In the solar system, Mars in particular, is considered as the most Earth-like of all planets, as it shows polar caps, and atmosphere with meteorological activity over a stony surface, a comparable rotation period (length of day), seasonal variations and a temperature not too different from that of Earth, compared to every other planet of our solar system. William Herschel made the first Map of Mars and found that ’its inhabitants’ would probably enjoy conditions similar to that on Earth in many respects. These opinions existed well until the first spacecraft Mariner4,reached at Mars and transmitted its famous photographs, showing a moonlike cratered terrain without any signs of considerable vegetation and measured atmosphere and temperatures much less comfortable for most creatures on Earth, although some experiments indicated that some primitive forms on Earth in many respects.

These opinions existed well until the first spacecraft Mariner 4, reached photographs, showing a moonlike cratered terrain without any signs of considerable vegetation and measured atmosphere and temperatures much less comfortable for creatures on Earth, although some experiments indicated that some primitive forms of Earth life could perhaps survive Martian conditions at least for sometime. After Mariner 4, Mariner 6 and Mariner 7 flew by Mars and determined that its atmosphere was mainly made up of carbon dioxide .Then Mars looked as lifeless.

Advantages of Rovers

Mars rovers are spacecrafts which move on the Martian surface after landing. Rovers have advantages over stationary landers, in that they:

1. Examine more territory.

2. Can be directed to interesting features.

3. Place themselves in sunny positions to weather winter months.

4. Advance the fledgling knowledge how to perform very remote robotic control (the latest two rovers on Mars are considerably more sophisticated than earlier ones).

Advantages of rovers over orbiting spacecrafts are that they can:

1. Make observations to a microscopic level.

2. Conduct physical experimentation.

Long term goals of mars exploration:

1. Determine whether life ever arose on Mars.

2. Characterise the climate of Mars.

3. Characterise the geology of Mars.

4. Prepare for human exploration.

Phoenix on Mars

Scientists believe that the Mars, the planet behind us in orbit around the Sun, probably has enough water under its surface. So, when NASA’s

Phoenix Mars Lander soft-landed in northern polar region of the red planet on May 25, 2008 to begin three months of examining a site chosen for its likelihood of having at least frozen water within reach of Lander’s robotic arm, scientists and lay people alike heaved a sigh of relief.

After travelling 679 million km through the cosmos, the probe had to decelerate from 21,000 kmph to a metre float to manage a safe touch down on the Red Planet’s arctic region. Phoenix entered the top of the Martian atmosphere, used a thermal shield to slow its entry into the atmosphere and then deployed a parachute to reduce its speed. Then the Lander fired up its thrusters to slow to 8 kmph and land on its three legs on the circum polar region known as ’Vastitas Borealis’, akin to northern Canada in Earth’s latitude. After safe landing, Phoenix unfurled its solar power panels and began collecting energy from the Sun; other wise its batteries could last just 31 hours.

Why searching for Martian North Pole?

NASA’s $ 420-million probe became the first spacecraft to land on Martian arctic surface, digging into the polar ice on a new mission searching for signs of life on Mars. On Earth, the arctic regions hold the history of the planet’s climate changes, which are locked layer-by-layer into the ice core. This is where the history of life is preserved in its purest form of organic molecules and cellular bacterial microbes and so forth.

Phoenix is intended not to search for life directly, but it should be able to determine if the Martian ice was ever liquid. Liquid water is an essential ingredient for life to exist.

Questions to be answered by Phoenix

Phoenix is a stationary lander equipped with a trench-digging robotic arm to bite into the Martian surface and scoop up samples of nearby soil and water. The probe’s top-mounted suite of ovens and wet chemistry instruments are designed to help determine whether the arctic plain landing site-a region similar in latitude to central Greenland or northern Alaska on Earth-could have once proven habitable for primitive life Phoenix also includes, Martian atmosphere –monitoring station, designed to provide daily weather updates during the probe’s planned three-month mission.