Potential Disruption to Communication Satellites Today

Forecasters at the NOAA Space Environment Center have warned that there could be disruption to satelitte systems today due to the arrival of a coronal mass ejection, or CME in the Earth's magnetic field. The mass ejection from the Sun's surface was observed on Wednesday and further erruptions are expected over the next couple of weeks. The disturbance was expected to produce a geomagnetic storm rated G-3. A G-5 storm is the strongest.

NOAA Region 484 developed rapidly over the past three days and is now one of the largest sunspot clusters to emerge during Solar Cycle 23. It is about 10 times larger than the Earth. This region, which is nearing the center of the sun, already produced a major flare, R-3 on the NOAA Space Weather Scales, producing a radio blackout on October 19 at 12:50 p.m EDT.

Larry Combs, a forecaster with the NOAA Space Environment Center's Space Weather Operations, said that this region has developed rapidly over the last three to four days. "It's somewhat unusual to have this much activity when we're approximately three-and-a-half years past solar maximum," he said. "In fact, just last week, solar activity was very low with an almost spotless sun." Solar cycles of high and low activity repeat about every eleven years, and the sun has been moving towards solar minimum for the past three years.

Further major eruptions are possible from these active regions as they rotate across the face of the sun over the next two weeks. Satellite and other spacecraft operations, power systems, high frequency communications, and navigation systems may experience disruptions over this two-week period.

The solar corona material is massive in size (they can occupy up to a quarter of the solar limb), and frequently accompanied by the remnants of an eruptive prominence, and less often by a strong solar flare. Just hours after blowing into space, a CME cloud can grow to dimensions exceeding those of the Sun itself, often as wide as 30 million miles across. As it ploughs into the solar wind, a CME can create a shock wave that accelerates particles to dangerously high energies and speeds

A CME was blamed for knocking out the Galaxy IV telecommunications satellite in May 1998 (although the satellite's maker, Hughes, has blamed a "random event"). That satellite failure temporarily disabled millions of pagers and other communications devices across the USA."

Posted to the site on 24th October 2003