As the brilliant colors of the aurora borealis, or northern lights, delight skygazers, Cornell University researchers are discovering how their physics affects satellite signals here on Earth.
A NASA-funded collaborative research team led by Steven Powell, Cornell senior engineer in electrical and computer engineering, launched a sounding rocket from Alaska's Poker Flat Research Range on Saturday, Feb. 18 at 8:41 p.m. Alaska Standard Time (Sunday, Feb. 19, 2012 at 12:41 a.m. EST) to collect data straight from the heart of the aurora.
The project -- the Magnetosphere-Ionosphere Coupling in the Alfven resonator mission -- involves 60 scientists, engineers, technicians, and graduate students from several institutions and NASA. From Cornell they include Powell, principal investigator for the mission; David Hysell, co-investigator and professor of Earth and atmospheric sciences; Robert Miceli and Brady O'Hanlon, graduate students in electrical and computer engineering; and Mark Psiaki, professor of mechanical and aerospace engineering. Researchers from Dartmouth College, the University of New Hampshire, the University of Oslo (Norway), Southwest Research Institute, and the University of Alaska Fairbanks also are making significant contributions to the mission.
"We're investigating what's called space weather," said Powell, who along with Hysell, Miceli and O'Hanlon, has been stationed at the rocket launch site, 30 miles north of Fairbanks, since the end of January. "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."
These include global positioning systems; (GPS) one of the scientists' main goals is to investigate the effects of space weather on GPS satellites.
The rocket is a 46-foot Terrier-Black Brant model that was sent arcing through the aurora 217 miles above Earth, sending a stream of real-time data back before landing 200 miles downrange. Instruments on board sampled electrons in the upper atmosphere that are affected by a form of electromagnetic energy called Alfven waves. These waves are thought to be a key driver of "discrete" aurora -- the typical, well defined and famously shimmering lights that stretch across the horizon.
The rocket payload separated into two parts once launched. One extended antennas to measure electric fields generated by the aurora. Other antennas 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 are likely interfering with GPS 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."