This batch of recovered Nimbus images was converted from film to digital; there was another [1] where the analog data from magentic tape was digitized.
Interesting. I was thrown off by their characterization of the images as "grainy 16-bit grayscale satellite pictures" as the word grainy seems to connote poor image quality, while 16 bits of gray is excellent. Perhaps what they are (confusingly) trying to say is a very good scan of grainy film.