“The issue is what does it mean culturally to send a robot versus send a person? We don't give ticker-tape parades to robots, we don't name schools after robots, we don't build statues to robots,” Tyson said.
Tyson says human beings have an inherent need to explore and that many people would sacrifice their lives to do so.
“If I said I need astronauts to go on a one-way mission to explore Jupiter, I am going to get a line wrapped around the block. There are people out there who want to explore,” Tyson said.
Weinberg understands the appeal of sending humans on short space flights, but he says astronauts cannot stay long in a hostile place like Mars.
“We cannot even do that on Antarctica. There is no economically self-sustaining colony on Antarctica and, compared to Mars, Antarctica is heaven,” Weinberg said.
But such prominent scientific figures as Steven Hawking argue that humans need to explore space because the earth cannot sustain them forever. While this is not an immediate concern, it is something that informs long-range thinking, according to NASA Deputy Administrator Lori Garver.
“As we can go further, I believe we will, and what we learn will be critical to the future of our very survival,” Garver said.
Weinberg says humans probably will develop the capability to travel far into space someday, but they have plenty of time.
“In the long run, the sun will become a red giant and will swallow the earth and we had better get off the earth before that happens; (but) that is billions of years from now,” Weinberg said.
Weinberg and other scientists say that humans should limit fantasies of living on another planet and put more effort into protecting the environment that sustains them here on this planet.