ANDENBERG AIR FORCE BASE, Calif. (Reuters) - A NASA spacecraft rocketed into orbit on Saturday to begin a two-year, $150 million mission to gather pictures of Earth's magnetic field that could help protect satellites from solar storms.

The IMAGE spacecraft was launched aboard a Boeing Co. Delta II rocket from Vandenberg Air Force Base in California.

IMAGE, short for ``Imager Magnetopause-to-Aurora Global Exploration'' spacecraft, began the first stage of its science mission an hour after liftoff at 12:34 p.m. PST (3:34 p.m. EST/2034 GMT).

IMAGE will, for the first time, give scientists the means clearly to view the Earth's magnetosphere, which extends beyond the planet's upper atmosphere, according to the Southwest Research Institute, a San Antonio-based engineering and science research organization and NASA's partner in the mission.

``Textbooks will have to be rewritten because we'll have a picture of what the magnetic field looks like,'' institute spokesperson Maria Martinez said by telephone from the Vandenberg base.

Images transmitted from the spacecraft will provide the first ever real-time data on space weather and help in protecting satellites from solar storms, Martinez said.

NASA said the IMAGE mission will provide global images of plasmas in the Earth's magnetosphere, showing how they are affected by the solar wind, the intense fluctuating streams of charged particles from the sun. Space storms disturb the planet's magnetic field and can damage spacecraft, disrupt communication satellites and cause electrical power blackouts.

Martinez said project managers received the first signal from IMAGE one hour after it was launched, but it will be about 40 days before the spacecraft begins making movies of the magnetosphere. It will take that long fully to extend all of the spacecraft's antennas and it will take some time to test its instruments and make sure they are all working, she said.