There are a lot of things that humans can do that robots can't. Adaptability/flexibility/decision-making are the biggest areas in which robots are very deficien

There are a lot of things that humans can do that robots can't. Adaptability/flexibility/decision-making are the biggest areas in which robots are very deficient. When the RTT is over a year, flexibility of the payload is a pretty big deal. We're also ultimately not just doing this for scientific knowledge, but also knowledge about how to best become an interplanetary species, and those kinds of questions are usually best answered with humans acting as willing test subjects/participants.