The dazzling sunlight that flooded the lake-front restaurant where I sat down with Chris Kraft in 2014 was nothing compared to the brightness in his eyes. He’d just turned 90 and was frustrated that NASA hadn’t flown any humans beyond low-Earth orbit since he was the agency’s first flight director during Apollo. As much as anyone else, Kraft had built NASA and put men on the moon. You would think he’d want to see humans on Mars soon. Instead, he spent the next 90 minutes eating pasta and explaining that Mars, for now, is best left to robots.
NASA’s justification for sending humans to Mars has something to do with jump-starting the search for life while furthering research and exploration on the red planet. However, even under the space agency’s most wildly optimistic plans, humans will not reach the surface of Mars until the late 2030s. During his lifetime, Kraft has watched the increasing sophistication of robots and artificial intelligence. He imagines that this progress will continue apace or even accelerate. With these trends, the robots and rovers of the 2030s will certainly have some impressive capabilities. If so, why should NASA spend 20 to 40 times as much to send humans to Mars when robots could be almost as able, at a fraction of the cost?
The human rationale
It’s a question perhaps best answered by one of the space agency’s foremost modern explorers, John Grunsfeld. Not only was Grunsfeld a five-time flier on the space shuttle and chief repairman of the Hubble Space Telescope, he also served as the agency’s chief scientist. I had a chance to put the question to Grunsfeld before he left NASA this spring.