It is an honor for this mission to be recognized by issuance of this special U.S. postage stamp. The Mars Pathfinder stamp is the third U.S. stamp subject to incorporate hidden images to prevent counterfeiting, while adding an interesting design element. The U.S. Air Force and Classic Movie Monsters stamps issued earlier this year also feature hidden images. Since its Independence Day landing, Pathfinder has returned 2.6 billion bits of information, including more than 16,500 images, as well as chemical analyses of rocks and extensive data on winds and other weather factors. After operating on the surface of Mars three times longer than expected, the mission began winding down last week as daily communications with the lander and rover were officially halted.
Martian dust includes magnetic, composite particles, with a mean size of one micron.
Rock chemistry at the landing site may be different from Martian meteorites found on Earth, and could be of basaltic andesite composition. The soil chemistry of Ares Vallis appears to be similar to that of the Viking 1 and 2 landing sites. The observed atmospheric clarity is higher than was expected from Earth-based microwave measurements and Hubble Space Telescope observations. Dust is confirmed as the dominant absorber of solar radiation in Mars' atmosphere, which has important consequences for the transport of energy in the atmosphere and its circulation. Evidence of wind abrasion of rocks and dune-shaped deposits was found, indicating the presence of sand.