IMAGE Detailed Mission Requirements (DMR)

Final - July 1998


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IMAGE 4145 -- Command Assembly Requirements

4145.1          The SMOC shall provide the capability to process commands
                for uplink to the spacecraft from previously generated command load files.

4145.2          The SMOC CMS shall allow the user to generate SCU loads.
                SCU loads include:

                4145.2.1 ATS

                4145.2.2 ATS patch

                4145.2.3 RTS loads

4145.3		The SMOC CMS shall notify the user of any errors or
                warnings encountered during load generation.

4145.4		The SMOC CMS shall notify the user if any loads are
                affected by any changes made to the system or the data used in the command
                load.

4145.5		The SMOC CMS shall allow the user to create, edit,
                generate, transfer, and delete ATS loads.

4145.6		The SMOC CMS shall allow the user to create a load and
                specify the load period start and stop times by selecting an activity plan
                period.

4145.7		The SMOC CMS shall enable the user to expand activities in
                the load.

4145.8		When modifying the load, the SMOC CMS shall allow the user
                to modify a time tag and command parameters that are inserted in the load
                as a result of expanding an activity.

4145.9		The SMOC CMS shall assign activities to either RTS or ATS
                memory based on the activity assignment.

4145.10	        The SMOC CMS shall construct RTS call commands to start the
                execution of activities assigned to RTS memory, assign the table number to
                the RTS call command, and assign these RTS call commands to ATS memory.

4145.11	        The SMOC CMS shall construct the auto switch command and assign it
                to ATS memory, if auto switching is enabled.  The time of the buffer switch
                command shall be either the time tag of the last command in the selected
                load period or the end of the load period minus a constant, whichever is
                later.

4145.12	        If an ATS activity expands beyond the load period, the SMOC CMS
                shall save those commands falling into the next period and include them in
                the next period's planning segment when the user promotes the load.

4145.13	        The SMOC CMS shall verify that the tables assigned to RTS's, used by 
                an ATS load, are of the type assigned for SCU use.

4145.14	        The SMOC CMS shall expand ATS activities in the load into absolute
                time tagged commands.

4145.15	        The SMOC CMS shall create the ATS load and ATS patch load
                file in the format described in the TBD.

4145.16	        The SMOC CMS shall enable the user to transfer load files to the
                spacecraft command processing system.

4145.17	        The SMOC CMS shall generate an integrated print report for ATS
                loads and ATS patch loads.

4145.18	        The SMOC CMS shall generate a load generation report for ATS loads
                and ATS patch loads.

4145.19	        The SMOC CMS shall log all ATS load and ATS patch load generation
                errors to the event log and load generation report.

4145.20	        The SMOC CMS shall verify that ATS loads and ATS patch loads do not
                violate the maximum ATS buffer size constraint.

4145.21	        The SMOC CMS shall verify that ATS loads and ATS patch loads do not
                violate the maximum number of commands constraint.

4145.22	        The SMOC CMS shall verify that ATS loads and ATS patch loads do not
                violate the number of commands per second constraint.

4145.23	        The SMOC CMS shall verify that ATS loads and ATS patch loads do not
                violate the minimum delay time constraint.

4145.24	        The SMOC CMS shall verify that ATS loads and ATS patch loads do not
                violate the maximum delay time constraint.

4145.25	        The SMOC CMS shall verify that ATS loads and ATS patch loads do not
                violate RTS activation constraints.

4145.26	        The SMOC CMS shall verify that RTS loads activated by ATS loads and
                ATS patch loads are uplinked and enabled.

4145.27	        The SMOC CMS shall allow the user to create, edit, generate,
                transfer, and delete RTS loads.

4145.28	        The SMOC CMS shall enable the user to select the table into which
                the RTS load will be stored.

4145.29	        The SMOC CMS shall allow the user to select the intended use for
                each RTS load.  The selections consist of the following:

                4145.29.1 Health and Safety (H&S)

                4145.29.2 SCU

4145.30	        The SMOC CMS shall validate that an RTS load is assigned only to an
                RTS table that is on the list of tables reserved for that type of RTS usage
                [SCU, H&S], available, and enabled.  An RTS table is available if it has
                never been loaded, the load in the table has expired, or the load in the
                table has been deleted.  An RTS table is enabled if the table status is set
                to enabled.

4145.31	        The SMOC CMS shall allow the user to specify a time at which the
                table assigned to the RTS shall be reserved to support it.

