NASA’s Opportunity rover drove about 3.5 meters (11 feet) late
Wednesday toward a rock outcrop in the wall of a small crater on Mars,
and mission controllers plan to send it the rest of the way to the
outcrop late Thursday.

Opportunity’s twin, Spirit, successfully reformatted its flash memory
on Wednesday. Flash is a type of rewritable memory used in many
electronic devices, such as digital cameras, to retain information
even while power is off. Problems with the flash memory interfered
with Spirit’s operations from Jan. 22 until this week. Engineers
prescribed the reformatting to prevent recurrence of the problem.

On Thursday, Spirit’s main assignment is to brush off an area on the
rock nicknamed “Adirondack” to prepare for a dust-free examination of
its surface. On Friday, controllers at NASA’s Jet Propulsion
Laboratory, Pasadena, Calif., plan to have Spirit grind off a small
patch of Adirondack’s outer surface and inspect the rock’s interior.
Spirit may start driving over the weekend toward a crater about 250
meters (about 270 yards) to the northeast.

For Opportunity, halfway around Mars from Spirit, controllers changed
plans Thursday morning. They postponed a trenching operation until
the rover gets to an area of its landing-site crater where the soil
has a higher concentration of large-grain hematite. That mineral
holds high interest because it usually forms under wet conditions.
The main science goal for both rovers is to find geological clues
about past environmental conditions at the landing sites, especially
about whether conditions were ever watery and possibly suitable for
sustaining life.

Instead of trenching, Opportunity will be commanded after it next
wakes up to drive about 1.5 meters (about 5 feet) farther, possibly to
within arm’s reach of one of the rocks in the exposed outcrop.

Before it began driving on Wednesday, Opportunity finished using its
alpha particle X-ray spectrometer for the first time. This
spectrometer, which assesses what chemical elements are present, took
readings on an area of soil that the rover had previously examined
with its microscope.

Each martian day, or “sol,” lasts about 40 minutes longer than an
Earth day. Spirit begins its 34rd sol on Mars at 3:22 a.m. Thursday,
Pacific Standard Time. Opportunity begins its 14th sol on Mars at
3:43 p.m. Friday, PST.