Below is the second article I wrote regarding sleeping in space, this one specifically deals with long term space travel.
How would you like to be paid $18,000 to lay in bed for 3 months and binge-watch your favorite shows on Netflix? You could work remotely, read, and play on the computer—all while receiving free medical diagnostics and room service. If this sounds good, then you may want to head over to the Flight Analogs Research Unit (FARU) in Texas. This is where NASA conducts bed rest studies, in which they pay participants to stay horizontal (actually, at a negative 6-degree angle) for months at a time while they run a plethora of tests.