It was sailing boats that set off from Europe in search of new trading routes and the new world to the East and West, and it seems that it will be sailing vessels that lead the way in the new world of space.
John F Kennedy called space 'this new ocean', and just as hundreds of years ago multiple ships from multiple countries scoured the oceans of the world so multiple countries and organisations are involved in the search for viable solar space sailing.
In June this year, Japan's kite-shaped 'space yacht', called the Ikaros, was successfully launched and started sailing through space using solar-power generation, heading for Venus.
Similar to an ocean yacht pushed by wind, the device has a square, ultra-thin and flexible sail measuring 14 metres by 14 metres that will be driven through space as it is pelted by solar particles.
The craft's polyimide reflector, only 0.0075 millimeter thick, has solar panel patches to exploit light for both propulsion and power and LCD panels that steer the craft by changing the reflectivity of certain segments. The sail is partly coated with thin-film solar cells to generate electricity.
Given Japan's success, sailing prospects seem better than ever. NASA plans to launch a sail this year, and in 2011, the Planetary Society expects its own craft will be ready to fly.
By the 2030s, the European company Thales Alenia Space hopes to launch 'data clippers'—essentially sailing hard drives that could shuttle data between probes exploring Saturn's and Jupiter's moons and Earth.
While solar sailing will lessen the time for space travel, we're still not talking about our own lifetimes. Les Johnson, now NASA's deputy manager for the Advanced Concepts Office, helped develop solar sails for the agency in the early 2000s. Besides their rather practical applications, as probes monitoring Earth's poles or as part of a solar storm warning system, Johnson says a craft could sail to the nearest neighboring star system in less than 1000 years—a feat he estimates would take 75 000 years using chemical propulsion.
Of course, for that you'd need a sail the size of Alabama deployed from a probe that's closer to the sun than Mercury.
Solar wind, made up of sun-spewed charged particles, might also prove a useful means to sail. Pekka Janhunen, a research fellow at the Finnish Meteorological Institute, has plans for what's called an electric sail. The craft would charge 50 to 100 tethers, each 20 to 30 kilometers long. The resulting electric field would reflect protons in the solar wind to propel the proposed 100-kilogram craft. Five European Union countries are discussing a 3-year project to build laboratory prototypes of craft components.
The launch malfunction that doomed its first solar sail, Cosmos-1, in 2005 has not discouraged the Planetary Society. The space advocacy group, based in Pasadena, Calif., expects that its LightSail-1 will be ready for launch in 2011. Three cube-shaped satellites, or 'cubesats,' each 10 centimeters to a side, will hold the 32-square-meter Mylar sail and the craft's electronics and controls.
With so many in the race, the next 20 years or so will be a fascinating time for the space scientists of the world and those who watch them.