Artist's rending of MGS in orbit around Mars.
Robot Explorers: US Unmanned Space Missions: page 20 |
| The US returned to study Mars for the first time in twenty years in November of 1996 with the launch of the Mars Global Surveyor (MGS) spacecraft. The Surveyor's mission has been to return data regarding Mars' surface features, atmosphere, and magnetic properties. Scientists have been using the data gathered from this mission both to learn about the Earth by comparing it to Mars, and to gain valuable information to aid in planning future missions. Although Mars and Earth shared similar conditions billions of years ago, they appear much different today. Comparing Mars with the Earth gives scientists insight into Earth's history and possibly its future. |
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The main instrument used by MGS is the Mars Orbiter Camera (MOC). The
camera has produced daily wide-angle images of Mars similar to weather photographs of the
Earth shown on the nightly news. In addition, the narrow-angle lens has been capturing
images of objects as small as 5 feet across. The image at left is a composite of MOC daily global images, acquired in early May 2002. This image shows what Mars looked like in its early northern spring. The retreating north polar seasonal carbon dioxide frost cap is seen at the top of this view. Other white features in the image are clouds of water ice crystals in the Martian atmosphere. The left half of this picture shows the Tharsis region, which includes several very large volcanoes. Olympus Mons, the largest Martian volcano, is as wide as the Hawaiian Island chain is long; it is the dark, somewhat circular feature at the far left. Toward the lower right, the system of deep Valles Marineris chasms can be seen. |
Another key instrument on board MGS is the Mars Orbiter Laser Altimeter (MOLA). The laser altimeter works by bouncing beams of light off of the surface of the planet to measure the heights of mountains and depths of valleys. The topographical map at right assembled from MOLA data is the most accurate altitude map ever made of the whole surface of Mars. |
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The MOC on MGS was used to image a portion of the surface of Mars, known as the "face" on Mars. In 1976 the Viking orbiter acquired an image that showed one of the thousands of buttes, mesas, ridges and knobs in the zone between the cratered uplands and low plains that looked remarkably like a human face. For decades this feature has been popularized in books, tabloids, talk shows and even a major motion picture as a "sign" left by "aliens". Given the popularity of this landform, the area was imaged with the high-resolution MOC several times. The latest image taken in 2001 was taken from a distance of about 300 miles, and combined with earlier images created the image shown here. Although this landform, which measures about 2 miles in length, has been determined to be a natural landform rather than an "alien artifact" by legitimate scientists, many (particularly those who are trying to sell you their pseudo-science books and materials!) still choose to believe in the alien nature of the "face on Mars". |
Copyright ©2004 Colleen Gino |
Images and content courtesy JPL and NASA. |
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