When former astronaut Don Thomas speaks to a group of young people, he often pulls out a life-like NASA illustration: two space-suited individuals embarking on the earth from a four-story landing craft.

“I love to show this picture to students and ask them, ?Do you know who these two astronauts are walking on Mars?? ” Thomas said. “I tell them, ?It?s you. These astronauts could be you or someone in your school who will be the first on Mars!? ”