All three novels in the acclaimed YA sci-fi trilogy featuring teenage space explorers who use real science to save humanity. After a visit to the Challenger Center, a group of young people are recruited to become real space adventurers by the mysterious Commander Zota. Sent into the future to save humanity, they venture to a moon base, a space station, and an asteroid! Each mission involves learning vital new skills and saving humanity. “These teenage Star Challengers team up in their quest to find innovative solutions to help them solve problems using real out-of-this-world science.” —Dr. Sally Ride, Astronaut