Two new reports from NASA’s Commercial Satellite Data Acquisition (CSDA) program evaluate data from the Umbra X-band Synthetic Aperture Radar (SAR) satellite constellation for NASA’s Earth science research and applications community. The results of these evaluations help inform NASA program management and the user community about the quality of these commercial data for use in NASA science.

He CSDA Umbra SAR Principal Investigator Evaluation Summary Umbra Synthetic Aperture Radar documents the findings of the evaluation teams. The teams had access to the Umbra archive, as well as the ability to commission the Umbra constellation with new acquisitions. The tasking capability allowed evaluation teams to test the usefulness of Umbra data in time-sensitive workflows and monitor areas experiencing rapid changes and/or emerging environmental conditions, such as harmful algal blooms.

Although the Principal Investigator’s Evaluation Summary supports the use of Umbra SAR data for NASA’s Earth science research and applications in general, it noted several strengths and weaknesses of Umbra’s X-band data. Strengths included access to a constellation of very high spatial resolution X-band SAR satellites; assignable access to high temporal repetition opportunities with rapid response; imaging flexibility with a variety of azimuth and incidence angles; and the company’s Open Data Program. In contrast, PI teams reported weaknesses, including issues with Umbra geolocation (noting large and small geolocation errors), limited software compatibility, metadata, and missing technical documentation.

Besides, he CSDA Umbra Umbra SAR Synthetic Aperture Radar Quality Assessment Report documents the results of radiometric and geometric analyzes performed by NASA subject matter experts (SMEs) recruited to evaluate the fundamental quality of the Umbra data following the joint evaluation guidelines of NASA and the European Space Agency (ESA) (ESA-NASA, 2024).

Conducted primarily on Single Aspect Complex (SLC) Tier 1 data products in Sensor Independent Complex Data (SICD) format, along with some additional Tier 2 products used in scientific usability evaluations by the evaluation team, CSDA SMEs found that the spatial resolution of the data matched Umbra specifications. However, the quality analysis results for geolocation accuracy did not universally match company specifications. Taking these results into account, the SMEs concluded that “the overall positioning performance of Umbra data did not meet the expected accuracy.

Regarding the radiometric performance of the data, which was evaluated in terms of absolute accuracy, stability and sensitivity, the SMEs found the data to “underperform.”[ed] relative to that of well-calibrated reference SAR systems.”

The CSDA program was established to identify, evaluate, and acquire data from commercial sources that support NASA’s Earth science research and application objectives. NASA’s Earth Sciences Division recognizes the potential impact that commercial satellite constellations can have in fostering/enabling efficient approaches to advancing Earth system science and the development of applications for societal benefit. Commercially acquired data can also provide a cost-effective means to augment and/or complement the suite of Earth observations acquired by NASA, other U.S. government agencies, and international partners.

To read the full reports, see the links under the “Assessment” heading on the CSDA Umbra Commercial Suppliers webpage.