That would be awesome PR, and not that expensive with starship.

But for low production rate things like telescopes, launch cost is almost negligible even at current launch prices.

A replacement for hubble could be launched with a single falcon 9. Building it would cost more than a billion.

The James Webb Telescope is at 10 billion USD and counting. Launch with very expensive Ariane 5 will cost maybe 200 million USD, so ~2%.

I don't know why you're being downvoted... maybe it's the "no charge" aspect of your post, but SpaceX offering to send up research telescopes for at-cost-of-launch, or maybe a little over, would be a great philanthropic endeavor.

It would be a great philanthropic endeavor indeed, but I personally have a problem with suggesting they have to do this to "pay back" to the community. They've already paid back to everyone who ever considers launching anything to space, by cutting off a zero out of launch costs - and they're about to cut off another zero.

Launch costs tend to be a small part of mission costs for bespoke scientific hardware - but what makes those missions expensive is a feedback loop: rare and expensive launches -> need to make best use of the mass budget -> increased complexity -> need to make more robust -> increased complexity -> more expensive -> rarer launches -> more expensive launches. SpaceX just kicked that loop into reverse. With that much cheaper launches, people can afford less robust and less complex missions, and do more of them, which lowers the costs as scale kicks in.

SpaceX is making space cheap. That's already a great gift to everyone.