Mars Rover Opportunity continues to Surprise us

Opportunity Completed 5000 days on the Red Planet.

Mars Rover Opportunity is about the size of a golf cart and was launched into space on 7th July 2003. It reached Meridiani Planum on 25th January 2004. This mission was planned for 90 days (Martian time). However, this robotic rover has surpassed all the imagination and is still active. It recently completed 5000 sols on the Red Planet on 16th February. The data provided by it is 55 times more than it was expected to give. The project manager of Opportunity, John Callas, is as surprised as we are and said,

“Five thousand sols after the start of our 90-sol mission, this amazing rover is still showing us surprises on Mars.”

Despite exceeding its anticipated lifespan by 13 years and 301 days, it continues to show us amazing surprises. It is still providing interesting and inquisitive pictures of the surface of Mars. The ground texture in the recent images shows stone stripes that are also found on mountain slopes of Earth. This pattern is created through repeated freezing and melting of wet soil. This strengthens the claim of the astronomers that Mars might have resources of water. Having said that, this can also happen due to the downhill transport of material, wind or a combination of both. These regions have been identified in ‘Perseverance Valley’, a path which cuts the western rim of the Endeavour Crater. About this valley, Ray Arvidson, Deputy Principal Investigator of Opportunity, said,

“Perseverance Valley is a special place, like having a new mission again after all these years. We already knew it was unlike any place any Mars rover has seen before, even if we don’t yet know how it formed, and now we’re seeing surfaces that look like stone stripes. It’s mysterious. It’s exciting. I think the set of observations we’ll get will enable us to understand it.”

The origin of this valley is highly uncertain at least for now. Soil and gravel have organized into narrow rows parallel to the slope. The interesting thing here is that alternating rows have variable amounts of gravel in them. Scientists are analyzing each and every clue very carefully in search of water. They are also trying to figure out how old these stripes are. The unclear situation is quite evident through the following statement of Robert Sullivan, team member of Opportunity from Cornell University. He said,

“Debris from relatively fresh impact craters is scattered over the surface of the area, complicating the assessment of effects of wind. I don’t know what these stripes are, and I don’t think anyone else knows for sure what they are, so we’re entertaining multiple hypotheses and gathering more data to figure it out.”

Another theory that is circulating among researchers is that this water near Equator of Mars came from the poles. Over the course of thousands of years, the tilt of the Red planet increases so much that ice on poles evaporates into the atmosphere. It later comes to the surface in form of frost or snow. Arvidson acknowledges this as he says,

“One possible explanation of these stripes is that they are relics from a time of greater obliquity when snow packs on the rim seasonally melted enough to moisten the soil, and then freeze-thaw cycles organized the small rocks into stripes. The gravitational downhill movement may be diffusing them so they don’t look as crisp as when they were fresh.”

Bernard Hallet of the University of Washington believes that these stripes are not exactly like the ones that are found on Earth. One of the places where the soil freezes every night is the summit of Hawaii’s Mauna Kea volcano. The results of many measurements taken there show that soil expands more when it is most widespread. On the freezing, the large particles are pushed up which then slide down due to gravity or wind. Areas with more large particles of soil experience less expansion. Continuous repetition of this mechanism forms these parallel stripes.

The twin rover, Spirit, went silent in 2010 but Opportunity continued to provide us with important information. It holds the world record for the off-world drive which is 45.1 kilometers and counting. It has sent a whopping 225000 images of Mars to Earth, till now. Every sol (Martian day) Opportunity passes on the Red planet will enable us to solve more mysteries related to it and know as much as we can.