Season four’s original run included three weeks of repeats (before the customary rerun season commenced after the first-run premieres finished). Since the series had just returned to the air in January 1963, this meant that the episodes were still very recent (“The Thirty-Fathom Grave,” for example, premiered less than three months before it was repeated!).
The Thirty-Fathom Grave (rerun)
Original air date: 01/10/1963
In His Image (rerun)
Original air date: 01/03/1963
Death Ship (rerun)
Original air date: 02/07/1963
Records are sketchy, but it’s doubtful that “Death Ship” was actually repeated on 5/16/1963: the episode was scheduled, but coverage of Project Mercury’s MA-9 mission started at 9:30 (in all fairness, it probably would've been in bad taste to show an episode about a doomed rocket crew while we had an astronaut in orbit!). I've included it here just in case (in case of what, exactly? I dunno).
The regular summer repeat season would commence on 5/30/1963, so we'll run 'em down in due course.