In TAS it was explained that the asteroid was the whole point of their expedition. Astronomers on Earth found it floating close by the planet so they sent up John to investigate, and then as an added publicity stunt the shuttle would land at one of NYC's airports.
That was why the shuttle crashed in NYC.
Thanks, though tbh having an asteroid swing by close to the Earth is a pretty "random" event so I'm not convinced that it's a better "origin". However it is a more interesting premise given that the astronauts are actually asking for trouble in the TAS version by bringing a sample back!