I know a lot of people experience vertigo, depending on what they are viewing.
The good news with a lot of newer laptops (and hardware configurable desktop PC's), is that you have two video outputs, and so could actually connect up two projectors, and in the OS set them up and "Extended Desktop" instead of just "Duplicate Screen", which means you could set up the projectors in such a way (edge to edge for the projected area) that it would be a massive viewable area of what's on the screen.
How cool would that be, if you have a large area to project on, such as a ceiling or very wide and tall wall!
Here is a projector for under $50 not including shipping):
https://www.amazon.com/dp/B01DMD7QTE/ref=cm_sw_em_r_mt_dp_U_GveeFb2WQEVKRAnd that has the usual connectors.
then this one, I like the look of it, very slim line, and under $55 - not including shipping):
https://www.newegg.com/p/0FC-00WR-00078That one is quite different, not only does it have some of the usual connectors on it, but you can also connect it via USB! and its probably quite bring at 400 lumens.
So you can see, there are a lot of choices, and they wont break the bank.
The first link above, I bought that one, and its pretty good for such a small projector. Just know though that at that price for each projector, if the bulb were to die, or anything else fail, its not going to be worth getting the bulb replaced, or the hardware fixed (warranty or not), and is pretty much disposable.
Still though, its very cool to do with one projector, and I think it would be amazing with a second one. So, I may just go ahead and buy another projector (probably the one in the second link), and give it a try.
Certainly food for though, on how to get more enjoyment out of Universe Sandbox without going crazy and expensive.
DeVoiD