4145.32	        The SMOC CMS shall allow the user to enter a time when the RTS load
                shall expire (i.e., the table occupied by the RTS load shall become
                available to be overwritten).

4145.33	        The SMOC CMS shall allow the user to set the table status
                (enabled/disabled).

4145.34	        The SMOC CMS shall alert the user of affected loads when an RTS
                table's status is disabled.

4145.35	        The SMOC CMS shall create the RTS load file in the format described
                in the Telemetry and Command Handbook and IMAGE CIDP to SI ICD.

4145.36	        The SMOC CMS shall generate a load generation report for RTS loads.

4145.37	        The SMOC CMS shall log all RTS load generation errors to the event
                log and load generation report.

4145.38	        The SMOC CMS shall verify that the RTS load does not violate the
                maximum RTS buffer size constraint.

4145.39	        The SMOC CMS shall verify that the RTS load does not violate the
                maximum number of commands constraint.

4145.40	        The SMOC CMS shall verify that the RTS load does not violate the
                number of commands per second constraint.

4145.41	        The SMOC CMS shall verify that the RTS load does not violate the
                minimum delay time constraint.

4145.42	        The SMOC CMS shall verify that the RTS load does not violate the
                maximum delay time constraint.

Response: Requirements will be met.


IMAGE 4146 -- Command Upload and Verification Requirements

CCSDS Command Options: The SMOC shall provide "lights out" (unattended) command uplink support for commands that conform to the following subset of the CCSDS command structure and services.
4146.1		The IMAGE SMOC shall provide the following CCSDS command
                services:

                4146.1.1 Telecommand Data Management Service for commands initiated by the
                SMOC.  This level interfaces with the spacecraft controller for command
                requests and produces command packets for eventual uplink.

                4146.1.2 Telecommand Data Routing Service for commands initiated by the
                SMOC.

                4146.1.3 Telecommand Channel Service for all commands.  This service
                handles the reformatting and encoding of commands and monitoring of the
                telemetry stream to determine the reception of the command by the
                spacecraft using the CCSDS Command Operations Protocol number 1 (COP- 1).

4146.2		The SMOC shall be capable of uplinking any CCSDS packet
                formatted command that conforms to the following limitations:

                4146.2.1 Version 1

                4146.2.2 Secondary header is optional

                4146.2.3 No greater than 233 bytes long

                4146.2.4 The Telecommand Transfer Frame shall be Version 1 with 2 virtual
                channels.  One virtual channel shall be utilized for non-packetized
                commands; the other shall be utilized exclusively for packetized commands.

                4146.2.5 The Telecommand Codeblock shall be 40 bits in length.

4146.3		Forward Link Management: The SMOC shall provide a mechanism
                to control access to the command link by Associate stations and IGSEs to
                control the grouping and formatting of commands for transmission.

                4146.3.1 The IMAGE SMOC shall provide a mechanism to enable and disable the
                issuance of commands by the IGSEs and each of the SMOC-provided ASIST
                stations.

                4146.3.2 The IMAGE SMOC shall provide the spacecraft controller with
                control over the content and formatting of commands within a CLTU,
                including the number of Telecommand Transfer Frames (hence Telecommand
                Packets) within a CLTU, error injection (for negative testing), and CCSDS
                control information.

                4146.3.3 The IMAGE SMOC will allow the operator and "lights out"
                (unattended) system to control the command "uplink" clock rate,
                continuously send the same command link transmission unit, and enable or
                disable ground processing of the COP-1 protocol.

4146.4		COP-1 Protocol Management: The SMOC will provide COP-1-protocol management 
                functions.

                4146.4.1 The SMOC shall support the COP- 1 protocol with supporting command
                buffer management.

                4146.4.2 Spacecraft controller control over the COP- 1 characteristics and
                options shall be provided in real time.

4146.5		Command Verification: The SMOC will provide command
                verification functions.

                4146.5.1 In addition to COP-1 verification, the SMOC will provide the
                capability to verify commands by telemetry verification.  This function
                will be operator enabled/disabled.

4146.6		Command Logging: The SMOC will provide command logging
                functions.

                4146.6.1 The SMOC shall maintain an online data set and printer log of all
                commands issued to the spacecraft, the source of command initiation, the
                time the command was issued, and the command verification status.

