When it comes to futuristic space travel, few concepts are more romantic than sailing on sunlight. Soar
above Earth, unfurl a jib and tack your
way through the solar system all the way
to interstellar space.
Solar sails have been a mainstay of
dreamers since Johannes Kepler, who
speculated four centuries ago that ships
would one day be powered by “heavenly
air.” But sun sailing is no longer fanciful
fodder for visionaries. Recent technological advances have moved solar sailing from science fiction to science fact.
Last year, Japan’s space agency
launched the world’s first solar sail into
interplanetary space; its metal-coated
membrane unfurled and caught the light
to begin sunjamming. And with help from
tiny “nanosatellites” that allow scientists
to pack folded-up sails in spacecraft no
bigger than a loaf of bread, NASA this year
sent its first sail skipping through Earth
orbit. Look overhead at the right time
of night, and you can spot the gleaming
streak of NASA’s NanoSail-D as it tumbles
closer to Earth, mission accomplished.
Within the next few months it will incinerate in the atmosphere in a bright flash.
In addition to the Japanese and U.S.
efforts, the privately funded Planetary
Society expects to launch its own sail next
year, as does a satellite design team based
After keeping scientists in suspense,
NASA’s NanoSail-D (illustration shown)
fanned out in space earlier this year.
at the University of Surrey in England.
Solar sail enthusiasts have waited
decades to see such flights. And one day,
they hope, solar sails will perform tasks
other spacecraft cannot: hover above
Earth’s poles to monitor climate change,
flit near the sun to watch for solar storms,
drag space junk out of orbit like a cosmic
maid or even journey to a nearby star.
“As far as solar sails go, we are on
the cusp of history,” says Dean Alhorn,
an engineer at NASA’s Marshall Space
Flight Center in Huntsville, Ala., who