QUESTION: 
What are some of the dangers in sending humans to Mars?

ANSWER from Steve Wall on February 1, 1997:
There are at least three immediate dangers to humans on the surface of Mars. 
First, there isn't any air to breathe (not the kind we humans need).
Second, it is too cold for humans without a lot of protection. 
Third, there is too much ultraviolet light.  
Longer term, there is also no food and no water (in the form we need it).

We think there may be ways to protect humans from those dangers and to allow
humans to stay on the surface for short periods of time by bringing the things
they will need with them.  If humans wanted to live on Mars for long periods of
time they would have to take something with them to provide them with ways of
growing food and producing water - and that's a lot harder job!