Evolving Scientific Software in Long-Running Observatories: Lessons from the TERENO Sensor Management Migration

Using the example of the TERENO observatories and their integration into the Earth & Environment DataHub, this contribution reflects on the challenges and opportunities of transforming legacy systems into sustainable, community-ready platforms. A central task was the migration of sensor metadata from a tightly coupled legacy system to the Helmholtz Sensor Management System, requiring a clear separation of data and metadata, adaptation to new API-based technologies, and reconciliation of differing data models and vocabularies.

The scale (thousands of devices and tens of thousands of parameters) and the presence of heterogeneous, project-specific edge cases further complicated the process. To address these challenges, we developed the Python-based ODM2SMS tool, enabling configurable, incremental, and reversible migration workflows. Automated processing was complemented by validation routines, staged testing environments, and targeted manual inspection to ensure scientific plausibility.