Cross field kicking of boulders

G39 says that Robots must be in the opponent’s courtyard to “launch” boulders.

G40 says a Robot cannot “cause” a boulder to move from the Neutral Zone into the opponent’s courtyard unless it is carrying the boulder.

To me, “launch” means other than rolling on the ground.

Does anything prevent a robot from being in the opponent’s Secret Passage area (not in the Neutral Zone), and kicking (punching) a boulder hard enough that it rolls under the Low Bar?

How fast does the boulder have to be rolling to breach the Cordura flap?

Once the Boulder leaves your robot, you are no longer in control of it, so it would violate G40.

The intent of g40 seems pretty clear to me. Getting a boulder into the opponent’s courtyard from the neutral zone requires bringing your robot fully through a defense too. (and not just poking your note through either)

That’s the point. If the bot only contacts the boulder while in the Secret Passage, then the “from” point is SP, and not NZ. When the boulder is in the NZ, the bot is not in control of it.

G38 Blue Box includes this for launching

shooting BOULDERS into the air or throwing in a forceful
way

The “or” would seem to exclude any requirement the the boulder be airborne.
I know examples from 2014 where forcefully rolling a ball on the ground was considered launching.
Based on that, I consider what you are proposing (forceful rolling) as “launching”. Hopefully, the Q&A clears this up and doesn’t just leave it to ref judgement with no guidance.

Your robot would project the ball from the secret passage, to the neutral zone and then into the courtyard. There isn’t a scenario where that isn’t the case I can see.

While I haven’t seen the rules enough to say if it’s illegal or not, it would take a lot of force to hit it through the flap. When I was looking at the field, someone was testing out how much force it took, and they had to throw a ball at it as hard as they could, multiple times until it went through. Therefore, not only is it probably illegal, but also unviable.