Mars Pathfinder

Thirteen participating scientists and a six-member team of experts dedicated to studying the atmosphere and weather on Mars will enhance the scope of scientific investigations as new members of NASA's Mars Pathfinder mission.

The scientists, selected from about 60 proposals submitted to NASA in response to an announcement of opportunity, will augment the existing science teams, direct new investigations not covered by the present teams, and perform interdisciplinary investigations using one or more instruments onboard the lander and rover.

"The purpose of the Participating Scientist Program is to allow the expansion of existing principal investigator teams as they enter the active period of mission operations, data collection, analysis and archival activities," said Dr. Matthew Golombek, Pathfinder project scientist at NASA's Jet Propulsion Laboratory. "These newcomers have a variety of interdisciplinary interests and areas of expertise that will augment our first direct studies of Mars in more than 20 years."

Mars Pathfinder, launched from Cape Canaveral, FL, on Dec. 4, 1996, is currently en route to the red planet and scheduled to land in an ancient flood basin called Ares Vallis on Independence Day. The lander carries a small rover that will roll off and explore its surroundings, and science instruments that will measure the composition of surface materials in a landing area that is hundreds of square meters in size. Direct measurements on the ground will establish what scientists call "ground truth," or validation of geologic features that will be studied from space by a companion orbiter, known as Mars Global Surveyor, and future orbiters.

Pathfinder's science instruments include a stereo imager called IMP, or Imager for Mars Pathfinder, mounted on an extendible mast on the lander, with 12 spectral filters for each "eye," an alpha proton X-ray spectrometer on the rover, and an atmospheric structure instrument and meteorology package. In addition, the rover carries forward stereo cameras and a rear color camera and performs a variety of technology and mobility experiments so that future rovers may be developed to more effectively navigate the surface.

Using these instruments, the newly selected investigators will carry out a variety of studies along with the existing imaging and spectrometry teams to understand more about the composition of the Martian surface, the structure of the Martian atmosphere and prevailing weather patterns on this planetary neighbor.

The science and technology investigations will be used to better understand:

- Mars surface morphology and geology at the scale of centimeters and meters, such as soils, rocks and hills, as well as their size and distributions on the surface.

- The composition and mineralogy of rocks, soil and surface materials using the spectral filters of the lander imager and the alpha proton X-ray spectrometer measurements.

- Basic soil mechanics and the magnetic properties of Martian dust. Soil mechanics such as cohesion, angles of internal friction and slippage will be determined by the rover. A series of magnets placed on the spacecraft will be imaged to determine the magnetic properties of dust that adheres to the wheels.

- The structure of the Martian atmosphere will be measured during entry and descent to understand variations in temperature, pressure and density with respect to altitude.

After landing, a meteorology package will tell scientists about the weather on Mars. Imaging wind socks will show the wind profile up to a meter above the surface. Imaging the atmosphere will determine aerosol characteristics, such as size and shape of airborne dust and water vapor abundance.

Tracking of lander telemetry signals will allow measurements of Pathfinder's location in space and the location of the pole of Mars. After a few months of tracking, scientists will be able to infer the interior structure of the planet and whether Mars possesses a metallic core.

In addition to the 13 new science members, six atmospheric scientists will become part of the Facility Instrument Science Team, which was selected to conduct instrument investigations to optimize operations and the science return from Pathfinder's Atmospheric Structure Instrument/Meteorology Package (ASI/MET) experiment. They will conduct the initial scientific analyses of data and produce calibrated, referenced data that can be used by the entire scientific community.

A complete list of selected scientists from all over the United States and Europe, including the names of their investigations and the scientists' home institutions, follows. Additional information about the Pathfinder mission is available on the World Wide Web at

The Jet Propulsion Laboratory manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C.

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