[Pseudoscience-is-malarkey (OP)]

The New Horizons spacecraft cost three-quarters of a billion dollars. Can the James Webb telescope get the same data without having to visit them?

[evan_au]

The James Webb Space Telescope cost $US10 billion. It was a gross budget blow-out!
- They considered canceling it several times, but then it became "too big to fail"

The JWST cannot take pictures of Pluto/Charon in anywhere near the same detail as an up-close fly-by.
- And it cannot take pictures of farther objects, either, like Arrakoth in the Kuiper Belt
- JWST is an infra-red telescope, and you need a much larger dish to get the same resolution as a visible-light telescope like Hubble. JWST has similar resolution to Hubble.
- Hubble was used in selecting Arrakoth as a target to visit beyond Pluto. Hubble can only see it as a faint dot of light, which moves against the background stars as Earth goes around its orbit.
- But New Horizons took high-resolution images of Arrakoth from up-close. Not possible with Hubble.

https://en.wikipedia.org/wiki/486958_Arrokoth