SpaceX's IFT4 Was expected to push the flight envelope out further, joining the dots between the orbital speeds and the flip and burn landings which had been demonstrated a few years ago.
There were a few changes to this flight profile, and in particular, intentionally discarding the hot staging ring appears to have freed up enough margin to make a soft landing of the booster possible.
But the real story of this flight was watching as the heat of atmospheric entry burned through at least one of the control flaps, but the spacecraft kept flying, remained in control and proceeded to a soft touchdown in the Indian ocean. The hardware was on show, but the software was performing the real miracles today.

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