I am a post-human adapted for permanent life in vacuum and micro-gravity. How might my physiology and biochemistry overcome the following challenges?
Please note I have a strong cultural aversion to augmenting my body in order to help me survive: i.e. enclosing myself in artificially-constructed protective shells, etc.
At this stage, I look similar to an enormous shining pangolin with interlocking plates of keratin-analogue that are alloyed with steel to protect against ionizing radiation. My radically engineered DNA and its unparalleled checksum and repair functions keep the doctor away. I can move these plates to help dissipate heat and - just like a Terran pangolin - curl up in a protective ball to shield my more sensitive parts. I have a reactive outercoating that allows me to alter my pigmentation (which I typically set to polished silver in order to minimise heat loss).
Part 3: Metabolism
I've reviewed some previous discussion around convergent solutions but pretty much the only thing I know about my metabolism right now is that I am a liquid breather (e.g. perfluorocarbons). I may be post-human, but I'm guessing water or an equivalent solvent is still essential to my metabolism. My large surface area helps cool me and prevent water loss, but I think I need a highly efficient recycling mechanism to survive without regular access to it.
The molecules fuelling your baseline metabolic pathways - carbohydrates, lipids and proteins - won't do unless I can crack them out of raw materials I have access to in the interplanetary medium, from asteroids, comets etc. Eating, drinking, in fact orifices in general, are also a no-no. You think it's difficult to grow rice in space, but have you ever tried eating a sandwich out here?
Although I live in complex societies with other vacuum adapts and homo sap, and therefore have access to abundant fuel/sustenance, I would like to be able to function independent of industrial civilisation. To live off my 'natural habitat' so to speak - even if this comes at the cost of winding-down to a lower metabolic gear, kind of like hibernating, or stockpiling rawmat when the going is good for consumption over extended periods.
Essentially there's not much food/fuel to be had out here in the void, and I'm not always hanging around easy sources of volatiles like a Kuiper belt object. At the same time, I need to maintain a relatively active lifestyle - overseeing asteroid mining operations, undertaking deep space repairs - rather than floating in circumsolar orbit gazing at the pretty lights of the Milky Way and the CMB all waking.
If necessary, I can dedicate significant amounts of time to activities to generating or harvesting metabolic inputs.
So, how do I convert fuel or food into energy to power my cellular processes out here in the big dark? What are said sources of fuel/food, and how does my body obtain and store them?