The U.S. Postal Service announced today it will issue a $3 Priority Mail stamp commemorating the historic Mars Pathfinder mission. The stamp will be officially dedicated in a ceremony at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif. on December 10.
"As one of the most significant achievements in the history of America�s space program, it is fitting that the Pathfinder Mission be honored on a U.S. postage stamp," said Postmaster General Marvin Runyon. "When this stamp lands in stamp collections or on Priority Mail pieces nationwide, it will be a reminder of the unmatched ingenuity that leads the world in space exploration."
Based on the first image received from the Mars Pathfinder after its landing on the Martian surface July 4, 1997, the stamp features the Sojourner rover resting on the Pathfinder with a panoramic view of the Ares Vallis region of Mars in the background. Informational text about the Pathfinder mission is printed on the reverse of the stamp sheet. Fifteen million of the stamps have been printed.
"That first historic image of Pathfinder and the rover sitting safely on Mars ignited worldwide interest in our efforts to explore Mars," said JPL Director Dr. Edward C. Stone. "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 hidden text -- Mars Pathfinder, July 4, 1997 and the letters USPS --is not visible to the naked eye but can be viewed by using a decoder lens, which is available through the Postal Service's Philatelic Fulfillment Center in Kansas City, MO. 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.
Scientific highlights of the Mars Pathfinder mission:
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.
Frequent "dust devils" were found with an unmistakable temperature, wind and pressure signature, and morning turbulence; at least one may have contained dust (on Sol 62), suggesting that these gusts are a mechanism for mixing dust into the atmosphere.
Evidence of wind abrasion of rocks and dune-shaped deposits was found, indicating the presence of sand.
Morning atmospheric obscurations are due to clouds, not ground fog; Viking could not distinguish between these two possibilities.
The weather was similar to the weather encountered by Viking 1; there were rapid pressure and temperature variations, downslope winds at night and light winds in general. Temperatures were about 10 degrees warmer than those measured by Viking 1.
Diversity of albedos, or variations in the brightness of the Martian surface, was similar to other observations, but there was no evidence for the types of crystalline hematite or pyroxene absorption features detected in other locations on Mars.
The atmospheric experiment package recorded a temperature profile different than expected from microwave measurements and Hubble observations.
Rock size distribution was consistent with a flood-related deposit.
The moment of inertia of Mars was refined to a corresponding core radius of between 1,300 kilometers and 2,000 kilometers (807 miles and 1,242 miles).
The possible identification of rounded pebbles and cobbles on the ground, and sockets and pebbles in some rocks, suggests conglomerates that formed in running water, during a warmer past in which liquid water was stable.
Engineering milestones of the mission included demonstrating a new way of delivering a spacecraft to the surface of Mars by way of direct entry into the Martian atmosphere. In addition, Mars Pathfinder demonstrated for the first time the ability of engineers to deliver a semi-autonomous roving vehicle capable of conducting science experiments to the surface of another planet.
The Mars Pathfinder mission is managed by the Jet Propulsion Laboratory for NASA's Office of Space Science, Washington, DC. The mission is the second in the Discovery program of fast track, low-cost spacecraft with highly focused science goals. JPL is managed by the California Institute of Technology, Pasadena, CA.