https://search.asf.alaska.edu/#/?maxResults=250&dataset=SMAP...
This lets you bulk download the .h5 files once you have an Earthdata account (https://urs.earthdata.nasa.gov/home )
or you can use the libraries if you'd like, https://github.com/nsidc/earthaccess or https://github.com/asfadmin/Discovery-asf_search