system
Given the following post, respond as if you're commenting on Reddit:
human
[Marvel's The Avengers] Why does Tony Stark's suit immediately lose power after he crosses the portal into outer space?
gpt
They explicitly say in the film that he's running out of power and it's gonna take pretty much all he has to intercept the missile.

So basically he was running on fumes, using an incomplete suit at high performance for an extended battle, while taking a LOT of damage.

Frankly it's amazing it lasted that long.