The United States has launched a prototype weather satellite, the first of a much-needed new generation of weather and climate satellites, officials said.

The successful launch at Vandenberg Air Force Base in California at 5:48 a.m. EDT Friday was called a significant achievement for a program that has been delayed by technical challenges, mismanagement, cost-overruns and a subsequent restructuring of the program, the Christian Science Monitor reported.

The data the so-called NPP satellite will provide is badly needed as the number of Earth-observing satellites is dwindling, scientists said.

The satellite is the first designed "to provide observations for both weather forecasters and climate researchers," Jim Gleason of NASA's Goddard Space Flight Institute in Greenbelt, Md., said.

Because research satellites such as NASA's Terra, Aqua, and Aura orbiters will be reaching the end of their missions over the next two to three years, the new satellite NPP is seen as an important bridge to keep the kind of data these other orbiters provided coming.

"NPP is very important," said Rick Anthes of the University Corporation for Atmospheric Research, which oversees the National Center for Atmospheric Research in Boulder, Colo.

Even with a successful NPP mission, the United States will see the number of Earth-observing satellites it launches dwindle just as the environmental questions they are designed to answer grow in importance, he said.

A reduction in Earth remote-sensing capabilities, Anthes said, would be one more signal the United States is losing its leadership in space to Europe and Asia.