1. The rate of descent.

2. Aerodynamic heating.

3. Decreasing forward velocity.

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 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.

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.

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.

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.

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.

1

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

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.

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.

1

V62T0439A
V62T0440A

LOS

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

1. Corresponds to circle numbers in Fig. A6 and the STS-107_Event_Sequence.pdf  document.

2. Prior to going off line the official report states that the sensor "Shows wire damage trend" with no other description.

The only sensors listed in the Event Sequence document that remained nominal while data was still being transmitted had the reference numbers 23, 24, 25 and 26 and were attached to the following devices,

Hyd. Sys. 3 Left Inboard Elevon Actuator Return Line Temp Hyd. Sys. 2 Left Outboard Elevon Actuator Return Line Temp Hyd. Sys.  Left Inboard Elevon Actuator Temp Hyd. Sys.  Left Outboard Elevon Actuator Temp

Per STS-107_Sensor_Failure.pdf  the 2 sensors which showed the greatest temperature increases were number 11 at 6°/min. for a total of 5 minutes, (+30°F), and number 17 at 14°/min for 1 minute and 38 seconds, (+22.87°F).  This was not anywhere near enough heat to cause damage to Columbia's left wing.  In addition to this some of the sensors showed temperature decreases before they went off line.

Any telemetry data referred to in the following section can be referenced from either STS-107 Timeline (Rev15) or STS-107 Ground Track (Rev15).

Fig. A7

Fig. A7 is a visual definition of sideslip.  As the Space Shuttle descends through the atmosphere it reaches a point where significant increases in atmospheric density result in a much greater rate of aerodynamic heating.  This heating effect is controlled by slowing down the rate of descent and bleeding forward speed as possible.  This is accomplished through the use of flight maneuvers.

The typical shuttle reentry involves 4 Roll maneuvers and 4 Roll Reversals.  The Roll maneuvers causes sideslip which results in the orbiter being off course.  The Roll reversal maneuvers are performed to put the shuttle back on its proper flight path.   

Fig. A8

Fig. A8 describes how the negative Beta is controlled and used to roll into the first flight maneuver.  Another method for slowing down the shuttle's rate of descent and airspeed is by flying with a very large Angle of Attack (AOA).  The AOA must be maintained at 40° from EI through the peak heating region.  This angle is difficult to hold and is part of the Digital Autopilot (DAP) reentry program.  If the autopilot is disabled the shuttle would level out very quickly resulting in a faster descent.

Because of this extreme AOA the lower surface of the orbiter takes the brunt of the heat load during reentry.  Therefore the entire bottom of the shuttle is covered with the heavy duty black tiles.

Fig. A9

Fig. A9 is from a C.A.I.B. press presentation on 04/26/2003 pb-20030408-01a.jpg.

Fig. A9 is a graphic from one of the C.A.I.B. technical presentations that were held once or twice a month to bring the press up to date on the progress of the investigation.  The graphic has been altered slightly with the addition of the red lines and text indicating event times and descriptions.  Because the chart has no units and no detailed explanation in the accompanying report text, its exact meaning and relationship to Columbia's attitude are unknown.  Its only value is in showing Roll and Yaw trends over the course of reentry.

Table A3 lists all of the RCS jet firings during reentry along with changes in position of the control surfaces, left and right elevons, bodyflap and speedbrake, (blue text relates to control surfaces and RCS Jet firings).  All of the data in Table A3 comes from STS-107-Timeline-Rev15.xls which also lists times when certain flight maneuvers were made.  These flight maneuvers are also listed in the table for comparison with other data.

Technical Article A1 Aero Moment Definition and its Effect on Flight Control

An Aero-Moment, sometimes also called an Aero-Torque, is simply a way of describing the leverage that is required to steer an aircraft such as the Space Shuttle.  For instance moving control surfaces such as the Space Shuttle's left elevons down into the airflow will result in an uneven force couple that will have a tendency to turn or rotate the aircraft to the left about its center of gravity, (negative Yaw), and also result in a positive Roll.  An Aero-Moment may also be the result of damage to one of the aircrafts surfaces that disrupts its aerodynamics.  This damage causes a drag force that is located some distance from the aircrafts center of gravity having an effect similar to the movement of a control surface altering the course and attitude.  It is then up to the pilot or autopilot to calculate the value of the damage induced Aero-Moment and determine the required corrective action.  Other factors such as wind may alter the attitude of an aircraft and or force it to drift off course.

For measuring course and attitude changes the Space Shuttle has three different types of gyroscopic sensors which collectively detect motion in any of the six degrees of freedom.  Data from the sensors is sent to the GPC's where the Flight Control software calculates the magnitude of the required restorative moment and decides how to respond.  Whether the corrective action takes the form of firing the corresponding RCS Jets or movement of the appropriate control surface depends on the phase of reentry flight.

The following sensors detect course and attitude changes,

• Inertial Measurement Units (IMU's)
  Senses the vehicle's attitude in inertial space relative to the flight path.

• Accelerometer Assemblies (AA's)
  Detects changes in the Yaw, Pitch or Roll angles.

• Rate Gyro Assemblies (RGA's)
  Detects linear motion along any of the three primary X, Y or Z axis.

The graph of Fig. A9 represents Aero-Moment coefficients calculated by the shuttle's flight control software using off nominal attitude and course values detected by the gyroscopic sensors as described above.  Attitude and course errors may be the result of many different external events, therefore the sensors onboard the Space Shuttle do not directly record Aero-Moment data.  The avionics system uses only the knowledge of how the shuttle's attitude and course have changed to calculate an Aero-Moment sufficient to counter the changes and restore the orbiter to its proper course and attitude.  The flight control system then sends a signal to one or more of the control surfaces ordering it through some degree of rotation.  Exactly how much the control surfaces must rotate to create the required Aero-Moment depends on the atmospheric density which is a function of aircraft altitude.  AltTA-A1_AeroMoments.htmhough the Digital Auto Pilot was unable to send the command to correct the errors to either the RCS system or the control surface actuators, the data was still transmitted to Mission Control.

The diagram below is a key to indicate how the various groups of RCS thrust jets affect the shuttle's rotation in the three primary rotational axis Yaw, Pitch and Roll.  Thrust from forward and aft jets can also be combined to increase the rate of rotation if required.  RCS jets may be used for translational motion as well when Fore and Aft jets on the same side are combined.  This will cause the shuttle to translate along any of the three primary axis while holding its Yaw, Pitch and Roll angles constant.

In engineering terminology a "moment" is a term that represents the leverage created by a force and a lever arm of some particular length.  Documents produced by the C.A.I.B. often use both terms, moment and torque, to describe the same action.  Although the two terms have similar meanings, torque is most often used to describe the power output of a rotating shaft or flywheel.

In the case of an Aero-Moment the force would be the extra drag created by the change in position of a control surface, the thrust from a maneuvering jet or damage to the surface of an aircraft which affects its aerodynamics.  The location of the force would be at the centroid of the control surface, the jet thrust cone or the point of damage.  The lever arm would be the distance from the force to the aircrafts center of gravity.

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

1. See the Thrust ID Code Reference sheet. RCSJetCode.gif

2. Event times may be moved back by 32 seconds, (see Update 05/15/2004).

Technical Article A2 Columbia's Final Attitude Changes

Factors affecting Columbia's final attitude:

The effects of yaw jets on flight control:

Fig. TA-A2-1 From document NASA_TM-1987-88281.pdf Fig. TA-A2-2 From document NASA_TM-1987-88281.pdf, Fig. 29 (Data is from a bank maneuver at Mach 24)

