To the naked eye, the stars are diamond flecks scattered across the inner surface of a celestial sphere. Telescopes have brought depth to our vision, mapping the true distances to cosmic objects. But the universe they reveal appears utterly beyond the human scale of space and time. Even the closest stars seem infinitely remote, and reaching them a thing of science fiction, save for a few dead and dying probes drifting outward for eternity.
Now, though, a cadre of researchers are working to make interstellar travel a reality, at least to our nearest neighbors. They are coalescing around an approach that could lead to closeup images of a star and an exoplanet just 25 years after mission launch.
The first generation of theoretical starship designs had featured massive vehicles propelled by fission or fusion drives. Top speed was estimated at about 10 percent of the speed of light, or 0.1c. This meant that a flyby mission to the closest star system, Proxima Centauri, would take over 42 years to reach its target.
In contrast, the new generation of starship designs are tiny, and they have no drives at all. The spacecraft have a mass of a few grams each. They’ll be accelerated out of our solar system by ground- or space-based lasers, traveling at an estimated 0.2c.
One version of this small-and-fast approach calls for sending a swarm of these puny flyers to the Proxima Centauri b exoplanet. Data would be returned by having the swarm emit light pulses in synchrony, detectable by telescopes on Earth. Put forward by a team led by Thomas Marshall Eubanks at Space Initiatives, this mission was selected for a 2024 phase one study by NASA’s Innovative Advanced Concepts program. It didn’t make the list for a phase two study this year, but Eubanks plans to retry in 2026.
With a swarm, “we could do gigapixel imaging of the planet,” says Eubanks. “That’s at a level where if it was a planet like Earth, we’d be able to see things like coral reefs and airports.”