Hello.
There is no real limit as to how long an astronaut could stay in space. The real limits are mostly food, and any medications that could be needed should anyone get ill. The human body does not do too well in near zero gravity because the body does not have to do much in the way of "work" since in near zero gravity, nothing weighs much. Therefore, during a regular day in space, an astronaut must do a lot of exercising to keep keep their muscles in sharp. Also, another problem that people run into is a greater than normal loss of calcium. To combat this problem, they must take quite a few supplements each day. The last main item is radiation exposure. That is one of the items still being worked on since the normal way to stop radiation exposure is by using a sheet or lining of lead. BUT since lead is the second heaviest element there is, (gold is more), the space ship would or could be too heavy to launch. Another way to block radiation is with an electronic field, sort of like the shields on the Star Trek ships. I hope this helps answer your question. BTW not sure of the current record in space, but a Russian spend over a year in space, in Mir.
Take care
There is no real limit as to how long an astronaut could stay in space. The real limits are mostly food, and any medications that could be needed should anyone get ill. The human body does not do too well in near zero gravity because the body does not have to do much in the way of "work" since in near zero gravity, nothing weighs much. Therefore, during a regular day in space, an astronaut must do a lot of exercising to keep keep their muscles in sharp. Also, another problem that people run into is a greater than normal loss of calcium. To combat this problem, they must take quite a few supplements each day. The last main item is radiation exposure. That is one of the items still being worked on since the normal way to stop radiation exposure is by using a sheet or lining of lead. BUT since lead is the second heaviest element there is, (gold is more), the space ship would or could be too heavy to launch. Another way to block radiation is with an electronic field, sort of like the shields on the Star Trek ships. I hope this helps answer your question. BTW not sure of the current record in space, but a Russian spend over a year in space, in Mir.
Take care
