Astronauts on the International Space Station get thick calluses on the tops of their feet instead of the bottoms, but today students tried out ways to make the final frontier a little friendlier for feet.

Not only did they get a chance to talk with NASA astronaut Jessica Meir about socks in space, over a video link between the space station and Seattle’s Museum of Flight, but they also ran their own experiment as part of an Astro Socks Challenge created by NASA and Microsoft Education.

The challenge, and the Earth-to-space chat, made a teachable moment out of a fact of life for long-duration spacefliers.

“Up here, we float,” Meir told the kids as she did a slow zero-G flip, “so if we don’t secure our feet somehow, then we don’t stay in place.”

To stay in place while they work with their hands, the station’s crew members hook their feet beneath the handrails and other fittings mounted on the station’s interior walls. But that rubs against the skin of the tops of the feet.

“Your feet aren’t really used to that,” Meir said. “When you first get up here, it takes some time to adapt to that, and your feet actually can be a little bit sore on the top as you’re using them to hold yourself down.”

That’s what makes socks in space so important. Even as she spoke, Meir wore dark blue socks with light blue tips (which happened to be color-coordinated with the uniform she wore). Wearing the right socks can soften the strain on a spaceflier’s metatarsals.

Does the sock design make a difference? For the Astro Socks Challenge, students in middle schools and high schools studied the physiology and the physics of footwear, and designed their own sensor-equipped socks. After today’s space chat, three students in orange astronaut suits put their socks to the test.

The kids took their seats in roller-equipped chairs, and then put on the socks and the frames that would measure the strain on the tops of their feet. When grown-up assistants pulled the chairs backward, the kids dragged their feet, and the sensors recorded how much of a load was being felt on the tops of the toes and the metatarsals. The metrics were instantly displayed on the big screen over the stage.

“Not only did they get feedback, but they can now go back and refine those designs and start working on them for the future,” Karon Weber, partner director at the Microsoft Education Workshop, told the audience. “I think your feet might be OK by the time we get to go to Mars.”

Going to Mars was on the minds of at least some of the students: Meir was asked more than once about her own path to becoming an astronaut, and what advice she would give for pursuing a NASA career.

“The common theme is a STEM field,” Meir said. “Science, technology, engineering, math. If you are interested in any of those fields, I really encourage you to pursue those. That is the best path if you do want to become an astronaut.”

And as it happens, today is the first day of a monthlong NASA recruiting drive for astronauts. Applicants generally have to have at least a master’s degree in a STEM field and two years of professional experience, or at least 1,000 hours of flight time in a jet aircraft — which means the kids at the Museum of Flight still have a long road ahead of them. But who knows? Maybe future astronauts will be wearing socks they designed themselves when they take their first steps on Mars.

The Western Washington students who attended today’s Earth-to-space video chat with Meir represented Rainier Prep in Seattle, Heritage High School in Marysville, Highline High School in Burien, International School in Bellevue, and Amelia’s Aero Club at the Museum of Flight.