Harold came over last Saturday and asked me a question I didn’t expect.

We were in the backyard, Harold helping me repair the fence where the post has been leaning since spring. He’s good with this kind of work; I’m better at watching than doing. We were working in the heat and talking about the mission — eleven days to launch — and Harold set down his hammer and looked at me.

“Do you think they’ll really make it back?” he said.

I said yes. I’ve said yes every time someone has asked me. I believe yes, for reasons I can lay out: the engineering is sound, the testing has been methodical, the team is extraordinary, the simulations have covered the failure modes. The probability is high.

But Harold shook his head. “I know you think they’ll make it back,” he said. “That’s not what I’m asking. I’m asking if you could actually think about it. If they don’t.”

I put down what I was holding and thought about it for a moment.

What would it mean if they don’t? If the descent engine fails, or the ascent engine fails, or the guidance computer fails in a way Jack Garman can’t fix, or the re-entry heat shield cracks, or any of a hundred things. What would it mean?

“It would be terrible,” I said.

“Would it change your mind? About the program?”

I thought about that for a longer moment. “No,” I said finally. “It would make me very sad. It would be a tragedy. It wouldn’t convince me that we were wrong to try.”

Harold nodded slowly. He went back to the fence post. We didn’t say anything for a while.

“You’ve been watching this for twelve years,” he finally said. “You deserve for it to work out.”

Coming from Harold, that’s about as sentimental as he gets. I told him I appreciated it. He shrugged and said the fence wasn’t going to fix itself.

Eleven days to launch.