The same is true for many other space missions, and quite frankly doesn't matter. For example, check the projections on the James Webb space telescope and see

The same is true for many other space missions, and quite frankly doesn't matter. For example, check the projections on the James Webb space telescope and see for yourself how the costs doubled and tripled. IMO we shouldn't look at it in terms of those costs; even if double and tripled they are not that high. Look at their effect on the larger picture.