be highly underrepresented making it rather slow (and inefficient).

Difficulty

High difficulty is a serious problem and was (and still is 2023)
a big critique point regarding the direct path.

(wiki-TODO: factor following out to: Direct path atom manipulation difficulties)

Doing single atomic manipulation with scanning probe microscopy is a very hard problem.

Especially when going only a bit out of 2D into 3D.

Especially materials (like diamond) that …
– feature strong covalent room temperature stable bonds
– are non conductive
– have small crystal lattice spacing
– don't like to form large scale atomically flat surfaces

Plus atom placement needs to be done in sufficient fast succession to form a proto-system in reasonable time …
– either by frequency (very difficult with macroscale tips pushing around nanoscale atoms)
– or by parallelism (multiple needle tips) other challenges here

Undesirability

Reasons for undesirably were clearly over-hyped. See: Grey goo horror fable
But it's clear that they came from overused misleading insidiously self suggesting biological analogies.

For "Molecular assemblers as advanced productive nanosystem (outdated)" it eventually became clear that
following this immediately self suggesting bio-analogy to living cells leads to a massively sub-optimal system.
For a proto-assembler that sub-optimality may be acceptable but there is still the matter of difficulty.
Optimal systems look very different. See: gemstone metamaterial on-chip factories

Old proto-assembler designs

Quite a bit of thought was put into the assembler model (wiki-TODO: link relevant parts in KSRM).
Either they where supposed to swim about in a solution
or there was some form of movement mechanism in a machine phase scaffold crystal envisioned like:

• sliding cubes (wiki-TODO: TODO add references)
• legged blocks (wiki-TODO: TODO add references)

Terminology

The term "proto-assembler" is not a completely new word creation here.
It likely has found some use in disussions arond the topic in the past.

Related

• Up: Molecular assembler
• Side: Molecular assemblers as advanced productive nanosystem (outdated)

The three problems of molecular assemblers that make them an outdated concept:

• Why ultra-compact molecular assemblers are too inefficient
• Why ultra-compact molecular assemblers are too difficult
• Why ultra-compact molecular assemblers are not desirable

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• Direct path