Basically, most good science in space flight has to do with the behavior of the human body in space. That is where we are lacking info, and where info can only be obtained by flying in space.
Even people who have successfully obtained a visa are sometimes being turned back at the airport. Such incidents have never happened in the past but are increasing now because even low level officers of the border patrol department are being entrusted with too much discretion power on how they execute the laws.
