As a kid with a precocious mind for science — she made it to the Intel competition semifinals in high school, after all — Natalie Portman dreamed of becoming an astronaut. But acting eventually grounded her among less celestial stars.

So the role of Lucy Cola, whose encounter with the vastness of the universe during a space-station mission triggers an existential crisis back on Earth in Noah Hawley’s “Lucy in the Sky,” was “a little bit of wish fulfillment,” Portman admitted. And it wasn’t merely the prospect of climbing into a spacesuit.

“Just to see a woman in complete humanity, with flaws, with strengths, is so lucky,” she said. “So often, a woman is adorable, or a badass, or a villain. You could sum her up in one word.”

“You don’t have a simple feeling about Lucy at the end,” she added.

“Lucy in the Sky” is loosely based on the tabloid-ready tale of Lisa Nowak, the astronaut who in 2007 drove from Houston to Orlando to attack her former lover’s new girlfriend — reportedly wearing a diaper to save time on her journey.

Alas, there’s no diaper in “Lucy in the Sky,” an omission that has whipped expectant audiences into a froth. “This is fictional, other than the sort of jumping-off point,” Portman said.

An Oscar winner for “Black Swan” and an outspoken Time’s Up advocate, Portman will soon be embracing another Type A woman: In July at San Diego Comic-Con, she lifted the hammer high as it was revealed that her Marvel character, Jane Foster, would be anointed female Thor in “Thor: Love and Thunder,” due in 2021.

Calling from Los Angeles, where she lives with her husband, the choreographer and filmmaker Benjamin Millepied, and their two young children, Portman, 38, spoke about navigating a traditionally male world, both onscreen and off.

These are edited excerpts from the conversation.

Let’s begin with the mystery of the diaper. Why isn’t there one, and what’s with our fixation?

Well, I think that it was the salacious element of the real story. For us, that wasn’t what it was about. We were trying to get into the heart of humans and not make it salacious. It seems to be a symptom of clickbait culture that getting my name and diaper in the same sentence is probably helpful for journalists.

Lucy has a mind-altering experience while floating alone in space that makes life back in Houston suddenly feel so small. Have you ever experienced anything similar?

You mean, like an existential crisis? [Laughs] Realizing our insignificance, and then weighing that with how much you feel everything. I don’t know a human that hasn’t faced that at some point.

And yet when Lucy behaves much like a man might in competing for the next mission, her supervisor castigates her for getting too emotional.

Noah had me watch “The Right Stuff” in preparation to get a sense of that very competitive, arrogant, hazing environment that goes on at NASA to get those seats. These daredevil personalities that are willing to strap themselves to a bomb and splash down in the ocean in basically a metal shell that just drops out of space. I mean, it’s really wild what they’re doing, and it’s a very specific personality.

And when you see the men doing it in “The Right Stuff,” it just seems so fun, and good-natured — guys just messing with each other, you know? But when you see me and Zazie [Beetz, playing Lucy’s rival] doing it, it comes off like, “Oh, that’s a catty woman in the workplace.”

That’s the same thing that I think she experiences when her suit starts filling up with water. She feels like if a man did that, they’d be like, “Oh my God, look. He’ll do anything just to finish the mission. What a hero.” With her they say, “Oh, you’re reckless and emotional.”

You didn’t actually have water in your helmet in that scene, did you?

We did fill up the helmet with water, which was scary, because apparently that’s a difficult thing to do with current special-effects technology. I am not that daredevil personality, so that was definitely a challenging day. Basically, I held my breath as long as I could, and then I could remove myself from the helmet as soon as I couldn’t hold my breath anymore. [Laughs] Oh, yes, it was a less pleasant scene to do, I must admit.

What struck you most from your research into female astronauts?

It’s interesting to note a profession where there’s usually one woman at a time. Even that recent story about how two women [were scheduled to do the first all-female spacewalk], but they only ended up having one suit, and one of them couldn’t go — which was so insane — shows this idea that there’s one slot for a woman that exists so often in powerful positions. There is one seat for a woman at the board table or whatever.

Lucy’s plight reminds me of the speech you gave in which you advised, “Stop the rhetoric that a woman is crazy or difficult.” Which leads me to Time’s Up. What are you most proud of accomplishing?

It’s been a really impressive thing how Time’s Up has been able to shape the conversation around pay equality and promote that. Of course, the U.S. women’s soccer team was really crucial in shaping that conversation. Michelle Williams just furthered it [in her Emmy acceptance speech]. It was really incredible to get to see how culture is shifting in talking about it. Then the recent changes in the New York law that was pro survivor of sexual harassment, abuse and assault was also really incredible. I think all of the conversation — women talking to each other, women talking publicly more — is inspiring to each of us. It makes us more capable of knowing even how to articulate what we’re feeling, what we need.

There’s so much to do still, but it’s also been a very rapid change and definitely feels like all of us have had a light-speed evolution in the past few years.

And now you’re about to embark on a new Thor film, your first since “Thor: The Dark World” in 2013. Three years ago you said that as far as you knew, you were done. How did the franchise lure you back?

The third one didn’t take place on Earth, where Jane lives, so it didn’t make sense for me to be there. When [the director Taika Waititi] came to me with this idea — that I get to be female Thor — it was a very exciting prospect. I think Marvel has been really wonderful at making their films look more like a reflection of the world and having superheroes of all different kinds of people. And to have so many female protagonists [with Angelina Jolie as Thena in “The Eternals”] is also really, really exciting. The “Black Widow” movie [starring Scarlett Johansson] looks amazing.

How does it feel to finally become a superhero?

I love getting to be part of something that is such a major part of entertainment for young people. It sets your mind-set to recognize injustice. I recently saw a sign at the climate march where this kid was like: “I grew up on Marvel movies. Of course I’m going to fight against wrong.”

So just how heavy is that hammer?

[Laughs] It’s heavy. I was surprised.