Fusion-powered space travel has long held the promise of rapid trips across the solar system: Mars in weeks, Saturn in months, Pluto in years.

For decades, such possibilities have remained theoretical, like something plucked out of a science fiction novel. But several companies are now working to build practical nuclear fusion propulsion engines, with significant milestones being hit.

Pulsar Fusion, a U.K.-based startup, hopes to launch a demonstration mission to space in 2027, while Princeton University and Helicity Space in the U.S. are continuing their own work on fusion drives.

If any of these efforts prove successful, missions across the solar system for robots and humans could be unlocked like never before, turning us into a true spacefaring species.

"If we continue on the current trajectory, everything we know about space travel is going to change within a decade," Stephane Lintner, CEO and co-founder of Helicity Space, told Live Science.

But is it too good to be true? Can the dream of nuclear fusion propulsion ever be fully realized, or will it remain a sketchbook fantasy? After decades of dreaming, we might be on the cusp of finding out...