And I really fail to see why we build ONE James Webb. What of there is anomaly at launch? Why not build two? If one fails, we have another. If both launch,

And I really fail to see why we build ONE James Webb. What of there is anomaly at launch? Why not build two? If one fails, we have another. If both launch, we have two telescopes! (Well, I don't know how difficult to have to instruments bobbing around L2 point). Most of the price of JW is research and development anyway. It will not be 2x the price, it will be much less, so even if we ignore the possible scientific output, from a purely financial perspective two would be a bargain. I just don't understand why we build one JW, and one Hubble, but we can afford 12 KHs and god know how many other spy telescopes...