4146.7		Command Screening: The system shall maintain a list of
                commands that will require spacecraft controller approval prior to the
                sending of the command.  The primary spacecraft controller must explicitly
                allow each of the critical commands to be forwarded to the spacecraft
                through the use of an independent real time directive.  The directive is
                issued by the primary spacecraft controller upon notification that one of
                the users (or the primary spacecraft controller) has entered the command
                into the command stream.  The command may also be explicitly canceled by
                the primary spacecraft controller.

                4146.7.1 The SMOC shall provide critical command checking from all users,
                with control of the command provided to the primary spacecraft controller.

                4146.7.2 Commands routed to the spacecraft shall be screened against a
                configured list of users, allowing the primary spacecraft controller to
                allow each user only an agreed-to set of spacecraft commands.

                4146.7.3 The primary spacecraft controller shall explicitly allow each of
                the critical commands to be forwarded to the spacecraft through the use of
                an independent real time directive.

Response: Requirements will be met.


IMAGE 4150 -- Spacecraft Telemetry Requirements

4150.1		The SMOC shall receive, quality check, decommutate, and
                process CCSDS real-time and play-back telemetry.

Response: Requirement will be met.


IMAGE 4151 -- Telemetry Reception Requirements

CCSDS Telemetry Options: The SMOC shall process the subset of CCSDS telemetry that conforms to the constraints delineated in the following subsections. Processing the data includes extracting data from the source packets, calibrating, and converting individual telemetry parameters as identified in the Project Database. State conversions, conversions to engineering units, and raw value display options are required.

4151.1		The SMOC shall process CCSDS channel access data units that
                conform to the following constraints:

                4151.1.1 Operational control field containing Command Link Control Word
                (CLCW) is present

                4151.1.2 Fixed format VCDU with Insert Zones

                4151.1.3 Packet data order is "forward"

                4151.1.4 Cyclic Redundancy Code (CRC) appended to each telemetry frame

4151.2		The SMOC shall record and distribute CCSDS formatted
                housekeeping packets that conform to the following constraints:

                4151.2.1 Version 1 packets

                4151.2.2 All packets have identically structured fixed format secondary
                header

Response: Requirements will be met.


IMAGE 4152 -- Data Decommutation and Conversion Requirements

4152.1		The SMOC shall decommutate CCSDS formatted housekeeping
                packets that conform to the following additional constraints:

                4152.1.1 The length of a packet for a given APID is a multiple of 16 bits

Response: Requirements will be met.


IMAGE 4153 -- Telemetry Data Routing and Processing Requirements

4153.1		The SMOC shall be capable of receiving and distributing
                real time and playback virtual channels as downlinked from the spacecraft

4153.2		The SMOC shall provide the capability to select a new
                telemetry data source and reinitialize the status and accounting parameters
                within 60 seconds of the request. This includes resetting the Current Value
                Table (CVT) to purge all previously received telemetry data.

Response: Requirements will be met.


IMAGE 4154 -- Telemetry Combinations Requirements

The SMOC shall process telemetry in the modes delineated in this section. Simultaneous processing of data from different virtual channels is required. Real time processing will occur as playback data is being received. Each processing mode is mutually exclusive.
4154.1		The SMOC shall be capable of receiving and distributing
                real-time and playback virtual channels as downlinked from the spacecraft.

4154.2		The SMOC shall be capable of receiving and processing
                previously recorded spacecraft data in the following combinations:

                4154.2.1 Replay of real-time only at rates of up to 40 times real-time

                4154.2.2 Replay of playback only

4154.3		The SMOC shall support recording of history data in
                real-time, postpass replay of recorded data, and history maintenance
                capabilities.

4154.4		The SMOC shall record all valid telemetry data.

4154.5		The SMOC shall provide a replay capability based on the
                ground receipt time, spacecraft time, virtual channel and ground station
                ID.

Response: Requirements will be met.


IMAGE 4155 -- Memory Dump Processing Requirements

Spacecraft Table Load/Dump/Edit: The SMOC shall support the capability to load, dump, and edit spacecraft tables.
4155.1		The SMOC shall provide labeled formatted table displays.
                Table values shall be obtained from the latest dump of a table and/or the
                configured table source.

4155.2		The SMOC shall create and edit partial/full table load
                files from STOL and from a screen editor.

4155.3		Load and dump files shall use the same format.

4155.4		The SMOC shall provide table Configuration Management.
                Multiple versions of the same table shall be allowed including the current
                flight values.  Configured tables shall be processed as defined in
                requirements 4155.1 and 4155.2.


