A space observatory or other spacecraft with the capabilities of JWST are going to be a “large, complex projects” for the foreseeable future simply because it is pushing the limits of precision and capability in manufacturing. JWST is expensive (arguably far more expensive than it should have been because it was not given funding priority to get the mission launched in a timely fashion). Again, even if there were funding to produce these in serial fashion, there just isn’t the technical throughput to design, build, and deploy these things by the dozens to achieve some hypothetical economy of. scale. They are incredibly complex machines and there are literally millions of hundreds of thousands of person-years of effort that has gone into JWST, and there is neither the trained technical base nor facilities to expand the pipeline to make spacecraft of this class by even an order of magnitude. Nor could you replace a JWST by a hundred smallsats; it does a very specialized thing that requires particular capabilities that can’t just be produced by a bunch of cheaper satellites ganged together.
This discussion is actually kind of ironic because when it comes to crewed exploration of Mars I point out that we could pepper the planet from pole to pole with Perseverance-type rovers for far less than the cost of a single crewed mission I get shouted down by the space enthusiast community claiming that human astronauts could cover far more ground and do more work in a month than these “slow and dumb” machines could do in the years that they would operate, notwithstanding the incredible difficulty and time lost in supporting human explorers both on planet and for the transit there and back. Of course, we could not afford to build hundreds of Mars rovers any more than we could build a continuous production like of large space observatories because of the technical requirements and limitation of available technical labor and facilities but the point remains that practical space science isn’t just about funding but the actual capability to produce and send spacecraft (or people) into space, and the surface-to-orbit transportation aspect is one small segment that isn’t even that much of a cost or capability driver for large programs.
You’ve hit on a salient point here; NASA tends to focus on big projects because they are less likely to get cut even in lean years, and part of the problem with cost growth on JWST was cutting down funding to some minimum and stretching out schedule which increased the overall cost by somewhere around US$ 2-3 B, while smaller projects get cut, often to pay for the crewed space program that produces very little in useful science beyond studies of human physiology in freefall and orbital space that are pretty much telling us that human beings do not do well in the space environment. It would be great to have secure funding along different levels of programs but NASA is ultimately at the mercy of the budget that Congress allocates, and despite the hue and cry that NASA doesn’t manage funding well they’ve often done amazing work on a relatively shoestring budget for uncrewed exploration.
“Big Science” projects get a lot of criticism for eating up the funding from useful smaller programs, and much of that criticism is valid as it stands, but there are certain things that can only be done with “Big Science”. We would not have statistically definitive evidence the Higgs Boson without the LHC, nor produce pentaquark particles with the Tevatron or other lower energy devices. Certain types of scientific work require large systems and massive budgets to be successful, and the answer isn’t to stop supporting “Big Science” but rather to make sure there are also dependable allocations for smaller but still useful scientific research.
Except no one is ever going to fund ten missions with the expectation that nine of them are likely to fail even if it were cumulatively cheaper than a single mission; not only is managerial psychology not going to accept failure after failure, but again there is the opportunity cost that comes with repeated failures vice having a successful mission and observatory that can be relied upon with high confidence.
The problem isn’t just “the harsh environment of space” (although it is quite challenging, and in particular the thermal issues that arise from only being able to cool through radiation) or “the stresses of launch” (again, a more significant challenge than you would imagine even with a supposedly “robust” design because a spacecraft with adverse modal dynamics can cause a launch vehicle to become unstable or break regardless of how much payload capacity it has) but the fact that a space observatory can’t really be serviced or maintained like a ground-based telescope, has to be able to operate with virtual autonomy save for communications, and doesn’t have any kind of stable foundation which means that it relies on extremely precise inertial systems and flywheels to maintain precise orientation versus the many tons of concrete and anchors into bedrock that keep terrestrial observatories from wantonly floating away.
It is certainly not the case that you could take a ground-based observatory design and just launch it into space on a sufficiently capable rocket with any expectation that it would work; space-based systems have entirely different design requirements and drivers, and again, the cost of failure and impact upon program schedules is far more of a driver than the cost of launch such that even if the cost of a replacement launch is negligible the loss of observing time, the opportunity cost of assigning technical labor and facilities to build spacecraft and run missions with low probability of success, and the human lack of tolerance for repeated (even if expected) failures just don’t make it viable to accept a mission with a 10% success rate, regardless of how much it might reduce cost.
Stranger