A few years ago, the Canadian astronaut Chris Hadfield made a music video. Click over to YouTube and you can see him, singing David Bowie’s “Space Oddity” as he drifts in zero gravity. The guitar has Velcro patches — adorable. If an extended space mission involves enough downtime for classic rock covers, how bad can it be?

Pretty bad. In “Spaceman,” at the Wild Project in Manhattan, the American astronaut Molly Jennis is sitting alone in her tin can, seven months into an eight-month journey to Mars. That’s pretty quick. But it’s a long enough time for Molly (unlike Mr. Hadfield, she has no International Space Station buddies to hang with) to grow increasingly maddened by the isolation and pressure.

Ingenious and punishing, “Spaceman” stays with Molly (Erin Treadway) as she checks her air pressure, fuel levels and trajectory. (The clever capsule is designed by Carolyn Mraz.) A superstar scientist and a gifted athlete, Molly seems made for a solo mission. Of course, this being theater, she has also been lumbered with a tragic back story, which may unmake her.

During her jaunt, Molly has devised rituals and coping mechanisms, like the made-up songs she sings to herself and her workouts with resistance bands. Sucking down a tube of eggs, she imagines making herself a steaming omelet. Scrubbing herself down with a wet wipe, she pictures a luxurious bath with Epsom salts. Every day she has to find time to answer interview questions for various networks. Molly’s voyage, you see, is corporate sponsored. Her spacesuit has Google and Coca-Cola logos emblazoned on it, and, among the big-time donors are the major networks, as well as a Japanese game show that dares her to eat zero-gravity marshmallows.