Sometimes you just want to have a dragon, giant scorpion or a superhuman that has a bit more realism behind it than "it's strong, fast, can jump extreme distances despite it's weight and it's smart, deal with it". The original question(s) were far too broad for a single post, so I'm making a series of posts about things like skeleton, muscles, nerves, immune system and more to try and get an answer on how to build some of the best but still scientifically semi-realistic creatures. My personal question mostly aims at a humanoid super-soldier, but I expect that most of the idea's would be useable in other creatures as well.
For completeness, here's a list of things that I think such a soldier needs to adhere to:
- Uses biological components to function
- Can regenerate wounds without needing to be brought to a certain facility for repairs (but if available they would use it). Regeneration does not have to be 100% successful, as long as they can continue at a high % of their original functionality it's OK.
- Can survive on food when necessary.
- Has ways to reduce the effects of radiation, both cosmological and from weapons (like a robot that's holding a Paricle Beam in close quarters).
- Can survive short periods out in space, preferably in a damaged space suit but naked if necessary.
- Has protection against extreme heat (lasers, Plasma, Particle Beams) and extreme cold (space, liquid nitrogen and other cold stuff weapons)
- When necessary, can still reproduce normally.
- Can survive breathing toxic air for extended periods of time (not very good on the details of what "toxic" is right there)
- Has a resistance to small-arms fire, either through protection and/or being able to keep going regardless of damage
- Can withstand immense amounts of recoil forces.
The goal of this post is to come up with idea's for the skeleton, what materials it needs to be build of, what shape it would be and how easy it would be to repair and maintain.
My personal take on this part is as follows:
Materials: Graphene, Carbon Nanotubes (CNT's).
Graphene seems like a perfect fit for a skeleton. It's Carbon-based like most of the body's structure (that isn't water), it's incredibly strong but it's not extremely brittle and it's lightweight. Any alternative functions that normal bone would do and Graphene couldn't would be taken over by bony calcium deposits.
Repairs and checks on how the Graphene bone is currently doing can be done by systems already in existance: Currently the body uses electric potentials to check how much stress a bone receives and then uses that feedback to strengthen or weaken the bone locally, this same process could be used to check for damage to the Graphene structure and have repair cells be activated/attracted to such area's.
Another advantage pointed out by Nick: Graphene can conduct electricity extremely well. When using an exo-skeleton you can make the person highly resistant to electrical attacks as the exo-skeleton would conduct the electricity into the ground without the surrounding tissue receiving much of the punishment.
Disadvantages could be that Graphene is a single molecule thick to gain it's properties, so you would need to have many many layers of graphene that aren't attached to one another to build the bones out of. Another possible problem is that the cells wouldn't be able to create a full-scale graphene layer and would only be able to build small portions of Graphene that has to be connected without being a single large molecule. An alternative is to roll up the Graphene into CNT's and put those into another material, like normal bone. There's a perfect size for these rolled up nanotubes that gives the best strength properties, and there's room enough to insert another smaller CNT inside for extra strength.
One big advantage is that you can vary the amount of Graphene or CNT's to give different strengths, in case you don't want people running around with skeletons 5x stronger than steel using 3D Graphene (just found out it exists: https://www.engadget.com/2017/01/09/mits-3d-graphene-is-ten-times-stronger-than-steel/), or even 300 times stronger than steel(http://theconversation.com/harder-than-diamond-stronger-than-steel-super-conductor-graphenes-unreal-5123)
For the shape I would use both an endo-skeleton combined with an exo-skeleton. With the weight issue's removed due to the skeletons strength and light weight, having an exo-skeleton won't make you collapse under your own weight. The addition of an endo-skeleton would help support the body especially in case the exo-skeleton is damaged and offer extra places for muscle attachments. The exo-skeleton would also serve as a perfect shield against incoming harm, with a single millimeter thick exo-skeleton possibly counting as 5 to 300 mm of steel.
To increase sensitivity, speed of repairs to damage and make it looking more like a humanoid rather than a humanoid crab, a layer of skin would still cover the exo-skeleton. This way damage on the outside of the exo-skeleton can be repaired more easily and the being has an easier time feeling his surroundings with a normal skin layer (don't worry we'll get to upgrading the skin to super-human status as well).
The biggest questions that remain for the Graphene for skeleton idea: Isn't Graphene too flexible? Does it need a material beneath it or through it to provide strength?
Can the body acquire enough Carbon and energy to form Graphene in large enough quantities to repair and maintain the body?