Higher-Resolution Views of the Universe Are Roadblocked by Formation Flying Technology
Space telescopes offer vastly superior sensitivity to ground-based systems, but enhancing their resolution requires spacecraft with sub-micron precision.
Angular resolution of telescopes is limited by the size of the primary optic. Coherent aperture synthesis (interferometry) gets around this by coherently combining signal from separated telescopes where the resolution is proportional to the baseline separation. This has been very successful in the radio (see Event Horizon Telescope) but in the optical regime requires extremely difficult optomechanics and controls, and the sensitivity on the ground is inherently limited by the coherence time of the atmosphere.
Foundational Capabilities (1)
Even small optical interferometers in space could vastly exceed the sensitivity of ground based systems, and directly image Earth-like planets around Sun-like stars, but this requires advances in precision (<1 micron) formation flying technology for spacecraft. [This is both an engineering bottleneck, and a scientific bottleneck]