Mars [ http://www.challeng…], the freeze-dried planet [ http://nssdc.gsfc.n…], orbits 137 million miles from the Sun or at about 1.5 times the Earth-Sun distance [ http://antwrp.gsfc.…]. It has two diminutive moons [ http://antwrp.gsfc.…], towering extinct volcanos [ http://antwrp.gsfc.…], an immense canyon system [ http://antwrp.gsfc.…], a thin atmosphere chiefly composed of carbon dioxide (CO2), a frigid average surface temperature of -63 degrees Celsius [ http://www.unidata.…], and permanent frozen CO2 polar caps which contain some water ice. Mars' surface presently lacks liquid water [ http://antwrp.gsfc.…] and has a reddish color because of an abundance of oxidized iron compounds (rust). A small terrestrial planet [ http://www.seds.org…], fourth from the Sun [ http://antwrp.gsfc.…], Mars has only about 3/8 the surface gravity of Earth. So for example, if you tip the scale at a hefty 200 pounds on Earth you'd be a 75 pound featherweight on Mars [ http://quest.arc.na…]. The low martian gravity will be good for NASA's Mars Pathfinder [ http://mpfwww.jpl.n…] spacecraft scheduled to land on Mars [ http://bang.lanl.go…] next Friday, July 4th [ http://www.lpl.ariz…]. Using rockets, parachutes, and airbags [ http://mars.sgi.com…], Mars Pathfinder [ http://mpfwww.arc.n…] will be the first spacecraft to touchdown on the planet since the Viking landers [ http://antwrp.gsfc.…] in 1976. Pathfinder is also scheduled to begin the first ever mobile surface exploration [ http://cmex-www.arc…] by releasing the robot rover [ http://ranier.hq.na…], "Mars Sojourner" [ http://mars.sgi.com…].
