Astronaut Dr Jessica Meir described the challenges of wearing a spacesuit from the 1970s in 2019.
It's "incredibly cumbersome," and "pressurized," she told Insider in an exclusive interview.
She said balancing and moving around in an oversized spacesuit was particularly difficult.
Wearing a spacesuit in zero gravity is hard - but it's even more difficult if it doesn't fit you.
That's according to Dr Jessica Meir, who took part in a historic all-female spacewalk at the International Space Station, alongside Christina Koch, in 2019.
Spacewalks, previously termed extravehicular activities, are customary operations but they pose a great risk to astronauts. During a spacewalk, a pair of astronauts put on spacesuits, step outside of the International Space Station, and work together in a vacuum of space, Insider previously reported.
Spacesuit fitting is crucial for astronauts because if there's too much room inside them, it can make the work more arduous or even downright deadly.
In an exclusive interview with Insider, Meir said the spacesuits that NASA developed in the 1970s are the same spacesuits that the agency's astronauts wear now.
"For everybody, the spacesuits are incredibly cumbersome," she said. "They're pressurized, so they're difficult to move around in."
Back in the 1970s, astronauts were mainly larger men, Meir said. The range of spacesuit sizes was limited because of budget constraints, so they were made to fit the majority of the astronaut population size.
But the sizing issue isn't gender-related, she said. "It's an overall size thing."
"The population didn't really look like me," Meir said, adding that the smallest size is a medium. "The tallest guy in my class wears medium and I'm wearing the same size."
Meir, who is also a physiologist, said it's more challenging for smaller astronauts like herself to learn how to maneuver in the spacesuit, which doesn't fit them correctly.
Balancing is a bit more difficult, she said.
But the challenges that come with wearing an oversized spacesuit unearthed a mastery for Meir. "It helps you be a better spacewalker because you've had to use your brain and be a little bit creative in terms of solving the problems," she said.
For example, Meir highlighted the importance of using leverage in space instead of simply reaching over and grabbing something.
Spacesuit fittings are difficult because microgravity results in astronauts becoming taller in space, Insider previously reported. Astronaut Anne McClain, who also participated in the all-female spacewalk, previously stated she grew two inches taller in space than when she launched.
The suits are incredibly expensive, too. NASA's current fleet of spacesuits reportedly cost between $15 million and $22 million in 1974. Today, that is the equivalent of $150 million, Insider's Andy Ash reported.
They're expensive because they have to protect an astronaut from the vacuum of space and from radiation coming from the sun and other bodies. They also need to offer protection against particles that are moving up to 18,000 miles an hour and could pierce the suit.
And while there may be a budget to create something new, engineers need to spend a lot of time developing suits alongside making sure that they're tested and certified, Meir said. "There's just a very long lead time," she added.
But progress is being made and new spacesuits are in development, according to Meir. "The new suits will be fitting a much wider range of people from the 99th percentile and they'll have a lot more mobility inherent in them," she said.