Friday, September 7, 2012

Reason #255: Curiosity

I wasn't sure at first what would become of Space Fridays now that all my posts are on Fridays, but considering that arguably my first Space Friday ever was devoted to the launching of the Curiosity rover aboard the Mars Science Laboratory, I knew that I had to devote at least one more entry to the mission now that it's arrived on Mars and is doing so well thus far.

Curiosity touched down on August 6th, a little over two kilometers from the center of Gale Crater, at what is now known as Bradbury Landing. After running diagnostics and sending back some early low-res images, NASA's Jet Propulsion Laboratory spent the next week removing all the rover's flight and landing software and installing all its surface operation software--the little guy is packed with so much equipment that it didn't have enough room on its drives for both.

After a few more days of tests and instrument checks, Curiosity used its ChemCam laser for the first time to vaporize a small amount of a nearby rock. The ChemCam's role is to then analyze the rock's composition via the light emitted in the vaporization. That first rock had a lot to say--both in the resulting data and on its Twitter page.

Finally, on August 29th, Curiosity was ready to take off toward its primary destination: Aeolis Mons, the aforementioned center of Gale Crater. Aeolis Mons is a three-and-a-half-mile-high mound of sediment kicked up in the impact that first created the crater almost four billion years ago. Between the geological material wrenched upward in the impact and the fact that water is more common the lower you go, the point where Aeolis meets the bottom of Gale Crater was deemed an optimal location to analyze as wide a range of Mars' compositional material as possible--not to mention possibly find conclusive evidence of past water and/or biological activity.

That doesn't mean that all the good stuff is there, though--NASA estimates that the journey to Aeolis Mons will take around a year, with stops all along the way to analyze more rocks, take pictures, measure atmospheric conditions and radiation, and so on. The ChemCam alone is expected to take readings from an average of a dozen different rocks per day, and that's in addition to more than a dozen other cameras and instruments on board.

Another interesting thing about the commute is how Curiosity will be measuring its progress. While it can keep track of how many times its treads are rotating, the unstable terrain means that that's not an accurate means of determining distance traveled. Instead, NASA developed a system called "visual odometry"--built into its treads are a series of gaps that translate into "JPL" in Morse Code. The cameras on Curiosity are able to analyze its own tracks to spot those indentations in the terrain and determine how far away they are; and therefore, how far it has travelled.

Once Curiosity reaches Aeolis Mons, it will spend around another year analyzing the site itself. While it contains the most extensive suite of lab equipment ever sent to Mars, its primary goal is to determine the planet's "habitability"--based on the atmosphere (and signs of what the atmosphere may have been like in the past), the sediment, the observed quanitites of water (or at least carbon dioxide), and the presence of the other chemical building blocks of life (or even existing organic carbon compounds), what the odds are that the planet once harbored life.

While that should give us more than enough data to keep busy for a while, the Mars Science Laboratory mission is also seen as the final step before the optimal means of testing Martian composition: sample return. Normally NASA's budget woes would mean that getting something all the way to Mars and back would be a good ways off yet, but the varying distance between here and there means that the ideal window for a round trip would be in 2016 or 2018 at the latest; waiting longer means spending even more money. So scientists are hoping to use that impetus to get a mission budget approved in the next couple years--meaning that we could be holding actual samples of Martian soil in our hands by the end of this decade.

Further Reading:

Curiosity Rover

Timeline of Mars Science Laboratory

Aeolis Mons

New 360-Degree Photo Shows Latest View from Mars Rover Curiosity

Mars sample return: Scientists hope to one day hit pay dirt

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