Valid justification for "GMO mech suit"

Question

I'm writing a story about a group of humans (or humanoid people) that are living on a spaceship that's orbiting a planet with high gravity; the force is too much for direct human involvement. There are limited technologies available to deal with the natural terrain of the planet, as it is incredibly hilly and have a lot of thick vegetation, and so expeditions to the planet are limited to accessible areas using vehicles to conduct experiments and general research.

So as a method to gain direct access to the natural land they take a native species and genetically modify it to be compatible to the human brain (removing extra limbs, altering it into a "bipedal" makeup, etc.). I call it a mech primarily because there is a space in the head where the "pilot" enters, is attached via needles in the spinal cord and advanced invasive EEG, and then put to sleep, limiting the functions to the mech instead of any conflicts between it and the pilot.

I want a valid reason as to why they couldn't just create a mechanic "mech" suit? Them developing a pilotable GMO that requires invasive brain surgery seems really steep, as far as cost/benefit. I have some ideas; their resources are limited, they want to interact with the environment in a more natural way, or something about the environment is especially corrosive or detrimental to the metal they have access to. But it feels wishy washy. At least to me.

(Also on a side note, could high gravity planets even create very large fauna/flora? Or is that unrealistic?)

Any advice would be wonderful! I'm also very flexible as to what I have currently, and any sorta ideas or suggestions you have story wise would also be interesting. The more hard-sciencey the better

Answer 1

The Power of the Human Brain

In this setup, the human brain can handle anything you throw at it.

We are already attempting to control prosthetics with our minds. I don't see why the arm can't be an extra arm or 4.

On the assumption that the human brain can handle all sorts of "enhancements", here is why a biomech is preferred.

Extra Sensory Perception

All of the senses from the the original organism are fed strait into the pilot's brain.

If the biomech can see Ultraviolet light, the pilot can now see UV Light. If the biomech has some non-human sense, the pilot now has those same senses.

Additionally, these are the sensors the evolution has chosen, not some spreadsheet on someone's cell phone.

Locomotion

Locomotion is hard. But, evolution solved it a long time ago. For a pilot, simple walking is easy. The pilots only need serious training if the biomechs are going to need the fine motor control found in sports.

Also, I see no reason why you have to modify your beast for bipedal walking.

Cost

Biomechs are cheaper to build.

Since the biomechs originate on that planet, you don't have to pay for the extra fuel needed to transfer the biomechs from the warehouse to the planet.

Because the biomechs have the ability to self-repair, biomechs are cheaper to maintain.

Answer 2

Bans on Mechas

Mechas and similar machines are banned by several international laws.

Most governments don't want to see their colonies getting heavy weaponry.

Most corporations want exclusive deals to supply the colonies with heavy machinery, so they don't want any local entities producing their own mechas.

Disruption of local life

These scientists want to cause the least possible disruption of local ecosystems so that they don't get wonky data, having a giant metallic robot stepping around, belching fumes, and leaving behind all kinds of detritus will certainly make the observation of undisturbed species almost impossible.

A good example are the mating habits of Grasshopers, for a long time they believed it was normal pratice for the female to devour the male after mating, but it was recently discovered that the female will only devour the male if under stress. (Possible source of stress: A scientist looking at her while she is trying to mate)

Answer 3

a valid reason as to why they couldn't just create a mechanic "mech" suit?

Mech suits require metal, which is in short supply on a spaceship.

Mine it, you say? But mining is a resource-intensive heavy industry: not something you'd do on a heavy-gravity planet unless the metal is really valuable.

Answer 4

Make all of their tech biological. Biology is a natural form of nanotech, if their normal way of doing things at this point of their civilization is to hijack genetic code to engineer everything - ships, computers, weapons, etc. (You should be able to program a cell to manufacture fiber optic cable - or plasma injectors, so you can just go nuts with this).

If for whatever reason they need a giant mech that's specifically adapted to some planetary environment, then growing a purpose build organism from local fauna with a wetware interface would just be standard operating procedure.