NanoSail-D is made of extremely lightweight gossamer fabric designed to glide into space. Image Credit: NASA/MSFC/D. HigginbothamPicture it — a sail boat floating across the starry sky. Well, it’s not exactly what you’ll see, but it is the idea behind NASA’s newest experimental mission.

Later this summer NASA will attempt to deploy and operate the first spacecraft in low Earth orbit propelled only by the power of sunlight. Solar sail propulsion uses sunlight to propel vehicles through space, much the way the wind pushes a sailboat through water. The technology requires intercepting the constantly streaming solar energy, called photons, with giant, reflective sails of lightweight material. Over time, the continuous pressure of the sun’s light provides sufficient thrust for a small spacecraft to travel in space and alter its orbit.

Sounds easy, right? On Earth, solar cells have been turning sunlight into electricity for centuries, so why hasn’t the space community succeeded in using solar power for in-space transportation?

read more: NASA – Sailing Ships in Space? Maybe..