[2ndDivisionVet]

Mars has no breathable atmosphere, hence we will always be in a relatively fragile shelter. It is no “Plan B” for Earth.

[aquila48]

What would YOUR plan B be in case, say, earth gets hit by a huge asteroid that kills all life on earth?

[Wonder Warthog]

".....hence we will always be in a relatively fragile shelter.

We will learn how to handle it. That is what humans do.

"It is no “Plan B” for Earth."

At present. In the not too distant future, there will be many.