Phased array nulls are industry practice. The U.S.military does the very same thing with GPS antennas on moving platforms.
Here is an unclassified description of how it works. The types of antennas on those Starlink birds are bleeding edge technology. I gave the best description I could without going into classified details or processes. I hold a National Geospatial Intelligence cert and have spent time doing consulting in that community as well as remote sensing for the same community while doing post doctoral work.
https://www.sciencedirect.com/science/article/pii/S2405959521000850
Outstanding… and thank you for the link. I’m an Old Crow™️ and retired Melpar/E-Systems EW engineer, but I have been out of the the business since Raytheon took over. Fascinating stuff!