Aligned, multiple-transient events in the First Palomar Sky Survey (researchgate.net)

Pre-print of a paper which studied 1950 "transients" which - in tl;dr terms - might be evidence of artificial objects in orbit before the satellite era.

Recent comment from one of the main authors:

https://x.com/DrBeaVillarroel/status/1949780669141332205

Previous work: https://www.nature.com/articles/s41598-021-92162-7