Half Donut Shaped feature - Sol54 Spirit Microscope

See half donut shaped feature on Sol 54 Spirit microscope images

Has anyone any ideas what this feature is - looks like nothing I've
ever seen - looks as thogh it's a tube like structure with a piece of
wall broken away - is this a result of RAT activity or are we seeing
an unatered feature ?

"Brian C" wrote in message
om...
See half donut shaped feature on Sol 54 Spirit microscope images

Has anyone any ideas what this feature is - looks like nothing I've
ever seen - looks as thogh it's a tube like structure with a piece of
wall broken away - is this a result of RAT activity or are we seeing
an unatered feature ?

It is the partial imprint of the Mossbaur Spectrometer.
The top half has been compressed flat. Due to the
uneven nature of the soil or the angle of the arm
or both the imprint is not completely circular.
The Sol 54 Spirit microscopic images page contains
before and after pics of the same spot.
The Sols 43, 49 & 50 Spirit microscopic images
and Opportunity Sol 12s,17 & 26 microscopic
images all show the same type of deformation
on other surfaces - also from the Mossbaur
Spectrometer.
http://marsrovers.nasa.gov/gallery/all/spirit.html
http://marsrovers.nasa.gov/gallery/all/opportunity.html
http://marsrovers.nasa.gov/mission/s...ru_mossbr.html

"Brian C" wrote in message
om...
See half donut shaped feature on Sol 54 Spirit microscope images

Has anyone any ideas what this feature is - looks like nothing I've
ever seen - looks as thogh it's a tube like structure with a piece of
wall broken away - is this a result of RAT activity or are we seeing
an unatered feature ?

It is the partial imprint of the Mossbaur Spectrometer.
The top half has been compressed flat. Due to the
uneven nature of the soil or the angle of the arm
or both the imprint is not completely circular.
The Sol 54 Spirit microscopic images page contains
before and after pics of the same spot.
The Sols 43, 49 & 50 Spirit microscopic images
and Opportunity Sol 12s,17 & 26 microscopic
images all show the same type of deformation
on other surfaces - also from the Mossbaur
Spectrometer.
http://marsrovers.nasa.gov/gallery/all/spirit.html
http://marsrovers.nasa.gov/gallery/all/opportunity.html
http://marsrovers.nasa.gov/mission/s...ru_mossbr.html

"Brian C" wrote in message
om...
See half donut shaped feature on Sol 54 Spirit microscope images

Has anyone any ideas what this feature is - looks like nothing I've
ever seen - looks as thogh it's a tube like structure with a piece of
wall broken away - is this a result of RAT activity or are we seeing
an unatered feature ?

It's a picture taken after they pressed the Mössbauer spectrometer's contact
plate into the soil. If you look at the pictures taken right before it,
they are from exactly the same spot, but before the indentation was made.
This has been done several times before, though I think this is one of the
more dramatic impressions that has been made. I'm kind of curious about the
dark spot at the top right - is that due to a difference in the soil, or
something on the plate? It's hard to tell, but it almost looks like a
portion of the pressed down soil was pulled up when the plate was lifted, as
if it was stuck to it.

In message ,
(Brian C) wrote:

See half donut shaped feature on Sol 54 Spirit microscope images

Has anyone any ideas what this feature is - looks like nothing I've
ever seen - looks as thogh it's a tube like structure with a piece of
wall broken away - is this a result of RAT activity or are we seeing
an unatered feature ?

That's the Mossbauer spectrometer impression. What's with the chunk
out of the side though? Has Spirit's Mossbauer been damaged?
--
R.G. "Stumpy" Marsh Timaru, New Zealand
http://marsh.orcon.net.nz/