Engineers are exploring propulsion methods that could enable longer-distance travel
Perhaps someday spacecraft will be able to take humans beyond the solar system.
GLENN HARVEY
Pilots in Star Wars enter a dimension, hyperspace, to travel between distant worlds. To merge onto this cosmic highway, ships are equipped with special engines called hyperdrives. With the push of a lever, the spacecraft zooms faster than the speed of light, traversing between star systems in just hours or days. Han Solo and his sidekick Chewbacca make the jump to hyperspace look easy (at least when the Millennium Falcon is in working order).
But Star Wars breaks the laws of physics to achieve such a feat. Off-screen, the technology to reach another star system doesn’t yet exist. However, emerging propulsion methods could brighten the future of interstellar travel.
Due to the nature of light and energy, it’s impossible to reach the speed of light, nearly 300,000 kilometers per second. It would take an infinite amount of energy. The fastest any human-made object has traveled is only about 0.06 percent of that speed. At that rate, it would take about 6,600 years to reach the nearest exoplanet, Proxima Centauri b, 4.24 light-years away.
A spacecraft traveling at one-tenth of the speed of light could shave the trip down to a quick 40 years. Future engineers could use nuclear power to achieve that, says Scott Bailey, an engineer at Virginia Tech. But developing that technology could take thousands of years.
Controlled fusion could help, says Cole Miller, an astronomer at the University of Maryland in College Park. Controlled fusion harnesses energy from combining atomic nuclei to create a steady supply of power. Researchers have been working on controlled fusion for about 70 years. But so far, these experiments have yet to produce more energy than they consume.
Not all vehicles in the Star Wars universe rely on hyperdrives; some“sun jammers” have huge sails thatcatch stellar winds — the constantstream of charged particles producedby stars — to move throughspace like a ship on the sea.
Recently, the nonprofit Planetary Society tested a similar concept. The crowdfunded LightSail 2 launched in 2019 and orbited Earth for about three years. Rather than relying on solar wind, though, the small craft’s solar sails used pressure from sunlight itself. Although light doesn’t have mass, it does have momentum. The solar sails intercepted sunlight with thin sheets made of reflective Mylar and other polymers. When speeding photons hit the sail, they bounced.
Using solar sails to propel a large spacecraft would be tough, Miller says. The thrust produced probably wouldn’t be strong enough to carry ships ferrying humans. Upscaling solar sails would offer unique benefits, however. Using sunlight would allow a spaceship to accelerate without fuel. And unlike objects on Earth, spacecraft aren’t slowed by air friction produced by an atmosphere. This would allow any spacecraft to continue gaining speed as long as it’s exposed to sunlight.
For now, spacefarers aren’t looking to travel to another star system. But even travel within the solar system, say, to Mars, could use a boost. To safely bring people to and from the Red Planet, some researchers are looking to ion engines. These thrusters create force by shooting charged atoms from the back of a spacecraft. Star Wars’ TIE Fighters, like the one flown by Darth Vader, navigate through space battles with them.
But real ion engines work best with straight paths, says Jarred Young, an engineer at the University of Maryland. “It’s essentially point-and-click propulsion.”
Ion engines aren’t as powerful as the chemical propellants in rockets, which create thrust by combusting fuel and oxygen-releasing substances called oxidizers. But chemical rockets burn for only a short time. Ion engines can last months or even years, possibly helping fuel trips to Mars, if engineers can design strong enough thrusters.
For now, reaching distant new worlds is only possible in fictional galaxies far, far away.
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