The Plots of either Roll Moment Vs. Time or Yaw Moment Vs. Time as the shuttle performs flight maneuvers should typically look similar to the 5 graphs of Fig. TA-A2-1.  The data should show a repeating pattern that changes from positive to negative as the shuttle rolls left then right and back to the left again. These diagrams may be used to confirm that no flight maneuvers were performed during STS-107.  When comparing the diagrams to Fig. A9 it is obvious that Fig. A9 does not contain any areas that resemble the curves to the left, even during the period where a roll reversal is said to have occurred. A set of graphs were derived from empirical data before STS-1 to predict how the RCS Yaw Jets would control the shuttle's yaw rate during reentry.  The derived data matched the actual flight data very closely.  Fig. TA-A2-2 contains two sets of data from a Mach 24 bank maneuver.  The graphs are analyzed here to determine if the relationship between Yaw Jet firing and Yaw Rate can be used to derive a function that can predict the shuttle's yaw rate for yaw jet firings with different parameters. Shuttle Yaw Rate as a Function of RCS Yaw Jet Number and Firing Duration The increase in Yaw Rate based on the firing of 2 right rear Yaw Jets for a total of 5.5 seconds is 3˚ per second.  Because the relationship between Yaw Rate and time is linear it can be used as a Rate Function to determine how other firing durations would increase or decrease the Yaw Rate. 0.2727˚ per second/duration of jet firing (seconds)/No. of jets When the shuttle is in an environment free of gravity and atmosphere this Yaw Rate would continue until the opposing Yaw Jets are fired to counter it.  During atmospheric flight other factors such as the use of control surfaces and drag forces would either increase or decrease the Yaw Rate once the jets have stopped firing.  Therefore, during atmospheric flight it is nearly impossible to determine how the Yaw Rate changes after the Yaw Jets stop firing unless the value is recorded. The derived Rate Function can then be used to determine how Yaw Jet firing events affected Columbia's attitude during reentry.  The most significant jet firing would be events 38 and 39 on Table A3 where Yaw Jets R2R and R3R fired for nearly 8 seconds continuously.  All of the other jet firing events were too short of duration to have an effect on the shuttle's trajectory. These values are then inserted into the derived Rate Function to find the final Yaw Rate after jet firing, 0.2727 * 8 * 2 = 4.36˚ per second positive yaw By multiplying the final Yaw Rate produced by the jet firing with the period of time that Yaw Rate was maintained and adding to this the initial Yaw angle whether it was positive or negative will give the final Yaw angle of the shuttle produced by that Yaw Jet firing. See explanation for RCS thruster location and direction of vehicle travel at bottom of section.

Columbia's final attitude:

Based on the calculations done above it is entirely possible that some attempt to correct an uncontrolled negative Yaw rate is what placed the Columbia in the final position of +90° Yaw.  A subsequent vehicle breakup with the left wing dispersing its material first would be the next logical event.  Although the conclusion reached using the simple derived Rate Function is entirely possible it requires some assumptions that have an unknown accuracy.  Fortunately an independent source of evidence exists that relates the final calculated Yaw angle to an eye witness account.  An amateur video taken of Columbia that begins after that final RCS jet firing and just a few seconds before vehicle breakup includes a high level zoom of the orbiter that clearly shows its attitude to be +90° Yaw or flying sideways with the still intact left wing facing windward.  The details of the Colony Texas video are on Technical Articled TA-A3.

The animation of Fig. TA-A2-3 describes a scenario such as the one described above where some degree of negative Yaw developed during the first several minutes of reentry.  This negative Yaw is suddenly counteracted by firing the right rear Yaw Jets for 8 seconds continuous.  Unfortunately the uncontrolled over correction resulted in the Columbia being left in the worst possible position, turned sideways to the Mach 18 airflow.  Essentially all of the aerodynamic normal accelerations are now being taken laterally on the shuttles airframe.  This is something that the orbiter was never designed for and the fact that the shuttle would breakup would have been a forgone conclusion to any flight engineer watching.

Fig. TA-A2-3

Attitude Graphs From the Official Investigation

The following four charts are from the official final report and are intended by that investigation to add legitimacy to its findings.  The definition of how the data is presented is contained in Vol. 5 Appendix G13 of the official final report.  The explanation for how the values for the coefficients are arrived at is quite complicated and would not add to the clarity of the information on this website.  If this information is required it can be found in the section of the final report mentioned above.  This is the same data presented in the graph of Fig. A9 with a clearer representation and added information.  It has been observed that the coefficient values shown on these charts from STS-107 are not outside the range of values collected from other shuttle missions.  This observation is verified by Time Line and Ground Track documents from the official investigation that at no point refer to the Yaw and Roll trends as being significantly greater than that recorded during any other shuttle mission, (until the last couple of minutes of reentry).  The fact then that the Columbia's flight control system was unable to control the attitude errors is further evidence that this portion of the shuttle's avionics was severely damaged early during reentry.  The main value of these charts then is the same as that of Fig. A9 which is to show the Yaw and Roll trends over the course of reentry.

Fig. TA-A2-4

Copyright © 2003 - 2007 ColumbiasSacrifice.com

Observational Analysis A1 12/31/2003 Analysis of Chris Valentine's Image Data

One of the images Chris Valentine created for his own website, (see links below), is referenced here as ChrisTimeline1.jpg.  This image has still shots from a video he took of the STS-107 reentry overlaid on a version of the STS-107 Ground Track.  Prior to February 1st Mr. Valentine received a time table  from NASA showing where to look in the sky, or where to aim a camera, in order to spot the Columbia during the reentry of STS-107.  The table has azimuth, elevation and range for a number of different time points and is custom oriented from your exact GPS location, (Latitude and Longitude).  By using this information it might be possible to check the validity of the time and location data that is provided in the STS-107 Ground Track documents.

Verification of position data shown in images:

In order to use this information we have to make a couple of assumptions.  First we have to assume that the clock on Chris's camcorder was set to the correct time.  Chris claimed to have set the time on it recently before the event, and when NASA viewed his video they said his time was, "6 seconds short of UTC", this is not unreasonable but would have meant approximately 24 miles of travel or 5.5° of angular displacement shown, so this can be factored in.  The only other assumption which is really the most important one is, where was the camcorder pointed at the precise times the different still shots were taken?  Chris seems to be confident  that the time stamps on his still shots correspond to the given data point times on the ground track and the time table.  Of course we have no reason to disbelieve Mr. Valentine but he was obviously busy operating the camcorder and not taking note of exactly where it was pointed.

We can make a fairly accurate check of the camcorders position relative to the Ground Track by observing the lighting conditions of the sky in the still images as well as the position of the sun.  For Chris's location, 35.57445 N. Latitude and -111.52940 W. Longitude, on February 1^st, 2003 the sunrise and sunset for Mountain Standard Time were 7:27 a.m. and 5:55 p.m. MST respectively per the Farmers Almanac, and the suns position would have been about 10.5° to the South at sunrise.  After performing this check by drawing check lines and measuring the various angles it has been determined that the data shown in the image is most likely accurate.

Note: Chris Valentine's original graphic used to create Fig. OA-A1-1 is here ChrisTimeline1.jpg.

Diagram with a map indicating the portion of the flight  path viewable by Chris Valentine as he recorded the STS-107 reentry.  The image contains other data such as the GPS coordinates for the end points and the time on location for the shuttle as it entered and then left the field of view.

Real time animation tracing Columbia's flight path across the United States:
Real time animation tracing Columbia's flight path across the United States from 13:53:00 GMT to end.  Animation includes super imposed video compilation created by Chris Valentine.

CNN animation: Columbia over Texas

Sonic booms during Space Shuttle reentry

This technical article from the NASA website, Shuttle_Reentry.pdf, explains how the Space Shuttle typically reenters Earths atmosphere listing the various phases of flight etc.  The document states that the shuttle does not enter subsonic flight until it has reached an altitude of 49,000 feet and is about 25 miles from the runway.  When the shuttle is above 50,000 feet very little of the sonic energy reaches the ground.

Therefore people on the ground usually only hear the sonic booms when the shuttle is between 80,000 and 49,000 feet.  Even then you would only recognize it as a sonic boom from the shuttle if you were listening for it.  Much of the time at those altitudes the sonic booms are barely audible and most people don't hear them at all.  The fact that so many people living near where Columbia broke up heard the sonic disturbance so prominently would almost certainly mean that the Columbia was much lower than 200,767 feet when she broke up, (see Table A4), and may have even been below 50,000 feet.

• A more complete explanation of shock waves
  and sonic booms

Technical Article: TA-A4; Shockwave Formation and Sonic Booms

UPDATE: 02/15/2004

It has since been determined that the spread sheet and graph of Table A4 and Fig. A10 do not accurately represent STS-107.  The true altitude data from STS-107 was replaced with either nominal data or data straight from another shuttle mission such as STS-5.  This was part of an effort to maintain a cover story that Columbia was flying normally for most of reentry.

Fig. A11

After the complete loss of communications occurred with Mission Control at 13:59:32, a contingency plan was put in place for what actions to take when the Columbia landed at its prescheduled time of 14:16:00.  It just didn't occur to those tracking the shuttle that the worst had happened until the reports of multiple contrails and debris falling all over central Texas began coming in.  No one in Mission Control Houston ever used the words "breach" or "burn through" anytime during reentry.  Fortunately some of the best accounts of Columbia's final minutes come from the amateur videos that have been widely seen.  If anyone observing the events in Mission Control thought that a burn through was happening as some later stated on television, they didn't mention it at the time.

Page Notes:

Reference documents for this page are available in the Download page under STS-107 Time Line & Reentry.