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Life on Mars?

1. The original igneous rock solidified within Mars about 4.5 billion years ago, about 100 million years after the formation of the planet. (Based on isotope ages of the igneous component of the meteorite)

2. Between 3.6 and 4 billion years ago the rock was fractured, presumably by meteorite impacts. Water then permeated the cracks, depositing carbonate minerals and allowing primitive bacteria to live in the fractures.

3. About 3.6 billion years ago, the bacteria and their by-products became fossilized in the fractures. (Based on isotope ages of the minerals in the fractures)

4. 16 million years ago, a large meteorite struck Mars, dislodging a large chunk of this rock and ejecting it into space. (Based on the cosmic ray exposure age of the meteorite)

5. 13,000 years ago, the meteorite landed in Antarctica.

6. The meteorite, ALH84001, was discovered in 1984 in the Allan Hills region of Antarctica.

The full article about life on Mars is available from NASA.

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Current and Previous Missions to Mars

• Mars Pathfinder -- NASA Mission to Mars (1996)
• Mars Global Surveyor -- NASA Mars Orbiter (1996)
• Mars Observer -- NASA Mission to Mars (1992)
• Phobos -- Soviet Mission to Mars (1988)
• Viking -- NASA Orbiters/Landers to Mars (1975)
• Mariner 9 -- NASA Mars orbiter (1971)
• Mariner 7 -- NASA Mars flyby (1969)
• Mariner 6 -- NASA Mars flyby (1969)
• Mariner 4 -- NASA Mars flyby (1964)

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As a December 2, 1996 CNN article says, "Sojourner is not much bigger than a toy radio-controlled car, but instead of spinning around a suburban driveway, it will -- if all goes well -- cruise the rocky surface of Mars." All did go well, and on July 5, 1997, Sojourner rolled down a ramp and into history, "becoming humanity's first autonomous vehicle to travel on the surface of another planet." (CNN July 6, 1997.) It didn't take long for the Rover to spring into action!

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Destination: Mars!

A decade of intensive Mars exploration has begun in 1996 as the United States successfully launched the Mars Global Surveyor in November and the Mars Pathfinder in December.

What are these two missions all about?

Mars Global Surveyor: The Mars Global Surveyor is the first of 10 NASA probes bound for Mars in the next decade and was designed to replace the NASA Mars Observer probe which disappeared mysteriously in 1993 just days before it was to reach the orbit of Mars. Surveyor will take 10 months to reach Mars and another six months to settle into a planetary mapping orbit. Later, it will descend into the Red Planet's thin atmosphere, using its wing-like solar panels as brakes. Surveyor will study the Martian surface and atmosphere, but will not land. (More information...)

Mars Pathfinder: The Mars Pathfinder spacecraft has successfully cruised directly to Mars, entered the atmosphere with a Viking-derived heat shield, and landed with the aid of parachutes, rockets and airbags! Its spectacular landing occurred on July 4, 1997, on a rocky plain in an area known today as Ares Vallis. Mars Pathfinder is the first spacecraft to return to the surface of Mars in almost 21 years and has begun an exciting era of exploration of the Martian surface! (More information...)

What other missions are planned?
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