[sliverstorm]

It is a form of humor on the part of the HN submitter. Though for the life of me I can't recall what type. It's not irony. Gross understatement?

[nandemo]

Not even that, since most astronauts don't really travel to space frequently. It would have to be "involves somewhat longish trips" to be a proper understatement.

Since the ad is for astronaut candidates, the frequent travel is presumably of the boring, Earth-bound type.

[sliverstorm]

Wry humor becomes much less funny when you insist on analyzing it and adhering to the so-called "facts"...

[nandemo]

You're right, of course. But I only jumped in after you started it. :-)