Instrument to assess aurora’s Alfvén effect on GPS
POKER FLAT RESEARCH RANGE, Alaska – A small rocket recently was launched into the aurora borealis in an attempt to discover how the northern lights affect signals on global positioning system satellites and other spacecraft.
The two-stage, 46-foot Terrier-Black Brant rocket reached a height of about 217 miles.
A two-stage Terrier-Black Brant rocket arcs through the aurora 200 miles above Earth as the Magnetosphere-Ionosphere Coupling in the Alfvén resonator (MICA) mission investigates the underlying physics of the northern lights. Stage one of the rocket has just separated and is seen falling back to Earth. Courtesy of Terry E. Zaperach, NASA.
“We’re investigating what’s called space weather,” said Steven Powell of Cornell University in Ithaca, N.Y., the lead investigator in the study. “Space weather is caused by the charged particles that come from the sun and interact with the Earth’s magnetic field. We don’t directly feel those effects as humans, but our electronic systems do.”
The mission, called MICA (Magnetosphere-Ionosphere Coupling in the Alfvén resonator), involves 60 scientists, engineers, technicians and graduate students from Cornell, Dartmouth College in Hanover, N.H., the University of New Hampshire in Durham, the Southwest Research Institute in San Antonio, the University of Alaska Fairbanks, the University of Oslo in Norway and NASA.
Instruments on board sampled electrons in the upper atmosphere that are affected by a form of electromagnetic energy called Alfvén waves. These waves are thought to be a key driver of “discrete” aurora – the typical, well-defined band of shimmering lights that is about six miles thick and stretches across the horizon.
A fish-eye photo taken by an automated camera near the entrance gate to the Poker Flat Research Range in Fairbanks, Alaska. Courtesy of Donald Hampton.
Once launched, the rocket payload separated into two parts. One part extended antennae to measure electric fields generated by the aurora. Other antennae and sensors measured electrons and ions interacting with the Earth’s magnetic field. In this period of high sun activity, called solar maximum, gases from the sun likely are interfering with GPS (global positioning system) transmissions, satellite Internet and other signals.
“We are becoming more dependent on these signals,” Powell said. “This will help us better understand how satellite signals get degraded by space weather and how we can mitigate those effects in new and improved GPS receivers.”
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