[ethbro]

Still much cheaper than shipping dirt to Mars.

[vkou]

It's even cheaper to construct and use all that stuff on Earth.

[adrianN]

That doesn't help a establish a Mars colony, which pretty much rules out that option if you want to establish a Mars colony.

[vkou]

It does, because you can figure out how to make all this stuff work[1] without spending hundreds of billions of dollars going to Mars. You'll also probably discover that you don't actually want to establish a Mars colony.

[1] We don't actually know how to make it work. The Biosphere 2 project was a spectacular failure, and it operated with a much less difficult set of constraints.

[ethbro]

Not risk adjusted.

[QAPereo]

Compared to the risk of Mars? I take your point, but let’s be realistic about our odds on Mars without Earth backing it all up.

[ethbro]

Granted. And initially, sure, but aiming long term for a single-planetary culture that took 3.8 billion years to develop seems shortsighted.

The risk of that life snuffing out may be small, but the time cost of replacement should that happen is huge.