The top level Sea Surface Salinity thredds catalog is here: https://www.star.nesdis.noaa.gov/thredds/socd/coastwatch/catalog_smos_smap.html
SMOS Aggregated: https://www.star.nesdis.noaa.gov/thredds/socd/coastwatch/catalog_smos_aggregated.htm
SMOS Per-file: https://www.star.nesdis.noaa.gov/thredds/catalog/SMOS/catalog.html
SMAP Aggregated: https://www.star.nesdis.noaa.gov/thredds/socd/coastwatch/catalog_smap_aggregated.html
SMAP Per-file: https://www.star.nesdis.noaa.gov/thredds/catalog/SMAP/catalog.html