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Sun 'ejection' killed TV satellite
January 21, 1997
Web posted at: 10:10 p.m. ESTFrom Correspondent John Holliman
ATLANTA (CNN) -- It sounds like science fiction: a cloud of solar radiation, blasted from the surface of the sun, destroys things on Earth.
That's not exactly what happened two weeks ago, but it isn't entirely the work of an overactive imagination, either.
The communications satellite Telstar 401 was orbiting 22,000 miles above Earth, relaying TV shows from all over the United States, when it went dead on the morning of January 11. Other satellites, including some operated by the Pentagon, also took a hit.
NASA scientists had seen a cloud of electrically charged particles, called a coronal mass ejection, leave the surface of the sun five days before.
They knew of the ejection because the SOHO satellite, located a million miles from Earth, is pointed constantly at the sun. It tracked the solar cloud as it moved toward Earth at about 600 miles a second.
The electrical clouds "go out in all directions, and the ones we get the best pictures of are the ones that are going out to the side because you watch it as it flows away from the sun -- just like squeezing toothpaste out of a tube -- it goes out," said George Withbrow, NASA Sun-Earth Director.
"The ones coming at the Earth are harder to see, but we do know they come ... because we can see the effects when they do get to the Earth."
A constellation of satellites hovers around the Earth looking at solar radiation, particularly large blasts such as the one that hit January 10-11.
Withbrow said the radiation caused the Northern Lights to glow much brighter than normal, enough for a satellite to register the increase from above. (14 sec. /160K AIFF or WAV sound)
He said there's no chance this kind of solar radiation could hurt people, as the Earth's magnetic field and atmosphere shields the surface.
But some electric power systems can have problems, as the power grids become loaded with extra currents, he said. That's what happened to the television satellite.
The sun causes trouble in 11-year cycles, and that's now at a low point. But in the year 2000, the cycle will peak, and damage to satellites and power equipment on the ground could increase dramatically.
Related stories:
- Solar radiation might have killed satellite - January 20, 1997
- Telstar 401 out of service - January 17, 1997
Related sites:
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- AAS Solar Physics Division
- NASA Solar Data Analysis Center
- Hiraiso Solar Terrestrial Research Center
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