First Certificate in English (FCE) 2 Open Cloze Practice Test 2026 - Free FCE Practice Questions and Study Guide

Think about how movement expresses entering a new area. When the goal is to start from outside and go into that area, we use into. So traveling into space shows the act of leaving Earth and entering outer space. Saying traveling in space would describe being inside space or moving within it, not the act of entering it. Traveling through space or across space sounds like moving across or through space as a path, not the moment of entering it. So the natural, precise choice is traveling into space.