NASA celebrated the fifth anniversary of the Curiosity Rover mission. They say the car-sized robot has gathered impressive data over the past years and that it is still making significant discoveries.

NASA even programmed the robot to sing happy birthday as he is all alone on the Red Planet – or so it is believed by earthlings -, though the outcome was not that good. In fact, the $2.5 billion mission was originally planned to last just two Earth years, but its results have been so promising that its period was extended.

Image Credit: NASA
The Curiosity rover. Image Credit: NASA

“I feel like we’re arriving at a second conclusion from the mission that’s just as powerful as the first, which is that habitable environments persisted on Mars for at least millions of years,” said Curiosity project scientist Ashwin Vasavada, of NASA’s Jet Propulsion Laboratory.

NASA’s Curiosity Rover mission was extended until October 2018

The Curiosity rover keeps doing science on Mars after five years. It landed the night of August 5, 2012, after being lowered by cables; that was a significant achievement and a moment of joy at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California. Since that moment on, Curiosity has learned a lot about its new environment. Its initial duties were to discover and take samples in the Gale crater to know if this vast basin was hospitable for microbes once. It also has found evidence of ancient water, and other compounds needed for life.

Due to the significant and compelling data provided by the Curiosity rover, NASA decided to extend the mission all the way until October 2018, because a lot of things need to be done yet. It is currently climbing Mount Sharp, at the center of the 154-kilometer-wide crater. It will also explore three new rock layers: one dominated by iron hematite, another by clay and the other one is dominated by lots of sulfate salts.  They will help scientists know how these layers fit into Mars’ history.

Curiosity might have discovered the proof of ancient life on Mars

The lens of the rover can take microscopic images; however, according to NASA, it is not capable of capturing preserved cells or microfossils. The rover just detects and analyses cells with its portable chemistry lab. Thanks to that ability, it has tested chlorobenzene, a small organic molecule with a carbon ring, in ancient mud rock. These molecules are needed to create cell walls and other structures.

It has also proved that Mars was a warm and wet place that had all the needed ingredients to create life.

“We’ve only found simple organic molecules so far,” says Ashwin Vasavada, a planetary scientist at NASA’s Jet Propulsion Laboratory who leads Curiosity’s science team.

Mars surface, in a picture taken by the rover’s Mast Camera (Mastcam) during the 538th Martian day, or sol, of Curiosity’s work on Mars (Feb. 9, 2014). Credit: NASA/JPL-Caltech/MSSS

About 3.5 billion years ago, Mars was a hospitable place. What NASA doesn’t know is how Mars stopped being a favorable environment for life and how it just became a cold and dry planet. The most accepted theory states that the sun debilitated – and continues to do so- Mars’ atmosphere as the Red Planet lost its protective magnetic field. The lighter elements were the first ones to disappear.

“That caused the climate to change from one that could support water at the surface to the dry planet it is today,” Vasavada explains.

Scientists hope they could get more information once the rover hikes up Mount Sharp where it might find evidence of the wet-to-dry transition.

Does water really flow in Mars?

The Curiosity Rover has found evidence of ancient water on Mars, but even today it can also be found. Some mineralized salts absorb water, releasing it in its liquid form when they break at a determined temperature. In 2015, the Mars Reconnaissance Orbiter sent images of shifting salt streaks which indicate an active flowing water source. Therefore, water might not be just a part of Mars’ history.

Mount Sharp has some streaks. Curiosity takes pictures of them every once in a while, so they can notice if they are moving. So far, these streaks have not shown movement.

On the other hand, Vasaveda said that the Gale Crater presumably remained habitable through periodic dry spells because there might have been groundwater, which outlasted lakes.

“So there’s a whole other era of water that’s, by definition, after the lakes,” Vasavada said. “It suggests that the water was there even longer than the timescale of the lakes.”

Another thing scientists want to discover is where does the methane on Mars comes from. Here on Earth, microbes are the primary methane producers. In Mars, its origin is not well defined. Curiosity is continuously monitoring methane levels. Since 2014, the levels had an incredible spike. According to Vasaveda, it could come from underground, because when minerals interact with subterranean water, they can produce this gas.