Mars. The red planet named after the Greco-Roman god of war has been the setting of numerous publications, from scientific journals to science fiction novels. In the science and astronomy community, Mars is a point of considerable interest, and NASA has created many space probes sent to unlock some of Mars’ mysteries. The latest robotic toy in NASA’s arsenal is the 2000 lb robotic rover called the Mars Science Laboratory. Nicknamed Curiosity, the rover is set to land on the Martian surface on August 6.
Curiosity’s mission will be to determine whether the red planet could ever have supported life. It will also examine the climate and geology of Mars. To explore the mystery of this planet, Curiosity will use a wide array of scientific instruments at its disposal. Various cameras, chemical spectrometers, radiation sensors, and other sophisticated tools are housed in the frame of the rover.
From left to right, 2003 Mars Exploration Rover, 1997 Sojourner Rover, 2012 Mars Science Laboratory
Compared to the 1997 Sojourner rover and the two 2003 Mars Exploration Rovers, Spirit and Opportunity, Curiosity will be twice as massive as the previous rovers combined, and its dimensions resemble that of a Mini Cooper automobile. Tasked to negotiate the rugged terrain of the Martian surface, Curiosity uses a “rocker-bogie” chassis. Using two rockers on each side, this chassis allows the wheels to climb over Martian rocks and obstacles while keeping the frame relatively level. Curiosity will be able to roll over obstacles 30 inches in height. The rover is powered by two radioisotope thermoelectric generators that produces electricity by using the natural heat produced by radioactive decay.
Delivering a payload on the surface of Mars presents interesting challenges for the engineering team. The atmosphere of Mars is thick enough such that a heat shield is required to protect the payload and retro-rockets alone is too unstable to provide safe and reliable deceleration. However, it is also thin enough such that aerodynamic braking, such as parachutes, won’t be entirely effective. A combination of both is needed to slow the payload safely and adequately. Although previous rovers used tetrahedron shell covered with airbags to cushion the landing, Curiosity’s enormous size compared to those rovers prevent this from being a viable solution. Instead, the reentry mechanism will use a sky-crane that hovers using eight rocket motors and lowers Curiosity on its wheels with cables and wires.
After Curiosity lands, it will conduct a mission lasting at least 685 Earth days, or one Martian year, in the Gale Crater. The rover will study the mineral composition of the rocks in the area and signs of organic molecules. The knowledge gained from Curiosity will help plan for future explorations, including planned manned missions, to Mars.
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