NASA and the Indian Space Research Organisation (ISRO) have jointly developed an advanced Earth-observing synthetic aperture radar (SAR) radar system, NISAR, with an anticipated launch date of April 2025. The NISAR mission will map nearly all of Earth’s surface every 12 days, collecting comprehensive measurements of land surface changes that inform Earth system models and provide timely information for disaster monitoring.
As NISAR prepares for launch, teams across NASA have been collaborating to ensure that the new mission data are ready to be operationally received, processed, and distributed by NASA’s Earth Science Data and Information System (ESDIS) Project. NISAR will be the first dual-frequency SAR to launch, and is expected to produce as much as 85 terabytes of data per day. Checking that the data can be integrated into NASA’s Common Metadata Repository (CMR) is a crucial step in confirming data pipeline readiness. CMR catalogs NASA’s Earth observation data and associated metadata records.
The Analysis and Review of CMR (ARC) Project team, which is part of the Interagency Implementation and Advanced Concepts Team (IMPACT) based at NASA's Marshall Space Flight Center in Huntsville, Alabama, contributed to this effort by conducting a detailed metadata quality assessment for 13 NISAR collections, along with one granule from each collection, to verify that the metadata was correct, consistent, complete, and meets CMR metadata standards. These standards are determined by the Unified Metadata Model (UMM).
The ARC team conducted reviews by using simulated data, supporting data documentation, and ARC’s metadata framework, which enabled them to identify and provide recommendations specific to metadata elements and assign a low, medium, or high priority to the recommendation. ARC has successfully used this framework to review metadata across all NASA Distributed Active Archive Centers (DAACs) to enhance consistency for all of NASA’s Earth observation data.
Ensuring the correctness, completeness, and consistency of the metadata before launch will allow NISAR data to be more discoverable, accessible, and usable by the community immediately after publication. Findings were reported to NASA’s Alaska Satellite Facility DAAC (ASF DAAC), which will be the primary archiver and distributor of NISAR data. While ARC has conducted an independent assessment, ASF DAAC will continually assess NISAR metadata throughout the life cycle of the mission by utilizing pyQuARC (beta), a customizable, open-source Python library that uses ARC’s metadata framework and allows data providers to assess metadata automatically on demand.