But as Joan had taken each small step forward, the world had kept spinning on its axis. Days had formed into weeks and months and years, which people marked with watches and calendars, all based on the only thing they had to tell what time it was: the stars.

As the Earth orbits the sun, it shifts toward the sun’s warm embrace. Then summer turns to fall, fall to winter. Soon it loops back around, and winter thaws to spring, spring to summer. Through it all, babies are born from stardust and grow taller. They begin to walk and talk and learn the days of the week, the months, the seasons. Then they look up at the sky, to see where they came from.

And the adults spend most of their days looking down. They fall in love and make mistakes and learn new things and feel tired. They lose people they love, and fail themselves, and change or never change. They get new jobs and fall out of love and convince themselves that if they just get this one thing, they will finally be happy.

Day in and day out, the Earth keeps spinning and revolving and sailing through the Milky Way. That is why time never stands still.

And that is why, small as they were, Joan’s choices had added up to something magnificent. In the changing of seasons these past four years, Joan had found it all.

Something she loved, someone she loved, the parts of her she had hidden within herself.

“Goodbye, my love,” Joan said as she kissed Vanessa’s temple.

“Come home soon,” Vanessa said.

It felt so good to Joan, to hurt to leave her.

“T minus ten…nine…eight…seven…”

Joan was in her flight suit, her helmet on. She was strapped to her seat in the mid-deck, lying on her back. The four guys on the crew, including Harrison, were sitting in the flight deck. She did not have a view out any window during ascent. All she could see were the lockers in front of her.

“Six…five…main engine start…”

The shuttle ignited, her bones vibrating as the ship came to life and began to quake. And it was a great relief to her—to shake like that.

She’d barely been able to sleep the night before—adrenaline running through every limb of her body. But the morning had been so slow, so methodical. She could not rush or indulge her excitement. Each item had to be checked off one by one, cross-referenced with Launch/Mission Control.

The difference between the outside of her—so controlled—and what ran inside her—such thrill—was jarring and hard to reconcile.

Until, now, finally, the outside was matching the inside. Joan felt an intense sense of equilibrium for the first time in days.

“…four…three…two…one…zero…and liftoff of the space shuttle Discovery.”