"Most of what we have learned about living in space is that we should not live in space. We are designed for gravity; without it, strange things happen to both body and mind. For each month spent in space, humans can lose up to two per cent of their bone mass. This means that each day, for hours on end, the ISS becomes the world’s highest-flying gym to keep its occupants fit. But even with such precautions, some returning space travellers require months of rehabilitation to readjust to life on Earth. Others, despite having access to the best facilities and treatments available, experience headaches, sight loss, and undiagnosed physical and psychological frailty for the rest of their lives."
http://www.aeonmagazine.com/nature-and-cosmos/greg-klerkx-sp...
It doesn't change the fact that I've greatly enjoyed his presence and I'm completely bummed that he's gotta come back to boring old Earth.
> Effective immediately, all education and public outreach activities should be suspended, pending further review. In terms of scope, this includes all public engagement and outreach events, programs, activities, and products developed and implemented by Headquarters, Mission Directorates, and Centers across the Agency, including all education and public outreach efforts conducted by programs and projects.
> The scope encompasses, but is not limited to:
> ...
> - Web and social media sites in development (excludes operational sites).*
So nothing is stopping an astronaut or kosmonaut with a Twitter and youtube account from talking to us down here, except maybe a scarcity of free time.