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Launches at Kennedy Space Center in Florida were managed by the on-site launch control center. At some point in the mission, authority was transferred to the mission control center in Houston, Texas.

Exactly what event determined the transfer of control centers?

  • Was it a certain altitude? Mission time? Some other sensor?
  • Was it something automatically detected and switched by computer?
  • Or did it require a person (e.g. the launch director or flight director) to manually push a button?
  • "Clearing the tower" is too vague. Who or what determines this? Is it automatic or manual?
  • This question states there is a transfer of authority, but does not answer this question.
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    $\begingroup$ When I first read "What event determined the transfer of control from Kennedy to Houston", my immediate response was "LBJ becoming president". I took a tour in Florida about 20 years ago, and the guide explained that the control center had been moved to Houston because it was obviously much easier for them to be in close contact with operations and to be more aware of what was happening from there. He also said that NASA's motto was "Yesterday the Moon, tomorrow Mars, today the shuttle.", with voice dropping and fading on the last word. Morale must have been pretty bad at the time. $\endgroup$ – Ray Butterworth May 17 at 13:58
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    $\begingroup$ @RayButterworth - That LBJ had anything to do with the Manned Space Center (now known as the Johnson Space Center) being located in Houston is a false meme. The first choice of the committee that selected the location was an Air Force base near Tampa that was about to be shuttered. The committee had to reevaluate when the Air Force reneged on their decision to close the base, with what was the second choice popping to the top. Cape Canaveral (now the Kennedy Space Center) was never in the picture. (continued) $\endgroup$ – David Hammen May 18 at 5:22
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    $\begingroup$ The Cape at that time was out in the boondocks, well removed from any population centers. One of the key criteria for the Manned Space Center was that it needed to be close to a major population center, preferably with one or more respectable nearby universities that could supply an educated workforce. The KSC area at that time had zip. (The further north one goes in Florida, the further South on gets.) Houston ranked highly, as did southern California. Year-round access to water (which turned out to not be needed) ruled out many northern coastal contenders. (continued) $\endgroup$ – David Hammen May 18 at 5:26
  • $\begingroup$ @DavidHammen: How about I post the matter as a formal question? Then you can get credit for a proper answer. $\endgroup$ – DrSheldon May 18 at 5:29
  • $\begingroup$ The prime southern California choice, San Diego, had a problem with being too close to Mexico. A 1947 incident in which a V2 rocket launched from White Sands veered south and crashed very close to a site where Mexican mining companies stored explosives still loomed large. That left Houston as the only viable contender. It turned out that the Air Force re-reneged on their decision to close that base near Tampa, and the rationale behind year-round access to water was never used. But at the time, Houston was the only logical choice after the first choice was removed from consideration. $\endgroup$ – David Hammen May 18 at 5:30
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For Space Shuttle:

In the flight software, "tower clear" was defined as the end of the vertical rise phase when it was OK to start the Single Axis Rotation (aka "roll program"). This happened when the vehicle center of mass was at 376 feet above the Fischer Ellipsoid.

Source - Ascent Nominal I-Loads Definition and Verification (not online)

However, "tower clear" is a phony breakpoint in authority. For all practical purposes, MCC-Houston was in charge after SRB ignition.

A1-5 FLIGHT DIRECTOR AUTHORITY

A. THE FLIGHT DIRECTOR IS RESPONSIBLE FOR OVERALL DIRECTION OF SHUTTLE FLIGHTS FROM SOLID ROCKET BOOSTER (SRB) IGNITION UNTIL CREW EGRESS OR GSE COOLING ACTIVATION, WHICHEVER OCCURS LATER:

  1. THE FLIGHT DIRECTOR IS RESPONSIBLE FOR REAL-TIME IMPLEMENTATION OF OPERATIONS WITHIN THE FRAMEWORK OF THE SHUTTLE OPERATING BASE (REFERENCE (REF.) RULE {A1-2}, REAL-TIME OPERATING POLICY).
  2. THE FLIGHT DIRECTOR IS RESPONSIBLE FOR PROVIDING RECOMMENDATIONS AND/OR OPTIONS TO THE MMT FOR NEAR REAL-TIME DECISIONS WHEN OPERATING OUTSIDE THE FRAMEWORK OF THE MISSION RULES OR THE SHUTTLE OPERATING BASE.

Emphasis mine. Source: Space Shuttle Flight Rules paragraph A1-5

You will search in vain for any example of KSC talking to the crew or sending a command to the vehicle after SRB ignition.

For Apollo:

Not a complete answer but the flight rules are explicitly different and authority does transfer at tower clear.

Complete ground control of the space vehicle passes to the flight director when the space vehicle reaches sufficient altitude to clear the umbilical tower.

Apollo 11 Mission Rules rule 1-21

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  • $\begingroup$ Thank you, this is the answer I am looking for. $\endgroup$ – DrSheldon May 17 at 15:13
  • $\begingroup$ Speculation as to why: After my scientific watching of youtube videos, the Shuttle clears the tower a lot faster than the Saturn V did. Probably not time to do anything anyway. $\endgroup$ – Organic Marble May 18 at 20:41
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Clearing the tower, that is, the rocket was away from its launch tower and was clearly in flight, as mentioned in the answer to this question.

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    $\begingroup$ Clearing the tower is the cue, but the question is asking about the mechanism of transfer. $\endgroup$ – Russell Borogove May 17 at 11:56
  • $\begingroup$ Yes, I noticed that after I posted. Oops! $\endgroup$ – Michael Stachowsky May 17 at 11:59
  • $\begingroup$ This is not at all a satisfactory answer. How is that determined? Human or computer? $\endgroup$ – DrSheldon May 17 at 12:38

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