Observational Analysis G1 11/15/2003 The OEX Data Recorder A "box" that happens to be "black" but not necessarily the, "black box".

• This section is supported by,

  • OA-F1 - The Case for the Final Report was Made Using OEX Data
    May be able to tell about the accuracy of data taken from the OEX.

  • TA-G1 - Space Shuttle Data Acquisition Systems and Recorders
    Attempts to sort out the confusing story behind the data recorders.

  • TA-G2 - Comparison of the Space Shuttle OEX Data Recorder to a standard Flight Data Recorder
    The first descriptions of the OEX claimed that it was the shuttle's "Black Box".

  • TA-G3 - The Use of Challenger's OEX Recorder in the 51L Investigation
    The OEX recorder was used extensively in the Challenger investigation.

Circumstances of the Discovery

If there was any single event that is capable of discrediting the entire final report that was produced by the C.A.I.B. it would have to be the discovery of the Orbiter Experiments (OEX) data recorder. The OEX was found by itself under a tree near Hemphill Texas on 03/18/2003.  The area where it was found had been searched previously but it is possible that search teams can miss even significant pieces of debris.  The data recorder was in exceptionally good condition considering that it was subject to all of the reentry forces and aerodynamic heating that all the rest of the debris was exposed to.

• So exactly who found the OEX recorder, how and where?  This is truly a story for the ages from the LA Times Butterfly on a Bulet series.

Comparison of Debris Condition:

Technical Article G1 Space Shuttle Data Acquisition Systems and Recorders There has been a great deal of confusion regarding the numbers of data acquisition systems and data recorders onboard the Space Shuttle.  The questions may have more to do with exactly " what" data is being collected and " when" rather than with what equipment is involved.  There have been at least 4 different data acquisition systems and associated recorders described for the Space Shuttle, Orbiter Experiments (OEX) Developmental Flight Instrumentation (DFI) Operational Instrumentation (OI) Modular Auxiliary Data System (MADS) The following information is as of 1988, (see No. 1 bottom). Recorders: The Space Shuttle has a total of three data recorders onboard.  There are two Operational Recorders located in Avionics Bays 1 and 2.  There is a third recorder known as the Payload Recorder located below the Mid-deck floor close to the payload bay.  The Payload Recorder may also be known as the MADS/OEX Data Recorder depending on which data acquisition system is in use. The Orbiter Experiments Program (OEX) allowed for placement on the shuttles Columbia and Challenger certain special experiments and instrumentation focusing exclusively on the entry phase of flight.  One of the primary components installed on the OEX equipped shuttles was an extra large capacity data recorder in place of the standard payload recorders mounted on the other shuttles. The Developmental Flight Instrumentation Package (DFI) was a single package containing a number of experiments that sat in the back of the orbiter's payload bay on missions STS-1 through 4 (Columbia) and STS-8 (Challenger), as one of the experiments planed for the OEX program.  Comprised of over 4500 sensors the primary purpose of the DFI package was to provide post flight certification of the orbiters subsystem designs prior to the start of operational shuttle missions.  The DFI package also contained its own data recorder. Operational Instrumentation (OI) is the standard telemetry and voice data collected on all shuttle missions and recorded to the Operational Recorders located in Avionics Bays 1 and 2.  Since the establishment of the Tracking and Data Relay Satellite (TDRS) system in the mid 90's it has probably been unnecessary to record all the data on a shuttle mission when it can be continuously transmitted to Mission Control.  It is therefore unknown if this data is still recorded during every shuttle mission as standard practice. Modular Auxiliary Data System (MADS) refers only to certain data collected by the Payload Recorder during specific periods of ascent and reentry.  After the DFI package was removed from Columbia and Challenger their OEX recorders would have simply been recording this same data if it was needed.  When this recorder was not recording MADS data it would be recording data from any experiments in the orbiters payload bay and or Mid-deck.  At some point the astronauts began recording experiment data to laptops made for that purpose making the Payload Recorder obsolete.  With the establishment of the TDRS system the shuttle could transmit data to Mission Control continuously even through the reentry blackout period.  Therefore it is unknown if the MADS data was even being collected after the TDRS system was in place. Fig. TA-G1-1 Fig. TA-G1-1 is a diagram of a Space Shuttle with the DFI experiments package installed in the payload bay.  After the DFI experiments had been completed over the course of several shuttle missions utilizing both the Columbia and Challenger, the DFI payload was removed.  Because the DFI used both internal instrumentation as well as external sensors located at different areas of the shuttle, its removal left many sensors with un-terminated wires where the DFI payload had been.  Besides being located where their removal would have been difficult and costly, many of the sensors collected raw date that may at some point be useful.  Therefore the wiring to those sensors was rerouted to signal conditioning units so that the data could be collected on the OEX data recorder. References: 1http://science.ksc.nasa.gov/shuttle/technology/sts-newsref/sts-inst.html#sts-inst/ 1http://www.spaceflight.nasa.gov/shuttle/reference/shutref/orbiter/comm/inst/ 2http://www.shuttlepresskit.com/sts-93/scom.htm 1.) These two website links contain identical data that is dated 1988 2.) The information from this link is dated 10/6/98 but its accuracy is unknown

