NASA in 2018 plans to launch the Near-Earth-Asteroid Scout, a $16-million probe equipped with a large sail that will harness power from the sun.
The sail is made from ultra-thin, reflective material. When photons from the sun hit the sail’s surface, they bounce off the mirror-like material and spread momentum throughout the craft – much like a cue ball transfers momentum to another ball after hitting it in a game of pool.
The continuous energy from the sun will keep the probe racing at up to 63,975 mph to its destination at the asteroid VG 1991.
Les Johnson, the Technical Advisor for NASA’s Advanced Concepts Office at the Marshall Space Flight Center, tells National Geographic the sun’s energy could dwarf power provided by chemical fuel.
“Since the sail doesn't use any fuel, we can keep thrusting as long as the sun is shining,” Johnson said.
NASA expects the probe to reach the asteroid in about 2.5 years after launch. It will take pictures of the rock while measuring its chemical composition, size, and motion.
NASA says this reconnaissance work will let it know if the asteroid is fit for humans to walk on.
The idea of solar powered sails emerged in 1924, when Soviet rocket scientists Konstantin Tsiolkovsky and Friedrick Tsander dabbled with the concept of spacecraft "using tremendous mirrors of very thin sheets."
In the 90s, the U.S. began funding such technology.
But recent advances could be accounted to something in your pocket.
“Back 25 or 30 years ago, electronics were not so lightweight,” Johnson says. “You couldn't imagine building a small enough spacecraft that didn't require a generous sail. With the advent of smart phones and the miniaturization of components, we're now able to make really lightweight, small spacecraft, which makes the size of the sail more reasonable.”
