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1996 NASA missions to Mars.

(Above) The Mars surface rover called "Sojourner (Below) The dry surface of Mars
Mars surface
In 1996 NASA launched two missions to Mars. First: The Mars Global Surveyor spacecraft took off in November 1996 to arrive in August 1997 and begin an orbital mission to provide detailed mapping of the Martian surface and weather information.

Then: in December, 1996 the Mars Pathfinder spacecraft carrying the Rover "Sojourner" (see left) was launched. It landed on the planet on July 4, 1997.
With the Pathfinder safely on the surface of Mars, the Sojourner was deployed and was directed from Earth to move across the Martian surface and return new science data.
Researchers believe that Mars may hold the key to answering questions about the history of the Earth.
The Pathfinder landing site on Mars was named the "Sagan Memorial Station" in honor of the scientist Carl Sagan.

About Mars Pathfinder
As part of NASA's Discovery Program, on December 2, 1996, a Delta II rocket launched the spacecraft "Mars Pathfinder" on a seven month journey to the Red Planet.
On July 4, 1997, it landed on the surface of Mars where it deployed Sojourner, a six-wheeled rover. This was the first in a planned series of inexpensive missions to other planets in Earth's solar system. This mission was unique in that the spacecraft landed on Mars without first entering into an orbit around the planet and the craft carried the first radio-controlled robot capable of moving across the the Martian surface to collect data.
When Pathfinder reached Mars, heat shields provided the protection the spacecraft needed as it entered the atmosphere at 17,000 miles per hour. The craft was aided by large parachutes, solid rocket motors, and airbags while making its way safely to the surface of Mars. The airbags, made of a material stronger than Kevlar with a tensile strength of 450 pounds per inch were 17 feet in diameter but took only two seconds to inflate. They enveloped Pathfinder - serving as a cushion.
The Pathfinder collided with Mars at a 30 degree angle, at about 65 miles per hour. When it hit the surface it bounced as high as 40 feet.
Once on the surface, and after righting itself, the Pathfinder deployed its three solar panels to provide power. It transfered data back to Earth from the camera which provided a view of the surrounding terrain.

About the rover called "Sojourner"

The micro-rover is a 6-wheeled, radio-controlled, small, robotic vehicle about 24 inches by 18 inches by 12 inches in size. It can move across obstacles up to 13cm in size. Each wheel is independently actuated and geared (2000:1) providing superior climbing capability in soft sand. The front and rear wheels are independently steerable, providing the capability for the vehicle to turn in place. The vehicle has a top speed of 0.4m/min.
The rover is powered by a solar panel backed up by 9 LiSOCL2 D-cell sized primary batteries, providing up to150W-hr. This combined panel/batteries system allows the rover power users to draw up to 30W of peak power while in direct sunlight (mid-sol) while the peak panel production is 16W. The normal driving power requirement for the rover is 10W.
The Mars Pathfinder project is managed for NASA by the Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California.

Chemical Components of the Mars Atmosphere

Element Symbol Percentage
Carbon Dioxide CO2 95.32
Nitrogen N2 2.7
Argon Ar 1.6
Oxygen O2 0.13
Carbon Monoxide CO 0.07
Water H2O 0.03
Neon Ne 0.00025
Krypton Kr 0.00003
Xenon Xe 0.000008
Ozone O3 0.000003

Past Successful Missions to Mars

(See also 1960-1996 listing of successful and unsuccessful Mars missions)
Spacecraft Name
Spacecraft Type
Nov. 28, 1964 - Dec. 20, 1967
Mariner 4
Reached Mars on July 14, 1965 and came within 9,920 km of the surface. Returned 22 surface photos and compiled data on the atmosphere.
Feb. 24, 1969
Mariner 6
Reached Mars July 31, 1969 and came within 3,437 km of the equatorial region. Returned numerous pictures and measurements.
Mar. 27, 1969
Mariner 7
Reached Mars Aug. 5, 1969 and came within 3,351 km of the South Pole region. Took over 200 photos. Analysis revealed no ozone in the atmosphere.
May 10, 1971
Kosmos 419
A lander was released from its orbiter but it crashed into the Martian surface. The orbiter returned data until 1972.
May 19, 1971
Mars 2
Orbiter/Soft Lander
A lander was released from its orbiter but it crashed into the Martian surface. The orbiter was still able to return data until 1972.
May 28, 1971
Mars 3
Orbiter/Soft Lander
Reached Mars December 2, 1971 and performed the first successful landing of a terrestrial craft on Mars which sent 20 seconds of video data to the orbiter then failed. Discovered the amount of uranium and thorium in the soil was similar to the amount found on Earth. The orbiter returned data until August 1972.
May 30, 1971-2
Mariner 9
Reached Mars Nov. 3, 1971 and went into orbit Nov. 24 for about one year. This was the first US spacecraft to orbit any planet other than the Moon. Took more than 7000 photos, covering 9O% of the surface. Captured images of four giant volcanoes.
July 21, 1973
Mars 4
Reached Mars Feb. 1974 but was unable to orbit. Returned some data and images.
July 25, 1973
Mars 5
Entered orbit Feb. 12, 1974 and quit unexpectedly after two weeks. However, it did return some useful data for future missions.
Aug. 5, 1973
Mars 6
Orbiter/Soft Lander
Achieved orbit around Mars on Mar. 12, 1974. A lander was launched and returned data on its way to the surface but crashed while trying to land.
Aug. 20, 1975 - Aug. 7, 1980
Viking 1
Entered into orbit about Mars on June 19, 1976. A lander reached the surface July 20, 1976 and provided images of the terrain, monitored the surface and searched for micro-organisms. The Lander continued to collect and send data from Mars for more than six years. During this time the orbiter continued to map the surface of Mars.
Sept. 9, 1975 - July 25, 1978
Viking 2
Entered into orbit about Mars on July 24, 1976. A lander reached the surface Aug. 7, 1976 and provided images of the terrain, monitored the weather and searched for micro-organisms. The orbiter continued to map the surface. Scientists are still processing Viking data in the 1990s.

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