Although launch costs are not insignificant, for a billion dollar payload they are not the driving factor. James Webb Space Telescope (JWST) grew from an initial estimate of US$1B at the program start in 1998 to over US$5B by Preliminary Design Review (PDR) in 2008 and then to US$6B at Critical Design Review (CDR) in 2010. Program delays and schedule slipped cost additional cost increases up to an estimated US$9.7B by launch (in part because of some additional testing and rework and inflation but mostly just for the need to keep the support team and activities in place and stretched out over those years instead of the scheduled deployment date in the 2015-2016 timeframe at CDR).
Space observatories are a very sophisticated and very niche space application and both the engineering expertise, skilled fabrication and assembly labor, and the facilities to test such a large spacecraft to the required conditions are all very limited and perennially in high demand (as they are essentially the same as unnamed national security payloads operated by the National Reconnaissance Office that frequently take priority), so even if launch was so dirt cheap that it was just a rounding error in total budget (which for JWST it effectively was) you still wouldn’t launch an observatory without extensive testing because of the lost of invested effort and cost that would represent. Large telescope optics are always ‘delicate’ instruments that require the highest possible precision feasible.
The “launch your sat into space and see how it does, then iterate as necessary” is a workable philosophy with CubeSats that are assembled by interns and low-cost junior engineers so enthusiastic about getting their foot in the door in the satellite industry that they’ll work for peanuts and mostly worthless stock options but is never going to be a viable approach with large satellite observatories or other really complex payloads. Space ‘enthusiasts’ often make the mostly artificial distinction between ‘NewSpace’ and ‘OldSpace’ companies, but the actual functional distinction is between microspace and macrospace: that is, payloads that are easy to fabricate and dirt cheap, doing simple things that aren’t mission critical or can be iterated quickly; and larger complex payloads that take years to design, fabricate, assemble, and test because of their innate complexity and mission critical need. Large space observatories are inherently in the macrospace category just because of the size, complexity, and necessary precision of the imaging systems regardless of how cheap the ride to orbit is.
Stranger