CONTACT: GARY GALLUZZO
100 Old Public Library
Iowa City IA 52242
(319) 384-0009; fax (319) 384-0024
Release: Sept. 7, 1999
UI team wins $4 million NASA contract to search for
water on Mars
IOWA CITY, Iowa -- University of Iowa professor and
space physicist Don Gurnett has won a $4 million NASA contract in collaboration
with the Jet Propulsion Laboratory (JPL) in Pasadena, Calif. to develop and
use radar in a search for underground water on Mars.
The UI investigation is part of an international project
aboard the European Space Agency's (ESA) Mars Express spacecraft scheduled
for launch in 2003. Formally known as Mars Advanced Radar for Subsurface and
Ionospheric Sounding (MARSIS), the joint Italian-U.S. project includes the
University of Rome and NASA's Jet Propulsion Laboratory and Co-Investigator
Gurnett at the University of Iowa. Under the terms of a contract with JPL,
Gurnett and his UI colleagues Rich Huff, Don Kirchner and Jim Phillips will
provide the 160-foot-long antennas and related electrical instruments that
the Mars-orbiting spacecraft will use to probe beneath the planet's surface,
as well as study the ionosphere in the Martian skies. Also, Rockwell Collins
of Cedar Rapids will collaborate with the UI in designing the radio transmitter
and coupling it to the antennas.
Gurnett says that the project offers an excellent
opportunity to learn what happened to the water that most scientists believe
was responsible for carving the planet's spectacular 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. However, water may exist just below the surface in the form of
permafrost and, farther down, as a 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, we should
be able to detect a strong radar reflection from the ice-water interface.
The hope is that we'll be able to detect the interface and tell how much water
Jeffrey Plaut, planetary geologist at JPL and co-principal
investigator of MARSIS, noted, "Much of the water may lie too deep for us
to detect, but the radar will be capable of showing boundaries between many
kinds of geologic materials, such as layers of lava, sheets of sand, sediments,
debris from impacts, and ice-rich rock and soils. Seeing into the third dimension
of the crust of Mars is what makes this a unique and exciting experiment."
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.
"Currently, very little is known about the ionosphere
of Mars. We'll 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 says. "The result should be a major increase in our knowledge of the
ionosphere around Mars."
The UI team is an excellent choice for this multidisciplinary
project because, as Gurnett points out, even though radar is not his usual
area of expertise, his 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 low-frequency radar provided by the UI team will penetrate deep
beneath subsurface rocks and permafrost on Mars. Gurnett's team has provided
low-frequency radio antennas for numerous spacecraft, including Cassini, scheduled
to arrive at Saturn in 2004.
Gurnett, who was recently elected to the prestigious
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,
engineering group manager Rich Huff, principal engineer Don Kirchner and design
engineer Jim Phillips, have 111 years of spacecraft instrument design and
construction between them.