[Bernard Marx]

Thanks for the ping. I spend a lot of my time grinding rocks of various kinds but I won't get into that. I think you're correct that this is very soft material and it gives the visual impression of being almost wet enough to create "mud" -- the big smear at the lower left -- and the "crumbs" left in the central portion of the grinding area.

When I use diamond-coated wheels to cut rocks it's done under a water spray to clear away muddy swarf that loads up the wheel and slows or stops the grinding operation. I presume Spirit's RAT can't do that and any moisture would come from the rock being ground. Doodad has an interesting idea about the software but my guess is the abrasive wheel on the RAT loaded up and it simply couldn't make any progress. This can also happen in dry material if the consistency is just right. But if I'm right about the "mud" this could possibly be confirmation of present water on Mars.

[Phil V.]

Here's a glyph of the target rock,"Humphrey". I assumed (perhaps incorrectly) that the Spirit team had chosen another block of basalt (hard stuff) to grind. It looked to me about the same as Adarondack, Spirit's first grind object. The microscopic images taken before the grind suggest the typical gas voids of basalt rather than vugs as Opportunity's object rocks.

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[Phil V.]

updated update . . .


Daily Updates - March 3, 2004

Spirit Status for sol 59
Rock Abrasion Tool Back in Action
posted Mar. 3, 6 pm PST

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.

Engineers identified the software issue that caused the rock abrasion tool to terminate its original planned grinding on sol 58. The minor bug will be fixed when new flight software is loaded at the end of March.

In the coming sols, Spirit will complete the alpha particle X-ray spectrometer observations of the rock abrasion tool hole and get an up-close view with the microscopic imager. The final images will be obtained for the full panoramic view of Spirit's current position. After miniature thermal emission spectrometer and panoramic camera observations of the hole are conducted, Spirit will continue on toward "Bonneville" crater.