American space agency NASA has already conquered previously unthinkable areas of exploration, such as the moon. NASA is now looking into new, bigger challenges. Episodes of `Space Voyages' take a look at some of the areas that the agency is looking to explore in the future. Among the challenges NASA wants to take on are developing travel into deep space - with the ultimate goal of sending people to an asteroid or Mars - and preparing for the possibility that people may someday be forced to leave Earth to save the species. The programme also explains how the accomplishments of early NASA astronauts and engineers have paved the way for the space exploration that occurs today.