Data Validation

Phoenix science archives are validated before being released to the PDS. Validation falls into two primary categories: automated and manual. Automated validation is performed on every product produced for the mission. Manual validation is only performed on a subset.

Automated validation is performed as a part of the archiving process, and is done simultaneously with the archive volume validation. Validations performed include such things as verification that the checksum in the label matches a calculated checksum for the data product (i.e., that the data product included in the archive is identical to that produced by the real-time process), a validation of the PDS syntax of the label, a check of the label values against the database and against the index tables included on the archive volume, and checks for internal consistency of the label items. The latter include such things as verifying that the product creation date is later than the earth received time, and comparing the geometry pointing information with the specified target. As problems are discovered and/or new possibilities identified for automated verification, they are added to the validation procedure.

Manual validation of the data is performed both as spot-checking of data throughout the life of the mission, and comprehensive validation of a subset of the data (for example, a couple of days' worth of data). These products are viewed by a human. Validation in this case includes inspection of the image or other data object for errors (like missing lines) not specified in the label parameters, verification that the target shown/apparent geometry matches that specified in the labels, verification that the product is viewable using the specified software tools, and a general check for any problems that might not have been anticipated in the automated validation procedure.