4155.5		The SMOC shall provide the capability to load and dump
                spacecraft memory.

Note:  The SMOC will not be required to maintain GRI for any instruments.

Response: Requirements will be met.


IMAGE 4156 -- Physical Channel Telemetry Data Processing Requirements

The SMOC shall perform the following functions for the physical channel of the IMAGE spacecraft.
4156.1		The SMOC shall be capable of accepting and processing IMAGE
                telemetry which has any combination of PN encoding and Reed Solomon
                encoding.

4156.2		In the normal mode of operation, the SMOC shall monitor the
                status of each physical channel, and notify the operator of errors.

4156.3		The SMOC shall provide data quality checking of the
                transfer frames and append the information to each source packet.

4156.4		The SMOC shall determine the quality of each transfer frame
                based on the frame decoding.

4156.5		The SMOC shall provide a user selectable switch to
                enable/disable the flagging as bad quality the data containing sequence
                errors in the VC frame count.

4156.6		The SMOC shall validate CLCW data quality.  If a transfer
                frame has an uncorrectable error, the CLCW will not be extracted.  If a
                quality error is detected, the SMOC shall generate an event message to
                indicate the error occurred.

4156.7		The SMOC shall be capable of storing abnormal (i.e. quality
                error detected) telemetry VCDUs to a file and printing that file.

4156.8		The SMOC shall receive and process up to 64 virtual channels.

4156.9		The SMOC shall monitor and display virtual channel
                statistics including quality, rates, number of frames, and Reed-Solomon
                corrections.

4156.10	        The spacecraft controller shall be able to dynamically select the
                virtual channels to be processed.

4156.11	        Data rates beyond the maximum rate shall be processed on a priority
                basis.

4156.12	        The frames shall be quality checked with real time operator
                notification of "bad" VCDUs.

Response: Requirements will be met.


IMAGE 4157 -- Real-Time Virtual Channel Processing Requirements

This section delineates the SMOC processing requirements for each virtual channel denoted by the spacecraft controller as real time. Up to two virtual channels (VC0, VC1) shall be processed as real time data that conform to the following constraint: The effective aggregate data rate is less than 100 kbps.
4157.1		The SMOC shall extract CCSDS formatted packets from each
                virtual channel based on packet application ID.  Each packet will be
                annotated with the physical channel identifier, virtual channel number,
                spacecraft time, virtual channel counter and quality of the telemetry frame
                from which it was extracted.

4157.2		The SMOC shall extract the spacecraft time from the packet
                secondary header (CCSDS Unsegmented Time Code (CUC)) and store it in the
                system.

4157.3		The SMOC shall monitor the data quality of each packet, and
                append the quality to each packet for subsequent distribution and display.

4157.4		Each received packet shall be monitored to verify that it
                is structurally complete and the length matches the length defined in the
                telemetry and command database.

4157.5		The SMOC shall provide the capability for viewing
                unformatted telemetry data.

4157.6		The SMOC shall correct any "byte swapping" and "word
                swapping" performed by the IMAGE C&DH system.

4157.7		The SMOC shall be capable of optionally checking any
                telemetered data item against a set of user definable limits, and then
                report limit failures.

4157.8		The SMOC shall maintain the last reconstructed value for
                each data item for use for displays, limit checking, automated test
                procedure control, and other application processes.

4157.9		The SMOC shall support the concatenation of bits from
                noncontiguous locations within the packet to form a single telemetry
                parameter.

4157.10	        The ground system shall provide data conversion from raw to
                engineering units, including polynomial (no degree
                limit), spline, piece-wise linear, logarithmic, exponential, and power
                conversion equations.

4157.11	        The engineering units conversion shall be able to approximate the actual 
                value to  +-1 % of the actual measurements given during calibration tests.

4157.12	        All data points for which limit checking is enabled shall be
                checked.
                
4157.13	        Limit checking will be performed on both analog and discrete
                telemetry parameters.

4157.14	        Limit checking shall include inclusive and exclusive range
                specifications, open and closed limit intervals.

4157.15	        Up to two sets of high/low limits can be defined for each telemetry
                parameter.  If two sets are defined for one parameter, the values of the
                switch mnemonics associated with the limit sets shall be checked to
                determine which limit set to use.

4157.16	        The SMOC shall set a filter factor for the number of occurrences of
                values outside of the normal limits in determining if a limit violation has
                occurred.

