NASA seeks OSU expertise

Stories by Pam Frost Gorder, Research Communications

Grant funds advanced sensor for global climate change

A grant from the National Aeronautics and Space Administration (NASA) will help Ohio State engineers design, build and test a prototype advanced sensor for studying the Earth's climate.

Through its Instrument Incubator Program (IIP), NASA awarded $921,000 to Joel T. Johnson, associate professor of electrical engineering, and Steven W. Ellingson, research scientist at Ohio State's ElectroScience Laboratory, for the three-year project.

While Johnson's research focuses on orbiting instruments that detect conditions down on Earth, his co-principal investigator brings a different kind of skill set to the project. Ellingson develops innovative techniques for ground-based radio astronomy antennas to receive signals from outer space.

"Our work may sound very different, but the issues involved for this sensor are very similar," Johnson said. "I'm just looking down at the Earth while Steve's looking up at the sky."

With fellow ElectroScience Lab researcher Grant Hampson, Johnson, Ellingson and their students will construct a sensor called a microwave radiometer, which is capable of precisely measuring sea surface salinity -- the amount of salt in the water. Changes in salinity reveal subtle circulation patterns in the ocean that play an important role in global climate.

The novel sensor will gather this information by measuring the small amounts of microwave radiation naturally emitted by the ocean.

Satellites with optical sensors can't detect sea properties at night, or through clouds, but microwave sensors can. A satellite equipped with the Ohio State radiometer would be capable of 24-hour observation over all the world's oceans.

The Ohio State researchers' main challenge will involve finding a way to eliminate signal interference from cell phones, air traffic control radar, and the myriad other sources of radio "noise" on Earth. The radiometer to be developed will include a special processing component to remove unwanted interference.

NASA's IIP program funds the development of technologies which could lead to future flight instruments that are smaller, less resource intensive and less costly, and which require less time to build.

This latest round of funding focused on earth science remote-sensing instruments. NASA selected 11 projects from around the country, for a total commitment of $29.6 million over three years.

Astronomer joins advisory panel

To gauge whether women are staking a greater claim in the scientific community these days, consider that Kris Sellgren came to join a prestigious NASA advisory committee through the "young girls' network" -- instead of the old boys' network.

Or so she joked recently.

True, NASA considered the professor of astronomy for its prestigious Space Science Advisory Committee (SScAC) at the suggestion of one of her longtime female colleagues at the agency. But the fact that she has previously served on 11 such advisory committees for various national organizations -- including four for NASA -- may have had something to do with her being selected.

In her latest appointment, Sellgren will help NASA decide on priorities and plans for space science projects ranging from the Stratospheric Observatory for Infrared Astronomy -- soon to be the world's largest airborne telescope -- to the Mars Exploration Program. Her colleagues will include astronomers and engineers from universities and observatories around the country, including Caltech, the University of Michigan, Massachusetts Institute of Technology, the Carnegie Observatories and NASA's Jet Propulsion Laboratory.

"The members come from so many different areas -- solar astronomy, planetary science, satellite engineering," she said. "I'll be there to represent the interests of infrared astronomy."

In Sellgren's specialty, astronomers take pictures of stars and galaxies with infrared, or heat, energy, the same way a normal camera takes a picture with visible light. Even when cosmic dust blocks the view of a distant object from Earth, astronomers can see it if they look in the infrared. The same technology can reveal newly forming stars draped in gas and dust, or capture an image of debris spiraling into a black hole.

"There are a few exciting infrared missions under development at NASA," Sellgren said, "and I'll be pushing for them."

Among those projects are the Space Infrared Telescope Facility, a 0.9-meter infrared telescope set for launch in July 2002 that will study objects ranging from our solar system to the distant reaches of the universe; and the Next Generation Space Telescope, a 6-meter infrared telescope which will replace the 2.4-meter Hubble Space Telescope in 2009.

During her three-year tenure on the committee, Sellgren will travel to meetings at NASA centers around the country to hear status reports from scientists for planetary science, astronomy, solar and other space science missions.

The job is a switch from a decade ago, when, as a scientist at NASA's Infrared Telescope Facility, Sellgren would have been the one giving the status report.

"I know what it's like to be the person who has to give the presentation, and it can be really nerve racking. It's definitely different to be on the other side of the table," she laughed.

Though Sellgren has yet to attend her first meeting, she knows the procedure. After hearing the presentations at a meeting, the committee members return home and exchange a flurry of e-mails. Is the pace of a project too slow, they may ask, or is it too fast, so that the schedule should expand to make sure all equipment is better tested before launch? Then, much like a supreme court rendering a decision, the committee writes an official report, which it sends to the NASA administrator through the NASA Advisory Council.

Her first meeting is scheduled for December in Cocoa Beach, Fla., the launch site for NASA's Space Shuttle missions.

next page...