“I’m so sad,” she says. Her voice is scorched from all the vomiting that happened after she woke up.

“I know. I am, too.”

We lie there, snow howling past the window, the quiet sounds of the hospital all around us. When the Russians are on a space walk, they just hang outside the ISS during each ninety-minute period of night, waiting for the next sunrise. It’s too dark, too cold, to get any work done. Getting in and out of your suit is such a hassle that it’s easier just to hang on to something and bob around in zero gravity. The Americans work through the night, but I think the cosmonauts have it right. Sometimes you just need to hang out and wait for the light. There’s always another sunrise. You can’t force things in the dark.

“You must think I’m a coward,” Nah says after a while.

I shake my head. “I wish I could be like you.”

She closes her eyes. “What a dumb thing to say.”

“It’s true.” I squeeze her shoulder. “You’re not afraid, Nah. Of anything. It seems like. I’m terrified. All the time.”

“I’m so afraid of living that I’d rather die.” She opens her eyes. “You literally want to fly to outer space on a bomb. You want to test fighter jets in the air to see if they work. What the hell are you talking about?”

I wave a hand. “I’m not afraid of heights. I’m afraid of … falling.”

I’d started to believe that if I worked hard enough, I could control the outcome of any problem put before me. Eliminate all possibility of human error. Be two steps ahead of the universe itself. Maybe River’s right. I’m clinging so tightly to everything in my life, thinking it will keep me from falling. From failing. But if you look at every space disaster in history, you know there is often nothing you can do. The Apollo 1 team died in a training because when their cabin caught on fire, they couldn’t get out—one of the hatches opened the wrong way. No one realized that was a problem until it happened. That was the engineers’ fault, not theirs. They never went to the moon. They never went anywhere.

“You always land on your feet,” Nah says. “Always.”

I reach out and comb my fingers through her long, black hair. “Not anymore, I don’t think. I’m beginning to realize I don’t know very much.”

She snorts. “Welcome to the club.”

“But you’re okay with not knowing. I wish I could be like that. Could like mystery. Ben’s favorite words are I don’t know. I HATE those words. I think the not-knowing is starting to drive me crazy.”

She sighs. “There’s something I don’t know that’s driving me crazy. Something I haven’t told you.”

Oh god.