At such depressed altitudes the atmospheric pressure is greatest, and temperature highest, perhaps resulting in ice melting for a while when Mars is closest to the sun. In contrast, NASA's Pathfinder lander, which also arrived in 1997 carrying the little rover Sojourner, was followed by millions of people over the Internet. The last pair of Mars missions sent by NASA were anything but successful. One group had used imperial units, the other metric. Three months later the Polar Lander probe was also a failure, contact being lost as it approached touchdown close to the south pole of Mars.
Critics argue that the history of Martian exploration has been littered with such failures.
During the 1960s and '70s a dozen Soviet satellites were either lost, or returned limited data. In 1988 radio contact with two further missions was lost during their cruise towards Mars. Another Russian satellite, including experiments contributed by various European nations, suffered a launch malfunction in 1996. Japan launched its Nozomi probe to Mars in 1998, but a propulsion problem has delayed its arrival until late in 2003. The Americans may have suffered similar setbacks, but their successes have altered views of the Red Planet.