Devyn Oh flips around a sign on the family’s front door. It says, “Flight Director Asleep on Mars Time, Come Back Later.” (Damian Dovarganes/ASSOCIATED PRESS)

The Ohs of California aren’t jet-lagged by a family vacation. They’re space-lagged.

That’s because dad David Oh is a flight director for the NASA mission that sent the Curiosity rover to Mars. As part of their job, everyone working on the mission needs to live on “Martian time.” A day on Mars is about 40 minutes longer than a day on Earth.

As an experiment, the whole Oh family — including mom Bryn and kids Braden, 13, Ashlyn, 10, and Devyn, 10 — shifted to Mars time along with David.

Forty minutes a day may not seem like a lot, but it adds up. Curiosity landed on Mars on August 6, so the days have been shifting for more than three weeks. One recent day, the kids ate breakfast at 3 p.m. and went to bed at 5 a.m.!

“It’s awesome, but it’s tiring,” according to Ashlyn.

But the family experiment is about to end. With the start of school, the Oh kids will need to move back to Earth time.