NASA solves mystery of doughnut-shaped rock
15 Feb 2014
NASA's Jet Propulsion Laboratory claims to have solved the mystery of a doughnut-shaped rock that appeared in front of its Opportunity Mars rover in January.
The 1.5-inch rock, dubbed Pinnacle Island, appeared on Opportunity's cameras on 8 January, and NASA determined it came to rest at some point in the four Martian days prior. According to NASA, it was probably a rock knocked out by one of the rover's six wheels, although the space agency did not rule out the item being debris from a nearby meteorite strike.
Opportunity deputy principal investigator Ray Arvidson of Washington University in St Louis said once NASA moved Opportunity a short distance, after inspecting Pinnacle Island, a rock that had the same unusual appearance could be seen directly uphill.
The broken rock, dubbed Stuart Island, looked like Pinnacle Island, and an examination using the rover's microscope and alpha particle X-ray spectrometer showed that it had very high concentrations of manganese and sulphur, elements which dissolved well in water and could have been layered down under a stream of lake bed, the researchers speculated.
The piece of rock 1.5 inches in width, white-rimmed and red-centred caused a stir last month when it appeared in an image the rover took on 8 January at a place where it was not four days earlier.
From more recent images, it was clear that the original piece of rock was struck by the rover's wheel, slightly uphill from where Pinnacle Island came to rest.
