Mars explorers still finding evidence of wet past
Sen—Ten years after their launch, NASA's Mars Exploration Rover Opportunity and the European Space Agency's Mars Express orbiter continue to inform us about the planet's wet history.
On July 7 it will be ten years since Opportunity left Earth and began its journey to the Red Planet, arriving in January 2004. The hardy rover, which at 1.6 metres long is about the size of a golf buggy, has so far travelled 22.5 miles (36.3 kilometres).
The rover has spent the last 20 months examining an area called Cape York on the rim of Endeavour Crater. NASA officials this week announced the robotic explorer is now moving to Solander Point, also on the rim of the huge crater.
Solander Point was chosen because it offers Opportunity the chance to study a taller stack of geological layering which may provide evidence about the different stages in the history of ancient Martian environments. Ray Arvidson, deputy principal investigator for the mission, said: "Getting to Solander Point will be like walking up to a road cut where you see a cross section of the rock layers."
The drive north is also favourable for Opportunity to charge its solar panels ahead of the Martian winter.
Recently NASA announced Opportunity had found further evidence of the watery past on Mars, with analysis of a rock called Esperance showing it was once covered in water.
"The Esperance results are some of the most important findings of our entire mission," explained principal investigator Steve Squyres. "The composition tells us about the environmental conditions that altered the minerals. A lot of water moved through this rock."
Opportunity's twin rover, Spirit, which launched on June 10, 2003 and also arrived in January 2004 also found evidence of that there was once water on Mars. Spirit stopped communicating in 2010. It still exceeded all expectations though, as both rovers were built for just a 3 month initial mission.
Although NASA mission manages state that Opportunity is showing some signs of aging, such as loss of motion in some joints, it is still able to move and communicate. The robotic explorer's 22.5 mile journey since its arrival was traced on a map released by NASA.
Map showing the 22.5 mile journey of Mars Exploration Rover Opportunity during its 112 months on the Red Planet. Image credit: NASA/JPL-Caltech/MSSS/NMMNHS
Another Mars explorer, which began studying the Red Planet in 2004, celebrated the tenth anniversary of its launch this week. The European Space Agency's (ESA) Mars Express orbiter launched on June 2, 2003 and entered orbit on December 25, 2003. It also released a lander, Beagle 2, which was declared lost after all attempts to communicate with it failed.
On its tenth anniversary, ESA released global maps of Mars showing its history as a wet and volcanic world. ESA also released a spectacular mosiac of Kasei Valles, a valley carved by floodwaters. The mosaic comprises 67 images taken with the orbiter's high-resolution stereo camera.
Kasei Valles Mosiac, imaged by ESA's Mars Express orbiter. Credit: ESA/DLR/FU Berlin (G. Neukum)