An astronaut planning a mission to a distant star shares 'an unpleasant truth I have to tell everyone'

As a species, we've long looked to the stars. They've provided navigational guidance, spurred our imaginations, and inspired us to explore.

We are explorers who have spread around the world and are now reaching into space - to Mars soon, we hope, and beyond. Some of our most popular fiction focuses on life spread across the universe, from Star Wars and Star Trek to video games like Mass Effect or the upcoming No Man's Sky.

So it's perhaps no surprise that when people find out about the 100-Year Starship project, which is designed to push humanity toward achieving what's needed to actually be capable of interstellar travel within 100 years, many are excited - and want to sign up to go.

But Dr. Mae Jemison, the astronaut in charge of the NASA- and DARPA-funded 100-Year Starship, has some bad news for those eager to join an interstellar voyage.

"There's maybe perhaps an unpleasant truth I have to tell everyone," Jemison tells Tech Insider. "Most of us are going to be on this planet; we're not going to go."

In this case, we should point out that 100-Year Starship isn't currently planning on actually constructing such a ship. They just want to to help make sure that it becomes possible to do so.

But even if we do meet the immense technological challenges blocking us from interstellar travel within the next 100 years, Jemison says that most of us are still going to live on this planet.

We might send a group of humans out to colonize a new star system, but even if that group includes thousands of people, we're certainly not going to send everyone who might be interested on such a journey. We just don't know that there is another planet out there that's suited for our unique biology, another place that might be a home for us. Even if we soon become capable of traveling the stars, it will most likely be far longer before we find a place as perfect for us as Earth.

"We're going to be on this planet," Jemison says. And though it might seem counterintuitive, that's exactly why she argues we need to figure out interstellar travel. Because if we can figure out the technology we'd need to live sustainably in space, we can probably figure out how to live sustainably on Earth right now as well.

And that's a clear and immediate challenge we all face, whether we'd be interested in an interstellar journey or not.