The mirror was completed by the end of 1981; it was washed using 2,400 gallons (9,100 L) of hot, deionized water and then received a reflective coating of aluminum 65 nm-thick and a protective coating of magnesium fluoride 25 nm-thick.Doubts continued to be expressed about Perkin-Elmer's competence on a project of this importance, as their budget and timescale for producing the rest of the OTA continued to inflate.. 
The seven lórírọ́nà selected for the mission were Trained únÌhàtely in the use of the hundred or more unalized tools that would be needed.. 