It was not until 1997 that NASA returned
to Mars.The Pathfinder mission proved to be one if it’s most successful.The
landing was made using a novel airbag system.The lander used a traditional heat shield to slow itself
in Mars atmosphere.It then deployed a parachute to reduce velocity even further.It
then release the heat shield and fired rockets to further reduce speed, the parachute tether was then cut and the lander airbags
inflated.It dropped onto the Martian surface and bounced.In one third Earth’s
gravity it bounced high and a lot.It struck the surface at 31 miles per hour (14 meters/second)
and bounced about 15 times, sometimes as high as 50 feet.After about a kilometer it came to a rest on
the Ares Vallis flood plain.This plain was chosen because if is
relatively flat and strewn with a large variety of rocks and boulders.It is believed to have been formed
by a catastrophic flood event.It is thought that the volume of water that created this plain was size
of the Great Lakes and took about two weeks.
Image from Pathfinder of the Ares Vallis boulder field and
Twin Peaks in the distance. Credit:http://mars.jpl.nasa.gov/MPF/parker/TwnPks_RkGdn_left_sm.jpg
The lander was composed of four petals looking like a small pyramid,
that that way it could be righted to the “base” side no matter what orientation in came to rest.When
the bags were deflated it was on it’s base side.The base being the side that when the petals opened
the Sojourner rover we ready to roll off and the cameras and other sensors where right side up compared with the surface.The rover legs were extended and the little machine slowly rolled off the lander and on to the Martian surface where it took soil composition readings, and over the course of the next few months
from July 4th to September 27th it rolled from one rock to the next using it’s X-Ray
Pathfinder Rover Sorjourner om Mars, summer of ’97NASA/JPL http://mars.jpl.nasa.gov/MPF/ops/rover_color_sol22_S0055.gif
Spectrometer to take readings of their composition
and give geologist some hard data to review.The Sojourner also carried two finger sized color and black
and white cameras in front, a color camera on the back and a laser system to help it avoid obstacles.All
commands for the rovers movement came from Earth via the Lander communication system.
Soujourner taking a reading from “Yogi”NASA/JPLhttp://mars.jpl.nasa.gov/MPF/ops/yogi-pres-col-2.jpg
