Dan and the US team, go forth and charge.
The only way to succeed without charging is with a volunteer corps and open source code, so unless you go that route you need to eat to develop.
I’m not a scientist in any capacity nor particularly interested in astrophysics, I do, however, love to explore universe and enjoy the beauty it has to offer. It was interesting to test gravity on extreme scales and see scales of distance.
I bought US 2 full-price on a whim while browsing Steam many moons back and never once regretted it and I’d be willing to shell out a good chunk of change for US 3. It’s what I’ll be using to install a love of the space to my daughters as they get older and my own playtime on the side.
Besides, it would be nice to see the US line expand development under blooming staff growth from fiscal success.
A good product is worth a good dollar, bottom line.