It's a "term of art" (https://en.wikipedia.org/wiki/Term_of_art) specifying that the data collected is passed through the scientific pipelines and being served out to researchers, rather than being used for testing/calibrations/commissioning. Similar phrasing include "science operations" and "science frames". There are lots of odd jargon in astronomy, but no weirder than say "firewall" (as given in the wikipedia article).