CINDI Investigates Stormy Weather in Space

Space Scientists Study Sun’s Effect on Temperatures in the Ionosphere

Sept. 10, 2008

Two satellite instruments built by UT Dallas researchers for a NASA-funded mission are showing the impact of low solar activity on the Earth’s ionosphere.

The phenomenon, which occurs when there is a decrease in sunspots, leaves the upper atmosphere cooler. The effects are being documented by the Coupled Ion-Neutral Dynamics Investigation (CINDI) project.

The goal of CINDI is to increase knowledge about the new field of “space weather.”

On April 16, the Air Force launched the CINDI experiments aboard a new experimental satellite called the Communications / Navigation Outage Forecast System (C/NOFS). The data returned from CINDI will help predict space weather that affects everyday people.

Scientists and engineers at the William B. Hanson Center for Space Sciences, under the guidance of UT Dallas physics professors Dr. Roderick Heelis and Dr. Greg Earle, built the two instruments that make up CINDI:

  • The Ion Velocity Meter measures the direction and speed of the ions as well as their density, temperature and chemical composition.
  • The second instrument, the Neutral Wind Meter measures the speed and direction of the neutral atoms and molecules in the near vacuum of space.

During periods of high solar activity, which correspond to high sunspot counts, the upper atmosphere of the Earth warms and expands.

According to Earle, UT Dallas professor and CINDI Co-Investigator , since late 2005 monthly sunspot numbers have been very low, and have not yet begun to rise significantly. CINDI data shows the impact of the past few years of low solar activity on the ionosphere.

“CINDI has encountered an extremely cold atmosphere in conjunction with an uncharacteristically long solar minimum period,” Earle said.

“The C/NOFS mission is the first attempt to perform quasi-real time predictions of space weather, through coordinated satellite observations and ground-based computer modeling.”

C/NOFS’ mission is to improve our understanding of space weather, much in the way weather satellites have improved our understanding of ordinary weather.

The upper atmosphere of the Earth starting at about 43 miles high is made up of neutral molecules and atoms mixed together with charged ions and free electrons.

The ions are produced when normal atmospheric gases absorb high-energy light from the sun. In our atmosphere, electrically charged particles can interact to interfere with the radio signals from communication satellites and GPS satellites.

The ability to predict when and where this interference will occur is very important to anyone who relies on satellites for communication or navigation

An Air Force space weather satellite is the latest to join the list of spacecraft carrying UT Dallas-built experiments. The list also includes several Apollo missions and the current NASA Phoenix mission to Mars that recently announced the first direct detection of water ice in the Red Planet’s northern polar regions.

NASA is funding both the CINDI instruments and the scientific analysis of the ionospheric data they are returning.


Media Contacts: Brandon V. Webb, UT Dallas, (972) 883-2155, Brandon.webb@utdallas.edu
or the Office of Media Relations, UT Dallas, (972) 883-2155, newscenter@utdallas.edu

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Dr. Greg Earle


Above: Dr. Greg Earle handles an ion velocity meter similar to the one that is flying on the satellite mission.   Below: On April 16, the Air Force launched the CINDI experiments aboard a new experimental satellite called the Communications/ Navigation Outage Forecast System.

Satellite carrying CINDI

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