(Sen) - NASA's Mars Science Laboratory (MSL) is now less than a month away from Mars. The largest ever rover will attempt an ambitious landing by sky crane when it arrives at the red planet on August 5 PDT (early on August 6, Universal Time).
The chosen landing site for the Curiosity rover is the Gale Crater where it will spend a Martian year looking for signs of microbial life.
As MSL reaches the Martian atmosphere, at about 125 kilometres (78 miles) above the surface, small rockets will be used to guide the spacecraft through the atmosphere toward the surface. 76 pyrotechnic explosions will be deployed during the descent to activate certain operations including deployment of a very large parachute to slow down the craft. Previous NASA rovers - Viking, Pathfinder and the Mars Exploration Rovers (Spirit and Opportunity) - all used a parachute to steady their descent. However, due to the size and mass of the craft - which weighs 900 kilograms - an airbag assisted landing used by previous rovers was not feasible. The mission owners therefore designed an alternative to the airbag - a crane. Curiosity will separate from the sky crane but remain attached, allowing the crane to lower the rover, wheels down, to the surface. Curiosity will be ready to begin its mission and the crane will be released.
Pete Theisinger, MSL project manager, said: "Every day is one day closer to the most challenging part of this mission. Landing an SUV-sized vehicle next to the side of a mountain 85 million miles from home is always stimulating. Our engineering and science teams continue their preparations for that big day and the surface operations to follow."
The sky crane is a new concept for delivery of a heavy rover and, if successful, could enable scientists to devise even larger robotic explorers for future missions.
The objective of the mission is to look for signs of whether microbial life ever existed or could still exist. MSL is the largest planetary rover ever built and carries the most advanced set of instruments ever sent to the Martian surface. The rover will analyze samples scooped from the soil and drilled from rocks. The record of the planet's climate and geology is written in the rocks and soil, in their formation, structure, and chemical composition. The rover's onboard laboratory will study rocks, soils, and the local geologic setting in order to detect chemical building blocks of life (eg carbon).
Once on the surface Curiosity will be able to travel at speeds of up to 90 metres per hour, though it is expected to travel at a slower average of about 30 metres per hour. The rover will be capable of rolling over obstacles up to 75 centimetres high.
The rover will powered by a radioisotope power system that generates electricity from the heat of plutonium's radioactive decay.
Curiosity has been designed to operate for a full Martian year (687 Earth days), though it could last longer. The Mars Exploration Rovers were designed to operate for just 90 days, yet Spirit kept going for over 6 years and Opportunity is still active. By last week Opportunity had spent 3,000 sols (Martian days) on the red planet (over 8 Earth years).
MSL launched from Space Launch Complex 41, Cape Canaveral Air Force Station, Florida, on 26 November 2011 atop a United Launch Alliance Atlas V rocket. During its journey to Mars a number of minor adjustments have been made to its flight path. In June NASA announced it was reducing the size of the landing target area from 20 kilometres wide and 25 kilometres long to 7 kilometres wide and 20 kilometres long. The change will see Curiosity land closer to Mount Sharp in the centre of the Gale Crater, thereby reducing its travel time to its main location of scientific investigation after landing.
NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, manages the Mars Science Laboratory mission for NASA.
The mission is costing US $2.5 billion.
NASA have created a video simulation of the challenging landing and interviews with team members: