Seems a bit strange for a diamond grinder. Is there a rock so hard? Is Spirit not able to supply enough power? Or is this more or less normal? Or is there a reason to go very slowly?

Waking up to "One More Time" by The Real McCoy, Spirit completed a successful, 2 millimeter-deep grind (.08 inches) into a target slightly left of the depression it made yestersol during its abbreviated operation. A five-minute brush to clean the hole followed.

Completing the sol, which ended at 8:31 p.m. Wednesday, March 03, Spirit's arm then switched instruments so the Moessbauer spectrometer could examine "Humphrey's" new shallow cavity.

Before this sol's four-hour grinding, the microscopic imager and the alpha particle X-ray spectrometer finished observations of yestersol's rock abrasion tool depression. To document Spirit's current position - about halfway to the "Bonneville" crater rim - the panoramic camera snapped the first of several images that, together, will provide a 360-degree view.