Orbital follows 24 hours in the lives of six astronauts abord the International Space Station. Like so many books, much of the story this novel tells is about grief.

Early on, the audience learns that Chie, an astronaut from Japan, has lost her mother while aboard the ISS. I sat on my floor and cried reading the early sections of the book featuring Chie. I just lost my 17 year old dog, and I had to watch her be put down over zoom. Orbital follows Chie's grief and anguish in such an tangible and empathetic way. She's so sad and is stuck so far away, unable to do anything but grieve and yearn to be home again, as it was. Sometimes, she ponders not wanting to leave the ISS because if she doesn't go back to Earth, than she will have never experienced a world without her mom in it. When the book switches to Chie's mother's point of view, as she lays dying on the steps to their house, she looks up into the sky, trying to find the spat that is her daughter on the ISS. She chooses to let go because she can only think how sad it would be fore Chie to come home only to watch her die. As Chie grieves, she brings the reader through the traditions to be followed, to lay her mother's body to rest. They will pick out the bones from her ashes, and while Chie doesn't want her family to wait for her to be back, her longing for there to be a piece of the long bone of her mother's arm, like a piece of her mother's strength is so sad.

The crew members aren't perfect paragons of humanity. They're flawed, jealous, and proud, and they have to deal with the rules enforced because of national competition between Russia and the US. They grapple with religion, lack of religion, and the fallibility of their human bodies against the void and beauty of space.
 
Orbital ends on a neutral note, not really coming to an end because it's just the end of the synthetically adhered to day on an the international space station that experiences 16 sunrises and sunsets over those 24 hours.