There are too many to list. Some of the major ones include the following:

-Oxygen recycling systems that allow closed environments (which includes submarines as well as spacecraft);

-Advances in solar panel technology that allows our spacecraft to power life support systems indefinitely;

-Discoveries about physiology of humans and other animals about what will be needed in space.

Unfortunately, even with these discoveries, life outside of Earth isn't currently possible with our current capabilities. It probably could be, but it'd be tremendously expensive, and persuading governments and taxpayers to pay for it is easier said than done.