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University of Iowa News Release

June 2, 2003

UI Search For Water On Mars Set For June 2 Launch

University of Iowa Professor and Space Physicist Don Gurnett is hoping to receive an uplifting word from western Asia on Monday.

That’s because Gurnett is part of a NASA-funded project to search for underground water on Mars, a project whose radar instrument is aboard the European Space Agency’s (ESA) Mars Express spacecraft using a Soyuz rocket and scheduled for launch at 12:45 p.m. CDT Monday, June 2 from Baikonur, Kazakhstan.

Called MARSIS (Mars Advanced Radar for Subsurface and Ionospheric Sounding), the joint Italian-U.S. project includes the University of Rome and the National Aeronautics and Space Administration’s (NASA) Jet Propulsion Laboratory and Co-Investigator Gurnett at the University of Iowa.

Gurnett and his UI colleagues Rich Huff, Don Kirchner and Jim Phillips developed the 130-foot-long antenna and related electrical instruments that the Mars-orbiting spacecraft will use to probe several miles beneath the planet’s surface, as well as study the ionosphere in the Martian skies. Rockwell Collins of Cedar Rapids designed the radio transmitter, which is coupled to the antennas. The entire MARSIS instrument weighs 12 kilograms, or about 26 pounds. The radar package is one of eight instruments aboard the craft, scheduled to arrive at Mars in late December.

Gurnett says that the project offers an excellent opportunity to learn what happened to the water that most scientists believe was responsible for shaping the planet’s deep canyons, some of which are longer and deeper than the Grand Canyon. Because the planet’s atmospheric pressure is extremely low, liquid water would have long ago evaporated from the surface. Results obtained by NASA's Mars Odyssey indicate that water exists just below the surface in the form of permafrost. Images from NASA's Mars Global Surveyor suggest that liquid water may periodically emerge from canyon and crater walls. Farther down, water may be liquid due to radioactive heating from the interior of the planet.

“Our objective is to use a low-frequency radar to penetrate the Martian surface to a depth of five kilometers -- about three miles,” he says. As the radar signal penetrates into the permafrost, scientists should be able to detect the interface and then map the locations of subsurface water across the planet. Other radar echoes should reveal boundaries between different kinds of geologic materials, such as layers of lava, sheets of sand, sediments, debris from impacts, and ice-rich rock and soils.

The other part of the project involves examining the Martian ionosphere, the electrically charged layer of the upper atmosphere that on Earth reflects radio signals back to the ground, sometimes hundreds of miles from their point of origin. Researchers will bounce radar signals off of the ionosphere and measure the time delay of the signals to learn the shape and height of the ionosphere.

Gurnett’s UI research team for many years has specialized in the construction of low-frequency, space-borne radio systems. Unlike the much-higher frequency radars normally used by airplanes and spacecraft to map surface features, the MARSIS low-frequency radar will penetrate deep beneath subsurface rocks and permafrost on Mars. The UI team has provided low-frequency radio antennas and receivers for numerous spacecraft, including Cassini, scheduled to arrive at Saturn in 2004.

Gurnett, a member of the National Academy of Sciences, is a veteran of more than 25 major spacecraft projects, including the Voyager 1 and Voyager 2 flights to the outer planets, the Galileo mission to Jupiter, and the Cassini mission to Saturn. He made the first observations of plasma waves and low-frequency radio emissions in the magnetospheres of Jupiter, Saturn, Uranus and Neptune and discovered lightning in the atmospheres of Jupiter and Neptune. Gurnett and his UI colleagues have over 120 years of spacecraft instrument design and construction experience between them.

STORY SOURCE: University of Iowa News Services, 300 Plaza Centre One, Suite 301, Iowa City, Iowa 52242-2500.

MEDIA CONTACTS: Gary Galluzzo, Writer, 319-384-0009, gary-galluzzo@uiowa.edu; Franco Bonacina, European Space Agency, 33-1-5369-7713