Qfyilyi

This may be a trivial question, but why did the amount of dirt on the ICC lens cover change so much between the two exposures? How much time elapsed between the two images? When will it be safe to remove the lens cover? Is the same cover used to protect against dust storms later on?

Image 1 is the later one, taken at 13:59 on the same day:

image 2 taken at 13:34:

This is the first image:

Here is the second image:

In the first image, beyond the dust particles, there is an almost unobstructed view of the surrounding and the horizon. In the second image, we see that there are obstructions, and it is obvious that the camera is placed somewhere on top of the main body of the craft.

Now, here is a schematics of the craft:

This shows that there are two cameras, one attached to the Instrument Deployment Arm (Instrument Deployment Camera), and one on the side, below the deck (Instrument Context Camera). All of the above lead to the conjecture that the first picture was taken by the ICC, while the second one was taken by IDC.

Finally, it is nice to see that my conjecture is confirmed by NASA here and here.

It appears that the question was actually about the two pictures taken by the ICC immediately after landing (I was under the impression that the second version was just a digitally processed version of the first image when I was watching the live event, but it turns out that they are two separate images).

So here is the first image, with the time stamp 13:34:21.

Here is the second image, with the time stamp 13:59:31, taken approximately 25 min after the first image.

In order to compare the two images, I made a GIF animation:

The first image is the one with more dense black spots in the upper right corner.

From here at least two things clearly stand out:

• Overall, the black spots are moving downward. This is most probably due to gravity.


• Especially towards the middle, many black spots are disappearing.

I am not an authority on InSight, and I can only conjecture here that the black spots are some sort of condensate (possibly water), and sublimation is responsible for the disappearance of the spots.

The images are taken half an hour apart, I suspect the first image was taken shortly after landing. That would mean the dust that was sent flying when the spacecraft landed has had time to settle in the second image.