Man first navigated the world using a sailboat—now, it might navigate the solar system in a similar fashion with the invention of the "solar sail," a satellite attachment hat uses the sun's radiation to move around the solar system.
Essentially a large square of extremely thin metal (it's one eighth the width of a human hair), the sail can be attached to a satellite to cheaply and constantly produce thrust. With a planned launch in 2014, the sail might be able to fly a satellite close to the sun to study solar flares—and alert scientists when one is incoming.
Once in space (it'll have to be launched from earth on a normal rocket), it's just like navigating the high seas, says Nathan Barnes, chief operating officer of L'Garde, a California-based company that's developing the sail in conjunction with NASA and the National Oceanic and Atmospheric Administration.
"With a boat, the wind's blowing one way, and you're going the other," Barnes says. "It's kind of like that."
The company showed off its sail to lawmakers on Capitol Hill Wednesday. If successful, the sail will be one of NASA's cheaper missions, costing less than $20 million.
During the mission, the solar sail will fly a satellite 1.8 million miles from earth toward the sun. The satellite will essentially "park" itself between the earth and the sun, using its propulsion to resist the sun's gravitational force and prevent it from being sucked into the sun.
The chosen point is double the distance from earth as NOAA's Advanced Composition Explorer, the satellite that alerts scientists to incoming solar flares. The L'Garde satellite will theoretically give scientists double the amount of time to warn satellite operators about solar storms, giving them time to shut down—and potentially preserve—critical instruments onboard.
"We're in constant communication with NOAA," says Barnes. "If there's a solar flare large enough that comes through and wipes out the sail, then, yikes—we better do something."
A solar sail is uniquely qualified to "park" a satellite near the sun. To resist the sun's gravitational force, traditional rocket thrusters would have to burn lots of expensive and finite fuel. NOAA's Advanced Composition Explorer sits at a spot known as L1—a point between earth and the sun where the gravitational pull from each is equal, so it can remain in that spot. In the future, solar sails might be able to be used to travel far beyond the solar system, because they'll never run out of fuel.
Arriving at L'Garde's parking spot will be tough—a missed calculation can be disastrous. Go too close to the sun and it'll be sucked in.
"There's some instabilities there. We're going to come at it gently," Barnes says. "There's a point of no return."