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NASA's most advanced planetary rover
August 20, 2012
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by Mark Ollig

“The Curiosity landing is the hardest NASA mission ever attempted in the history of robotic planetary exploration,” said John Grunsfeld, associate administrator for NASA’s Science Mission Directorate, at NASA Headquarters in Washington.

Equipped with 17 on-board cameras, this six-wheeled, 1,982-pound, car-sized, robotic-rover called the Mars Science Laboratory (MSL) Curiosity, traveled more than 350 million miles on its voyage to Mars.

Currently, the MSL Curiosity rover is located approximately 158 million miles away from us, stationed on the surface of the planet Mars since its landing Aug. 5.

Curiosity is being powered not by solar cell panels (as were the previous, smaller rovers, Spirit and Opportunity), but with something called a Multi-Mission Radioisotope Thermoelectric Generator (MMRTG).

The MMRTG draws its power by generating electricity from the heat caused by the natural decaying of the 10.6 pounds of Plutonion-238 which is encased inside the rover.

The Plutonion-238 is a non-weapons grade material, and is constantly dissipating heat, which powers the Mars rover during the day and night.

There are advantages to using this “nuclear battery” (as NASA calls it) instead of solar cells – which are dependent upon sunlight.

Some advantages of using the MMRTG:

• Curiosity will be able to operate 24 hours a day.

• Longer mission: Using the MMRTG with Plutonion-238 means Curiosity should have a minimum operational lifetime of 14 years.

• The MMRTG is smaller and lighter, compared to a typical rover’s solar power plant.

• There is no need for a separate heating system, as “waste heat” from the MMRTG is circulated throughout the rover and is used as a thermal control system to keep its instruments, computers, mechanical devices, and communications systems within their operating temperature ranges.

• MMRTG has little or no sensitivity to cold, radiation, or other effects from being in space or in the Martian environment.

• Much more of the surface of Mars will be able to be explored.

“Curiosity is a geo-chemical experiment we are sending to Mars,” said Ashwin Vasavada, Mars Science Laboratory deputy science manager of NASA’s Jet Propulsion Laboratory.

Curiosity is seeking to find evidence of the conditions needed which could have sustained life on Mars in the past.

“We’re not actually looking for life; we don’t have the ability to detect life if it was there. What we are looking for is the ingredients of life,” said John Grotzinger, project scientist, Mars Science Laboratory Mission.

Scientists are looking to see if Mars could have ever supported microbial life.

This robotic, exploring vehicle takes with it to Mars, 10 science instruments.

The total size of these instruments is 15 times larger than the scientific payloads the Spirit and Opportunity Mars rovers have.

One of these tools includes Chemistry and Camera (ChemCam).

ChemCam is a laser-firing device that will shoot a highly focused pulsed laser beam at rocks from a distance. The beam, according to NASA, produces a flash of light from the ionized material, or plasma, which can be analyzed to identify chemical elements in the target. This laser device is the first of its kind to be used on Mars.

Another instrument Curiosity will use is a drill and scoop, which is located at the end of its 7-foot robotic arm.

This will allow the rover to gather soil and powdered samples of various rock interiors; these samples will be filtered and sent into one of Curiosity’s instrument laboratories for further analysis.

Curiosity is located inside the Mars Gale Crater, which has layers of rock extending from its mountainous edges. The specific scientific experiments designed for exploring these layers are within the rovers driving distance.

NASA reported observations from orbit over Mars “have identified clay and sulfate minerals in these lower layers, indicating a wet history.”

Some have said Gale Crater was once a large lake or ocean.

Curiosity has an onboard central computer that continuously monitors its operational status, and verifies commands are being executed. This computer also manages communications to and from Earth, and to spacecraft orbiting Mars which can relay any information from the rover to Earth.

The planning for this latest Mars rover exploratory operation began in 2004.

The cost for the Curiosity mission to Mars: $2.5 billion.

The Curiosity rover will be able to traverse the surface of Mars at a top speed of 1.5-inches per second.

I had finished my junior year of high school when on July 20, 1976; NASA’s Viking 1 Lander became the first spacecraft to successfully land on Mars after detaching from the Viking 1 Orbiter, which continued to circumnavigate the red planet.

The Viking 1 Lander took soil sample measurements and sent pictures of the Martian landscape back to Earth.

The second picture sent to Earth was a 300-degree panoramic view of the Martian surface. You can see this picture at: http://tinyurl.com/ct76qts.

The picture of the famous “Face on Mars” located in the Martian Cydonia region, taken in 1976 by the Viking 1 Orbiter, can be seen here: http://tinyurl.com/8emryo9.

The Viking 1 Lander used two Radioisotope Thermal Generator (RTG) units which contained a plutonium 238 element.

The Viking 1 Lander was operational on the Martian surface region called Chryse Planitia, for six years. It ended communications with the Earth on November 13, 1982.

The Viking 1 Orbiter ended communications Aug. 17, 1980; however, it will continue to orbit Mars until 2019.

To stay current on the up-to-the-minute news regarding NASA’s latest robotic rover mission to Mars, check out the MSL Curiosity Rover homepage at: http://mars.jpl.nasa.gov/msl/.


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