4157.17	        The SMOC shall provide the capability to accept temporary changes
                to limit processing in real time.

4157.18	        The SMOC shall provide discrete state conversions as identified in
                the Project Database (PDB).

4157.19	        The capability to display states of discrete variables in different
                colors is required.

4157.20	        The SMOC shall provide the capability to dump and verify the
                contents of the SCU memory, tables and stored command system.  Additionally
                the system shall process messages generated by the flight software.

4157.21	        The SMOC shall extract real-time "SCU and CIDP-Generated" event
                packets, log them to the line printer, make them available to a system
                spacecraft event page, and maintain a queue of at least the capacity of the
                onboard event buffer.  The system shall store all events to disk.

4157.22	        The SMOC shall provide a mechanism to refer to real-time telemetry
                and system named variables, and temporarily modify the limits and curves to
                be used locally at a controller station.  All variables shall be accessible
                "as downlinked", as :"raw transformed to host bit order", or "converted to
                engineering units".

4157.23	        The user shall have the ability to turn on/off the limit
                checking on an individual point basis, globally or for several
                telemetry points by associating a list of telemetry points with a name.
                The control of limit checking shall
                apply only to the local spacecraft controller's station.

4157.24	        The user shall have the ability to temporarily modify, delete, and add 
                limits and conversion coefficients for telemetry database items.  These 
                modifications shall apply only to the local controller's station and be 
                valid until termination of the current on-line session.

4157.25	        The system control language shall provide a capability to
                compose mathematical expressions of system variables of pre-launch and
                on-orbit activities, including functions of one or more variables, common
                unary and binary operators, and logical expressions.

4157.26	        The system shall support the modularization and execution of
                subprocedures.  The system shall support flow control expressions, such as
                unconditional branching, conditional branching, and looping.  The system
                shall support conditional, unconditional, and timed waits (pauses in
                execution).

4157.27	        The spacecraft controller shall have full interactive control in
                real-time over the execution of procedures, including stop, start, abort,
                wait, branch, and subprocedure execution.

4157.28	        The currently executing procedure on a spacecraft controller
                station shall be suspended (placed in HOLD mode) whenever the procedure
                contains an invalid statement.

4157.29	        The SMOC shall provide the capability to enable procedure
                suspension when the limit checking subsystem local to the spacecraft
                controller station detects a limit violation.

Response: Requirements will be met.


IMAGE 4158 -- Playback Virtual Channel Processing and On-Board Recorder Management Requirements

Playback Virtual Channel Processing: This section delineates the requirements for each virtual channel denoted by the spacecraft controller as a playback virtual channel. The effective aggregate rate shall be less than 6 Mb/s. Playback data shall be stored as the data is received from the spacecraft.
4158.1		Stored playback housekeeping data shall be delivered to all
                IGSEs via the same format as the real time interface as described MIDEX
                IGSE/SGSE Interface Requirements Control Document.

4158.2		The SMOC shall optionally compare the playback data against
                real-time data taken over the same time period and report discrepancies in
                the data.

4158.3		The Solid State Recorder (SSR) will be sized to hold at
                least two orbits worth of data.

4158.4		The SMOC will be able to command the SSR in any of the
                following manners:

                4158.4.1 The SMOC will be able to command a complete dump of the SSR
		and this dump will take no longer than a 30 minutes.

                4158.4.2 The SMOC shall be able to command a normal dump of the SSR where
                the dump will automatically begin where the previous dump ended, and the
                dump will automatically end when it reaches the end of recorded data or
                current record pointer.

		4158.4.3 The SMOC shall be able to command a frame-by-frame
                dump by specifying the physical address of any frame in the SSR.
                The frame addresses are telemetered to the ground in the VCDU
                secondary header.

Response: Requirements will be met.


IMAGE 4159 -- Data Decompression Requirements

4159.1          The SMOC shall decompress all compressed science data.

4159.2		The SMOC shall use the RICE method of decompression as described 
                in the CCSDS Lossless Data Compression, Blue Book, 121.0-B-1.

Note: Decompression parameters shall be fixed for life-of-mission.

Response: Requirements will be met


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Author and Curator:

Dr. D.R. Williams, dwilliam@nssdc.gsfc.nasa.gov, +1-301-286-1258
NSSDC, Mail Code 633, NASA/Goddard Space Flight Center, Greenbelt, MD 20771

NASA Approval: J. L. Green, james.l.green@gsfc.nasa.gov
Last Revised: 04 November 1998