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Date: 2015-10-07; view: 550.

It would certainly be interesting to visit Mars. Although it is smaller than Earth it is surprisingly earthlike and that holds clues about the evolution of humanity's mother planet. Its day, for example, is only half an hour longer than Earth's and unlike other extraterrestrial planets it has annual seasons. A Martian year lasts about twice as long as a terrestrial one.

Space flight is a risky venture. A complex piece of apparatus cannot easily be repaired when it is millions of miles from home. Some missions to the planet have gone kaput since the space age began. Each of these craft either did not get to Mars at all or broke off communication before it could sent back anything useful. They may have fallen victim not to broken equipment but to what scientists jokingly refer to as "Great Galactic Ghoul" that seems to protect the planet from nosy people.

Although Russians and Americans have concentrated on manned space flight, many of the most important discoveries have resulted from unmanned probes of the solar system. Most of what is known about Mars first came from the spacecraft that were launched in the direction of Mars about two decades ago. The spacecraft passed close by the Red Planet and two capsules were landed on Mars. The craft was able to map the entire surface of the planet and show that it is covered with craters. More than 50,000 photographs were taken.

The first spacecraft which visited the planet showed that there were no signs of any civilisation and enthusiasm began to wane.

Public interest in the planet Mars was rekindled when it was announced that the study of the meteorite from Mars that had been found in Antarctica suggested that Mars supported life. And even though a group of scientists have since doubted the data, the possibilities that Mars is inhabited, albeit by early bacteria, looked realistic.

A new wave of spacecraft has recently set off to explore the Red Planet almost at the same time — NASA's Mars Global Surveyor, a Russian craft with instruments from Finland, France, Germany and other countries and the second NASA probe called "Mars Pathfinder." This trio actually formed the vanguard of a possible decade-long flotilla of Mars-bound ships.

The mission exceeded the expectation.

It returned 2.3 billion bits of new data from Mars and explored more than 200 square metres of the surface. It also obtained 16 measurements of rocks and soil chemistry and successfully completed the numerous technology operations. It really captured the imagination of the public.

One of the most important goals of the mission was to look for evidence of a formerly warm, wet Mars. "The Mars Pathfinder" showed that large portions of the planet were once covered with water. There may even have been a Martian "ocean." The mosaic of the landscape revealed a rocky plain, that most probably had been deposited and shaped by catastrophic floods. The obtained images show semirounded pebbles, cobbles, and boulders similar to those deposited by terrestrial catastrophic floods. Despite some signs of slow erosion by the wind the rocks have changed little since they were deposited by the flood. One of the most striking features picked several decades ago was a set of channels. They were not the channels that people's imagination had cut into the planet's surface. But they did look that they might have been cut by running water. This time it was possible to tell that the channels actually ran downhill into the "ocean" and that they were not man-made.

The mission also fulfilled one of the main tasks: it filled in the blanks on the map of Mars.

"The Pathfinder" sought rocks which could be clues to the early climate of Mars and clues to which conditions were once conducive to the development of life. Soil samples were collected. The dog-sized Mars rover, a six wheeled cart, walked slowly from rock to rock at the speed of one centimetre a second. It analysed the chemical composition of the rock. It does so when it is bombarding the rock in question with alpha particles. Chemical elements have "finger prints" of their own and when they are hit with such particles they respond in a different and characteristic way. The confirmation of the presence of these minerals increased scientists' understanding of the role that water played in the planet.

Some information about the interior was also obtained. Large meteorite impacts had previously escavat-ed something that looked like mud and scattered it across the planet surface. This time two dart-like "penetrators" dropped on the planet from a great height and burrowed themselves up to six metres deep into the Martian soil. Their findings will help geologists understand how Mars evolved over time.

Analysis of overall results suggests that Mars was once more Earth-like than previously appreciated.

Information from other missions will help answer the crucial question about our neighbouring world. Are we alone in the Universe? Carl Sagan, an outstanding scientist, estimated that there may be as many as one million advanced civilizations in this galaxy alone. When the rovers were sending the first images of the surface of Mars, everyone was glued to the television screens. Nowadays the mysteries of the Universe are being brought right to your living room.