It's not a competition.

Yes it is. A healthy one too, that's how the moon landing happenned.

Why not 0 km?

While it would be fun to punt a billion dollar spacecraft into the sun just to see the weird spikes on the telemetry data, you can't actually get any realtime data from the probe during close solar approach. Stars emit quite a lot of RF, and the antenna on Parker has to be small enough to fit behind the sunshield. Parker has to survive each perihelion in a functional state in order to downlink readings.

Presumably after the end of the scheduled mission there will an attempt to get funding for an extended mission to take it in closer. My impression is they can't put it on the official schedule if it's not funded, and speculatively funding spacecraft operations decades into the future would take big chunks out of NASA's budget.

> While it would be fun to punt a billion dollar spacecraft into the sun just to see the weird spikes on the telemetry data, you can't actually get any realtime data from the probe during close solar approach.

Such a glaring blind spot could potentially hinder law enforcement to the point that visibility into future investigations goes completely dark.

What would it take to blow up the sun?

Nothing, it's already blowing up.

Add some H, burn it all, burn all the He, repeat for heavier elements up to Fe then boom.

A large bomb.

Maybe they could go at night?

Lasers? Cooling system?