Space exploration is intrinsically interesting to young learners. Children gaze at the stars and marvel at what it might be like to live "out there!" With the July 2020 launch of the Mars 2020 Perseverance Rover mission, and its landing in 2021, there is no better time to capitalize on engineering and science in the news. This mission is particularly historic with NASA's announcement that the Mars 2020 Rover is designed to be the initial stage of multiple missions that will return the first Martian rock samples back to Earth for analysis. Further, this mission will pave the way for human-occupied missions to Mars slated for the 2030s. NASA missions involve discrete engineering challenges like developing objects and tools that withstand space travel, but they also involve deep consideration of the processes and systems needed to complete the entire mission. The authors designed an engaging learning environment focused on developing the processes and systems needed for a successful mission to Mars. This article describes a long-term voyage undertaken by intrepid fifth-grade Mars explorers. The aim was not a single engineering challenge; instead it was to promote engineering-based systems thinking.