There's only one s in the name thus it makes no sense as you pronounce it. Also probably everyone else will read it /jupi-star/.

No, people will read it as a variation on jupyter, as intended, and jupyter is pronounced (by pretty much everybody) as jupiter.

So Jupystar is pronounced like Jupistar.

Jupis, like lupis.

People try to be too clever with these portmanteaus, and end up with either something unfortunate or unpronouncable.

>So Jupystar is pronounced like Jupistar.

That's what I said. But differs to what you said before. /Jupi/ has only one stress; your previously mentioned pronunciation requires two, also two s rather one that exists in the word.

> Sorry, but you can't unhear it.

I'm sorry, but I can barely hear it in the first place. The lexical stress in Jupystar is entirely different to what you're claiming.

Jupyter is pronounced like Jupiter.

Jupystar must therefore be pronounced like Jupistar.