Ionosphere: Rocket Carries USU Experiment
By Greg Lavine
The Salt Lake Tribune
March 21, 2002
Members of the CODA team (Coupling of Dynamics and Aurora Experiment)
install Utah State University-built equipment on a Black Brant V rocket
at the Poker Flat Research Range in Alaska. USU's Space Dynamics Lab
was part of a NASA project to better understand the region where the
atmosphere meets space. The 15-minute rocket ride took place Feb. 21
(Courtesy of USU)
Scientists have long puzzled over the area where Earth's atmosphere meets space, a place too high for planes to fly and too low for satellites to orbit.
A Black Brant V rocket knifed through the turbulent region on a 15-minute flight last month as part of a Utah State University/NASA experiment in the lower ionosphere. The Feb. 21 launch from Alaska's Poker Flat Research Range carried two recording devices from USU's Space Dynamics Lab.
"There's no doubt it's one of the less well known regions of the atmosphere," said Charles Swensen, an associate professor of electrical and computer engineering at USU. "It's just such a hard region to get to."
The zone stands between 75 and 100 miles above the Earth. High-altitude balloons and certain planes can go up close to 20 miles at best. Satellites orbiting at about 112 miles are close a fiery end as they are about to be dragged into the atmosphere.
"This is research into how the sun-Earth connection works," said James Clemmons, lead investigator for the project from the Aerospace Corp.
Swensen said this part
of the atmosphere resembles a beach. Like ocean waves striking the shore,
waves from the lower atmosphere rise up to create turbulence.
Hurricanes and wind blowing across mountains can spark these rising waves. The waves swirl gases and particles in the lower ionosphere.
USU's partners on the
project included Aerospace, a nonprofit company that provides engineering
services to federal government agencies, and Clemson University. The Coupling
of Dynamics and Aurora experiment, or CODA, launch was delayed a month from
its January schedule.
"The weather was uncooperative, and so was the activity of the sun," Swensen said.
Ideal launch conditions called for clear skies and a significant change in the sun's magnetic field. Magnetometers monitored the magnetic field changes.
As the sun's magnetic field alters, this change the solar winds sailing toward Earth. Different speeds or densities of solar winds hit the Earth's magnetosphere like a hammer. The magnetosphere helps shield the planet from dangerous particles coming off the sun.
Swensen said electrical
currents are constantly traveling through the lower ionosphere in jet stream-like
patterns. Changes in solar winds alter the strength of the electrical currents,
which is part of what USU is studying.
A trio of tracer rockets chased after the USU-equipped lead rocket. Each tracer rocket released puffs of special chemicals that reacted with the atmosphere's oxygen to glow.
"Those three rockets
went up and painted stripes in the sky," Swensen said.
Glowing chemical puffs, visible at night, gave researchers information on wind patterns. This helped
USU researchers study the flowing electrical currents.
The Atomic Oxygen Experiment was one of USU's instruments on the rocket.. Ultraviolet rays from the sun cause oxygen's two molecules to split. The resulting single oxygen molecules are atomic oxygen.
USU's device measured how much atomic oxygen was present outside the rocket. NASA coats the Space Shuttle with Teflon to prevent the corrosive atomic oxygen from damaging the spacecraft.
The other device, USU's Plasma Frequency/DC Probe, counted free electrons. These electrons, torn from their atoms by the sun's rays, offer clues about the depth of the region. Free electrons make up the ionosphere.
Some data were transmitted during the flight. Other information will be extracted from the USU devices and studied in the coming weeks. Poker Flat Range crews recovered the rocket from the Alaskan tundra.
Swensen said this project could lead to determining how humans affect this part of the atmosphere. The data could create a baseline for monitoring future changes.
More accurate space weather predictions could eventually result from projects such as this. Activity in lower ionosphere impacts conditions in the higher area where satellites roam. Future experiments could help satellite owners protect their equipment from adverse conditions.