Space laser will generate clean fuel

17 Jun 2002

A space-orbiting laser will blast Earth's water to make hydrogen for fuel cells.

Space laser

Japan's National Space Development Agency and the Institute of Laser Engineering (ILE) at Osaka University have joined forces to launch a space-orbiting laser that splits water into its hydrogen and oxygen constituents. Cruising at a geostationary orbit, the laser will target Earth-based tanks of water to generate hydrogen to power fuel cells.

The system is based on a satellite that houses a large Fresnel lens to capture and focus solar energy. The sun's photons will then be used to pump an infrared Nd-glass solid state laser, co-doped with Cr, that will be attached to the satellite.

"The [solid-state] laser will be tens of meters in length and just a few millimeters in diameter," said ILE researcher Kazuo Imasaki. "Current experiments show lasing levels of 100 W but in a few years we expect to have reached 10 kW."

The researchers expect to launch the laser over the next ten years, by which time they hope to have boosted lasing powers to gigawatt levels. They are also expecting the conversion efficiencies of their lasers to reach 30%.

To generate the energy, the laser will be directed at water tanks 100 m by 300 m in size, cited on Japanese islands in the Pacific Ocean and Japan sea. The team believes it will be able to focus the laser to within a 100 m range of its target.

Explaining that the researchers are carrying out their technique from space to avoid the limitations of night on Earth, Imasaki says: "Depending on the weather conditions, the laser can penetrate cloud which is up to a few kilometers thick."