I'll just dive right in...

We're in the middle of nowhere, Utah, at the Mars Desert Research Station, training for an expedition to the FMARS station at the rim of Haughton Crater on Devon Island in the Canadian High Arctic, where we're going to pretend to be astronauts for four long months. Think of it as a dress rehearsal for a real manned mission to Mars, in which we can test out equipment, logistics, methods, protocols and, of course, human psychology.

I met my crewmates just a few short days ago, and am delighted - and relieved. They're all sound folk: level-headed, smart and fun. Four months in a very small (about 1000 square feet) habitat in a hostile environment, never going outside without a spacesuit, will require strong inter-personal skills and a steady personality. I hope I'm up to the standard.

We're going to Haughton Crater because it is a great Mars analog. It is dry, cold, barren of vegetation, and is an old impact crater of the kind that are common on the red planet. However, one of the ways in which it is very un-Mars-like is the large fauna - that is, polar bears. It turns out that they tend to hang out around the hab on Devon Island. Now, I like polar bears, and wish them all the best in dealing with human encroachment and climate change, but I'd rather not help them out directly as bear food. So, we're getting weapons training, just in case.

We spent the afternoon learning how to handle various kinds of firearms, and strategizing about how to avoid bears in the first instance, how to scare them off if that fails, and, as a last resort, how to shoot them. The kick from the pump-action shotgun left me with a bruised shoulder, but I do now feel like, at a pinch, I might be able to convince a polar bear to look for food elsewhere.

Then, we played with the ATVs which will serve as Mars exploration vehicles, and practiced putting out fires with extinguishers. Now we're back in the hab, listening to country music and drinking beer. It's been that kind of day.

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