Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Nautilus-X (Non-Atmospheric Universal Transport Intended for Lengthy United States eXploration) is a multi-mission space exploration vehicle imagined by the Technology Applications Assessment Team by NASA. The spacecraft was designed for long duration (one to twenty four months) exo-atmospheric space journeys for a six people crew. In order to limit the effects of microgravity on human health, the spacecraft is to be equipped with a centrifuge. The spacecraft itself is relatively cheap by space system standards as it would only cost US$3.7 billion. In addition, it may only need 64 months of work.