Tracking the causes of space-sased weather disruptions

Mar 17, 2011 By Ellen Ferrante
This image shows an NSF-funded ISR radar in Resolute Bay, Nunavut, Canada, which is similar to the ISR used in this study. An ISR is a tool used for upper atmospheric and space physics research that takes measurements of the Earths upper atmospheric and space regions from 60 km up to 1000 km. The ISR takes measurements such as: ionospheric electron density, ion composition, plasma temperatures and electric fields. Credit: Craig Heinsleman

Space weather-based disturbances in the Earth's upper atmosphere cause disruptions that affect space-based communication and navigation signals, such as GPS and radio signals.

Radio Aurora Explorer (RAX) is a space weather research satellite that is designed to investigate the causes of these weather disturbances.

RAX is the first satellite constructed under the National Science Foundation (NSF) CubeSat-based Space Weather and Atmospheric Research Program. Since September 2008, the project has been carried out jointly by SRI International, an independent, nonprofit research institute headquartered in Menlo Park, Calif. and the University of Michigan in Ann Arbor, Mich.

About 40 students worked on various satellite subsystems at different stages of the project, the majority of them from the University of Michigan. Three students from Worcester Polytechnic Institute visited SRI and worked on the radar.

"RAX demonstrates that low-cost cubesat missions that are mainly designed, built and operated by students as part of their university education and training can provide key measurements for space weather research and monitoring," said Therese Moretto Jorgensen, a program director in the Division of Atmospheric and Geospace Sciences at NSF.

Professional team members include principal investigators Hasan Bahcivan of SRI and James Cutler from the University of Michigan, as well as approximately 10 project managers and engineers.

"Space weather terminology took a hold in the last decade or so with the increasing public use of satellite technology and the vulnerability of spacecraft and space-based technology to solar and geomagnetic activity," explained Bahcivan. "Among many adverse effects of space weather is the degradation or disruption of space-based communication and navigation signals, for example, the signals."

These degradations occur in the upper part of Earth's atmosphere between altitudes of 100-500 kilometers (62-310 miles) and are caused by geomagnetic storms. A geomagnetic storm is a disturbance of the Earth's magnetosphere, or the region in space where the Earth's magnetic field controls the motion of charged particles, in response to solar activity such as coronal mass ejections or solar flares.

"The effects of a geomagnetic storm include an increased population of radiation belt electrons, energetic particle precipitation into the Earth's , auroras (northern lights) and strong electric currents in the ionosphere [a portion of the upper part of the Earth's atmosphere that is ionized by solar radiation]," said Bahcivan. "Space-based technologies, and in extreme cases, electric power grids on the ground become vulnerable during a geomagnetic storm."

Consequently, the effects of the disturbances include signal fading and phase distortions. For example, one type of distortion called scintillation, which is conceptually similar to the twinkling of the stars, can make GPS signals unusable.

To seek answers to where these disruptions occur and under what conditions, the RAX was launched on Nov. 21, 2010 via the Space Test Program aboard a Minotaur-4 vehicle in Kodiak, Alaska. According to Bahcivan, after a three-week period, the researchers conducted their first radar experiment using the Poker Flat Incoherent Scatter Radar, which is operated by SRI International under a cooperative agreement with NSF.

"Overall, the experiment showed that the radar system is working nicely," said Bahcivan. "Although background interference existed sporadically, it was manageable."

Bahcivan explained that RAX experiments must be conducted in coordination with ground-based radars. A typical experiment is conducted by illuminating a turbulent ionospheric region using a powerful ground-based incoherent scatter radar, or ISR.

An ISR is a scientific tool used for upper atmospheric and space physics research that takes measurements of the Earth's upper atmospheric and space regions from 60 kilometers (37 miles) up to 1000 kilometers (621 miles). Measurements taken by ISRs include ionospheric electron density, ion composition, plasma temperatures and electric fields.

In addition to the Poker Flat ISR, NSF supports other ISRs, including Millstone Hill in Massachusetts, Resolute Bay in Canada, Arecibo in Puerto Rico and Jicamarca in Peru.

