US medical schools are not known for their flexibility. Even if there was a shot in the dark that some schools would accept it (and, to be fair, the AMCAS Course Classification Guide would have astrophysics count as a BCPM course, for what it's worth), it would pay you dividends in mental peace to just take what they're asking you to take.
Ultimately you would not be doing yourself any favors missing out on that content anyway, because it's tested on the MCAT, so you will learn it anyway, might as well get some credit for that and unambiguously fulfill the requirement.
I'm always bewildered to see questions like this because this is such a long, uncertain, high-stakes sort of path that even if I could get away with it in theory, the panopticon that is the admissions process (and its actors) itself makes the price of "creativity" around requirements far too steep for any applicant.