The Mars Rover Mission
Are we alone in the universe? It is perhaps the biggest question humans have posed. In our efforts to answer it, we have developed complex telescopes, which have let us discover distant planets that may be suitable for extraterrestrial life. But while telescopes monitor mysterious planets in the far reaches of the galaxy, the Mars rovers have been studying the possibility of life right in Earth's neighborhood.
A Mars rover is a robotic explorer, a wheeled vehicle that navigates and collects evidence on Earth's next-door neighbor. Like remote control cars, the rovers are controlled and driven by scientists on Earth. Since 2003, three successful Mars rover missions have landed on Mars, gathered materials, taken photographs, and transmitted the data back to Earth.
The rovers Spirit and Opportunity touched down on Mars in 2004. Both have sent back evidence indicating that water once existed on the planet. In fact, Spirit landed in what appears to be an ancient lake bed. Three years later, one of Spirit's wheels uncovered a piece of ground rich in silica, a mineral that some scientists believe resulted from an ancient geyser or acidic steam.
Spirit has also found goethite, a mineral that can only be produced from water. Opportunity discovered clay deposits, another material that forms from moisture. The Mars rover Curiosity, which landed in 2012, has transmitted pictures of a landscape where there may once have been fast-moving streams. The patterns on the ground indicate that the streams emptied into standing bodies of water. For Mars to have had flowing water, as the evidence suggests, it would have also needed a thicker atmosphere than it now has, as well as warmer temperatures. Such a place, with liquid water and even falling rain, would have been a friendly environment for microbial life.
The rovers are also looking for carbon. Curiosity was the first rover able to pull soil samples for this kind of analysis. It was specially built with a small oven that heats the soil scooped from the planet. The heated soil emits gases. Scientists then analyze the gases that the sample gives off, checking them for evidence of organic compounds. These are any of numerous chemicals that contain carbon, which, like water, is a necessary ingredient for life.
The soil samples seem to contradict Curiosity's photos. So far, the samples gathered by Curiosity have not turned up carbon compounds. The lack of carbon compounds indicates that Mars never had the thicker, warmer atmosphere required for a water cycle-and for life. Some scientists take this to mean that flowing water never existed on Mars, or very little of it did.
Curiosity's soil analysis suggests that Mars has always been too cold and had air too thin for water, let alone microbes, to form. The Mars rovers may provide confusing data, but they are quite effective at collecting it. This is largely due to their mobility. Before the rovers, missions to Mars used stationary landers, which cannot move around to explore different territory. With the rovers, scientists can maneuver to areas of interest or away from hazards. Unlike their predecessors, the rovers can be directed away from Mars's giant dust storms, which reduce visibility and damage the machines.
But a Mars rover can deliver even without its mobility. On May 1, 2009, the wheels of Spirit became embedded in soft soil. Efforts to get Spirit moving again failed. Still, the rover continued to transmit data to Earth from its stuck position until March 22, 2010. wheels of Spirit became embedded in soft soil. Efforts to get Spirit moving again failed. Still, the rover continued to transmit data to Earth from its stuck position until March 22, 2010.
Regardless of the challenges, the rovers have exceeded expectations. Before they were launched, engineers set a goal for Spirit and Opportunity to travel up to forty meters per day and reach a total distance of one kilometer each.
Both surpassed this estimation by far. When Spirit finally broke down, it had lasted over twenty times longer than its planned lifespan. Opportunity lasted over fifty times longer than expected. Mars rovers will continue to explore Mars, searching for evidence of water and carbon-and thus evidence of extraterrestrial life.
Based on the text, why are Mars rovers important?
They have found carbon and flowing water on Mars.
They were the first human-made objects on Mars.
They have each successfully relayed helpful information.
They are showing scientists how to analyze soil in a new way.