The RAX radar receives scattered signals from ISRs in space. However, some of the scattered signals arrive back at the ISR. These scattered signals contain information about the background properties of the particular region being tested.

By measuring plasma properties using non-turbulent background signals, scientists can determine which conditions give rise to plasma turbulence that cause degradation and irregularities in space-based signals. Scientists also can measure the electric field of the region, which provides critical information about plasma turbulence.

"Therefore, the goal of the RAX science mission is to determine which ionospheric conditions give rise to plasma turbulence," said Bahcivan.

"RAX helps provide better knowledge of fundamental physical parameters related to ionospheric irregularities," said Jorgenson. "This will lead to improved models of the ionosphere that can predict the occurrence of irregularities and thereby help mitigate their adverse affect on systems that rely on trans-ionospheric radio waves, such as GPS."

Bahcivan explained that the RAX mission adds to ongoing efforts by measuring the irregularities with much higher spatial resolution and higher angular resolution with respect to the Earth's magnetic field, enabling a powerful diagnostic capability for ionospheric plasma turbulence.

Explore further: Astronauts to reveal sobering data on asteroid impacts

add to favorites email to friend print save as pdf

Related Stories

View of the Upper Atmosphere

Dec 05, 2005

Scientists from NASA and the National Science Foundation discovered a way to combine ground and space observations to create an unprecedented view of upper atmosphere disturbances during space storms.

Student-built satellite scheduled for launch

Sep 08, 2010

( -- A 6.5-pound satellite is scheduled to become the first stand-alone spacecraft built by Michigan students to go into orbit and perform a science mission.

Recommended for you

Astronauts to reveal sobering data on asteroid impacts

5 hours ago

This Earth Day, Tuesday, April 22, three former NASA astronauts will present new evidence that our planet has experienced many more large-scale asteroid impacts over the past decade than previously thought… ...

Rosetta instrument commissioning continues

6 hours ago

We're now in week four of six dedicated to commissioning Rosetta's science instruments after the long hibernation period, with the majority now having completed at least a first initial switch on.

Astronaut salary

6 hours ago

Talk about a high-flying career! Being a government astronaut means you have the chance to go into space and take part in some neat projects—such as going on spacewalks, moving robotic arms and doing science ...

Red moon at night; stargazer's delight

Apr 16, 2014

Monday night's lunar eclipse proved just as delightful as expected to those able to view it. On the East Coast, cloudy skies may have gotten in the way, but at the National Science Foundation's National Optical ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

3 / 5 (2) Mar 17, 2011
It is encouraging to see that NSF is now studying "Space-S(B)ased Weather Disruptions"

S => B typo in headlines.

With kind regards,
Oliver K. Manuel

More news stories

Cosmologists weigh cosmic filaments and voids

( —Cosmologists have established that much of the stuff of the universe is made of dark matter, a mysterious, invisible substance that can't be directly detected but which exerts a gravitational ...

Hubble image: A cross-section of the universe

An image of a galaxy cluster taken by the NASA/ESA Hubble Space Telescope gives a remarkable cross-section of the Universe, showing objects at different distances and stages in cosmic history. They range ...

Hackathon team's GoogolPlex gives Siri extra powers

( —Four freshmen at the University of Pennsylvania have taken Apple's personal assistant Siri to behave as a graduate-level executive assistant which, when asked, is capable of adjusting the temperature ...

Better thermal-imaging lens from waste sulfur

Sulfur left over from refining fossil fuels can be transformed into cheap, lightweight, plastic lenses for infrared devices, including night-vision goggles, a University of Arizona-led international team ...

Researchers discover target for treating dengue fever

Two recent papers by a University of Colorado School of Medicine researcher and colleagues may help scientists develop treatments or vaccines for Dengue fever, West Nile virus, Yellow fever, Japanese encephalitis and other ...

Study recalculates costs of combination vaccines

One of the most popular vaccine brands for children may not be the most cost-effective choice. And doctors may be overlooking some cost factors when choosing vaccines, driving the market toward what is actually a more expensive ...