Downthread I describe a cheap and easy way of exerting complete control over your martian colonists by systematically removing parts of their bodies then charging them for those functions to continue. https://twitter.com/pookleblinky/status/1388320020267216896

Accelerating bone density loss is easily done by corticosteroids.

Since colonists can be medically screened and quarantined, and then placed in sterile environments on the way there, you can jack them full of corticosteroids with far less concern than on earth.

Cheap, easy, your colonists will piss out half their bones on the way to mars. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4613168/

Once they arrive, their kidneys will be shot. Remove them, mount a dialysis port.

Charging them for dialysis is easy and already a solved problem.

Modifying their digestive tract is harder.

Their diet will be mostly insects, you want to modify their gut flora with more powerful chitinases. Once you do that you can remove most of their lower intestines

Here's the problem: you can't have your indentured servants able to sabotage things by letting their gut flora digest their environment.

The easy way to do this is to simply take advantage of stereoisomers. Have their gut flora require a dietary additive like L-glucose

This way, you can control your indentured servants even more by threatening to withhold this otherwise useless chemical.

And, they can't make bombs out of their shit, intentionally or not.

So now your indentured servants have 50% the bone density of earthlings, pay you for their most basic metabolic processes, and you can feed them garbage to recycle. Also you control the air they breathe.

You own them.

This is not enough, though. There's still a risk of sabotage and insurrection.

This is solved by getting them addicted to a substance that is cheap and easy to synthesize but which has terrible withdrawal symptoms such as seizures.

Encouraging biological synthesis of such substances is easy, cheap, and they'd do it anyway.

Now your indentured servants know they are 36 hours from convulsing on the floor if they break a minor rule that doesn't warrant harsher penalties.

All in all, it'd be pretty easy. Already totally possible. Any corporation would do this to its workers, today, if it could get away with it.

In space, no one can hear you try to unionize.