OMG! There is the answer! All our LO's were sucked up by aliens, experimented on, and sent back down with us! Thank God we now know...I will sleep better tonite! Hahahaha!
Before current astronauts go into orbit they are checked to ensure they have no head colds (or other problems) and then they are sequestered for a few weeks. Nobody wants to be in orbit with a head cold but more important nobody wants to bring a cold virus into the space station where it could infect people forever. But what about AD?
There was a show on TV about what a trip to Mars would be like and the human factors involved especially if problems developed. A major concern with trips expected to take years to complete.
What nobody mentioned was the possibilty of an astronaut DEVELOPING dementia during the trip! Perfectly healthy when they leave, but then cant remember what buttons to push once they get there. <gasp!> No longer competent at performing the scientific speciality that put them on the trip.
Imagine being forced into being a caregiver for your fellow scientist/astronaut on another planet? I wonder how much caregiving they would actually do? How much resources they would expend on a person who is only going to get worse ???