One of the rules in engineering is that you really shouldn't engineer near the limits of your materials. For instance a modern day hammer is so well below what can easily be made with steel and wood that we don't worry about its reliability; even a 50% reduction in strength because of a flaw would still give you a pretty useful hammer, or if the person wielding the hammer is unusually strong, still not a problem.
As a blacksmith, I will point out that I have had many a hammer break on me: not just Chinese recast engine blocks on whatever scrapwood they could handle it with, but name-brand hammers that should have had better quality control. I'm not even particularly strong, but for heavy forging work or repetitive striking of hardened steel tools will take a toll eventually, and some are flawed right out of the box with hidden cracks in the handle or an improper heat-treatiment of the head, or once a beautiful handmade hammer had an issue with the wedge, also handmade, not being properly applied, allowing the head to go flying off after a few uses. Engineering a hammer isn't hard, but don't assume that because it's just a lump of metal on a stick that it's impossible to mess up.
Mars is barren, extremely inhospitable, wasteland. Why are they in such a hurry to send meatbags there ?
Because when, inevitably, someone kickstarts a nuclear war, releases a 100% deadly disease, or we're all turned into computronium by our new AI overlords, having an offsite backup, even a primitive one, seems like a really good thing. Sure, it won't be self-sufficient at first, but if we never start, we'll never get there at all, and then it might be too late.
Not to mention, their kids don't want to be caught dead at their dad's former homeland.
I know a few techs who decided, upon living the US a few years, that the arranged marriage waiting for them back home was a crap deal, and made arrangements to stay. In one case, a woman I worked with, her father confiscated her passport and refused to let her return for a month until the arranged wedding collapsed when the groom also declined to marry for someone else's benefit.
The star of riches is shining upon you.