I'm looking for a countable noun for an act of taking a picture by a satellite, to say for example several "action of taking a picture". I think that word "shooting" doesn't fit here.
I want to say something like this:
This satellite performed 10 [taking a picture acts] over the last day.
I don't want to say "took 10 pictures last day", instead I want to focus on the act itself.
another example
we got corrupted data from the navigation system during 5th [taking a picture act].
Here corrupted data in no way relates to taking a picture. Taking a picture act here just marks a period of time when it happened.
Best Answer
We also say that a satellite camera does sampling and scanning, so countable nouns would be samplings and scans.
P.S. The phrase OP uses, "taking a picture acts" [sic], is meant to be a generic placeholder, of course, but "picture" is vague and imprecise nonetheless. Lay folk tend to use the terms "picture" and "taking a picture" for a very wide array of activities, still photography, thermal scans, radar imaging, and so forth. Satellites could be doing any or all of those things.
But let's stipulate that OP is referring to using a camera with a high-resolution optical magnifying lens to capture visual detail. Even then we could use the terms "sampling" and "scanning". To sample means to "take a representative selection of something", and there is no requirement that the selection be a tiny amount, or that it be of a physical substance. A satellite-mounted camera could take snapshots at periodic intervals which is a kind of sampling, or it could take snapshot-after-snapshot in fairly rapid succession, thereby simulating a terrain "scan". Even a "moving picture" is simply a collection of snapshots.
Another way that sampling is used in satellite imaging is with respect to the granularity or resolution of the image. The distance between pixels might correspond to one meter to one centimeter. So the image itself is only a kind of sampling of the terrain's visual detail.