Fallout from the second eruption at 2048 GMT was expected to reach Earth's atmosphere late Thursday, the National Oceanic and Atmospheric Administration (NOAA) said.

The Japanese space agency reported losing communication with one of its satellites, Kodama, on Wednesday at the beginning of the magnetic storm, the biggest in some 30 years.

The storm erupted from the sun early Tuesday, around 1100 GMT, firing electronically charged gas straight towards the Earth.

Scientists said the sun's eruptions were significantly stronger than recent blasts, and that the magnetic storm reached the Earth's atmosphere just about 19 hours later. The solar winds' speed was about five times greater than normal, said Bernhard Fleck, a scientific official at the Solar and Heliospheric Observatory (SOHO) staffed by NASA and the European Space Agency.

As a precaution, the two crew members of the International Space Station have been ordered to spend periods of time sheltered in the Zvezda service module, which offers them higher protection from increased radiation levels.

The solar storm could damage some communications satellites, and possibly land-based power grids, but scientists said they won't know precisely whether this could occur until about 15 minutes before the shower falls into the Earth's atmosphere.

Commercial airliners can also experience higher levels of radiation during such solar storms.

The solar eruption will continue to affect the Earth's magnetic field for the next two weeks, experts say.

The sun's most powerful explosion of flares and gases into space occurred in April 2000, but that burst was directed away from the Earth.

SPACE.WIRE