Conclusions From Engineering Analysis

Introduction:

The initial baseline event in the scenario from the official final report on STS-107 created by NASA's Columbia Accident Investigation Board (C.A.I.B.), is a foam debris strike to the leading edge of Columbia's left wing during launch and ascent on January 16, 2003.  This debris strike would have resulted in severe damage to one of the RCC panels 7, 8 or 9.  This event was then the official root cause of the disaster.  This theory requires that the damaged area or breach be large enough to disrupt the shuttle's aerodynamics beyond the ability of the orbiter's complex avionics system to compensate.  The breach must also be an inlet for super heated plasma that circulated through the interior of the left wing attacking sensitive cable harnesses as well as the shuttle's airframe.  It was this damage occurring inside the left wing that caused the anomalous telemetry from the various temperature sensors and resulted in the failure of the left wing itself.  The wing failure was quickly followed by the loss of control of the orbiter and its subsequent breakup.

Based on the available information it can be noted that this anomalous telemetry data was not being discussed as a potentially critical flight issue by Mission Control Center (MCC) personnel during reentry, see STS-107_Reentry_Text_J.pdf.  The reason why the flight engineers at MCC were not reacting more seriously to the unusual telemetry being transmitted from Columbia that morning was not a lack of concern over a potentially disastrous situation, it was because the telemetry data being transmitted from the shuttle did not reflect the seriousness of the situation.  Although the anomalous temperature readings and eventual failure of the sensors was discussed, it was quickly determined that the failures occurred randomly and that there was no common thread among the affected units.  If the sensor data reflected more serious problems onboard the orbiter the failures would result in some distinct data pattern within the downloaded telemetry.  The temperature reading and sensor failures were written off as instrumentation errors.  Therefore the flight engineers monitoring Columbia's reentry at MCC were completely unaware that the shuttle's attitude and flight path were continuously drifting away from their nominal values beginning at about 13:52:32 GMT.

Voice communications with the Columbia were also affected to the point of being virtually nonexistent after 13:47:32 (EI+203).  The crew cabin video being recorded by Laurel Clark using the handheld camcorder also ended at 13:47:32.  Although the official explanation for the existence of the crew cabin video is that it was retrieved from the camcorder after the unit was found in the debris field, most of the available data on the shuttle's systems state that the video signal is streamed live to MCC the same as voice telemetry.  Additionally the two signals are transmitted over different systems with the voice signal using the S-Band PM system while the video uses the S-Band FM system.  It is unknown if the failures actually occurred at the input devices themselves, (the camcorder and the crews microphones), or if the damage occurred elsewhere within the communications system.  However, the fact that the shuttle continued to transmit telemetry data with only random brief blackouts suggests that a good portion of the Columbia's communications system was still functional.

Determining how much damage the shuttle had:

Without a doubt the Space Shuttle Columbia broke apart due to extreme stresses applied to the airframe after the orbiter lost control during Mach 18 atmospheric flight.  Although it is possible that the Columbia lost control as the result of a breach in the leading edge of the left wing at RCC panel 7, 8 or 9, that is certainly not the only possibility.  Analysis of the available data for STS-107 as well as past shuttle missions and NASA technical reports provide a more plausible explanation.  The voice and video telemetry ended abruptly at 13:47:32 just before the first Roll maneuver was initiated at 13:49:32 with the beginning of numerous interruptions in data transmission occurring at 13:50:00.  It has also been noted that almost immediately after the Roll maneuver was started the Time Line lists an "Off Nominal External Event" at 13:51:19 that is never explained in detail.  The negative Yaw and positive Roll trends that resulted in the eventual loss of control of the orbiter began at 13:51:46 while the first off nominal sensor readings were seen at 13:52:17.

The reentry of STS-107 after 13:52:17 is dominated by periodic interruptions in data transmissions, RCS jet firings and continued anomalous sensor data that does not fit any known pattern for a system failure.  The pattern of communication interruptions and RCS jet firings suggests a continuous switching between the PASS and BFS flight software.  This would mean that the four main GPC's were passing the flight control function to the backup GPC while they reset themselves.  The GPC running the BFS software would then immediately attempt to pass flight control back to the main GPC's.  All the while the flight conditions and the error messages emanating from the avionics system continue to become more and more serious with neither system controlling the reentry flight.  This would mean that either all of the GPC's were too damaged to function properly or the flight control software was corrupted or both.  Something occurred during the time period after 13:47:32 that significantly damaged much of the Columbia's avionics systems.  Although the damage was wide spread it seemed to be confined to electronic components only.

