According to Stephen Hawking, "If one is considering the future of the human race, we have to go [into outer space] ourselves ... If the human race is to continue for another million years, we will have to boldly go where no one has gone before."
At any moment, the human race could become extinct due to some type of global disaster since we all continue to live on the same planet. The human race must expand outside the comfort of Mother Earth and into the unknown. This type of mission will require time and should be held as a long-term goal for humanity. Manned space flight won't solve any of immediate problems on the Earth, however it can provide us with another outlook or perspective on said problems which then can lead to new answers.
"A new manned space flight program would do a lot to restore public enthusiasm for space and for science generally," said Stephen Hawking. Public interest in space has always been greatest when humans were involved directly. Human space exploration has the potential to influence interests and educational decisions of parents and children, especially towards the field of science. The outreach potential of manned space flight also has the ability to create significant commercial opportunities, directly and indirectly. It will also provide new knowledge, such as answers to fundamental questions regarding the origin and evolution of planets and life.
"Why We Should Go Into Space." Why We Should Go Into Space (n.d.): n. pag. Www.nasa.gov. 21 Apr. 2008. Web. 7 Apr. 2015. http://www.nasa.gov/pdf/223968main_HAWKING.pdf