The following information obtained from UNAVCO's online DOI system:
(https://www.unavco.org/data/doi/search/search.html)

NASA’s Global GNSS Network (GGN) - MCM4-McMurdo GPS Station P.S.
Start: 25-Jan-1995
End: 14-Nov-2022
Operators, GNSS, 2005, NASA’s Global GNSS Network (GGN) - MCM4-McMurdo GPS Station P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/3HY6-CJ28