Trosper first started working on Mars, if only virtually, in 1997 for NASA’s Mars Pathfinder mission and its small, hitchhiking rover, Sojourner. She has also worked with the rovers Spirit and Opportunity—and works now with the latest Mars rover, Curiosity. For each of those missions, controllers worked on Mars time to coincide with daylight operations on Mars, but they didn’t stay on Mars time for long.

“When we landed the Mars Pathfinder, we did Mars time,” Trosper said in a phone interview from the Jet Propulsion Laboratory. “That’s the first time we ever did Mars time.” They stayed on Mars time for only a month. Having an extra 40 minutes to the day every day quickly added up—the difference between 6 p.m. on Earth and 6:40 p.m. on Mars one week turned into the difference between 6 p.m. on Earth and 11:20 p.m. on Mars a week later. Unlike time-zone differences, where the time on the clock is different but days pass in the same 24-hour increments, the time differences between Earth and Mars compound quickly.

It proved exhausting for the controllers as they tried to keep the same time as Pathfinder for daylight operations on Mars, while outside JPL the sunrise, sunset, and the surrounding society stayed on Earth time. NASA officials had wanted to keep them on Mars time for three months, but the controllers had enough, and by some accounts rebelled.

“That mission was a little easier to operate,” Trosper said, “and easier to transition off Mars time.” The Pathfinder lander didn’t move at all, and Sojourner never traveled far from the landing site. When the twin rovers Spirit and Opportunity landed in 2004, Trosper and JPL controllers went on Mars time again and stayed on that schedule for three months. Trosper also led planning for Curiosity’s surface operations prior to its landing on Mars in August 2012, including figuring out how long to stay on Mars time to work with the newcomer to the Red Planet. Again, it was about three months. The controllers have been getting better at adjusting to Mars time even as the rest of California stubbornly stuck to Pacific Time. Some controllers even had family members adapt to the same Martian time zone, kept shades down during the Martian “night” even as the California sun shone brightly, and otherwise tried to follow a slightly longer daily routine. Yet by the end of 90 sols, they would find the rest of Earth had advanced 2.5 days ahead of them. (So far, scientists are leaving it to eventual explorers and emigrants to Mars to devise official names for “week-sols” and months, though you can find recommended names on the web and in fiction. JPL controllers for each mission simply number individual sols from the time a craft lands on Mars, starting with Sol 1.)

Trosper had it even rougher. While she was on Mars time with Curiosity, she was also on baby time with her youngest of three children, born shortly before Curiosity landed. Her baby and Curiosity were both very demanding of her time. Perhaps because of those dual demands while working on Mars time, “I can hardly remember it. It did go really fast. As much as you’re exhausted, it just flies by.”