USU Embarks on NASA Cloud Study April 25

Cirrus clouds, stratus clouds, cumulus clouds – since ancient times, people have gazed skyward and pondered fluffy wisps of white and angry gray thunderheads.

Utah State University physics professor Mike Taylor looks beyond the Earth’s visual atmosphere to the mesosphere, where the highest clouds, called noctilucent or “night-shining” clouds – invisible during daylight – form at the edge of space.

“The mesosphere is the coldest region in our solar system up to the orbit of Saturn,” Taylor says. “Very little is known about the icy clouds that develop in this region.”

Taylor is a member of NASA’s science team for the Aeronomy of Ice in the Mesosphere or “AIM” mission, which launches a spacecraft into orbit April 25. USU’s Space Dynamics Laboratory designed and built one of the instruments that will fly on the spacecraft and collect information about how and why noctilucent clouds, also called polar mesospheric clouds or “PMCs,” form.

PMCs occur some 50 miles above the Earth’s surface and are only visible at twilight, as the sun sinks below the horizon and illuminates the elusive formations. Historically seen only at higher latitudes, Taylor spotted the clouds from his east bench Logan home back in the summer of 1999.

“I was sitting on the deck with my brother-in-law when I saw them and jumped up to grab a camera,” says Taylor. “We ended up running about the neighborhood photographing the clouds with both still and video cameras.”

Taylor’s chance glimpse remains the lowest documented sighting of PMCs from the continental United States. But the frosty clouds are being seen more frequently at lower latitudes – farther from their polar homes – and they seem to be growing brighter and more numerous. Could they be yet another harbinger of global climate change?

“We can’t say for sure. We don’t have enough information,” says Taylor. “That’s one of the things AIM will help us study – we’ll be examining links between lower and upper atmospheric phenomena.”

SDL’s SOFIE, or Solar Occultation for Ice Experiment, instrument will measure a variety of atmospheric components, including temperature and water vapor, to probe the chemistry involved in forming the clouds, says Taylor.

“We still don’t know what makes up the clouds,” says Taylor. “We know the ingredients, but we don’t yet have the recipe.”

He looks forward to traveling to Alaska this summer with a team of USU undergrad researchers to set up field data collection stations at two sites about 30 miles apart. “With the AIM spacecraft in orbit, we’ll be able to collect data from both above and below the mesosphere,” says Taylor. “This will be a golden opportunity to learn more about these mysterious clouds.”

The AIM mission is a poignant venture for Utah State. NASA granted SDL permission to include an engraving on the SOFIE instrument in memory of engineer Brandon Paulsen. A USU graduate who began working at SDL while still a student, Paulsen, 32, was involved in the design of SOFIE prior to his death from cancer in 2005.

Principal investigator for the AIM mission is James Russell III of Virginia’s Hampton University. Principal investigator for the SOFIE instrument and a co-investigator for the AIM mission is Larry Gordley, president and CEO of Virginia-based aerospace company, GATS, Inc.

Other instruments aboard the spacecraft include the Cloud Imaging and Particle Size Experiment and the Cosmic Dust Experiment built by the Laboratory for Atmospheric and Space Physics at the University of Colorado-Boulder.

The AIM spacecraft is scheduled for launch Wednesday from California’s Vandenberg Air Force Base. The spacecraft will be propelled into space aboard a Pegasus XL rocket launched over the Pacific Ocean from a modified Lockheed L-1011 TriStar aircraft. AIM will follow a polar orbit some 300 miles above Earth during its two-year mission.

Related links: