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Overview of Anomalous Events
During Columbia's Reentry
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Updated 10/25/2007

 
 
 

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Columbia's Reentry During STS-107

General reentry explanation:

The simplest explanation of what occurs during a Space Shuttle reentry is a careful balance of three things.

  1. The rate of descent.

  2. Aerodynamic heating.

  3. Decreasing forward velocity.

If the shuttle descends too quickly through an increasingly dense atmosphere it will suffer extensive thermal damage that may burn through the skin of the orbiter resulting in its loss.  If its forward speed is not decreased sufficiently or if it has not descended to the correct altitude at the right time, it will not be in the proper position for landing and will either have to land at an alternate site or crashed into an unpopulated area after the crew has escaped.

 

Eqn. A1

Reentry Flight Control Parameters 

1.)  1Heating Rate Equation

Qmax  <  70 Btu / Ft.2-Sec.

k  = 4.4695199x10-9

r = Gas Density (Slugs / Ft.3)
V = Velocity (Ft. / Sec.)

2.)  Normal Acceleration Equation

an = L cos a + D sin a

an max  <  2.5 G

L  = Aerodynamic Lift.  See Eqn. A3-1
D  = Aerodynamic Drag.  See Eqn. A3-2

a = Angle of Attack (Degrees)

3.)  Dynamic Pressure Equation

q = 1/2 rV 2

qmax   <  300 psf

r = Gas Density (Slugs / Ft.3)
V = Velocity (Ft. / Sec.)

  1. Determined empirically during Space Shuttle flights and is based on a one dimensional adiabatic steady state heating model.  It is the heating rate for stagnation regions of the shuttles surface during high Mach number reentry atmospheric flight.

Eqn. A2

Six Degrees of Freedom Equations for Space Shuttle Reentry

rc  = Distance from center of

Earth to vehicle C.G. (Ft.)

Q  = Geodetic Longitude.

F  = Geodetic Latitude.

Vr = The Earth's relative

velocity. (Ft./Sec.)

g  = Flight path

angle. (Deg.)

Y  = Velocity Azimuth

angle. (Deg.)

w  = Earth's rotation

rate. (Deg./Sec.)

s  = Vehicle bank

angle. (Deg.)

Eqn. A3

Lift and Drag Equations

5.)       CL0 = -0.14490

6.)       CL1 = -0.02924

7.)       CD0 = -0.07854

8.)       CD1 = -6.15920(10)-3

9.)       CD2 = -6.21408(10)-4

L   = Aerodynamic Lift. 

D   = Aerodynamic Drag.

r  = Gas Density (Slugs / Ft.3)

V   = Velocity (Ft. / Sec.)

Sref  = Shuttle reference surface area (2,690 Ft.2)

m = Mass of shuttle (203,000 lbs.)

CL = Coefficient of Lift.  (Mach > 2.5)

CD = Coefficient of Drag.  (Mach > 2.5)

a = Angle of attack (Degrees)

 

To help keep the aerodynamic heating to a minimum the shuttle has an extremely shallow rate of descent.  A typical reentry starts with the shuttle at an altitude of 76 miles and a distance of 5,063 miles from the landing site this is equal to a rate of descent of only 1.5%, see "Reentry Aerodynamics", in the document, Shuttle_Flight_Properties.pdf.  However, simply flying with a constant shallow rate of descent isn't enough due to changes in the properties of the atmosphere as you drop through it as well as local weather conditions.  To accomplish the feat of keeping temperature distance and velocity in perfect balance, the shuttle also has a suite of complex guidance software that takes it through a few fairly simple flight maneuvers designed to keep all of those factors in perfect balance.  By taking sensor reading from different areas of the shuttle and the outside atmosphere for temperature and pressure, as well as being fed other data such as current altitude and distance from the landing site, the shuttle's computers calculate the correct time to perform the maneuvers.  A human pilot can not take all this data and make all the calculations fast enough to control the shuttle through the critical phases of reentry.  It has been estimated that increasing the rate of descent just a few percent at the wrong time could lead to a worst case scenario.  This is why the shuttle must be on auto pilot for most of reentry and also why the avionics system is so important that it has a total of five identical flight computers and no less than two backup units for every other flight critical system.

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A similar map showing time zones around the world is also available.

World Time Zones

February 1, 2003 STS-107:

Eyewitness accounts of the Columbia's last few minutes indicate that the shuttle was losing material from very early on during reentry.  Some initial accounts report debris shedding being spotted by ground observers at 5:45 a.m. PST This was probably not possible when the shuttle was high over the middle of the Pacific Ocean.  Other accounts and at least one video tape made in California at 5:53 a.m. indicated that debris was coming off the shuttle at that point.  Some witnesses said it looked like the shuttle was, "dropping flares", as it flew over California. At this time the shuttle was at an altitude of 233,450 Ft. and had just barely reached its maximum temperature.  This would tend to indicate that damage was being done to the shuttle well before 5:53 a.m. and well before the maximum temperatures were reached.  This is also the point where temperature anomalies and sensor problems started to be noticed.

Deorbit burn:

At 08:15:30 a.m. EST (13:15:30 GMT) the Columbia initiated de-orbit burn for 2 minutes and 38 seconds to position itself for Entry Interface (EI).

STS-107 Reentry Data

Pre De-orbit burn data

  • Orbit Inclination: 39°

  • Location (latitude/longitude in degrees):  -35.00000 S. / 85.0000 E.

  • Time:  13:15:00 GMT

  • Altitude: 929,016 Ft. (175.95 statute miles)

  • Velocity: 17,496 mph (25,661 Ft./Sec.)

Post De-orbit burn data

  • Orbit Inclination: 39°

  • No change

  • Location (latitude/longitude in degrees):  -33.58333 S. / 98.1667 E.

  • Change:  757.39 statute miles

  • Time:  13:17:38 GMT

  • Burn duration:  2:38

  • Altitude: 929,016 Ft. ( 175.95 statute miles)

  • No change

  • Velocity: 17,319.7 mph (25,401 Ft./Sec.)

  • Change in velocity: - 176 mph

 

Entry Interface (EI):

Entry Interface then began at 13:44:09 GMT.  Entry Interface is defined as the point when the shuttle has attained, or descended to, an altitude of 400,000 Ft.  per the Reentry document on the NASA Human Space Flight Website.

STS-107 Reentry Data

Entry Interface

  • Location (latitude/longitude in degrees):  30.83313 N. / -167.5564 W.

    • Change 7580.00 statute miles

  • Time:  13:44:09 GMT

    • Change 00:26:31

  • Altitude: 395,010 Ft.  (74.81 statute miles)

    • Change 534006 Feet

  • Velocity: Mach 24.56 x (speed of sound @ Alt. = 1,431 Ft./Sec.)
                         = 35,145 Ft./Sec. (23,963 mph)

    • 1Change +9,774 Ft./Sec. (6665 mph)

  • Reentry Angle setup between De-orbit Burn and EI = 0.7644°

    • After EI the angle is typically adjusted to between 1˚ and 1.5˚.

  1. It is unknown why the increase in velocity between the end of the deorbit burn and EI is so great.  If it is not an error it may by a byproduct of the entry process.  The value will be checked further until it is confirmed.

Reentry flight maneuvers:

The shuttle crew  initiated the OPS 304 guidance program at 5 minutes prior to EI per the STS-107 reentry instructions, see the flight documents  Entry_check_list_STS-107_a.pdf and Entry_check_list_STS-107_b.pdf.  OPS 304 is a closed loop guidance program designed specifically to control the shuttle through the peak heating phase of reentry from EI+400 to EI+1200, see Fig. A10 for the definition of the peak heating region.  OPS 304 uses closed loop feedback to determine when and where to initiate the Roll / bank maneuvers that reduce the rate of descent and bleed off the excessive forward speed.   Because the RCS Roll jets are deactivated at Qbar = 10 psf the shuttle uses the elevons and Yaw jets to perform maneuvers.  The basic operation of the Orbital Maneuvering System (OMS) and RCS are described on page Technical Overview of the Space Shuttle Orbiter.

Fig. A1

Fig. A1 to the left depicts a typical Space Shuttle reentry.  The area inside the red rectangle represents the final approach and landing phase shown in Fig. A3.  If Columbia had made it to this part of reentry it would have had to make a 270˚ right hand turn in order to land on Kennedy Space Center's runway 33 at 9:16 EST. as was anticipated.

 

Fig. A2

Fig. A2 shows the two typical flight paths across the United States for landing at Kennedy Space Center (KSC) depending on the shuttle's orbital inclination.  For STS-107 the orbital inclination was 39˚ and the associated flight path would have been the Maximum Westerly Approach.

Based only on this diagram, it would appear that the Columbia was significantly off course during the STS-107 reentry when compared to what is considered to be the typical nominal Maximum Westerly Approach flight path.  However, it is unknown if the Space Shuttle follows the exact same flight path every time or if the path is dependent on the particular circumstances of the flight.  Therefore the Columbia may not have been off course at all but the possibility is presented here only for discussion purposes.

 

Fig. A3

Fig. A3 shows how the Space Shuttle makes its final approach to land at KSC on runway 33 which was the designated runway for STS-107.  What is most notable is the 270˚ right turn the shuttle needs to make in order to land.

 

 

 

Fig. A2 & A3 are from NASA document FS-2000-05-30-KSC
(Landing the Space Shuttle Orbiter at KSC)

 

Detailed Description of Flight Maneuvers in the Entry Subphase of Space Shuttle Reentry
Taken from the NASA Space Shuttle reference manual section on reentry.
Also available here Space Shuttle Reentry.

Guidance performs different tasks during the 1Entry, 2TAEM and 3Approach and Landing subphases.  During the 1Entry subphase, guidance attempts to keep the orbiter on a trajectory that provides  protection against overheating, overdynamic pressure and excessive normal acceleration limits.  To do this, it sends commands to flight control to guide the orbiter through a tight corridor limited on one side by altitude and velocity requirements for 4Ranging (in order to make the runway) and orbiter control and on the other side by thermal constraints. 4Ranging is accomplished by adjusting 5Drag Acceleration to velocity so that the orbiter stays in that corridor. 5Drag Acceleration can be adjusted primarily in two ways: by modifying the 6Angle of Attack, which changes the orbiter's cross-sectional area with respect to the airstream, or by adjusting the orbiter's 7Bank Angle, which affects lift and thus the orbiter's 8Sink Rate into denser atmosphere, which in turn affects drag. Using 6Angle of Attack as the primary means of controlling drag results in faster energy dissipation with a steeper trajectory but violates the thermal constraint on the orbiter's surfaces. For this reason, the orbiter's 7Bank Angle (Roll control) is used as the primary method of controlling drag, and thus 4Ranging, during this phase. Increasing the 9Roll Angle decreases the vertical component of lift, causing a higher 8Sink Rate. Increasing the 10Roll Rate raises the surface temperature of the orbiter, but not nearly as drastically as does an equal 6Angle of Attack command. The orbiter's 6Angle of Attack is kept at a high value (40°) during most of this phase to protect the upper surfaces from extreme heat. It is modulated at certain times to ''tweak'' the system and is ramped down to a new value at the end of this phase for orbiter controllability. Using bank angle to adjust 5Drag Acceleration causes the orbiter to turn off course. Therefore, at times, the orbiter must be rolled back toward the runway. This is called a 11Roll Reversal and is commanded as a function of azimuth error from the runway. The ground track during this phase, then, results in a series of S-turns.

Technical Footnotes:

  1. Entry:
    The first subphase of reentry from EI-5 min. to where vehicle is traveling at 2500 Ft./Sec. (83,000 Ft. altitude).

  2. TAEM (Terminal Area Energy Management):
    The second subphase of reentry begins at 2500 Ft./Sec. to altitude under 10,000 Ft.

  3. Approach and Landing:
    The third subphase of reentry from under 10,000 Ft. altitude and the shuttle lined up with runway and ends with orbiters weight on nose gear after touchdown.

  4. Ranging:
    The process where the shuttle's guidance system continuously calculate the required altitude and velocity based on distance to the runway.

  5. Drag Acceleration:
    The physical flight parameter adjusted to accommodate the results of the Ranging calculations, (Optimum value is
    33_Ft./Sec.2 .  Adjusted using either Angle of Attack or Bank Angle).

  6. Angle of Attack:
    Angle between an aircrafts longitudinal axis and its direction of travel.

  7. Bank Angle:
    Rotation about vehicle velocity vector (direction of travel).

  8. Sink Rate:
    An aircraft rate of descent into the atmosphere.

  9. Roll Angle:
    Rotation about vehicle longitudinal X axis.

  10. Roll Rate:
    Change in vehicle Roll angle with time.

  11. Roll Reversal:
    Turns shuttle back towards runway to correct Bank Angle error.

 

UPDATE: 12/20/2003

A transcript of voice communication during reentry between the shuttle crew and Mission Control Huston is in the document STS-107_Reentry_Text_J.pdf.  In this transcript at 13:41:35 Commander Rick Husband states' "Two minutes to entry interface.", to the other crew members.  Then again at 13:43:42 Commander Husband says, "OK. We're just past EI.".  If an official time for entry interface is not given then we know that it occurred somewhere in the 7 seconds between 13:43:35/42, the time 13:43:37 could be picked arbitrarily and made the official time of EI for use on this site.  The problem is that an official time for EI is given and it's 13:44:09, 32 seconds after the point where Commander Husband tells his crew that they just passed EI.

It could simply be assumed that Commander Husband checked his watch for the time not realizing it was off by 32 seconds or that Commander Husband was simply in error.  However several of the astronauts, Husband, McCool and Clark who are all veterans of at least one other shuttle mission, make statements about seeing plasma out of the front and side windows after 13:43:37 and well before 13:44:09.  If the time at which Columbia reached EI was changed after the loss of the shuttle as an effort to cover up something that happened to Columbia during reentry, the reason for the change cannot be found.  Since the Columbia was traveling at Mach 25 before EI the 32 seconds translates into 217 miles of travel over open empty ocean with no discernable observations or data points which may have required the 32 seconds to prove their legitimacy.

After looking at Fig. A10 and the STS-107 Ground Track documents, it does not appear that a 32 second shift would have significantly changed any of the data that creates the chart, (any changes in velocity, altitude or angle of attack would be negligible to nonexistent).  Based on the analysis done on Chris Valentine's visual data, the shuttle was where it was supposed to be when it was supposed to be there much later in reentry showing that other location data was not affected by a 32 second time shift.  EI may have been moved to accommodate the substitution of STS-5 telemetry data for STS-107 data as an early step in a cover up process when little to nothing was know about the shuttle data.  Because many of the data analysis posted on this site were done assuming that EI occurred at 13:44:09, that value will be maintained for the time being.

Any place where a total time after EI is referred to such as EI+500, 32 seconds can be added to give the time after EI per the cockpit intercom transcript  (EI+532).


Theory Under Consideration:

If a cover up exists within the Columbia investigation, then the 32 second shift in EI time may be connected to the additional 32 seconds of data taken from the 1OEX data recorder after LOS occurred at 13:59:32.  Most likely all of the error messages and aerosurface position data were shifted 32 seconds forward along with the time of EI so that there would be 32 seconds of data available after LOS.  However, this has not been proven.

05/15/2004

Based on the only definition for Entry Interface that has been found, it has been determined that the time of EI was shifted by 32 seconds specifically to alter the reentry timeline.  Entry Interface is defined as the point when the shuttle has descended to an altitude of 400,000 Ft. per the Reentry document on the NASA Human Space Flight Website.  The official altitude at EI has consistently been given as 395,010 Ft. for STS-107, (in direct conflict with NASA's own definition).  Therefore, EI occurred at the earlier time, 13:43:37, with the 5,000 Ft. difference accounting for the 32 seconds.  Much if not all of the telemetry data that is time stamped between 13:59:32 and 14:00:00 should be moved back 30 to 32 seconds with shuttle breakup then confirmed as occurring at LOS.  The effect this time shift has on other telemetry data throughout the STS-107 Timeline and Ground Track documents is currently unknown.

There are currently no plans to change the times of any events or telemetry data contained in the various tables and sections of this site.  The 32 second shift would not seriously affect any of the key findings and it is impossible to know how much data would need to be shifted if none at all.  If the time shift does have an effect on any of the conclusions it will be noted.

  1. It has been shown that the OEX recorder was removed from Columbia before STS-107 and was then planted in the debris field after the exterior was made to appear heat damaged.


Critical Systems Failures During Reentry

NASA's STS-107-Timeline-Rev15.xls Excel file gives a detailed list of anomalous events as they occurred.  That data was then used to create a ground track presentation in STS-107 GTrack Rev 15.pdf.

Fig. A4

If we had to state a time and location where Columbia's fate was sealed for the STS-107 mission, it would not be somewhere over the Atlantic shortly after launch on January 16, 2003.  It would instead be at 13:47:32 (EI+203) over the middle of the Pacific Ocean at an altitude of 298,446 Feet during her reentry, see Fig. A4.

What makes this location so suspect is that it was the end of both Laurel Clark's crew cabin video and marked the end of any and all significant voice communications with Mission Control Houston.  The Space Shuttle had not lost voice contact with Mission Control to such an extent since the Tracking and Data Relay Satellite TDRS system was put in place in the early nineties.  Typically the shuttle's avionics system would find a suitable backup for the voice transmitter and bring it on line, but that didn't happen during STS-107.

By 13:50:00 data transmissions from the shuttle were being affected as well.  Within two minutes after that the bits of data that were getting through indicated off nominal aero increments that were not being corrected by Columbia's avionics systems.

Communication failures:

The first events were loss of communication from the external S-Band antennas.  Fig. A5A and A5B show the location of all external Antennas on the Columbia.  The purpose and operation of the S-Band antennas is further explained in, Effects of hypersonic flow during reentry of the Space Shuttle, Communications:  and Technical Overview of the Space Shuttle Orbiter (Avionics and Communications Systems), Communications Systems.

Fig. A5A

Fig. A5B

UPDATE: 12/21/2003

After once again closely scrutinizing the transcript of verbal communications during reentry that has been carefully reconstructed in the document, STS-107_Reentry_Text_J.pdf, a fact not previously noticed is a complete lack of voice communication between the shuttle crew and Mission Control Houston after 13:47:32 (EI+203).  Although Mission Control personnel are buzzing with the many strange and random anomalous events that begin some time after 13:51:00, there are no conversations with the crew about the failures.  The transcript contains some verbal ques from Mission Control personnel that may be attempts the contact the crew, but with the exception of Commander Rick Husbands two different moments when he is able to broadcast some cryptic syllables such as, "Bu" or "Uh", the loss of verbal communication continues to the end.

The STS-107 GTrack Rev 15.pdf and STS-107-Timeline-Rev15.xls documents only list brief communication blackouts that result in loss of data but do not indicate a total loss of air to ground verbal communication.  An interesting note is that 13:47:32 is also the exact time that Laurel Clark's camcorder failed marking the end of the crew cabin video released by NASA.  Because the camcorder failed completely at the exact same time that verbal communications were lost, the two events may be related.

07/23/2004

Many people have written in claiming that besides the two times that Rick Husband was able to send those very brief messages to Mission Control after 13:47:32 he can clearly be heard saying, "Feeling that heat Mission Control", at about 13:48:00.  To my knowledge this was never part of the transcript.  When William Harwood, the creator of the transcript STS-107_Reentry_Text_J.pdf, was questioned about any additional voice communications besides what he put in the document his response was as follows.

There were no other transmissions from the crew beyond what you see in my transcript or in NASA's version.  All ascent/entry air-to-ground traffic is broadcast in the open (even during classified military missions) and if there had been something else, we'd have all heard it.  I don't have any doubt about that at all.

Just FYI, something like this came up after Challenger, i.e., rumors of on-board recordings that went beyond the official ICOM transcript.  Those stories were equally bogus, in my opinion.

William Harwood
CBS News

 

Table A1 lists all of the communication loss events between the shuttle and mission control which resulted in the missing data shown in the Time Line documents.  Each event includes the time, duration and what hardware was involved.  What is not shown in the chart is the complete loss of voice communication after 13:47:32.  Although this was the most significant anomalous communication failure none of the official investigation documents mention anything about it.  It is unknown why the shuttle continued to transmit telemetry data and not voice communications.  A possible reason is that voice communications are carried on the S-Band PM two ways system while data is typically carried on the S-Band FM system which transmits only and cannot receive.  Another possibility is that what ever affected electronic systems onboard the orbiter had a much greater affect on microphone components than other systems.  See, Technical Overview of the Space Shuttle Orbiter (Avionics and Communications Systems), Communications Systems.

This news story confirms how uncommon such a loss of communications is at this point in our space program, "The Shuttle Blackout Myth Persists".

The crew cabin video released by NASA is said to have come from a video tape in a camcorder which survived breakup and was found in the debris field.  This video is available for viewing on various news sites, CBS news Space Shuttle reentry video.  It can also be downloaded from Inside KSC.com here Crew Cabin Video 100 MB.

Table A1
The following communication failures occurred during reentry
Event Time
(GMT)
Duration
(Sec.)
Transmission antenna affected Remarks

1

13:50:00 1

Upper Left S-Band PM Antenna (S-Band Ant. No. 1).

Unexpected Return Link Comm. drop-out.
2 13:50:04 2 Upper Left S-Band PM Antenna (S-Band Ant. No. 1). Unexpected Return Link Comm. drop-out.
3 13:50:16 4 Upper Left S-Band PM Antenna (S-Band Ant. No. 1). Unexpected Return Link Comm. drop-out.
4 13:50:25 3 Upper Left S-Band PM Antenna (S-Band Ant. No. 1). Unexpected Return Link Comm. drop-out.
5 13:50:42 1 Upper Left S-Band PM Antenna (S-Band Ant. No. 1). Unexpected Return Link Comm. drop-out.
6 13:52:09 6 Upper Left S-Band PM Antenna (S-Band Ant. No. 1). Unexpected Return Link Comm. drop-out.
7 13:52:25 1 Upper Left S-Band PM Antenna (S-Band Ant. No. 1). Unexpected Return Link Comm. drop-out.
8 13:52:29 2 Upper Left S-Band PM Antenna (S-Band Ant. No. 1). Unexpected Return Link Comm. drop-out.
9 13:52:49 6 Upper Left S-Band PM Antenna (S-Band Ant. No. 1). Unexpected Return Link Comm. drop-out.
10 13:53:32 2 Upper Left S-Band PM Antenna (S-Band Ant. No. 1). Unexpected Return Link Comm. drop-out.
11 13:54:14 8 Upper Left S-Band PM Antenna (S-Band Ant. No. 1). Unexpected Return Link Comm. drop-out.
12 13:54:26 - - Comm. switched to upper right antenna.
13 13:55:33 2 Upper Right S-Band PM Antenna (S-Band Ant. No. 2). Unexpected Return Link Comm. drop-out.
14 13:56:00 3 Upper Right S-Band PM Antenna (S-Band Ant. No. 2). Unexpected Return Link Comm. drop-out.
15 13:56:55 2 Upper Right S-Band PM Antenna (S-Band Ant. No. 2). Unexpected Return Link Comm. drop-out.
16 13:59:32 - -

LOS

Data taken from STS-107-Timeline-Rev15.xls and STS-107 GTrack Rev 15.pdf

These breaks in the communications between the Columbia and Mission Control are all listed as anomalous events for reentry.  However, the communications systems including the transmitting and receiving hardware as well as all of the antennas are all located well away from the left wing and do not have any associated cable harnesses that run through that general area.  Therefore a breach in the left wing does not explain any of the anomalies that occurred with the shuttle communications system that morning.

Sensor failures:

The next events were the beginnings of sensor anomalies.  The STS-107_Event_Sequence.pdf  document from NASA contains diagrams that show the time and location of the various sensor failures and off nominal readings.  The document STS-107_Sensor_Failure.pdf contains similar information but is an older version.  Note that both documents were released before the OEX data recorder was found and therefore neither contains the OEX data that has been determined to be questionable and most likely fabricated.  Because many of these events are mentioned during reentry by Mission Control personnel it may be possible to verify the data by comparing the events to the transcript of voice communications in the STS-107_Reentry_Text_J.pdf document.

Fig. A6

Fig. A6 is from STS-107_ Event_Sequence.pdf released by the C.A.I.B. on 03/14/2003.  The image has been modified slightly to provide more information in a compact format.

Fig. A6 is a modified version of the image that is published with STS-107_Event_Sequence.pdf.  The diagram graphically shows the approximate X - Y location of all the affected sensors grouped and color coded by their associated wiring cable harnesses.

Table A2 is a summary of sensor activity from EI to LOS (Los Of Signal) that is taken from the same document as the image.  The numbers on the sensors in the image correspond to the numbers in the column labeled Sensor Ref. No.  and are the same as used in, STS-107_Event_Sequence.pdf.  The numbers do not correspond to the order of events.

The most puzzling of the sensor anomalies were those monitoring the supply water dump nozzles and the vacuum vent near the forward fuselage.  The suspected breach in either RCC panels 8 or 9 is too far from these to have effected the units or their sensors and wiring.

Fig. A6 shows the temperature sensor cable harness for hydraulic systems 1, 2 and 3 return lines as having a close proximity to the left wing leading edge near RCC panels 7, 8 and 9, the exact location of the wing breach that exists in the C.A.I.B.'s failure scenario.  This is why the investigators concluded that the wiring harness was attacked by heat which caused the anomalies that were recorded, (see Table A2; Events 1, 7, 8, 9, 10 and 14).

It has been shown on this site that the Space Shuttle left wing wiring diagrams such as that shown above in Fig. A6 were created after the Columbia disaster for use with the official investigation.  These diagrams portray sensor cable routings that are not accurate.  The sole purpose of these diagrams is to further legitimize the existence of a breach in the leading edge of the shuttle's left wing and point directly to it as the source of reentry sensor electrical anomalies. The differences between the wiring diagrams doctored by the C.A.I.B. and the actual wire and cable routing used on all the shuttles is clarified in detail in one of the Space Shuttle technical sections.  See, Technical Overview of the Space Shuttle Orbiter (Wings, Tail, Body Flap and Control Surfaces), Wiring harness routing.

Table A2
The following anomalous sensor readings and failures occurred during reentry
Event Time
(GMT)
MSID 1Sensor
Ref. No.
Sensor affected by event Remarks

1

13:52:17 V58T1703A 1 Left Main Gear Brake Line Temp D Off nominal temp rise.
2 13:52:32

V62T0439A
V62T0440A

33 & 34 Supply Water Dump Nozzle A/B Off nominal temp rise.
3 13:52:32 V62T0519A
V62T0520A
35 & 36 Waste Water Dump Nozzle A/B Off nominal temp rise
4 13:52:32 V62T0551A 37 Vacuum Vent Off nominal temp rise.
5 13:52:41 V58T1700A 2 Left Main Gear Brake Line Temp A Off nominal temp rise.
6 13:52:41 V58T1702A 3 Left Main Gear Brake Line Temp C Off nominal temp rise.
7 13:52:56 V09T1006A 4 Left Inboard Elevon Lower Skin Temp Off nominal temp downward trend.
8 13:52:59 V09T1006A 4 Left Inboard Elevon Lower Skin Temp Sensor goes offline.
9 13:53:03 - - Left outboard Elevon wide-band accelerometer (10 Gs peak to peak) signal saturation indicative of failure
10 13:53:10 V58T0394A 5 Hyd. Sys. 3 Left Outboard Elevon Actuator Return Line Temp 2Sensor goes offline.
11 13:53:11 V58T0157A 6 Hyd. Sys. 1 Left Inboard Elevon Actuator Return Line Temp 2Sensor goes offline.
12 13:53:34 V58T0193A 7 Hyd. Sys. 1 Left Outboard Elevon Actuator Return Line Temp 2Sensor goes offline.
13 13:53:35 V62T0439A
V62T0440A
33 & 34 Supply Water Dump Nozzle A/B Return to normal temp rise rate.
14 13:53:35 V62T0519A
V62T0520A
35 & 36 Waste Water Dump Nozzle A/B Return to normal temp rise rate.
15 13:53:35 V62T0551A 37 Vacuum Vent Return to normal temp rise rate.
16 13:53:36 V58T0257A 8 Hyd. Sys. 2 Left Inboard Elevon Actuator Return Line Temp 2Sensor goes offline.
17 13:54:10 V58T1701A 9 Left Main Gear Brake Line Temp B Off nominal temp rise.
18 13:54:20 - - Start of slow Elevon trim change on left wing (Time approx. +/- 10 sec.) counteracts buildup of aero drag.
19 13:54:22 V34T1106A 10 Mid. Fuselage Left Body Line Temp Off nominal temp rise.
20 13:54:22 V09T1724A 28 Left Aft Fuselage Sidewall Off nominal temp rise.
21 13:54:24 V58T0405A 11 Left Main Gear Strut Actuator Temp Off nominal temp rise.
22 13:54:53 V51T0574A 18 Main Landing Gear Left Hand Outboard Wheel Temp Off nominal temp rise.
23 13:55:12 V58T0842A 13 Hyd. Sys. 3 Left Hand Forward Brake Switch Valve Rtn. Line Temp Off nominal temp rise.
24 13:55:41 V34T1118A 27 Mid