Tycus (1999) on Netflix

Plot summary

Peter Crawford, an astronomer, finds a comet on a collision course with Earth in 1989 and brings the news to a council that will not listen. Ten years on, the comet, named Tycus, is closing in, and it is headed not for the planet itself but for the moon, whose shattered fragments would be drawn down by Earth's gravity. Crawford has begun hollowing out a vast underground city beneath the Sierra Mountains to shelter a chosen few. Jake Lowe, who has been looking into the work in the mountains, learns how few places the refuge holds and asks Crawford to admit his pregnant wife as well. Crawford agrees, because he wants his own wife and daughter inside too.