The world’s first solar-sail-powered spacecraft, Cosmos 1, met its demise in 2005 when it fell into the ocean before ever reaching orbit. But dreams of solar sails propelling spaceships haven’t died, and Carl Sagan’s Planetary Society is gearing up to launch the LightSail-1 solar sail craft by the end of 2010.
Solar-sail technology has long been theorized to be one of the keys to long-term interstellar flight. Sails are theoretically propelled by the pressure of photons (light) pushing against them. Initially, the pressure moves the sails slowly, but the constant push eventually propels the sails to high speeds.
LightSail-1 won’t go on a high-speed journey through the Milky Way, however. The bread box-sized device will pop out of a rocket, unfurl its four sails to an area of about 340 square feet, and drift in space for a few days while the Planetary Society tests its ability to be accelerated and be controlled.
The $1.8-million, privately-funded journey is the first in a series of three planned LightSail missions. LightSail 2 will carry scientific instruments and float in space for a few months, and LightSail 3 is expected to prove that solar sails can provide an early warning station for geomagnetic storms that disturb satellite technology.
Solar sails probably won’t propel us, Star Trek-style, to far-off galaxies–it would take 100 years for a solar sail-powered ship to reach another star system–but they might just be our best hope for space travel in a resource-constrained world.