What is this disc over Area 51

Hi everyone,

I was searching on Google Earth the other night around Area 51 and found something interesting in an image. I am hoping someone here might know what it is. There is a round disk in the air covering a corner of the building and it is creating a shadow on the ground.

I am sure there is a reasonable explanation for what is in the image, like maybe a satellite dish? Does anyone know what it is? Or direct me to a previous thread if this has already been discussed before. I couldn't find a thread with this in it after I searched for one.

I am new to google earth so I am not sure how to post a link to it directly, if you go on google earth and do a search for area 51 then just scan the area for it. It is in the upper left of the area 51 search results.

Or here are the coordinates: 37°14’50,10” N 115°49’10,51” W

I would go with a mesh antenna. The white center is closer to one edge than the other, indicating it is set an angle like an antenna would be. You can also see the building through the disc, indicating that it's not solid.

That is Building 123 (Dish Antenna Building) and 124 (Utility Building for Dish Antenna). At the bottom of the picture you can just see a tiny bit of Building 122 (Range B.E. Office). They are located close to the east end of EG&G Road at the southwestern edge of Groom Dry Lake.