What will the next footprints on the Moon look like?

One option NASA engineers considered was to add “active heating” elements to the boots to provide additional warmth. But loot radiators come with a trade-off, says Fester. “If you’re actively heating, you need to draw energy from somewhere.” This would mean batteries and wiring that could add weight to the boots and general cargo carried by astronauts.

Since astronauts must explore the lunar surface for long periods of time and potentially build a permanent base on the moon on future missions, even small amounts of extra bulk could make getting around less efficient. Engineers will have to make sure the boots fit as perfectly as possible, but they’ll face other challenges their counterparts at Apollo didn’t: the variety of astronaut body sizes. Artemis will see the first woman step on the Moon. This will mean that a much greater range of boot sizes may be required than on the Apollo missions, where the astronauts were all male and were nearly all the same height, age, and weight.

“We’re looking at ways to work with people to get a boot that’s right for them,” says Fester, who spends many hours walking around with prototype boots and suits to test how they feel. But instead of making numerous custom sizes, the boots will come in select sizes that can then be adjusted with padding inserts and external adjustment mechanisms.

“The AxEMU moon boot will be much more comfortable and mobile than those used during the Apollo missions,” adds Ralston.

Astronauts will also spend a considerable amount of time before starting training in their boots to ensure they perform as expected on the Moon. “They’re going to train and train in these boots, try different options, until they get the perfect fit,” says Fester. “Taming Moon Boots is just as important as taming a new pair of shoes.”

And for those who like a little more comfort, there are always lower-tech solutions. “I personally wear two socks on each foot; it feels so much better for six hours,” says Fester.