Is the core designed to be reusable or is that a one-time-use part?

I'd assume if they are landing it, it is reusable. It'd be sort of wasteful to pack fuel for landing, if we were just going to dump the module.

It can be reused, just won't be as it's an outdated model.

They still want it back for data.

The core was supposed to land on the barge, but the video footage got disconnected and they said they don't know what happened to it yet.

Oh, perhaps I have the name wrong. I meant the part connected to the payload with the Merlin engine designed for vacuum, above the three main rockets (the center of which must be the core).

That's the 2nd stage. It's still attached to the payload I believe, so that they can test mid-course corrections to the transfer orbit.

It will relight its engine again in about five and a half hours to depart Earth orbit for interplanetary space.

Thanks.

reusable of course.