MSMS crosswalk to Dublin Core, DataCite 4.7 and PDS4 1.26: tested mappings and converter

Tested crosswalk from the Mission Scientific Metadata Schema (MSMS) v1.0-draft.2 to DCMI Metadata Terms (Dublin Core), DataCite Metadata Schema 4.7 and the PDS4 Information Model 1.26 (common dictionary, Product_Document label), with the data and code used to test it. The package contains the crosswalk in SSSOM, CSV and JSON formats (132 mappings: 40 MSMS elements and four relationships × three standards); the 11 Chandrayaan pilot records; Python scripts for conversion, XML Schema and Schematron validation, round-trip reconstruction and analysis; all converted records; and the results. The README explains the match categories, measures, results, inter-rater agreement (summary only), corrections to the dictionary’s proposed PDS4 alignments, reproduction steps and limitations. Data and documentation: CC BY 4.0. Code: MIT. Third-party schemas are not redistributed; see specs/README.md.Version 1.1 adds two further export conditions: (B) PDS4 with the Mission (msn 1.3.3.0) and Processing (proc 1.4.0.0) discipline dictionaries, and (C) export with MSMS element labels in shared fields, for all three standards. It also adds an exact-only semantic-retention measure, splits round-trip outcomes into normalised match, altered form and recovery through labels, separates shared-field failures into values written and values not written, and includes an audit of the PDS4 shared-field failures. All outputs were reproduced from a clean rerun. This version supports every result in the accompanying journal manuscript.