Shameful Experiment by Emily Tilton

In an effort to escape her troubles on Earth, nineteen-year-old Tilly Squires inadvertently stows away aboard a spacecraft headed for Saturn, but when she ends up damaging equipment critical to the ship’s research mission she finds herself the subject of an entirely new experiment.
With their original objectives no longer feasible due to Tilly’s carelessness, the mission will instead explore the potential impact of sharing a female partner on the morale of the crew.