NASA postponed the launch of the Atlantis Space Shuttle, scheduled for this morning, after engineers discovered a malfunctioning fuel cell. "Proton-Exchange Membrane" fuel cells have powered in-flight electrical systems on NASA missions--and provided astronauts their drinking water--since the 1965 Gemini 5 mission.

Remember the hydrogen economy? You are forgiven if the answer is no. In 2003, President Bush ushered in an age of research that within a generation might yield fuel-cell cars powered on hydrogen. The initiative came at the insistence of then-Energy Secretary Spencer Abraham, who thought the country should finally find something to talk about other than automotive efficiency standards and Alaskan oil drilling.

The Space Shuttles' fuel cells need attention from time to time, but overall have served missions extremely well. So where are our futuristic cars? Numerous problems prevent companies from commercializing them. For one, no one produces hydrogen in quantities necessary. There is little incentive to do so, because auto-makers haven't solved how to safely and efficiently store the fuel on board. Once those problems are solved, energy companies can start to think about how to retrofit their hundreds of thousands of gas stations around the country. For now, hydrogen-advocates will have to settle for the Space Shuttle fleet.