Pathfinder

Credit: NASA

[My apologies for the break over the past three days. While I've never promised that Areology would be a "Mars Picture of the Day"-type blog, I've tried to keep that type of schedule since the beginning. Unfortunately, this past weekend was rather busy, and I hadn't had time to prepare posts in advance. This type of break may happen from time to time in the future, but I'm hoping that the occurrences will be few and far between. Now, back to our continuing series of missions to Mars.]

The third and final launch of the 1996 launch window (Mars Global Surveyor had been the first) was of the Mars Pathfinder mission. On December 4th, Pathfinder lifted off on a Delta II rocket, and arrived seven months later, on July 4, 1997, on Ares Vallis. Ares Vallis is a channel that flows out of Margaritifer Terra, through the Xanthe Terra highlands, and into a delta-like region of Chryse Planitia. Ares Vallis was chosen as the landing site because it is an ancient flood plain that was theorized to contain a wide variety of rocks deposited during a possible catastrophic flood. Upon the successful landing of Pathfinder's lander, the landing site was named "The Carl Sagan Memorial Station" in honor of the late astronomer; Sagan had died 16 days after the launch of Pathfinder. (Asteroid 2709 Sagan is also named after Carl Sagan.)

The mission of Pathfinder was primarily one of testing new and cheaper technologies. Pathfinder was the second in a series of mission in the Discovery Program that NASA sponsored to launch low-cost spacecraft frequently under the motto, "cheaper, faster and better," which itself was a reaction to the loss of Mars Observer. Among the new technologies tested on this mission were large airbags used to cushion the impact of landing of the lander (as opposed to the much heavier and more expensive rocket-landing system used on the two Viking missions), an automated obstacle avoidance system (currently being used by the two Mars Exploration Rovers, Spirit and Opportunity) and, of course, Pathfinder's tiny rover, Sojourner.

The above image is the first photo taken from the Pathfinder Lander.