His GitHub site mentions: "This script processes NASA SMAP L1B .h5 data files", but he doesn't say how he obtains these data files. Is he using an API, or is he using something like an RTL-SDR to pull the data directly?
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
And there’s some info here: https://smap.jpl.nasa.gov/data/
Very cool stuff!