"[The particles] pose a danger to humans because of cumulative radiation exposure and also by damaging the spacecraft on which they are dependent," said Mike Xapsos, a researcher at NASA's Goddard Space Flight Center unaffiliated with the new research.
When killer electrons collect in large numbers, they can penetrate a spacecraft and build up a significant electrical charge.
The charge is released as a type of electric bolt that can devastate sensitive equipment.
"One common effect is that they cause solar arrays to degrade, and those often supply power to spacecraft," Xapsos said.
Study co-author Friedel explained that magnetic storms and other "space weather" can dramatically impact killer electron levels.
(Read related story: "Space Weather Could Scrub Manned Mars Mission" [August 9, 2005].)
"In the outer radiation belts, things are very dynamic," he said.
"Particles can get lost, wiped out completely in a very fast time range, and they can become reaccelerated to levels far exceeding the average levelthree orders of magnitude upin just a couple of days."
"The main reason we're trying to come up with models of the radiation belt [is to] predict when these events are going to happen."
NASA's Xapsos said that understanding space weather remains difficult but our knowledge is increasing.
"We cannot control this kind of space weather any more than we can control the Earth's weather," he said.
"However, having a better understanding of the process helps us make more accurate predictions of when spacecraft can expect trouble and how to deal with it."
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