If some external event or force caused widespread damage to the Columbia's electronics and electrical systems, it is very possible and even probable that the Caution and Warning System suffered crippling damage as well.  Therefore it is not at all out of line to assume that the Caution and Warning System was unable to respond to most if any of the system failures which plagued Columbia during the STS-107 reentry.  The conclusion of this analysis is that neither the crew of the Columbia nor the flight engineers at Mission Control were aware of any issues with the flight control system or any other orbiter system until nearly the end of the STS-107 reentry flight.

Whether or not foam struck the left wing of Columbia and caused damage during its ascent to orbit on January 16, 2003 is irrelevant to the loss of the orbiter during reentry on February 1st, 2003.  What is clear from the evidence collected is all that does count is what happened to Columbia at 13:47:32 GMT (EI+203) during reentry.  That is the point in time when Laurel Clarks camcorder stopped functioning and was also the end of nearly all voice communication between the Columbia and Mission Control as well as the beginning of flight control anomalies.  At EI+203 the Columbia encountered something that destroyed or crippled nearly all of the electronic equipment onboard the orbiter leading to a loss of flight critical systems.

What really happened to Columbia:

The breakup of Columbia was really the result of two separate but closely related flight control and attitude stability issues.  They are related by their complete dependence on the shuttle's complex avionics systems to maintain their respective values within specified parameters.  However, neither issue causes or has an effect on the other aside from random interplay of their respective aerodynamic properties.

The first issue was the shuttle's inability to accurately control the negative yaw that was slowly building up.  The Columbia's flight control system initiated the first flight maneuver at 13:49:32 (EI+323), per STS-107 Time Line Rev. 15, by establishing a negative beta, (the angle between the vehicle heading and the direction of travel also designated as b).  The Space Shuttle typically begins a rolling or banking maneuver in this manner because of the unusually extreme angle of attack (40°) that it must maintain during the first half of reentry, (flight maneuvers are performed to slow down the rate of descent and decrease the shuttle's forward speed).  Typically the shuttle would control the negative beta using a combination of the rudder, speed brake and body flap to begin a flight maneuver, but this apparently never happened during the reentry of STS-107.  At 13:51:46 (EI+457) the time line states that, "the Inertial sideslip angle (Beta) goes and stays Negative until LOS", which would say that the shuttle began turning or rotating to the left and continued to do so until LOS.  The reentry time line then continues to list the occurrence of other flight maneuvers as they would normally happen over the course of a typical reentry.  However, the problem is that these two statements are mutually exclusive, if the shuttle continued rotating or yawing to the left until LOS then it could not have performed any flight maneuvers and visa versa.  It is believed that no flight maneuvers were performed after EI+457 during the reentry of STS-107.  This points to a severe degradation of the main flight control system and all of the redundant backups.  The only possible maneuver performed after EI+457 was the 8 second duration Yaw jet firing starting at between EI+891 and EI+923, (this is what changed the shuttles attitude from Yaw = between 0° and -30° to Yaw = +90° as seen during the close-up in the Colony Video).

The second issue was the Columbia's loss of pitch stability during reentry leading to a greatly increased rate of descent and severe overheating of the TPS.  The shuttle's pitch control is directly related to the angle of attack that must be maintained at about 40° throughout the first half of reentry.  The 40° angle of attack is necessary to increase the shuttle's lift and drag properties which slows the rate of descent and bleeds off forward speed.  Virtually the entire reentry of a Space Shuttle is controlled by the complex Digital Autopilot.  This is because it would be impossible for a human pilot to maintain the 40° angle of attack as well as perform the on the spot calculations required to determine how and when flight maneuvers should be performed.  If the reentry flight path is not followed correctly either the shuttle will be subjected to heat damage or it may miss its intended landing location.  It is then a reasonable assumption that if the guidance and control functions are damaged there will be nothing to maintain the 40° angle.  The shuttle's angle of attack would then quickly return to a value of about 0.  This scenario fits with the altitude of Columbia being 34,500 Ft. at 13:59:32 (EI+923) instead of 200,700+ Ft. as would have normally been the case, see the Observational Analysis OA-B1.  The Columbia simply descended far too fast, see Fig. A9.  This finding directly supports the conclusion that all flight control systems onboard the Columbia were damaged and left useless.