When data from the OEX was used:

Since the discovery of the OEX data recorder it has been understood that the information taken from the old magnetic tape reels inside was used to fill holes in the time line and recreate what occurred after LOS at 13:59:32 GMT on February 1, 2003.  The first overviews of the revision 15 documents, both the Time Line and Ground Track, would lead one to believe that OEX data was used on them based on the extended telemetry after LOS.  It is currently unknown when revision 15 was released to the public on the Columbia investigation website, but based on the official dates, those documents clearly could not contain OEX data.

The dates that those documents were released for official use are on their front pages, and shown below, although the public may not have seen them until sometime later.  It was also reported that the magnetic tape from the OEX data recorder needed extensive cleaning before the data could be extracted from it.  The revision 15 data was published 8 days prior to the actual discovery of the OEX data recorder.

After its discovery in the debris field the OEX recorder was sent to Imation to clean and recover the magnetic tape.

STS-107 Time Line Rev. 15:  Date of approval by the OVE working group 03/10/2003

Note: Rev 15 BASELINE corrects typo's, adds S-Band comm drop out data, & adds new debris observations & jet firings nearest the debris observations.  Rev 15 was been baselined by the OVE Working Group Team as of 3/10/03.

STS-107 Ground Track Rev. 15:  Release date 03/13/2003

Events Summary, and Sighting Data Based on the Rev 15 Master Time Line.

OEX Data Recorder found and retrieved in nearly perfect condition:  03/18/2003

Data found on the OEX magnetic tapes was used to fill in the missing data, especially after LOS, in the Time Line and Ground Track documents.  This is largely considered to be the most important find of the debris search and made the final determination of what caused the Columbia disaster possible.

The Space Shuttles flight data recorder:

Shortly after STS-107 and the loss of Columbia the main stream news media began reporting that the OEX data recorder was the Space Shuttle's Flight Data Recorder.   Most people are at least a little familiar with airline crash investigations from watching news reports that follow in the days after such a tragedy.  In the case of a passenger jet crash almost everyone knows that the first item the crash investigators will be looking for is the planes Flight Data Recorder or "Black Box".  The Flight Data Recorder is a crash survivable unit and generally contains enough information to give investigators the ability to recreate what happened on an aircraft the last few minutes before it crashed.  The reason that Flight Data Recorders are found so quickly after the crash of a passenger jet is that they contain a locator beacon that sends a radio signal guiding investigators directly to it.  Even in the event of a water crash a signal is still transmitted up to a recovery ship.

The idea that evidence critical to determining the cause for the loss of Columbia probably came from the Rogers Report on the Challenger disaster.  A unique set of circumstances allowed the Challenger's OEX unit to be retrieved in good condition.  Data from the Challenger's OEX recorder significantly helped the investigators determine why the shuttle stack exploded shortly after liftoff closing that investigation.

The fact is that the OEX recorder was installed on Columbia simply to record data from a special group of experiments performed during the first few shuttle flights.  These experiments were designed to verify all of the engineered flight parameters and validate the shuttles flight and guidance software.  It appears that the Space Shuttle was not originally designed with a crash survivable flight data recorder / "Black Box" like the ones installed in commercial jets.  The reason why such a device was not included in the shuttle is unknown unless it was considered unnecessary along side other redundant systems, or possibly it was determined that no such device would survive the destruction of a Space Shuttle given the massive forces and extreme temperatures involved.  This page contains an excellent description of the construction and operation of a typical crash survivable flight data recorder designed for commercial use, How Black Boxes Work.

