They are half-inch wide 7-track tapes. It's the 7-track bit that makes them difficult to read (I have a half-inch machine but it's 8-track). I think it was NASA and a few other government agencies using this 7-track format (or 1-inch 14-track), rather than the 1/2-inch 8-track / 1-inch 16-track used in audio studios.

The workflow for these tapes is described on the Chilton Computing website [1].

(Note: this is analogue 7-track, not to be confused with the digital 7-track format used by early IBM mainframe machines).

[1] http://www.chilton-computing.org.uk/acl/applications/satelli...