KENNETH CHANG In a flawless,triumphant technological tour de force,a plutonium-powered rover the size of a small car was lowered at the end of 25-foot-long cables from a hovering rocket stage onto Mars early on Monday morning. The rover,called Curiosity,ushers in a new era of exploration that could turn up evidence that the Red Planet once had the necessary ingredients for life or might even still harbour life today. If anybody has been harbouring doubts about the status of US leadership in space, John P. Holdren,the presidents science adviser,said at a news conference,well,theres a one-tonne,automobile-size piece of American ingenuity,and its sitting on the surface of Mars right now. No other nation has yet successfully landed a spacecraft of any size on Mars. For NASA,it was the seventh success in eight chances. Curiosity is far larger than earlier rovers and is packed with the most sophisticated movable laboratory that has ever been sent to another planet. Touchdown confirmed, Allen Chen,an engineer in the control room,said at 11.00m am India time,followed by cheers and hugs. Two minutes later,the first image popped onto video screens a grainy,64-pixel-by-64-pixel black-and-white image that showed one of the rovers wheels and the Martian horizon. A few minutes later,a clearer version appeared,and then came another image from the other side of the rover which showed its shadow. Over the first week,Curiosity,part of a $2.5 billion Mars mission, is to deploy its main antenna,raise a mast containing cameras and take its first panoramic shot of its surroundings. The rover will not scoop its first sample of Martian soil until mid-September at the earliest. The sky crane technique STEP 1: ENTRY The spacecraft entered the planets upper atmosphere about 81 miles above the surface of Mars,at a speed of more than 13,000 miles an hour STEP 2: BRAKING The craft used the thin Martian atmosphere to reduce its speed to about 1,000 miles an hour,while thrusters allowed it to steer toward the landing area STEP 3: PARACHUTE A 51-foot-wide parachute slowed the descent further. The protective heat shield fell away,exposing landing radar and a camera to record the landing STEP 4: SKY CRANE After the parachute detached,the descent stage,that is attached to the rover,fired rockets to slow itself,then used a crane to lower the rover to the surface. STEP 5: LANDING The rovers wheels were deployed to help absorb the shock of landing. After the rover touched down,the descent stage flew a safe distance away What next for Rover Curiosity is to spend two years testing rock samples from different layers of the landing site trying to determine if Mars could ever have supported microbial life The science behind it POWER Dust can cover solar panels on Mars,so Curiosity will generate its own power. Eleven pounds of plutonium dioxide generates heat,which is converted to electricity and used to recharge two lithium-ion batteries VISION Extending 7 feet above the ground,a mast holds Mastcam,a pair of high-definition cameras,and ChemCam,which can measure the composition of rock after shooting it with a laser DRIVE Each of the 20-inch aluminum wheels has its own motor REACH The rovers 7-foot arm carries several tools,including a camera,an X-ray spectrometre,and a drill,brush and scoop for collecting samples ANALYSIS The rovers body holds experiments for detecting ground water,measuring naturally occurring radiation and analysing soil and rock samples delivered by the robotic arm
