The Space Mission Adventure, 4 #4 (PB) (2012)

Ziggy and his friends can't wait for space camp, where they'll get to learn about weightlessness and how astronauts eat--and use the bathroom--in space! But Ziggy has another goal: he wants to meet some aliens. Purple, three-headed Martians, preferably, just like in his Mega Mighty Martian Blaster game.

Once he gets to camp, Ziggy learns that real-life space travel is even more exciting than what he imagined. But when a mysterious, shiny stone appears, Ziggy can't help but wonder if his dream of alien contact has just come true...