
NASA has selected an ancient flood plain on Mars as the landing site for the 1996 mission of Mars Pathfinder, one of the first in a new generation of small, low-cost spacecraft. Eons ago, when water flowed on Mars, great floods inundated the landing site, located on a rocky plain in an area known today as Ares Vallis. The site is 850 kilometers (527 miles) southeast of the location of Viking Lander 1, which in 1976 became the first spacecraft to land on Mars. Pathfinder will be the first to land on Mars since the twin Viking landers arrived almost 20 years ago. The spacecraft, scheduled to arrive at Mars on July 4, 1997, will parachute down to Ares Vallis at the mouth of an ancient outflow channel chosen for the variety of rock and soil samples it may present. The target landing site, at the center of the landing ellipse, is 19.5 N, 32.8 W.
From the indomitable LPI:
The Mars Pathfinder spacecraft landed near the center of this ellipse, as planned, on July 4, 1997. The ellipse is the original target area, 300 kilometers long and 200 kilometers wide. Mars Pathfinder landed only 50 kilometers from the ellipse center. This landing site is outside the mouth of the huge water-cut channel of Ares Vallis (19.33°N, 33.55°W) that empties into the lowlands of Chryse Planitia near the Viking 1 lander site. At its landing site, Pathfinder and its rover were able to see and analyze rocks that were washed down Ares Vallis during its floods. These rocks could come from the ancient southern highlands and from plains that are huge basalt lava flows.
This landing site was chosen in April 1994, when 60 scientists gathered at the Lunar and Planetary Institute in Houston. Their goal was to find sites where Mars Pathfinder could land and survive (flat surface, low elevation, latitude between 5° and 20°N), and return important information. Each scientist had a favorite site, and the Pathfinder program managers considered them all. Ares Vallis was chosen because it seemed relatively safe (flat and low), was known fairly well (the Viking spacecraft had taken detailed images of the area), and probably would provide important rock samples for Pathfinder to view and analyze.
Also:
nssdc.gsfc.nasa.gov/planetary/image/marspsite.gif
www.lpi.usra.edu/publications/slidesets/marslife/slide_36...