Rapid descent, overheating & negative b:

The Columbia did not perform any flight maneuvers to slow down its descent and instead maintained a constant rate of descent throughout reentry with an Angle of Attack (AOA) of 0°.  This caused Columbia to descend much too rapidly which resulted in significant overheating of the Thermal Protection System (TPS).  This overheating is evident in many of the debris photos which virtually all show extensive melting and burning of thermal tiles.  It is also not only possible but probable that a burn-through occurred at more than one spot on the orbiter which would have worked to weaken the shuttle's airframe.  Although the amount of damage Columbia sustained prior to breakup will never be known, the weakening of the airframe by itself may not have been enough to destroy the Columbia.  This is because the orbiter was more than half way through the region of highest aerodynamic heating when it broke up and it remains possible although extremely unlikely that Columbia could have exited that portion of reentry safely.  The problem then was that the negative beta which started early during reentry and remained uncontrolled finally became an issue.  During the last minute either Rick Husband or William McCool shut off the autopilot and burned the right rear RCS Yaw Jets for a full 8 seconds in an attempt to correct the negative yaw that must have become quite noticeable, possibly -30° to -40° Yaw.  However, this action overcorrected the shuttle's attitude to the point where negative yaw became positive and continued until it reached +90° Yaw, see Technical Article TA-A2 Columbia's Final Attitude Changes.  This would have placed the Columbia at a right angle to its flight path putting massive lateral aerodynamic forces on the orbiters damaged airframe immediately resulting in the dramatic breakup captured by amateur photographers, see Fig. TA-B1-3.  Error messages regarding the left RCS system near the end of the Time Line document probably meant that system was offline and unable to re-correct the positive Yaw.

Damage to electronics onboard the Columbia:

The shuttle was designed with triple and quadruple redundant electronics systems as well as other systems such as the hydraulic fluid supply and electric power generation that are divided into three completely separate entities.  Based on the extensive maintenance and testing done prior to each mission, the chance of losing all of the systems that perform some function for the shuttle is far too small to calculate accurately.  For all of the guidance and control systems to be affected by something that would normally occur during space flight is generally considered impossible, the Columbia had all of the backup systems it needed to make it through the mission.  This means that something completely abnormal and unaccounted for affected all of the equipment onboard the orbiter and not just a mechanical or electronic glitch that affected one or two units.  Extensive research has led to only two existing possibilities for this scenario.  1.) An Electro Magnetic Pulse (EMP) from a nuclear blast near the Columbia during reentry.  This would certainly do it if the missile carrying the warhead were launched at exactly the correct time to intersect the Columbia's flight path.  This is not impossible, however, according to the accounts written about high altitude nuclear blasts that occurred in the 1960's and 1970's the effects of such an event would have been visible for many miles.  There were no such reports of anomalous activity in the sky at that time which would have matched the effects of a high altitude nuclear blast.  2.) The Columbia passed through a region of high speed beta particles intended to mimic the effects of an EMP.  All of the academic papers written on the subject state that it is possible to produce such an effect for the purposes of ballistic missile defense.  It is known that especially during the Cold War several countries attempted to create such a system to protect them from ICBM attack.  The relative success of these systems is unknown and the information can be assumed to be held secret.

HAARP:

The High Altitude Auroral Research Project (HAARP) facility located in Alaska is capable of producing just such an EMP effect. Marshall Smith of the Brother Jonathan Gazette and Brojon.org website monitored the transmissions from the HAARP facility and posted a portion of his transmission log to his site.  The log states that the HAARP transmitter was in a mode that had the necessary frequency and power level required to destroy the electronics of incoming ballistic missiles at the same time Columbia was reentering the atmosphere.  This would have easily done the same thing to an incoming space shuttle.  However, no one else is known to independently monitor the HAARP system and this information cannot be verified.  The only additional clue that Columbia was flying through a field of charged particles were the early reports of what appeared to be a purple lightning bolt zapping the shuttle over the Pacific.  More than one person is known to have photographed this phenomenon when they were observing the shuttle as it flew over the Pacific Ocean and the California coast.  A member of the investigation board immediately went to California to view and retrieve the photographs.  At this point the photographs have never actually been seen by the public and their current whereabouts are unknown.