The much-anticipated movie The Martian opens today, and I plan to be there, come hell or high water (and we might actually get some of that here in New York!). The book is amazing hard sf, and the movie promises to be more of the same. Hopefully, it continues a recent trend in realistic space movies.

A key plot point is that stranded Mars astronaut Mark Watney survives by turning his habitat into a potato farm.

I spoke with space crop researcher Bruce Bugbee, director of the Crop Physiology Lab at Utah State University to find out whether that’s actually realistic. In a word: yes.

Bugbee says the book and the movie get it right, that you could actually grow terrestrial plants in Martian soil, and, yes, you’d have to mix it with your own waste, since there’s no actual nutrients in the soil.

The closed loop farming shown in the movie is essential for extraterrestrial agriculture, says Bugbee, and one of the biggest hurtles still to be overcome by researchers. The issue isn’t creating a sealed environment; we’ve got that down cold, so to speak. No, the bigger problem is what to do with excess gases and moisture. You need what Bugbee calls buffers to balance out rising and falling demand as people come and go and plants grow. As he explains in my Popular Mechanics article:

“Let’s say you’re Mark Watney and everything is in balance on Mars for you, and now two people come for dinner,” Bugbee says. “Not only do you need food for those people, but as soon as they walk in the door, you need more oxygen for those people. Right now. They’re breathing.” Stored oxygen would have to be on hand to make up the difference.

Read my complete article on