PDS_VERSION_ID                = PDS3
RECORD_TYPE                   = STREAM
OBJECT                        = TEXT
  NOTE                        = "Comments on Mars Exploration Rover 
                                 APXS EDR data" 
  PUBLICATION_DATE            = 2008-08-12
END_OBJECT                    = TEXT
END


            COMMENTS ON MER APXS EDR DATA

August 12, 2008.
----------------

The EDR label file size indicated in the label is incorrect.  This is 
due to a missing carriage return at the end of the label entry for 
MISSION_PHASE_NAME.

Note: This is true of all APXS EDRs released.


May 21, 2007. 
-------------

PDS labels for files in the CALIB directory have been provided.


April 27, 2007. Release 12, Sols 901-990
----------------------------------------

Labels for MER 1 data in this release still have the same error for 
TLM_INST_DATA_HEADER_ID as reported for Release 11.


February 1, 2007. Release 11, Sols 811-900
------------------------------------------

A minor systematic error occurs in the PDS labels of APXS EDR products
in this release. The value for the keyword TLM_INST_DATA_HEADER_ID is
not a valid ASCII character. The value should be 3.


February 3, 2006. Release 7, Sols 451-540
-----------------------------------------

This release includes a document describing a change that occurred
to the APXS instrument on MER-B (Opportunity) and its effect on the
calibration of data acquired by that instrument. The document is in
the file MERB_APXS_INCIDENT.ASC (ASCII text version) and 
MERB_APXS_INCIDENT.PDF (PDF version) in the DOCUMENT directory of the
MER-B APXS EDR and RDR archive volumes. The document applies only to
the APXS on MER-B.


February 28, 2005. Release 3, Sols 91-180
-----------------------------------------

In releases 1 and 2 of the MER archives was an issue with the
calibration data for the APXS instruments on both rovers.  The APXS
calibration data were swapped for the two rovers with the files
for Spirit located with the Opportunity data set and vice-versa.
The error resulted from the sensor heads being unintentionally swapped
shortly before launch during a very late refurbishment of both
instruments.  There are data that indicate conclusively that the
instrument swap occurred.  The calibration data are still valid,
but were associated with the wrong spacecraft.  The issue has been
corrected for release 3 of the archives (this release).


October 4 and 25, 2004. Release 2, Sols 31-90
---------------------------------------------

The CALIB directory contains several ASCII files with APXS
measurements of samples done with the flight instrument in a
laboratory before launch.  The samples include chemical compounds and
11 geostandards.  Elemental compositions of the geostandards are also
provided.

The calibration data are provided in comma delimited files.  PDS
labels will be added to the archive when they are available.