Complex sentence: Through this, Vincent becomes close to a co-worker, Irene Cassini; though a valid, Irene is aware of her higher risk of heart failure will prevent her from joining a Gattaca mission.
Split into simpler sentences: Through this, Vincent becomes close to a co-worker, Irene Cassini. Though a valid, Irene is aware that her higher risk of heart failure will prevent her from joining a Gattaca mission.