
The latest NASA Mars mission will include a mobile laboratory – the Curiosity rover – that will explore the surface of Mars. Once Curiosity lands, it will maneuver through varied terrain, sampling the environment by drilling into rocks, scooping up terrain, and traveling over the broadest area scientists have yet explored on Mars. During its planned 23-month mission, Curiosity’s ultimate goal will be to search for evidence of past or present life on Mars and to look for any geologic records that might have preserved signs of life. The landing site chosen is near a mountain that contains minerals usually formed in water, and the presence of water is an important marker for possible life.
About the size of a small truck, Curiosity has a number of built-in features, like geology lab, a laser for vaporizing and analyzing rocks, a whole array of cameras, and a special suspension system to keep it stable while moving along rocky terrain. Curiosity’s design represents an upgrade over previous Mars rovers, Spirit and Opportunity, including many more instruments and sensors and an enhanced mobility system.
During its descent from Martian orbit, Curiosity will perform a series of S-shaped drops before reaching the surface. Just before landing, a parachute will deploy to slow the descent and then small rockets will power upward to further slow and buffer the landing.
Once on the surface, Curiosity will move around using six wheels, each with its own motor and the steering capacity to turn in place 360 degrees if needed. The rover adjusts based on what the wheels are doing to always stay balanced, even when one, two, or even three wheels are going over a rock or other obstacle. The rover constantly adjusts and compensates to make sure the weight load on all the wheels stays constant. This stability comes at a cost: the rover is relatively slow, with a top speed of only 4 cm per second.
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Classroom Activity: Rover Forces
Students are given a series of images of Curiosity in action, each one showing a different configuration of wheel placement and height. For each scenario, students work alone or in groups to analyze, discuss, and draw the forces – including how the suspension system would need to compensate in each case to maintain rover stability.
Discussion Questions: Is it important to take Martian gravity into effect when thinking about relative forces? Under what circumstances might the rover actually tip over? Do you think it could recover and right itself? If you could change the design of the rover, what would you change – and why?
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