The Onboard Medic Simulation is an unseen computer used for medical purposes. Present on the Biologic Space Laboratories vessel, it simulates a medical procedure in preparation for an actual surgery and predicts a prognosis for the patient. At the beginning of Metroid Fusion, Samus Aran was infected by an unknown parasite, later called X, during a science mission on SR388. She was transported to Galactic Federation Headquarters for treatment. The Onboard Medic Simulation on the BSL vessel gave her a 0.873% prognosis of survival as the Parasite quickly infected her nervous system and left her in a deep coma. Fortunately, the Federation surgeons quickly devised a vaccine from the baby's preserved Metroid cells, killing the X inside Samus and saving her life.