After two years exploring the Martian surface, the Curiosity Rover has finally reached its primary science destination – the foot of Mount Sharp, officially known as Aeolis Mons. Now that it’s there, it will begin its ascent of the rock formation, drill into rocks and analyze the different strata in the hopes of learning more about the history of the Red Planet. This is an event a long time in the making, and may prove to yield some of the greatest scientific discoveries ever made.
Located in the heart of the Gale Crater, Mount Sharp is like a layer cake, holding a chronology of past events reaching back billions of years. Because of this, it is an ideal place to find evidence that the Martian surface and atmosphere were once capable of supporting life. It took two years and one month for Curiosity reach the foot of this mountain, which lies some 5500 meters (18,000 feet) above the floor of Gale Crater.
The mountain is the central peak in a crater that measures 154 km/96 miles in diameter and which was formed when a meteor impacted the surface between 3.5 and 3.8 billion years ago. Beyond a certain size, and depending on the gravity of the planet, craters like this all have a central peak. But Mount Sharp represents something much more, otherwise NASA and the Jet Propulsion Laboratory wouldn’t be bothering with it.
Basically, Mars scientists believe that after its creation, the Gale crater was completely filled with sedimentary material from a series of huge floods, or by dust and ice deposits like those that happened at the Martian polar caps. The deposition over 2 billion years left a series sedimentary layers that filled the crater. Following the deposition of the layers, there was a long period of erosion which has finally led to the condition of the crater today.
The erosion by some combination of aeolean (wind) forces and water (additional flooding), scooped out the huge crater, re-exposing most of the original depth. However, covering the original central peak are many sedimentary layers of debris. Gale crater’s original central peak actually remains completely hidden and covered by sedimentation. And it is this that attracted scientists with the Curiosity rover to the base of Mount Sharp.
Within the sedimentary layers is a sequential record of the environmental conditions on Mars going back over 2 billion years. While at the base, Curiosity will be able to examine the oldest sedimentary layers; but as it climbs the flanks of the mountain, it will be able to step forward in time. Each layer and its age will reveal information such as how much water was present, whether the water was alkaline or acidic, if there is any organic compounds.
The discovery of organic compounds on Mount Sharp could be “Earth shaking”, since the discovery of organics is of very high importance to this mission. Already, over the two year trek, Curiosity has seen numerous signs of the flow of water and sedimentation. Interestingly enough, evidence began to turn up way back in Yellowknife Bay — one of its first destinations, which it visited almost two years ago. But as of yet, signs of organic compounds have remained illusive.
What’s more, Curiosity sadly lacks the necessary equipment to look for evidence of microbial fossils or other signatures of life. Fortunately, the next rover – the Mars 2020 rover – will be equipped with the necessary tools to work out whether Mars ever harbored life. In any case, because of the lack of organic compounds in Yellowknife, NASA decided to continue to Mount Sharp, which is currently the best place to dig up scientific data about Mars’ past.
Curiosity is currently at the base of Mount Sharp, in a region called the Pahrump Hills, where it will continue on to the Murray Formation. Once there, it will take a drill sample of some rock and then continue up Mount Sharp towards the Hematite Ridge where two drill sites await. This farthest site is about 8 km (5 mi) away from its present position, and Curiosity has driven only 9 km since it landed in 2012. So there’s plenty of trekking and work ahead!
One of the greatest challenges is finding a path that will reduce the stress on Curiosity’s wheels, which have been put through some serious wear and tear in the past two years. Because of this, the rover is being driven in reverse for the time being, and the team is looking the path with the least amount of sharp rocks. However, the Mars Curiosity remains confident that the mobility system will be capable of surviving the ten year life span of the rover’s power supply.
And be sure to check out this “Curiosity Rover Report” that talks about this historic accomplishment, courtesy of NASA’s Jet Propulsion Laboratory: