Mary Roach has made a career out of pushing her audience's squick button. She's written books about corpses (Stiff), the afterlife (Spook), and sex (Bonk), and every time the topic ventures into issues that could turn disastrous if handled indelicately, she defuses the situation with a deft application of nerdy humor. Her new book, Packing for Mars, addresses the problems inherent in sending human bodies into outer space, and those problems are inherently messy. Our bodily fluids didn't evolve with space travel in mind, and so science and engineering have had to confront and outsmart our messiest realities: shit, piss, vomit, farts, filth, and sex.

When asked over the phone how she manages to write about effluvia without turning her books into an endless succession of fart jokes, Roach says, "I'm not interested in it just for its own sake—you know, shit and vomit—although some people would find that hard to believe." What interested her in writing Packing for Mars is that "it is a really complicated engineering challenge to figure out how to create a zero-gravity toilet that is humane and that works. And just the thought and the expertise and the technology that has gone into this very sort of tee-hee grade-school issue I found just fascinating."

Her straight-faced reportage explaining how engineers refer to errant pieces of fecal matter that fly out of shuttle toilet bowls—they call the floating turdlets "escapees"—is more notable to the casual reader (Jon Stewart made much ado about this factoid during Roach's appearance on the Daily Show last week) than the fact that her research skills are magnificent. That is as it should be, really—good reporters disappear from their stories if they're doing their job right—but the amount of work behind the scenes of Mars is staggering.

Roach works very hard to exonerate one of America's earliest astronaut chimps in Mars: A shady journalist invented a story suggesting that a chimp named Enos masturbated during NASA training exercises. The story became a legend, which over time transubstantiated into the "fact" that Enos masturbated during a postflight press con- ference. Roach quadruple- checks the story, tracking down the source of the rumor and ultimately debunking it. It's a lark about chimp masturbation, to be sure, not breaking the story on Abu Ghraib, but one still has to admire Roach's journalistic fortitude.

The most impressive trick of all, though, is that when you've finished gulping up every anecdote and wry footnote in Mars (one could read just the footnotes of a Roach book and still come away satisfied and entertained), you'll suddenly realize that you've just read a concise, thorough history of human space travel. Roach has explained our entire history with the void—from the Soviet-era space race to our current aimlessness as a species—and slipped it inside a book so entertaining to read that it feels like a succession of pithy anecdotes about bodily fluids. That's not accidental; that's a kind of science. recommended

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