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MRO Faces Huge Solar Flare
View the MPEG animation on the NOAA site (no audio).
Image and animation credit: NOAA
You might not often consider forecasts for other planets or stars. After all, they don't affect you, right? WRONG! Solar flares, or sudden bursts of energy from the Sun, can interrupt communication and electricity here on Earth. Guardians of in-flight spacecraft are especially sensitive to volatile solar forecasts since the emissions from our warm star can damage them severely. September 7, 2005 saw the fourth largest solar flare in the last 15 years!
The Mars Reconnaissance Orbiter, on its way to Mars since August 12, 2005, was undamaged by the solar storm. The spacecraft is approximately 160 million kilometers (over 99 million miles) from the Sun and moving farther away each minute. Solar flares can travel deep into our solar system. However, they become less energetic the farther they travel and thus less of a threat to our spacecraft.
"Solar flares emit energetic particles that can cause what we call a single event effect. These events can wreak havoc on modern electronics. The damage can range from a reset of a computer to the complete destruction of an electrical subsystem," said Phil Barela, mission assurance manager for the Mars Reconnaissance Orbiter Mission.
When these energetic particles hit the electronics, they can blast holes through the active circuitry. Sometimes the particles will hit the electronics in just the wrong spot and cause the part to fail. NASA and JPL extensively test electronics to ensure all electronic parts can withstand a minimum threshold for a single event effect. All parts must undergo actual radiation testing, which bombards the parts with energetic particles (to the minimum threshold the team has established) and the devices must work during and after this testing, Barela explained.
"We were lucky on this one," Barela noted. "The region 808 solar flare occurred on the the Sun's surface that was not facing the Earth. This allowed most of the solar flux to travel in the opposite direction from Earth. However, when the solar flare location traveled back into direct line of sight with Earth (as the Earth rotated around the Sun), the concern was that further solar activity might occur from this active region. In addition, we designed the spacecraft to withstand the worst solar flare activity that we have ever measured."
Credit: NASA/JPL-Caltech
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