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Technical Article G1

Space Shuttle Data Acquisition Systems and Recorders

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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,

  1. Orbiter Experiments (OEX)

  2. Developmental Flight Instrumentation (DFI)

  3. Operational Instrumentation (OI)

  4. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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