The Ranger 5 mission launched 57 years ago today. In a photograph of the launch, there's an irregular shroud of wrinkled white material either next to or wrapped around the upper Agena stage of the booster:
It appears to be connected to the launch tower, and unless it was moved away very soon after the point at which the photo was taken it seems like it couldn't avoid interfering with the larger-diameter Atlas stage which will be presently coming to meet it. (Please excuse the mixed tenses in this sentence.)
I couldn't find video of this particular launch, and I don't see anything similar in photos of other Ranger launches.
If I had to guess I'd say it's an insulation blanket, but I don't have anything to back that up.
What is this material? What is happening to it at the instant shown in the photo, and what happens to it as the rocket moves up through or past it?