NASA MSL: Apparent Mystery of Mars 'doughnut' rock solved

NASA image shows before-and-after of the same patch of ground in front of NASA's Mars Exploration Rover Opportunity 13 days apart documenting the arrival of a bright rock onto the scene, on January 22, 2014

NASA scientists were finally able to explain the origin of the mysterious rock shaped like a jelly doughnut that appeared near the rover Opportunity in early January.

The small, round object suddenly popped up in pictures taken 12 days apart by the US space agency's decade-old Opportunity rover.

On December 26, 2013, it was not there. On January 8, it was. But what is it?

The explanation is somewhat prosaic: the 1.5 inches (four centimeters) wide, white-rimmed, red-centered rock, dubbed Pinnacle Island, is a piece of a larger rock that was broken and moved by Opportunity's wheel in early January.

"Once we moved Opportunity a short distance, after inspecting Pinnacle Island, we could see directly uphill an overturned rock that has the same unusual appearance," said Opportunity Deputy Principal Investigator Ray Arvidson of Washington University in St. Louis on Friday.

"We drove over it. We can see the track. That's where Pinnacle Island came from."

However, the rock is unusual and scientifically significant.

A close examination with Opportunity's spectrometer showed "high levels of elements such as manganese and sulphur, suggesting these water-soluble ingredients were concentrated in the rock by the action of water," NASA said.

This image taken by the panoramic camera on Opportunity shows the rover's Moessbauer spectrometer (circular device in center).

"This may have happened just beneath the surface relatively recently," Arvidson said, "or it may have happened deeper below ground longer ago and then, by serendipity, erosion stripped away material above it and made it accessible to our wheels."

Opportunity is one of two Mars Exploration Rovers. Its companion, Spirit, stopped communicating with Earth in 2010.

Both have lived long beyond their planned 90-day missions and have made important discoveries about water on Mars and environments that might have supported microbial life in the distant past.

NASA Mars Opportunity: MRO restarts hunt for habitable sites

Opportunity rover’s 1st mountain climbing goal is dead ahead in this up close view of Solander Point at Endeavour Crater. 

Opportunity will ascend the mountain looking for clues indicative of a Martian habitable environment. 

This navcam panoramic mosaic was assembled from raw images taken on Sol 3385 (Aug 2, 2013). 

Credit: NASA/JPL/Cornell/Marco Di Lorenzo/Ken Kremer (kenkremer.com)

MRO, NASA's most powerful Mars orbiter has been given the green light today (Aug. 5) to capture new high resolution spectral scans that are absolutely crucial for directing the long lived Opportunity rover's hunt for signatures of habitability atop the intriguing mountain she will soon ascend.

In a plan only recently approved by NASA, engineers are aiming the CRISM mineral mapping spectrometer aboard the Mars Reconnaissance Orbiter (MRO) circling overhead to collect high resolution survey scans of Solander Point – Opportunity's 1st mountain climbing goal along the rim of huge Endeavour Crater.

"New CRISM observations centered over Solander Point will be acquired on Aug. 5, 2013," Ray Arvidson told reporters.

Arvidson is the mission's deputy principal scientific investigator from Washington University in St. Louis, Mo. NASA's decade old rover Opportunity is about to make 'landfall' at the base of Solander Point, the Martian mountain she will scale in search of the chemical ingredients that could sustain Martian microbes.

So the new spectral data can't come back to Earth soon enough, and all this is taking place as NASA's Curiosity rover celebrates her 1st Birthday on the Red Planet. .

Currently, the science team lacks the same quality of high resolution CRISM data from Solander Point that they had at a prior stop at Cape York and that data was crucial because it allowed the rover to be precisely targeted – and thereby discover a habitable zone, Arvidson stated.

"CRISM collected lots of overlapping measurements at Cape York to sharpen the image resolution to 5 meters per pixel to find the phyllosilicate smectite [clay minerals] signatures at Matejivic Hill on Cape York."

"We don't have that at Solander Point. We only have 18 meters per pixel data. And at that resolution you can't tell if the phyllosilicate smectite [clay minerals] outcrops are present."

Today's new survey from Mars orbit will vastly improve the spectral resolution – from 18 meters per pixel down to 5 meters per pixel.

"5 meter per pixel CRISM resolution is expected in the along-track direction over Solander Point by commanding the gimbaled optical system to oversample that much," Arvidson explained.

Opportunity rover’s view from very near the foothills of Solander Point looking along the rim and vast expanse of Endeavour Crater.

Solander Point is the 1st Martian Mountain NASA’s Opportunity will climb and the rovers next destination.

Solander Point may harbor clay minerals indicative of a past Martian habitable environment. This navcam mosaic was assembled from raw images taken on Sol 3374 (July 21, 2013).

Credit: NASA/JPL/Cornell/Marco Di Lorenzo/Ken Kremer (kenkremer.com)

The new CRISM spectral survey from Mars is essential to enable the science team to carefully study the alien, unexplored terrain in detail and locate the clay minerals and other water bearing minerals, even before the rover arrives.

Clay minerals form in neutral pH water conducive to life.

But it took some cajoling and inter team negotiations to convince everyone to move forward with the special but crucial CRISM imaging plan.

Since MRO is getting on in age – it launched in 2005 – NASA and the spacecraft managers have to carefully consider special requests such as this one which involves slewing the MRO spacecraft instruments and therefore entails some health risks to the vehicle.

"CRISM has been operating at Mars since 2006 and sometimes the optics on a gimble have actuators that get stuck a little bit and don't sweep as fully as planned."

Nevertheless, Arvidson told me a few weeks ago he was hopeful to get approval.