The following edition of the text was used in the creation of this study guide: Harvey, Samantha. Orbital. Penguin Random House, 2023. Kindle AZW file.

Orbital follows a day in the life of six astronauts on the International Space Station: Chie from Japan, Nell from the UK, Shaun from the US, Pietro from Italy, and Russians Anton and Roman. The story is divided into chapters, each covering one orbit of Earth over 24 hours.

In the opening chapter, Orbit minus 1, the astronauts begin their day, waking up in a galley still decorated from the previous night's party. Roman, who wakes early, keeps a tally of his days in space to stay grounded in time, which is crucial in the space station’s constant cycle of sunrises and sunsets. Shaun reflects on a postcard from his wife, depicting Velázquez’s painting Las Meninas, which reminds him of their first meeting in a class discussing the painting. Chie has recently shared that her mother passed away.

During Orbit 1 and into Orbit 2, the astronauts joke with ground control about a concurrent mission to the moon, exercise, and Chie muses that as long as she’s in space, her mother's death doesn’t feel real. In Orbit 3, they monitor a typhoon heading toward Indonesia and the Philippines. The narrative shifts briefly to Japan, where an elderly woman—Chie's mother—dies peacefully while hoping to live long enough to see her daughter return from space. The astronauts, while able to observe the typhoon’s enormity, remain powerless to intervene.

In Orbit 4, ascending, Shaun contemplates the Earth's indistinguishable borders and reflects on how meaningless they seem from space. Anton and Roman conduct lab experiments with human cells, leaving Anton in awe while Roman remains indifferent. The narration touches on the illusion of Earth being the universe's center and humanity's quest for extraterrestrial life. Meanwhile, four astronauts at Cape Canaveral prepare for a moon landing, making the space station crew feel their mission is mundane by comparison. Nell and Pietro attach a spectrometer during a spacewalk. Pietro wonders if robots will eventually replace astronauts.

In Orbit 4, descending, the crew pauses to photograph the typhoon. The narration shifts to the Philippines, where people are urged to evacuate. A fisherman, reflecting on his astronaut friend Pietro, recalls meeting him during a vacation when Pietro helped retrieve a lost knife while diving. The scene then shifts to Antarctica, where biologists watch auroras. On the space station, Roman watches the same auroras and calls the crew to join him.

In Orbit 5, ascending, Anton dreams of Michael Collins's iconic photograph of the lunar module and reflects on the idea that Collins was the only human not in the picture. Shaun recalls disliking the first moon landing as a child, while Nell remembers being deeply affected by the Challenger disaster, lighting candles for the astronauts for years. In the lab, Chie experiments on mice, some genetically modified for space survival, others struggling. She reflects on their inevitable death, urging them to adapt to zero gravity. Roman uses packet radio to try communicating with Earth, recalling how a Soviet astronaut, Sergei Krikalev, was trapped in space after the USSR collapsed, relying on radio for news.

In Orbit 5, descending, Nell and Pietro monitor the typhoon while Pietro reminisces about his honeymoon in the Philippines when he met the fisherman. Chie reflects on a photo of her mother labeled "Moon Landing Day," linking it to her decision to become an astronaut. Chie’s mother survived Hiroshima as a baby, saved by her father's illness that kept her home from the market where her mother died. Orbit 6 explores the division between American, European, Japanese, and Russian toilets, reflecting Earth's political tensions, though the astronauts largely ignore them. They complete tests to measure their physical and cognitive health.

In Orbit 7, Nell recalls her first spacewalk. The narration reflects on the irrelevance of politics when viewed from space, yet acknowledges its visible impacts on Earth, such as oil spills, melting glaciers, and polluted reservoirs. It also notes the irony that the rocket sending them to space burned as much fuel as a million cars. In Orbit 8, ascending, the typhoon intensifies as it approaches the Philippines. Nell reflects on her husband in rural Ireland, who chose to live there due to her astronaut training keeping them apart. He believes those with complex inner lives need simple outer ones, while those with adventurous outer lives need to quiet their inner worlds. In Orbit 9, the narration imagines an alien civilization discovering Voyager 1 and 2, while the astronauts watch the lunar rocket pass by.

In Orbit 10, the astronauts handle housekeeping. Anton hides a lump on his neck, fearing it would cut the mission short for others. He contemplates ending his marriage. Pietro checks typhoon updates, worrying about his fisherman friend. Shaun reflects on how the moon mission overshadows their work, despite its importance for future missions. The crew dines together in the Russian quarters, discussing childhood candies. Chie shares a story about climbing a mountain with her mother, which makes Anton cry. Roman later speaks with a woman in Vancouver on packet radio, who questions the purpose of their lives before revealing her husband's recent death. Shaun attempts to write about the future of humanity in space for a newspaper and asks Pietro for help. When Shaun shows Pietro a postcard of Las Meninas, Pietro suggests the dog is the painting's subject.

In Orbit 11, Shaun prays for the lunar astronauts and Chie in her grief. Chie finds the mice floating freely as she urged earlier, which overwhelms her with grief, and she curls up in the lab. In Orbit 12, the astronauts watch a movie about Russian cosmonauts possessed by aliens, all falling asleep during the film. In Orbit 13, the narration condenses the history of the universe into a single year, with human history occurring in the final seconds. The astronauts wake at 1:30 a.m. after falling asleep during the movie, say goodnight, and go to bed.

In Orbit 14, ascending, the typhoon hits the Philippines, causing widespread destruction. The narration describes the storm from space, noting the astronauts are asleep and miss it. Nell and Shaun unknowingly share the same dream of a small circular flame. Orbit 15 depicts the view of the Earth as the astronauts sleep.

In Orbit 16, the lunar astronauts discuss odd news stories with mission control. The scene shifts to a church in the Philippines where people, including the fisherman and his family, shelter from the typhoon. Miraculously, the church remains intact. The novel ends with descriptions of the sounds of electromagnetic vibrations from various planets, concluding with the sound of Earth.