asteroid or artifact?
In the frame number 4 an "object" appear in the upper left corner. I am not sure hot to classify it, it does not look like some artifacts appearing in other images but it is difficult to tell it is an asteroid since it appears in only one image
Artifact. If you look at it, it is a lot sharper then the rest. That is 1 of the things of the small artifacts: they are very well defined at the edges.