Some skilled scientists work aboard the International Space Station. Other scientists hope to be among the first to travel to Mars. In this fun must-read for space enthusiasts, readers get to learn about each experience and decide which they'd rather do. As they do, they'll discover more about the ISS and the red planet, expanding their knowledge of science and space. Breathtaking photographs and amazing facts add to the high-interest text, which incorporates foundational components of the science of reading.