Ideas on Viewing the Inside an Industrial Furnace

My company is doing an R&D project where we need to view customer parts inside of a vacuum furnace that will reach 2100 F in temp and 2 bars of pressure during the heat treat process. Installing a viewing window is very unlikely because we would need to install it on the bottom of the furnace and because of the furnace's make up it would result in severly lowering the furnace's lifespan. Does anyone know if there are any cameras/housing that could handle these conditions inside the furnace or have any other ideas on how i could go about achieving this. It does not have to be a live feed it could be a recording that we retrieve after the process is over. Any help is greatly appreciated thank you.