Satellites to Launch for Northern Lights Study

An international team of scientists will begin gathering the most detailed information yet about the ever-changing northern lights as a multiyear research project launches five satellites from Cape Canaveral, Fla., next month.

The NASA-funded mission called THEMIS (Time History of Events and Macroscale Interactions during Substorms) is scheduled for launch on Feb. 15. THEMIS is led by the Space Science Laboratory at the University of California at Berkeley, while the Canadian component of the project is funded by the Canadian Space Agency (CSA). In Canada, THEMIS will ultimately involve scientists from the Universities of Alberta, Saskatchewan, New Brunswick and Calgary; Athabasca University, CSA and Natural Resources Canada.

An artist's concept of the five-satellite mission THEMIS, which will provide scientists with more information about the northern lights. (Image: NASA)

The University of Calgary's THEMIS team is operating a network of ground-based observatories (GBOs) across Northern Canada. The THEMIS satellites will probe dynamic processes of astrophysical interest in near-Earth space, while the GBOs will create mosaics of the night sky, capturing changes in the northern lights that are an essential part of the information needed to answer the questions that THEMIS is targeting. The ground and space-based THEMIS observations will enable scientists to pinpoint the cause of brilliant explosions of shimmering light known as "auroral substorms."

The aurora borealis, or northern lights, is a display of the strongest light emitted by the Earth's upper atmosphere. (Photo: ©Jouni Joussila)

"This is a very exciting moment for us because we are expecting to greatly enhance our understanding of these space disturbances that are both beautiful and powerful," said University of Calgary (U of C) physics professor Eric Donovan, leader of the Canadian THEMIS component. "The next few years are going to be very busy for us and our THEMIS colleagues at NASA and the University of California at Berkeley."

The U of C operates 16 GBOs located in communities across northern Canada (four more in Alaska are operated by UC Berkeley), which consist of automated all-sky cameras that use time-lapse digital imaging and special optics to record auroras in the northern skies. The five satellites are on orbits designed so that they come together in conjunctions over central Canada every four days.

During these conjunctions, the cameras will be used to determine the onset of auroral substorms, while instruments on the five satellites will provide measurements of changes in energetic particle populations and the magnetic field in space. The mission will last at least two years, during which time the GBOs will record more than 200 million photographs.

The aurora borealis as seen from space in an image taken by NASA's Polar spacecraft. (Image: NASA)

Auroras are caused by the interaction of charged particles from the sun, also known as the solar wind, with the Earth's magnetic field. Auroral substorms are the unpredictable bursts in auroral activity that take place when energy stored in the tail of the magnetic field is released and travels along magnetic lines to the polar regions, where it causes spectacular displays of iridescent light.

These storms are not fully understood and previous studies have not been able to determine where in the magnetosphere the energy of the solar wind transforms into explosive auroras. Auroral substorms have also been linked to disturbances of telecommunications systems on Earth and damage to satellites.

For more information, visit: http://sprg.ssl.berkeley.edu/themis