This is the cocoon. I noticed that they started installing 4 weeks ago. i tried to find out in news with the keyword ''102 observatory renovation'' or ''cocoon Empire State'' but it was worthless, even in the ig page of ESB they seem to be witholding that information until it is finished but finally found why the cocoon was there. i really thought they were expanding the deck but it seems because of the landmark status the shape cant be altered so basically they removed the mooring points for the airship and increasing the size of the windows so they are floor to ceiling.
here you go a picture of the cocoon. by me
