Malfunctioning Fuel Cell May Force Shuttle Down

A weakening electric generator on space shuttle Columbia could force the astronauts to cut short their 16-day science mission and return to Earth as early as Monday.

The generator, called a fuel cell, has been losing voltage since Friday’s liftoff, maybe even before, NASA mission operations director Jeff Bantle said Saturday. If the loss continues at a high enough rate, the seven astronauts would have to turn off that fuel cell and land, he said.

By Saturday night, the decline in voltage had slowed considerably. And astronaut Michael Gernhardt said the problem was not interfering with the crew’s round-the-clock laboratory work, and that the shuttle was getting all the power it needed.

Columbia’s two other fuel cells are working fine, but National Aeronautics and Space Administration flight rules require that all three be operating properly in orbit.

Neither the shuttle nor crew was in any immediate danger, and laboratory operations were proceeding normally, Bantle said.

The fuel cells use hydrogen and oxygen to produce electricity and water in orbit. If those two fuels mixed - a possibility when voltage drops significantly in a fuel cell - the unit could explode.

Bantle said the fuel cell would be shut down long before there would be any chance for the fuels to mix.

And he emphasized that the voltage could stabilize for good, allowing the astronauts to remain in orbit the full 16 days.