The Very Pulse of the Machine Astronaut Martha Kivelson is left alone on the surface of Io after an SEV accident causes the death of her partner, Burton. With dwindling oxygen and support from her space station hours away, Kivelson attempts to drag Burton's body across the moon back to their landing craft. After taking morphine to numb the pain of a broken arm, Kivelson begins to experience hallucinations. She hears Io itself speaking to her through Burton, provoking her interaction. Desperate to reach her destination in time, she takes amphetamine, worsening her hallucinations. She eventually comes to view the moon as a machine whose purpose is "to know [her]", before falling unconscious. Waking up with critical oxygen levels, Kivelson jumps into a river of thermal liquid and seemingly assimilates into the moon, suggesting her hallucinations are in fact real. Her voice is later heard reporting back to Earth's station.