There’s a lot to address here but in short: VFIAX is an index fund, it tracks the S&P500 index, it’s not actively managed, SpaceX will likely be in the S&P500, so my comment around VT applies to VFIAX (as far as the question of exposure is concerned) but to a greater extent than VT (see VT’s composition vs VFIAX’s composition).

Obligatory not financial advice, I’m not an expert, don’t make any financial decisions based on hacker news comments, etc