In the book there is a fun scene where the lights go out on the Hail Mary and Rocky doesn't realize and is astonished by how helpless Grace is.
I read about how for the movie they added actual circadian lights to the ship sets and I'd love to hear Grace explain that to Rocky. Like Rocky is trying to learn more about the incredibly long list of things humans require to function well (so he can correctly nag and monitor). Grace explains that the ship has lights that ramp up and dim on a schedule to mimic light on Earth and Rocky is mystified.
Grace: If it's too dark, it makes human brains sick. We get depressed and sleepy.
Rocky: What?? Everything make human brain sick!
Grace: Too much light? That makes human brain sick too. We have trouble sleeping and it makes us anxious.
Rocky: This sounds fake. This is joke, question?
Grace: The light level changing helps my brain know when it's time to sleep.
Rocky: Lights not work! Grace always ignore sleep time!
