President Trump has said he wants to “unlock the mysteries of space” and “focus on stretching the envelope of space exploration.”

Dr. Scott Parazynski, a retired astronaut and a professor of practice at both ASU’s Schools of Biological Health and Systems Engineering and Earth and Space Exploration called the crewed mission idea an “audacious challenge.”

“If you have a crew on board, the complexity of the mission increases substantially,” he told NBC News. “You are committing to making it a perfect round trip. You need to have the life support systems, the launch abort system and the recovery systems built into the vehicle the first time around.”