Photonic Propulsion Could Be Our Ticket To The Stars

Brilliance | Dec. 16, 2017

Right now, the Voyager I spacecraft is hurtling through space at 35,000 miles per hour. That sounds fast, until you consider that it only recently left our solar system, 37 years after its 1977 launch. As impressive as our feats of spaceflight have been, there's an elephant in the room. Physics professor Philip Lubin laid it out clearly when he wrote, "While we all dream of human spaceflight to the stars in a way romanticized in books and movies, it is not within our power to do so." To get there, we're going to need to go much, much faster, and our current propulsion systems just aren't hacking it.

Enter: photonic propulsion. Lubin is leading a project called DEEP-IN (Directed Propulsion for Interstellar Exploration) that's studying the possibility of using lasers to propel spacecraft faster than ever before. How fast? Research models say the system could send a 220-pound (100-kg) probe to Mars in three days, and a crewed spacecraft in around a month. That's about five times as fast as what we're currently capable of. Photonic propulsion works in a similar way to a solar sail: both rely on light particles known as photons, which bounce off of a reflective material to transfer kinetic energy and help them accelerate through the frictionless vacuum of space. But while a solar sail is beholden to the handfuls of photons that come from the sun, the lasers used in photonic propulsion pelt the sail with a concentrated, controlled dose of light that can help it reach much greater speeds.

Of course, there's a lot to do before a month-long trip to the Red Planet is possible. We'd need a powerful enough laser, a big enough sail, and—importantly—a way to slow down once we got there. Still wrapping your head around how it all works? Explore the benefits and challenges of this new technology in the videos below.

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