Since the 1970s, humans have landed multiple vehicles on the red planet in the name of exploration and science. The various landers, or rovers as we call them today, have spent almost thirty years analyzing environmental conditions, soil samples and more in order to determine if our closest cosmic neighbor could have once supported microbial life.
After one Martian year or 687 Earth days (sols), everyone's favorite rover--Curiosity--has successfully completed her main objective. That's right folks, Curiosity has determined that Mars could have once supported microbial life. However, her mission is not over and she continues the arduous journey to Mount Sharp. To celebrate this momentous occasion, the rover performed a very human-like ritual - she took a "selfie". So why is this exciting and what does it mean for us aside from the fact that we landed a vehicle on another planet?
One Year of Science:
One of her first discoveries after landing was an ancient riverbed, not too far away at Yellowknife Bay the rover discovered that there could have been life once in the Martian landmark Gale Crater. This historic discovery resulted from two mudstone slabs. Curiosity drilled into the slabs and after sample analysis, she detected the presence of "mild water" - an ingredient essential to life. If Mars ever hosted life this crater would have made an excellent home.
Curiosity also recorded atmospheric data integral to our path to Mars. By analyzing natural radiation levels we have a better understanding of the protection humans will need to shield them from radiation on Mars. Elemental analysis of the Martian atmosphere also showed very little Methane gas (a biologically produced gas) and indicated the planet lost its atmosphere from the top down - meaning the lighter elements in the upper portion of the atmosphere were the first to disappear.
The rover took a small break from driving in order to perform more science and analysis on a location known as Windjana. This sandstone drilling site proved very interesting as it contained more magnetite than any previous sample collected. David Blake, Curiosity's Chemical and Mineral Instrument (CheMin) principal investigator said:
"Windjana has more magnetite than previous samples we've analyzed. A key question is whether this magnetite is a component of the original basalt or resulted from later processes, such as would happen in water-soaked basaltic sediments. The answer is important to our understanding of habitability and the nature of the early-Mars environment."
Early analysis indicates the sandstone has a more diversified mineral content and any other sample tested. In addition to the magnetite, the Windjana samples contain an something unusual - orthoclase. A type of feldspar high in potassium, orthoclase is abundant in the Earth's crust but has never been detected in Martian soil, until now. The Windjana sandstone is thought to be a derivative of the sandstone found along the rim of Gale Crater and shows signs of complex geological processing like would occur in several melting events. The Windjana site is a place where an ancient river flowed and contains evidence of water and rock interactions.
As of mid-May, Curiosity has left the Windjana site and has headed west. Since then she has traveled nine-tenths of a mile (1.5 kilometers) over the last 23 days for a grand total of 4.9 miles (7.9 kilometers) since landing. Last last year, Curiosity suffered some wheel damage as a result of rougher then expected terrain. As a result, the team has had to alter routes as well as driving techniques in order to help ensure she can make it to Mount Sharpe.
To help reduce the potential wheel damage, the team selected a route to Mount Sharpe with a lower slope and where scientist to find out answers about the ancient environment through analysis of geological layering. Arriving at Mount Sharpe has been a key mission objective for Curiosity as scientists predicted this would be the best place to find any evidence of life on the red planet. Surprisingly, the evidence was discovered very close to Curiosity's landing site. Based on her findings so far, Curiosity has raised the bar for things to come.
Once the rover reaches Mount Sharpe, Curiosity will be looking for more evidence of life but also how conditions evolved. The new path and entry point to the mountain is approximately 2.4 miles (9.3 kilometers) ahead of the rover's current location. With the help of the Mars Reconnaissance Orbiter (MRO), researchers have scouted out a safer albeit longer route to the target. The current path will contain both sandy patches as well as rocky terrain and the team will be ready to compensate and adapt to whatever terrestrial issues come their way. Curiosity's project manager at JPL, Jim Erickson, describes these issues as good opportunities to learn and will help in future rover developments.
"When you're exploring another planet, you expect surprises. The sharp, embedded rocks were a bad surprise. Yellowknife Bay was a good surprise."
Curiosity is managed managed by NASA's Jet Propulsion Laboratory in Pasadena, California and continues to provide unprecedented data about Mars as well as a plethora of rover selfies. To learn more about how Curiosity is able to take these self-portraits and how they are pieced together to form the stunning panoramas we see click here.