Editor’s Note: Meg Urry is the Israel Munson Professor of Physics and Astronomy at Yale University and recent president of the American Astronomical Society. The opinions expressed in this commentary are hers. View more opinion on CNN.

CNN  — 

March is Women’s History Month, so it would have been a great moment for the first all-women spacewalk, with astronauts Anne McClain and Christina Koch. That was NASA’s plan this week, until it realized it had a problem: two women astronauts, but only one space suit available in their size. So instead of McClain, a man – Nick Hague – will join Koch for the spacewalk, wearing the large suit that is flight-ready.

Meg Urry

To some, the change of personnel seems like a small thing, and NASA does say that the women’s spacewalk milestone will happen eventually.

But it’s another disappointing reminder of how gender bias shapes our world. From the start of human space flight, the deck was stacked against women. The first seven Mercury astronauts were household names to any 1960s schoolkid – but very few knew about the “Mercury 13,” the group of women who passed the same grueling tests that the men did. They, too, were some of America’s finest astronaut candidates. But their privately funded training was canceled almost before it began.

In 1963, the Soviet Union made Valentina Tereshkova the first woman in space, but it took another 20 years for Sally Ride to become the first American woman to break that barrier. Mass and volume are precious commodities in a rocket – shouldn’t women have been well suited to the program from the beginning?

NASA started selecting women astronaut candidates in 1978. In 1984, Kathryn Sullivan became the first American woman to walk in space. She wore the Extravehicular Mobility Unit modular space suit, which was designed to fit 95% of women and of men. This ecumenical approach to tailoring didn’t last, however.

In the 1990s, budget pressures limited a new NASA space suit design to medium, large and extra-large sizes. Meanwhile, a 2003 study found that eight of the 25 women astronauts at that time could not fit into the available space suits, preventing them from being assigned to space walks, whereas all the men could find a good fit.

Wouldn’t the best approach be to catalog the attributes most needed in space, and then decide who might meet them, regardless of sex? If budget becomes a concern, the support systems could be tailored to those who satisfy the highest priority needs – independent of sex or any other irrelevant characteristic.

NASA isn’t alone in just expecting women to meet male norms. In my field, physics, greatness is often equated with aggressiveness and assertiveness. Yet professional style has little to do with scientific discovery – and aggression can, in today’s world of large collaborations, be detrimental.

It’s 2019, folks, and women are everywhere – in science, in politics, in business, in operating suites, in coal mines, in the military, in the Space Station. It’s past time to recognize that physical spaces and equipment should be sized appropriately. Some might worry we can’t afford the expense or storage space for “extra” sizes. But we can’t afford not to utilize the talent that comes in non-male-standard sizes.

Even the word “extra” implies there is a norm, and that women aren’t it. Let’s normalize difference. It would be a fitting nod to women’s history month to recognize that no one size is the standard, no one gender is the one that doesn’t belong.

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    An all-woman astronaut crew has special meaning for me, as a woman working in a mostly male profession. Women share experiences and obstacles that simply don’t confront men in the same situations. I really liked the idea of those two women working hard, together, to upgrade the Space Station for NASA, for America and for all the little girls who are thinking of becoming something grand.

    Difference is good, even great. It’s known to lead to greater innovation. But sometimes sameness is hugely innovative too.