SpaceX founder Elon Musk is worried that a trip to the red planet could be thwarted by a third world war.
The billionaire entrepreneur told GQ that the colonization of Mars could be delayed, possibly indefinitely, if not done soon.
"There's a window that could be opened for a long time or a short time where we have an opportunity to establish a self-sustaining base on Mars ... before something happens to drive the technology level on Earth below where it's possible," he said in the interview.
Musk's SpaceX was the first private company to resupply the International Space Stations and now seeks to develop reusable rocket technology to get humans and cargo to the red planet.
"We need to acknowledge that there's certainly a possibility of a third world war, and if that does occur it could be far worse than anything that's happened before," Musk told GQ. "Let's say nuclear weapons are used. I mean, there could be a very powerful social movement that's anti-technology."
Musk also noted that in case of a major cataclysm on Earth — natural or man-made — having a human colony in space would ensure the long-term survival of humankind.
"You back up your hard drive," Musk told GQ. "Maybe we should back up life, too?"