Mobile nanoscale robotic device

There are a lot of types of mobile nanoscale robotic devices known by now. They ore often overlooked though since they are hidden behind the many terms used in SciFi that all vaguely refer to mutating omnivorous molecular assemblers. Non mutating and non omnivorous molecular assembler where an early concept that is now an outdated concept!. For the goal of advanced productive nanosystems nanofactories are targeted now.

Types

tethered -> probably unproblematic:

• J. Storrs Hall's "Utility foglets"
• Elasticity emulating microcomponents (specialised weaker form of utility foglets)
• Microcomponent maintenance devices
  Devices for low throughput maintenance purposes in products. While the products are actively running they could e.g. exchange radiation damaged parts and keep the products (e.g. motor material inside infrastructure) functional for arbitrary long spans of time. In contrast to molecular assemblers they would be incapable of self replication or mechanosynthesis.

untethered in water -> maybe problematic:

• medical naorobotic devices (e.g. Robert Freita's "Respirocyte") (bloodstream)

untethered in air / airborn -> probably more problematic:

• radioactive cleanup devices - due to their target problem they may become worse than the radiation
• diamondoid waste cleanup devices - macroscale devices will hopefully suffice

truly problematic:

• nanoscale devices which self replicate
• nanoscale devices which self replicate and emulate mutation (in a the limited way in which this is possible)

Note: such things will only become producible with advanced nano-factories and a lot of deliberate dedicated programming work.

About often taken incorrect assumptions

What advanced (non malicious) nanorobotic devices do not do and are not:

• NO self replication: this capability is for all practical purposes unnecessary and difficult (but achievable)
• NO mutations: they do mutate as much as the software on PC's does - not at all - emulation on a higher level is certainly possible - it is done today and is called evolutionary optimization. => Nanoscale robotic devices can not adapt other to new environments. (They can not adapt to changes in space or time. Redesign at the macro-scale is necessary.
• NO "omnivores": they can not digest process a very wide variety of food resources. See: atomically precise disassembly.

Details about some types

A note on molecular assemblers

Molecular assemblers are by now considered:

• impractical (inefficient and harder to reach than nanofactories)
• undesirable (because of real forms of grey goo - less crazy than the SciFi depictions but still bad)
• but not fundamentally impossible (given sufficient effort advanced nanofactories should be programmable to build them)

For more details please go to the dedicated page.

A note on airborne nanoscale robotic devices

They could become problematic in great numbers. Especially deviced made from diamond may cause problems for all lung breathing life on earth. Silicosis a kind of lung damage often observed in mining workers may occur. Biominerals should be a lot less problematic and act more like natural dust. In severe quantities they may create shadows hampering plant growth and even endanger planes.

Related: Much bigger but still small airborne atomically precise devises. (pollen-size to mosquito-size) J. Storrs Hall introduces them as "Aerovores" a term drawing from biological analogy

If they extract carbon from the atmosphere and simply expell in form of graphite chips black graphite snow may fall that has effects remotely similar to oil spills.

Malicious mobile robotic nanoscale devices

Air poisoning

Airborne devices may extract from the atmosphere solely for self replication act slowly so they do not get detected by their waste heat and at some point start to produce nasty gasses like cyanide (HCN) or nitrous gasses (NOx) and may release them suddenly and in huge amounts.

Limiting effects: high altitude radiation, limit of available elements, low concentration of CO₂ (usage of beta carbon nitride makes nitrogen available as building material) [todo: find which calculations have been done on (UV unshielded) radiation damage check them and include them here]