The Space Shuttle was designed with two Operational Data Recorders located in Avionics Bays 1 and 2.  These recorders together with their associated sensors, signal conditioning hardware and controllers were known as the Operational Instrumentation System.  The job of this system was to continuously record and download to Mission Control certain telemetry and voice data.  Another system for collecting data during shuttle missions was the Modular Auxiliary Data System (MADS).  This system recorded data from selected sensors for pressure, temperature, vibration and strain located at strategic points on the orbiter during specific periods of ascent and reentry.  The purpose of the MADS was to provide data that would help the engineers more easily determine the orbiters response to different flight conditions.  The MADS data was recorded to the MADS Recorder also known as the Payload Recorder which recorded data from experiments in the orbiters payload bay and Mid-deck.  The data in the Payload/MADS Recorder was then typically downloaded after the shuttle mission.

Up until the launch of STS-1 much of the shuttle's design was based on theoretical parameters, in addition to wind tunnel testing and data from the X15 program.  The engineers involved needed firm data in order to fine tune the orbiters structure and flight control system.  It was determined that a package of five experiments called the Developmental Flight Instrumentation (DFI) package could be placed onboard the shuttles for the first few flights to collect necessary data.  Being that the Columbia and Challenger were the first operational shuttles they had, In addition to the standard set of sensors that would be installed on all the shuttles, many additional sensors that were intended to feed data to the DFI experiments.  It was also determined that the amount of data that would need to be collected from the DFI package would require a recorder with a much larger capacity than the standard Payload/MADS recorders that would be installed on the other shuttles.  The Columbia and Challenger were fitted with an Orbiter Experiments (OEX) Recorder that had nearly 4 times the capacity of the standard MADS recorders.  After the DFI program was over and the experiments package was removed from the shuttle's payload bay, the OEX recorder simply performed the same function as the Payload/MADS recorders did on the other shuttles.  The only additional difference being that the Columbia and Challenger now had a large number of sensors, wiring and equipment that initially was used by the DFI package and now had no use consuming both needed space and weight.

The direct reason for recording data during reentry was the 10 minute blackout period that spacecraft traditionally went through during the early part of reentry.  The ionized plasma that formed underneath a spacecraft as the result of hypersonic flight made transmitting radio communications down through the atmosphere impossible.  This problem was solved with the completion of the TDRS array which allowed reentering space craft to beam signals upward back into space and then relay them down to mission control.  See Communications and Hypersonic Flight.  The completion of the TDRS array in the mid 90's made the MADS/OEX obsolete which is substantiated by the lack of references to the MADS/OEX system in shuttle post flight reports after this period.  Previous to the full deployment of the TDRS system, shuttle post flight reports would reference flight data as having been recorded by the MADS/OEX.  This is not to mention that the oversized reel to reel data format had been obsolete many years before that.  The Payload Recorder itself was made obsolete when the astronauts began recording experiment data on a computer called the, "Payload and General Support Computer", which is simply an IBM 755c laptop designed specifically for that task.

It is currently unknown whether or not MADS data was being recorded on recent shuttle missions.  Recording MADS data would be the only function of that recorder since the payload data functions were now completely obsolete with the introduction of the, "Payload and General Support Computer", for recording experiment data.  Assuming that the MADS data was still being recorded only during short periods on ascent and reentry, this would more than likely be seen as a waste of resources when the data could be transmitted down to Mission Control and recorded there.  The value of having an onboard MADS recorder would also depend on the usefulness of the data that was being collected and the reliability of the TDRS system.  It is unlikely that NASA would support the upkeep of 20 year old reel to reel data recorders for just a few minutes of redundant recording.

A document from the NASA website regarding orbiter upgrades lists the replacement of the MADS with an Integrated Vehicle Health Monitoring System (IVHMS) as a high priority.  It also stated that this is a phase 1 upgrade that would be carried out in 1999 with the first flight in 2000.  This timing fits Columbia's overhaul period perfectly.  In addition to this all of the news articles posted regarding Columbia's maintenance period state that a major overhaul of the data acquisition system either will be done or had been done.  One of the news article on the page, Columbia's Recent Overhaul, contains the following sentence, "Technicians also removed 1,000 pounds of old wiring and equipment used to monitor Columbia's earliest flights 20 years ago.".  The whole MADS/OEX system weighs a little less than a thousand pounds.  None of these documents contain a statement saying precisely that the OEX recorder was removed or replaced but all of the evidence points in that direction.

OEX crash survivability statements are recanted in the STS-107 Final Report: