Last updated September 13, 2017 at 9:30 am
Since landing on Mars 5 years ago, NASA’s Curiosity rover has been looking for clues about ancient Martian life.
Curiosity is the latest in a line of spectacularly successful Mars rovers. The first, Sojourner, landed in 1997 and demonstrated that it was possible to land and operate a robotic rover on another planet. Sojourner was followed in 2004 by Spirit and Opportunity, robotic geologists tasked with uncovering clues about ancient water activity on Mars. Spirit operated until 2010, when we lost contact, but Opportunity is still going strong, and still sending us lots of valuable information about Mars.
Curiosity landed on Mars on 6th August 2012. Weighing 900kg, Curiosity is 5 times heavier than Spirit and Opportunity and so it needed a far more complex sequence of landing manoeuvres to reach the ground safely. During a nerve-wracking chain of operations dubbed Curiosity’s 7 minutes of terror, Curiosity slammed into Mars’s atmosphere, survived the fiery heat of entry, and deployed a parachute. But Mars’s thin atmosphere meant that the huge parachute only slowed the rover’s descent to 350 km/h, so to make a gentle touchdown, Curiosity discarded the parachute and was lowered to the ground by a flying rocket-powered sky-crane.
Powered by a 4.8 kg lump of plutonium, Curiosity is following its older siblings Spirit and Opportunity, trying to find out whether Mars could ever have supported life, and paving the way for human exploration of the red planet. Curiosity is not looking for life itself, but is trying to discover whether Mars ever was, or still is, suitable for alien microbial life. To do this, Curiosity is equipped with 17 cameras and a suite of scientific tools and instruments that make it a mobile Mars Science Laboratory.
Curiosity (right) compared to Sojourner (front centre) and Spirit and Opportunity (left). Credit: NASA
Curiosity getting ready to take a drill sample. Credit: NASA/JPL-CALTECH
Curiosity landed in Gale Crater, a 3.5 billion year old, 154 km wide meteorite crater, which wind and water has filled with sediments over the eons. Gale crater is named after 19th century Sydney astronomer Walter Gale. Curiosity is studying these sediments to learn about the geological history of Mars. We now know that the crater was filled with water for millions of years, long enough for life to start evolving. Curiosity has also uncovered methane and other important ingredients for life in Mars’ rocks and atmosphere.
But major puzzles still remain. For water to last so long, Mars must have had a thicker atmosphere, warmed by the greenhouse effect of large amounts of carbon dioxide that has since been blown away by solar wind. However, the rocks Curiosity has studied don’t contain the carbonate minerals we expect from an atmosphere once rich in carbon dioxide.
Curiosity is far from being the last chapter in the robotic exploration of Mars and is laying the foundations for the Mars 2020 Rover that will look for amino acids, the building blocks of proteins and of life. It probably has one of the best Twitter accounts (@MarsCuriosity) with a following of over 3 million, and it’s been a delight seeing the images that it sends back to Earth. With space agencies, organisations such as Lockheed Martin, and billionaire entrepreneurs like Jeff Bezos and Elon Musk all making plans to send humans to Mars, it’s all thanks to our Curiosity that human exploration of Mars could soon follow.
Artist’s concept, Curiosity approaches Mars in its aeroshell. Credit: NASA/JPL-Caltech
Curiosity uses a camera on its robotic arm to take a selfie. Credit: NASA/JPL-Caltech/MSSS
Curiosity watches the Martian sunset from Gale Crater. This was the first sunset observed in colour by Curiosity. Credit: NASA/JPL-Caltech/MSSS/Texas A&M Univ.