If SpaceX puts up a livestream and then scrubs for technical reasons, this market resolves No.

If it can't launch due to weather or range violations, then the market remains open.

If the hold down clamps release, this market resolves Yes.

If the engines ignite but the hold down clamps don't release, this resolves No.

SpaceX is allowed to pause the countdown or recycle before ignition; as long as their livestream keeps going I still count that as their first attempt.

(Let me know if you can think of more corner cases, and if these conditions make sense!)