In space, any food produced would have to be grown inside, sealed away from the outside environment to protect it from the vacuum or near-vacuum of space or Mar

In space, any food produced would have to be grown inside, sealed away from the outside environment to protect it from the vacuum or near-vacuum of space or Mars. We will grow it in greenhouses or perhaps vats (staples like corn or wheat can be replaced by fermented foods like @solar_foods or @feedkind, using ultimately solar power, this is actually more efficient than photosynthesis and with a much smaller environmental footprint than agriculture) and certainly not have free grazing cattle (which is the biggest land use in the US). On Mars, we’re already beginning to master solar/battery-electric flight, so perhaps we may not need so many surface roads and we can place trains and such underground. Our footprint on the planet Earth could shrink by an order of magnitude even as our economy and quality of life improve (the density effect on economic productivity is well-established—and Mars will be really expensive to live on unless in large, dense cities... suburban sprawl being prohibitively expensive). These are all things that are fairly hard to prove on Earth as the whole system has an inertia due to developing with abundant fossil fuels, but on Mars we will be forced to rely entirely on renewable (mostly solar but perhaps wind and geothermal) or nuclear power, so a Martian society becomes a blueprint and a powerful proof of concept of how Earth life can be..