SDL Blasts into the Upper Atmosphere

February 25, 2002

LOGAN — Utah State University's Space Dynamics Laboratory (SDL) launched two instruments into the upper atmosphere Feb. 21 aboard a Nike-Orion sounding rocket from Poker Flat Research Range, Alaska, as part of NASA's CODA (Coupling of Dynamics

The CODA program is the latest in a series of NASA-sponsored experiments designed to study the thin upper atmospheric region that is too high for airplanes and balloons, but too low for satellites. This region is a harsh environment that scientists are trying to more fully understand.

"This area of the upper atmosphere seems to behave in a manner similar to ocean waves breaking on the shore," said Charles Swensen, PhD, principal investigator and associate professor at Utah State. "Atmospheric waves created in the lower atmosphere travel upward and break in the upper atmosphere and are believed to cause strong wind currents and turbulence."

CODA collected data as the rocket launched almost 100 miles into space and continued taking measurements as it fell back to Earth. The mission lasted for a brief 15 minutes, but the science team was extremely pleased with the data obtained.

Researchers are looking at several different aspects of the ionosphere by using sensors built at SDL. One sensor is the Plasma Frequency/DC Probe (PFP), which measures the number of free electrons along the rocket's path, giving scientists a measurement of the depth of the ionosphere.

"The electrons have been ripped off their atoms by the Sun's x-rays and ultraviolet rays and are just floating in this region," Swensen said. "The free electrons create the ionosphere."

The other sensor is the Atomic Oxygen Experiment (ATOX), which measures the amount of atomic oxygen along the flight. Atomic oxygen occurs as oxygen found on Earth's surface rises upward and is split. It is extremely reactive and corrosive, and is the reason the space program uses Teflon® on the shuttle and space station to protect surfaces.

Information was collected while scientists monitored the effect the aurora was having on this region. According to Swensen, CODA made measurements during a diffuse aurora, which happens more frequently and is the dull red glow that is visible when the aurora can be seen from Logan.

"The aurora occurs in the ionosphere," said Swensen. "CODA measured the affect it had on winds and air turbulence in the neutral atmosphere."

The overall goal of CODA is to help scientists predict space weather. This will help military, governmental and commercial agencies know when space weather will affect their satellites. This forewarning will enable satellite operators to take action to protect them from space weather.

"Understanding how the space environment affects these systems becomes more important as we become more dependent upon spacecraft in our evolving technological society," Swensen said.

After lift-off of CODA, a campaign of three rockets was launched, leaving chemical tracers in the sky. The chemical trails were visible for about thirty minutes, as scientists viewed them with cameras on the ground. Data collected from the tracers will be used to determine wind direction and speeds by tracking the trail of the tracers.