Buckeye engineers contribute to NASA’s groundbreaking soil moisture mapping satellite

On January 31, NASA successfully launched its first Earth satellite designed to monitor soil moisture globally. Known as the Soil Moisture Active Passive (SMAP) satellite, Ohio State engineers participated in the research that made it possible.

Joel Johnson, chair and professor of electrical and computer engineering, said approximately six different Ohio State projects have contributed to SMAP research over the years. 

During its three-year mission, SMAP will orbit the Earth, measuring the moisture in the top two inches of soil to produce the highest-resolution, most accurate soil moisture maps ever obtained from space. The data will be used to enhance scientists' understanding of the processes that link Earth's water, energy and carbon cycles.

According to NASA, the mission will help improve climate and weather forecasts, allow scientists to monitor droughts and better predict flooding, and help forecast crop yields and assist in global famine early-warning systems.

SMAP uses both a radar and microwave radiometer to monitor the Earth, Johnson said. The radiometer measurements are susceptible to corruption by man-made radio-frequency interference (RFI) from other transmitters.

Since 2001, Johnson's team has focused on separating RFI from the natural microwave signals used in measuring soil moisture levels. Over time, he said, NASA determined this could be applicable to the SMAP project and RFI detection technologies were added to the satellite design in 2009.

"It is a three-year mission, but often Earth science satellites last much longer," he said. We will be working to help improve RFI removal throughout." 

During the post-launch press conference, NASA thanked those university students from around the country who participated in the SMAP research. Several graduate students and one researcher from the College of Engineering’s ElectroScience Laboratory are among those involved in the project, including Jeff Ouellette, Mustafa Aksoy and post-doctoral researcher Alexandra Bringer.

Ouellette has worked on the project for the past five years and was a NASA Earth and Space Science Fellow for three of those years. His work focuses on the empirical analysis and refinement of radar algorithms to provide more accurate soil moisture predictions. 

“SMAP is one of the most exciting projects in the remote sensing field,” Aksoy said. “It’s very exciting to see it is finally in orbit.”