Astronauts --- Weightlessness

It seems that weightlessness is fun, but it places great demands on astronauts' body.
They feel nauseated, dizzy and disoriented, and their head and sinuses sewll and their legs shrink at first. In the long term, their muscles weaken and the bones become brittle. The effects on the body can do severe damage on a long voyage.
Let's have a discussion on weightlessness!

Encountering Microgravity
How Astronauts Feel in Mircogravity
Countermeasures to deal with Microgravity

Weightlessness Spacesuit Life in Space Shuttle Life in Space Station