(cough cough) Excuse me!

I was watching a TV show about the New Horizons spacecraft currently en route to Pluto, and the narrator mentioned that it was launched with an Atlas booster, "America's most powerful booster."

The Atlas 5 is a good booster, though I'm still a bit wary of its Russian-made engine, not because it is Russian-made but because it seems to run at an unbelievably high chamber pressure. I seem to recall a chamber pressure of something like 300 Bar, versus the 70 Bar or so that the F-1 ran at. That's a lot of pressure and I find it a tad worrisome. But it is still a good booster, far and away more capable than the Delta II family. But the claim that it is America's most powerful booster is not true.

The Delta IV Heavy lifts more than the Atlas 552, and the Space Shuttle lifts more yet.

Why does this bother me? I don't know. My only defense is that it is very late at night and I'm very sleepy, but my legs hurt and I can't sleep, so I post useless rants.