Curiosity rover marks seven years of Martian exploration
The rover landed in Gale Crater on Aug. 5, 2012. This location was chosen after NASA’s Mars Reconnaissance Orbiter (MRO) detected signals of clay at the site, a sign that lakes and streams flowed there billions of years ago. Its mission was to determine whether the planet was once habitable for microbial life, before its climate changed from warm and wet to cold and dry.
Curiosity‘s study of rocks within the 96-mile- (154-km-) wide Gale Crater confirmed it once hosted a network of lakes and streams that could have been habitable for as long as several hundred million years. Over that time, clay minerals were left behind as a result of water interacting with sediment in those lakes and streams.
To date, the rover has traveled a total of 13 miles (21 km), where it studied a variety of terrains. In 2014, it began to climb Mount Sharp, a 3.4-mile (5.5 km) mountain that rises from the middle of Gale Crater.
Unlike NASA’s earlier, solar-powered rovers Spirit and Opportunity, which landed on Mars in 2004, Curiosity runs on nuclear power via a multimission radioisotope thermoelectric generator (MMRTG), meaning it is far less vulnerable to dust storms, which can prevent solar-powered rovers from recharging, causing them to lose power.
Curiosity has been in an extended mission since its primary mission was completed within one Martian year, which equals approximately two Earth years.
Early in its travels within Gale Crater, the rover traveled over gravel and pebbles, terrain too small for drilling. Currently in a high-clay content region along Mount Sharp, the rover has since drilled into the crater’s surface 22 times, Although the drill ran into problems on several occasions, mission engineers successfully came up with innovative techniques to work around these problems.
Since June of this year, Curiosity has been traversing more complex geological terrains, including “Strathdon,” an area made up of hardened sediment layers. Significantly different from the flatter, thinner layers the rover previously encountered, this region could have been shaped by a combination of both flowing water and wind.
At an outcrop named “Teal Ridge,” whose features also suggest a complex geological history, Curiosity captured a 360-degree panorama.
“We’re seeing an evolution in the ancient lake environment recorded in these rocks. It wasn’t just a static lake. It’s helping us move from a simplistic view of Mars going from wet to dry. Instead of a linear process, the history of water was more complicated,” stated Valerie Fox of Caltech, co-lead of Curiosity‘s clay unit campaign.
The rover is now exploring the clay-rich side of Mount Sharp initially detected by MRO from orbit. Drilled samples there have revealed some of the highest levels of clay minerals Curiosity has found on the Martian surface. However, in a mystery that continues to stump scientists, samples taken from other regions on Mount Sharp, where MRO did not detect large amounts of clay, show similarly high clay levels. One theory is that dust present on the latter, flatter terrain obscured clay signals there far more than it did on the former, which is covered in pebbles.
Recently, Curiosity detected high levels of methane in some parts of Gale Crater’s atmosphere. On Earth, atmospheric methane is produced largely through biological processes, especially by microbes. But methane can also be produced by geological processes, specifically, interaction between hot water and rock, so the presence of the gas does not amount to proof of life.
Curiosity has enough power remaining to operate for approximately another seven years and remains in good health.
Video courtesy of NASA / JPL
Laurel Kornfeld is an amateur astronomer and freelance writer from Highland Park, NJ, who enjoys writing about astronomy and planetary science. She studied journalism at Douglass College, Rutgers University, and earned a Graduate Certificate of Science from Swinburne University’s Astronomy Online program. Her writings have been published online in The Atlantic, Astronomy magazine’s guest blog section, the UK Space Conference, the 2009 IAU General Assembly newspaper, The Space Reporter, and newsletters of various astronomy clubs. She is a member of the Cranford, NJ-based Amateur Astronomers, Inc. Especially interested in the outer solar system, Laurel gave a brief presentation at the 2008 Great Planet Debate held at the Johns Hopkins University Applied Physics Lab in Laurel, MD.