I'm not sure how this'll work out, but I plan to compare its size to Madama Butterfly who's super close to the asteroid in this frame. And to compare Madama's size, I'll compare her fist to Bayonetta herself, who's fistbumped and gotten in a few very clear shots to compare. I'm still trying to figure out how I'm gonna go about finding Bayonetta's height though.
Then you find the shape that's closest to that asteroid- looks like an ellipsoid, so you look up a calculator, like this one for example, punch the numbers in and you should get the volume.
However, at a glance I think Bayonetta's satellite feat should be more impressive- not 100% sure though, so it might be worth trying anyway. What will be difficult about that calculation would be to find something to compare the meteorite's size to.
Feel free to tell me if I wasn't clear enough, explaining stuff is weird