Science Scoops: Spacecraft Snaps Record Image
by Stephen James O'Meara
On November 5, 2001, nearly five years to the day after it was launched, NASA's Mars Global Surveyor spacecraft took its 100,000th picture of Mars. No other spacecraft has taken as many pictures of the Red Planet. NASA's twin Viking orbiters have come the closest, returning a total of about 55,000 images of the planet between 1975 and 1980.
And just what was the 100,000th snapshot? The new digital image shows a 1.5-kilometer-wide portion of a valley north of Olympus Mons, the largest known volcano in the solar system. The valley floor is covered by windblown dunes, a common sight on Mars. Its slopes show dark streaks where debris has slid downward. The image is fairly hazy, due to the effects of a global dust storm that engulfed the entire planet between July and October.
So far, about two-thirds of the images returned from Mars Global Surveyor have been examined, cataloged, and archived on the Internet. The images can be viewed freely on the Web site of Malin Space Science Systems, the San Diego company that operates the camera on behalf of NASA.
- What do you think pictures of Mercury's and Venus's surfaces would show? Write a description of what the surface of each planet might look like. Draw pictures to go along with your descriptions of Mercury's and Venus's surfaces.
[anno: Answers will vary but could include the following features. The surface of Mercury would be clearly visible because Mercury has no atmosphere. Its rocky surface has many craters that make it look similar to the surface of Earth's Moon. The surface of Venus would be more difficult to see because a thick layer of clouds, made up mostly of sulfuric acid, covers it. The surface of Venus has a few craters and may shows signs of weathering and erosion caused by the sulfuric acid in its atmosphere.]