The biggest thing you should focus on is getting your ACT up. 30 as a sophomore is actually really solid, but most people that attend ND made between a 32 and 34. You know that, though, so I think you’ll be fine. Also, making some As for the next 2 years of high school will probably help you out.
Sticking with all of these extracurriculars would work out really well for you, but stick with the ones you care about, as colleges like to see commitment over a long period of time. Something that you could add that would help you out would be something service oriented, as something like 90% of incoming freshmen did some kind of community service extracurricular. (The NASA internship sounds awesome!)
The biggest thing I can stress to you is this: there are so many awesome applicants out there (and I think you’ll be one of them), but as so many people here on this board have experienced, nothing is ever a given, even when the statistics all seem right. You can see the post I made like this back in December here:
http://talk.collegeconfidential.com/university-notre-dame/1830620-notre-dame-chances-ill-chance-you-back-for-sure-p1.html
Even though everyone on this post said I had very good chances, as I statistically lined up with everything ND wants in an applicant, I’m currently on the waitlist.
My point is this: if you really, really want to attend ND, don’t just aim for the statistical center of the kids that got in. Do something that really sets you apart and makes you unique.
If things continue like they have been, ND’s acceptance rate will keep falling by a point and a half for the next few years. If you do something that really sets you apart (I don’t know what, that’s up to you and what you’re passionate about), you’ll have no problem convincing any college that you’re deserving of admission.
I hope that I haven’t totally discouraged you - even though you’re on track to getting into ND as you are right now, you should aim as high as you can. Just do your best, as that’s all that anyone can ask of you. I hope I’ve been helpful/motivational 