NSIDC- National Snow and Ice Data Center
NSIDC offers hundreds of scientific data sets for research, focusing on the cryosphere and its interactions. Data are from satellites and field observations. All data are free of charge. - https://www.re3data.org/repository/r3d100010110
They are different funding sources sharing the same basic catalog system with NASA DAAC; but the staff are often different, the processes are usually fairly different, and even the type of data archived is different.