THE Red Planet's spell of loneliness is over. After the Viking's visit 21 years ago, planet Mars has another guest. The Pathfinder.
The plan worked perfectly. The 600-kg spacecraft pierced Mars' gossamer-thin atmosphere at more than 26,000 km per hr; its parachute opened and slowed its descent; the air bags first billowed out to cushion its landing and then deflated to allow the lander to step out, and the diminutive Sojourner dismounted for its maiden reconnaissance of Mars. The cosmic drama reached its denouement when the six-wheeled wonder toy (280 mm tall, 630 mm long, 480 mm wide and 11.4 kg light) sent a stunning impression of the Martian landscape.
Shot into space on December 4 last year, Pathfinder touched down, as planned, in Ares Vallis, the famous floodplains of Mars, exactly seven months and 496 million km later. The solar-powered rugged rover—toughened to fight Mars' ruthlessly cold climate (-26°C during day and -87° C at night)—is well equipped with a camera assisted by gyroscopes and lasers which prevent it from tripping over boulders, falling off a cliff or plunging into chasms. Path-finder has a month to accomplish its assigned tasks after which the Martian elements will take over. But the static lander will continue to survey conditions for a year.
The Sojourner's movement is controlled at the Jet Propulsion Laboratory in Pasadena. Before the rover leaves the lander, its camera will scan the lie of the land and transmit its observations to JPL where they'll be converted into 3-D images. The robot will then be manoeuvred to a desired point and instructed to take pictures and carry out scientific analyses. But the going will be slow since the cosmic knight-in-the-armour cruises at a leisurely 39.6 cm a minute, and its messages travel millions of miles (or 22 minutes to and fro) to reach earth.
The Sojourner has already sent stunning pictures of the famous Mars canals, objects of controversy ever since 19th century astronomer Schiaparelli declared they were irrigation canals. The $250 million mission will help answer scientific queries on whether there is, or was, life on Mars; whether Martian life evolved the way it did on Earth; whether the deep furrows that characterise parts of the Martian visage were chiselled by gushing streams of water; whether vast quantities of water lie trapped as permafrost in Mars' bowels; what caused the once warm and wet planet to turn into a cross between Sahara and Siberia, among other things.
Pathfinder, of course, is not the first to investigate Martian mysteries. Ever since the erstwhile USSR's Mars 1 flyby in 1963, US and Soviet missions have visited the planet regularly: eight Mariner flybys, the Mariner 9 orbiter which returned "the most exciting images ever obtained in planetary exploration", and finally the late '70s Viking expeditions that established the search for life on Mars as the dominant theme of Mars explorations.
The '80s, however, proved inauspicious. Four probes, three Soviet and one US, were lost in oblivion. The most discouraging was the failure of the Russian Mars 96 mission in November 1996, reportedly the most ambitious mission launched by any country. Russia wasn't the only loser. Germany, France and Finland spent more than $200 million on the mission. The failure of Mars 96 virtually sunk any future European attempt at Mars exploration. Pathfinder's success, therefore, comes as a shot in the arm for the disheartened space community.
In fact, NASA plans to launch 10 spacecraft to Mars within the next decade. Pathfinder is already there. The Global Surveyor, launched on November 7 last year, will reach Mars this September. Its agenda: to identify whether ancient wet environments once existed on Mars. NASA's ambitious project will culminate around AD 2005 with a mission to bring back rocks from Mars to Earth.
The mid-'70s robotic explorations of Mars yielded no clues to life on the planet. But interest was renewed after the announcement last August that a meteorite found in Antarctica may contain evidence of past life on Mars. President Bill Clinton hailed the discovery as "stunning" and pledged that the US space programme would "put its full intellectual power...behind the search for further evidence of life on Mars."
For some Americans, the exploration of Mars seems the only way to rejuvenate an intellectually-fatigued nation. To quote Robert Zubrin of the National Space Society: "Mars will not allow itself to be settled by people from a static society—those people won't have what it takes—not just technology, but scientific outlook, creativity and free-thinking individualistic inventiveness. We still do." Little wonder, the Path-finder touchdown coincided remarkably with the American Independence Day.
