Researchers
from SRI International and the University of Michigan have taken the
first-ever measurement of naturally occurring auroral turbulence
recorded using a nanosatellite radar receiver. The research was done
with support from the National Science Foundation (NSF) and NASA’s
Educational Launch of Nanosatellites (ELaNa) Initiative.
The
distinctive radar echoes recorded on March 8 were taken with the Radio
Aurora Explorer (RAX) CubeSat. The RAX nanonsatellite measured
turbulence over Fairbanks, Alaska that was a direct result of a
geomagnetic storm triggered by the largest solar flare in the past five
years. The Earth’s high latitude ionosphere, a region of the upper
atmosphere associated with solar-driven aurora or “northern lights,”
becomes highly unstable when large currents flow during geomagnetic
storms. RAX was specifically designed by SRI and the University of
Michigan to measure this auroral turbulence from an orbital vantage
point inaccessible to traditional ground-based radars.
“The
RAX radar echo discovery has convincingly proved that miniature
satellites, beyond their role as teaching tools, can provide high
caliber measurements for fundamental space weather research,” said
Therese Moretto Jorgensen, Ph.D., Geospace program director in the
Division of Atmospheric and Geospace Sciences at the National Science
Foundation.
The
project’s mission was to use small satellites called CubeSats to
remotely explore formation of charged particle filaments created in
response to intense electrical currents in space. These plasma
structures, a form of turbulence called field-aligned irregularities
(FAIs), can distort communication and navigation signals such as global
positioning systems (GPS). During the recent solar flare, RAX measured
FAI echoes using the Poker Flat Incoherent Scatter Radar (PFISR), an NSF
research radar operated by SRI.
“The
recently collected radar echoes allow us to determine the root cause
and to possibly predict future disturbances in the auroral ionosphere –
disturbances that can severely compromise communication and GPS
satellites,” said Hasan Bahcivan, Ph.D., a research physicist in SRI’s
Center for Geospace Studies, and principal investigator of the RAX
mission.
A
team of University of Michigan students under the direction of James
Cutler, Ph.D., an assistant professor in the Aerospace Engineering
Department, designed, built, and operated the satellite and gathered the
radar echo data.
RAX
was the first CubeSat to be selected as part of an NSF program to use
small satellites for space weather and atmospheric research. The RAX
CubeSat is a three liter satellite weighing three kilograms. It was
launched by NASA on October 28, 2011, and has since completed 18
experiments.
This material is based upon work supported by the National Science Foundation under Grant No. ATM-0838054.
University of Michigan’s Radio Aurora Explorer CubeSat
Source: SRI International