EarthDaily, a satellite imaging company, announced on Monday that it has been awarded a $3 million contract by NASA to evaluate the compatibility of its observations with the long-running Landsat program. The assessment, conducted jointly with the U.S. Geological Survey, will scrutinize how well EarthDaily's data aligns with the Landsat record, a cornerstone of Earth observation for decades. The work primarily covers data handling and technical support; the scientific performance of the imagery has not yet been judged.
The evaluation highlights a nuanced trade-off across EarthDaily's spectral bands. Its visible and near-infrared imagery offers a nominal resolution of 5 meters per pixel, a significant improvement over Landsat's 30-meter resolution. However, in the shortwave infrared and thermal bands, EarthDaily's pixels are larger than Landsat's, meaning they capture less detail in those wavelengths. Specifically, EarthDaily's shortwave infrared pixels are 95 meters across, compared to Landsat's 30 meters, while thermal pixels are 120 meters versus Landsat's 100 meters. This disparity could complicate direct comparisons, especially for users tracking changes in crop health, water resources, or fire damage over time.
Calibration is the critical factor, as a change in sensor response can be mistaken for a change on the Earth's surface. The company's technical guide mentions binning some bands to improve signal quality, but detector response, noise, and calibration remain essential for meaningful comparisons. The USGS notes that Landsat's thermal data is natively sampled at 100 meters and then resampled to a 30-meter grid during processing, which does not add true detail but standardizes the output.
EarthDaily also reported that eight of its planned ten satellites are now in orbit, with a two-day land-imaging cycle. The company aims for daily coverage of about 92% of the land surface, excluding Antarctica, once fully operational. Its swath width is 240 kilometers, about 30% wider than Landsat's 185 kilometers, allowing more ground to be covered in a single pass. However, these figures describe collection capacity, not the frequency of cloud-free observations, which can limit optical data utility.
The company's calibration approach includes correcting detector gain, aligning spectral bands, and using ground references to cross-check against Landsat and Sentinel-2. Chief Executive Don Osborne emphasized that trustworthy measurements are essential for understanding change, but the fine detail offered by 5-meter pixels answers a different scientific question than Landsat's broader coverage.
NASA's existing Landsat–Sentinel harmonization method illustrates the complexity involved. It uses a common 30-meter grid, consistent atmospheric correction, and adjustments for viewing angles and band differences. A common pixel size alone cannot bridge the gaps between sensors.
NASA's commercial transition initiative has identified water extent, bathymetry, and fire products as initial priorities, requiring both the right wavelengths and frequent observations. The agency insists that commercial products must demonstrate value while preserving Landsat's quality and continuity. The December 7 community town hall will seek input on product specifications, calibration, and business models, indicating that the evaluation is just the beginning.
While the $3 million award is a vote of confidence, it does not guarantee that EarthDaily's data meets Landsat's scientific standards. The announcement lacks specific acceptance thresholds or validation results, leaving the scientific community to await further details.
