The article does say
“The mirror segments have undergone a series of polishing and cryotesting cycles.”
I forgot to add
“The mirror segment, an engineering development unit, was successfully polished to an accuracy of less than 20 nanometers, or smaller than a millionth of an inch. The process, called cryo-null figuring, ensures that when the mirror reaches cryogenic temperatures, it will change its shape into the exact optical prescription needed for its mission.”
It’s a mirror that can fix itself if there is a problem!
It was micro gravity that the Hubble people screwed up, IIRC.
Well, let’s just say that NASA is such a bureaucratic organization that I have severe doubts they actually learn their lessons.