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The principal of my tiny school in Japan was presenting to a student to suggest he make a speech on the Space Shuttle's reentry aspects.

He included newspaper articles on the Columbia space disaster.

From Daily Yomiura newspaper 2003, a Japanese space expert called Nabuo Nakatomi speculated that incorrect angle of reentry caused the Columbia shuttle reentry disaster. Was there any truth that incorrect reentry angle was a contributing factor?

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    $\begingroup$ Could it be spelled Nobuo Nakatomi (which shows up in searches for Japanese space experts) rather than "Nabuo"? This is unfortunately paywalled so I can't read it, but google results includes Alternative international cooperation in space dev... include "Need for more cost-effective space application projects – ... space experts with the preconception in the ... Nobuo Nakatomi, Japan's Design Ideas Was." $\endgroup$
    – uhoh
    Jun 10, 2023 at 5:53
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    $\begingroup$ Nakatomi is also mentioned in Japan Times' 2003 article Japan praises China's spaceflight (also paywalled) I think step one will be to FIND the "Daily Yomiura newspaper 2003" quote and get it translated to find out what they actually said. Is this plucked from a list of several speculative possibilities just moments after the event, or is a serious theory even after much more information was available? $\endgroup$
    – uhoh
    Jun 10, 2023 at 5:57
  • $\begingroup$ The Space Shuttle Columbia disaster happened on February 1, 2003, so an undated quote from 2003 could be from anywhere between hours and almost a year later. Anyway, you've asked about a contribution - I think the final report will include information on the reentry and if there was any significant deviation from nominal it will be mentioned there, so this question is certainly answerable. $\endgroup$
    – uhoh
    Jun 10, 2023 at 6:02
  • $\begingroup$ The same amount of heat is generated when decelerating from 27,000 km/hr, no matter whether you enter on the correct angle of entry or not. It only impacts how quickly it builds up. $\endgroup$
    – RonJohn
    Jun 12, 2023 at 14:42

1 Answer 1

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tl;dr Trajectory issues were considered in the failure investigation but were determined to be non-contributing.

While the physical cause of the Columbia accident (damage to the thermal protection system from an impacting chunk of foam shed from the External Tank) is well known, other causes were considered and eliminated during the investigation.

The methodology used was construction of a "fault tree", described here in Columbia Accident Investigation Board (CAIB) Report Volume 1, Chapter 4:

The NASA Accident Investigation Team investigated the accident using “fault trees,” a common organizational tool in systems engineering. Fault trees are graphical representations of every conceivable sequence of events that could cause a system to fail. The fault treeʼs uppermost level illustrates the events that could have directly caused the loss of Columbia by aerodynamic breakup during re-entry. Subsequent levels comprise all individual elements or factors that could cause the failure described immediately above it. In this way, all potential chains of causation that lead ultimately to the loss of Columbia can be diagrammed, and the behavior of every subsystem that was not a precipitating cause can be eliminated from consideration. Figure 4.1-1 depicts the fault tree structure for the Columbia accident investigation.

generic example of a fault tree

CAIB Appendix D03 lists all the possible causes from the fault tree that were eliminated as potentially contributing to the failure. "Incorrect trajectory" was considered and eliminated: four trajectory-related entries are listed in the fault tree by "Fault Tree Element" name and description (apologies for all caps - direct quote).

  • AC - AERODYNAMIC BREAKUP DUE TO IMPROPER ATTITUDE / TRAJECTORY CONTROL
  • ACCF - IMPROPER ATTITUDE/TRAJECTORY CONTROL DUE TO COMMAND FAILURE
  • ACEF - IMPROPER ATTITUDE/ TRAJECTORY CONTROL DUE TO CONTROL EFFECTOR FAILURE
  • SFOML-WING-7-14 - HIGHER HEATING DUE TO OFF NOMINAL TRAJECTORY

Note that a white background in the following images means the cause was eliminated.

portion of the fault tree table - relevant text extracted above

portion of the fault tree table - relevant text extracted above

portion of the fault tree table - relevant text extracted above

References:

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    $\begingroup$ Kudos as ever for the amount of work you put into this stuff. $\endgroup$ Jun 12, 2023 at 7:34
  • $\begingroup$ I don't see any point where the evidence is explicitly stated so plenty of space for someone else to post an answer. $\endgroup$ Jun 13, 2023 at 23:00
  • $\begingroup$ @user2617804 what else would you like to see? No one in the MCC reported any trajectory issues during entry, so it's obvious that there were none. But I dislike to post "absence of evidence" answers, so I found a CAIB document where the hypothesis was explicitly rejected. $\endgroup$ Jun 14, 2023 at 2:10

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