Naomi and I had such different childhoods. She’d tagged along with Valerie to countless conferences and holidays on Valerie’s planes; I zipped across the high-speed rails and bridges. Growing up, my mother could go into a grocery store at close to midnight and still have the full selection of fruit and vegetables on display, wrapped in shining plastic, most of it destined to rot in a landfill. It seems so shockingly wasteful with the benefit of hindsight. Then again, so much is.

And so we arrive at the question people who read this book will want to know: what has my mother been doing the last thirty years? Naomi had no shortage of work, overseeing projects of carbon-trapping algae, or assisting with reforestation, or continuing the work she began in her biomes and on the Atalanta. She lived her life out of the spotlight as much as she could. No great scandals.

From afar, we watched the later tragedies. The Atalanta II. The Clymene. How Earth’s future dimmed, brightened, dimmed again. The struggle for Mars.

Month by month, year by year, Cavendish must have seemed even further away for her.

A very few people would say that Valerie’s plan did work, after a fashion. Killing so many had sparked those who were left into action, in a way that all the facts and figures didn’t do beforehand. Part of me wants to think that they’re wrong, that humanity would have pulled it together before Earth broke so badly. Another part of me fears they were right.

I called Grace when I found out that Valerie died. My sister already knew, naturally. Her face was on my screen, my own in miniature in the corner. We look nothing alike. Grace looked like Dad, her skin tanned like his when she’s planetside, pale when she’s not. I’m tall, with flaxen hair that is straight and flat. I’m broader compared to Grace’s bird bones. My skin is always red—my mom calls it ruddy-cheeked. I think she thinks that sounds better, but it makes me feel like a wind-whipped fisherman. When Grace and I introduce ourselves as sisters, there is always the split second of confusion strangers can’t quite hide.

When I told Grace what I was doing, her expression had closed.

“Do you think she’ll actually tell you the truth, Iris?” my sister had asked. “Valerie and Mom are more alike than you think.”

I’d chewed the inside of my cheek at that. And now, after I have the story, my sister is only partially right. Naomi and Valerie were similar, but their differences were starker. I didn’t mention my suspicions to Grace: that my mother had video visits with Valerie once every few months, for years. Long after what happened two years after they returned to Earth.