关于这张图
Engineers are checking to make sure that MIRI is precisely positioned with the ISIM as it slides into position. They have to make sure it's installed exactly where it needs to be within the width of a thin human hair. Visible is MIRI's pickoff mirror, which is the protrusion on the right side of the instrument that looks like a periscope on its side. This is where MIRI grabs light coming from the telescope optics. Also visible is the silver-colored base of MIRI's cryocooled shield, already installed on the ISIM structure and with a hole in it for MIRI's pickoff mirror. MIRI itself has speci…