Carbon dioxide collector
(speculativity warning)
Micro airships:
- have a very lightweight bubble as main body in a size range between 10um and 100.000um
- use hydrogen as lifting gas
- use their surface for harvesting of solar energy
- are capable of water capture and splitting for compensation of hydrogen diffusion loss
- may be capable of carbon dioxide capture ond splitting
- may be capable of self replication
- may (if malicious) create some nasty gasses
good ones and bad ones
Good ones are not self replicating maybe drop the extracted carbon down in form of graphite chips stop carbon extraction at a certain level and care about their fate after their end of service. They have a rather big size that makes handling them easier and may also watch out for bad ones. Bad ones use the extracted carbon solely for self replication and at some point start to produce nasty gasses like Cyanide (HCN) or nitrous gasses (NOx) suddenly and in huge amounts
Both of them may endanger planes and create shadows hampering plant growth.
Questions
To investigate: If replicative how fast could they replicate (doubling time) depending on diameter?
What is the limiting factor solar-power for hydrogen generation, diluteness of CO2 ore something else?
To investigate: Can they be made to actively navigate? Their high volume to mass ratio makes this rather difficult when there's even the slightest bit of wind. Flattening the bubbles drops the aerodynamic resistance significantly.
alternate forms
for swimming ones - micro ships - essentially the same reasoning applies. They need only plain air as lifting medium must be sturdier can use the wind for propulsion and are easier to collect manually (skimming) if something goes wrong.
extraterrestrial application
(SciFi warning!)
The upper layers of the Venusian atmosphere would be the perfect place for replicative micro airships.
If the extracted carbon can be sealed good enough against the frequent and powerful strokes of lightning (questionable)
and the extracted carbon can be hold at high altitudes until the lower atmosphere have cooled enough so that the carbon could be put to the ground without reigniting (questionable)
then you end up with a cool superdense (too dense for humans) oxygen atmosphere (and a very dangerous situation). Now its the question whether the excess oxygen can be bound into the soil or ridiculous amounts of hydrogen or other abundant reducing elements have to be carried over.
Off topic question: What would a Venus with its over 100 day long day and higher solar constant look like if all the carbon where bound and most of the oxygen where trapped into water?
