From: ORION::GLLKES "Galileo/K.Simmons" 15-JUN-1987 22:10 To: GALILEO Subj: From: ORION::SIMMONS "Karen Simmons at LASP/Colorado" 12-JUN-1987 15:09 To: GLLKES Subj: Today is Friday, Jun 12, 1987 10:58 AM EDT No. Delivered From Subject Lines 1 Jun 11 13:45 REBBETT FUNCTIONAL REQUIREMENTS DOCUMENT 678 Posted: Thu Jun 11, 1987 1:45 PM EDT Msg: MGIH-2616-1619 From: REBBETT/I/JETPRO/J.P.L. To: KSIMMONS CC: RMATTINGLY Subj: FUNCTIONAL REQUIREMENTS DOCUMENT FOR McNUTT AND WHITE (Insert in 625-205, Galileo Orbiter Functional Requirements Book, Vol II) Custodian: R. Ebbett APPROVED: System: ____________________ M. R. Landano Subsystem: ____________________ G. McNutt Principal Investigator: ____________________ C. Hord JET PROPULSION LABORATORY NO. GLL-4-2024 FUNCTIONAL REQUIREMENT PROJECT GALILEO EXTREME ULTRAVIOLET SUBSYSTEM *Denotes changes ---------------------------------------------------- 1.0 SCOPE This document established the functional requirements of the Galileo Orbiter Ultraviolet Spectrometer Subsystem (EUV) which is used to provide spectral measurements in the spectral range of 500 to 1200 A APPLICABLE DOCUMENTS The documents listed in this section form a part of this Functional Requirement GLL-4-2024 NOTE GLL-3-100, Galileo Orbiter Requirements and Constraints, applies to this document. Requirements of other Galileo level 3 documents may also be applicable. It is the responsibility of the user to adequately acquaint himself with the organization and pertinent content of the level 3 documents, as well as with the material contained herein. FUNCTIONAL REQUIREMENTS Jet Propulsion Laboratory GLL-3-100A Functional Requirements, Galileo Orbiter Requirements and Constraints GLL-3-110 Functional Requirement, Galileo Orbiter Flight Equipment Functional Block Diagram and Interface Listings GLL-3-170 Functional Requirement, Galileo Orbiter Functional Accuracies and System Capabilities GLL-3-180 Functional Requirement, Galileo Orbiter Configuration GLL-3-190 Functional Requirement, Galileo Orbiter Structural Design Criteria GLL-3-200 Functional Requirement, Galileo Spacecraft Inertial Properties GLL-3-210 Functional Requirement, Galileo Orbiter Design Criteria for Temperature Control GLL-3-220 Functional Requirement, Galileo Orbiter Flight Electronic Equipment Design GLL-3-230 Functional Requirement, Galileo Orbiter Equipment List and Mass Allocations GLL-3-240 Functional Requirement, Galileo Orbiter Environmental Design Requirements GLL-3-250 Functional Requirement, Galileo Orbiter Power Profile and Allocation GLL-3-260 Functional Requirement, Galileo Orbiter Flight and Support Equipment, Electrical Grounding and Interfacing GLL-4-2024 GLL-3-270 Functional Requirement, Galileo Orbiter Data System Intercommunication Description and Requirements GLL-3-280 Functional Requirement, Galileo Orbiter Telemetry Measurements and Data Formats GLL-3-290 Functional Requirement, Galileo Orbiter Command Structure and Assignments GLL-3-310 Functional Requirement, Galileo Orbiter Flight Software Requirements GLL-3-1110 Functional Requirement, Galileo Orbiter Support Equipment Functional Block Diagrams and Interface Listings OTHER DOCUMENTS Jet Propulsion Laboratory PD625-52 Project Galileo Policies and Requirements for Science Investigators PD625-232 Orbiter System Configuration Management Plan IRD 512335 Galileo Command and Data Subsystem Interface Control Document DRAWINGS 10086754 Extreme Ultraviolet Subsystem Interface Control Drawing 10085825 Circuit Data Sheet Index and Guide 3.0 FUNCTIONAL REQUIREMENTS 3.1 General The functional requirements of the EUV shall be to measure the composition and scattering properties of the upper atmosphere and identify atomic and molecular gases. 3.2 Sensing The EUV shall detect and measure ultraviolet radiation over a 120 nm band, in the range of 40 to 120 nm emanating in the torus and disc of Jupiter. GLL-4-2024 3.3 Field-of-View The instrument shall have a fixed field-of-view. 3.4 Data Processing The analog signal from the detector, shall be digitized, tagged, and stored in buffer registers until read by the CDS. Data readout shall be in fixed format. 3.5 Signal Interfacing The instrument shall accept command and timing signals from the command and data system (CDS) for control of EUV internal functions and data sampling. Interface circuits shall also be provided for transferring data to the CDS. 3.6 Power Conversion 30 VDC power shall be accepted from the power system (PPS) and converted to the necessary voltages for circuit operation. 4.0 FUNCTIONAL DESCRIPTION 4.1 Instrument Description The EUV shall be an objective grating spectrometer with a mechanical collimator, light shall enter the instrument through an aperture, pass through a mechanical collimator and onto a concave grating. The light spectrum reflected by the grating shall then illuminate a UV detector at the focal plane of the grating. The light shall be converted to electrical pulses indicative of the number of photons at particular wavelengths within the spectrum. 4.2 Major Functional Elements 4.2.1 Optics and Sensing The optics and sensing portion of the EUV shall consist of a protective cover, an open mechanical collimator, a concave dispersion grating, and a detector sensitive to light in the extreme ultraviolet spectrum. Figure (TBD) shows the configuration of the optical elements. GLL-4-2024 4.2.1.1. Protective Cover The protective cover shall be a thin door, spring loaded, using pyrotechnic devices to release the mechanism for opening. The cover will be mounted on the front of the instrument. 4.2.1.2 Collimator An open mechanical collimator shall be required with and aperture size of 27.4 cm2. The FOV shall be 1.0 X 0.1 degrees. 4.2.1.3 Detector The EUV detector shall convert the light transmitted by the optics into electrical pulses. The detector shall consist of a photocathode, a microchannel plate electron multiplier and an anode array. The array shall consist of 128 anodes in a single row, alternately connected for two output channels of odd-numbered anodes and even- numbered anodes. The anodes shall be sequentially gated to the video lines by on-chip shift registers and grating circuits. The charge accumulated at each anode shall be proportional to the light intensity at that particular wavelength as dispersed. 4.2.2 Electronics The electronics shall consist of analog and digital processing circuits, integrators, analog to digital converters, output registers, timing and control, low voltage power supply, high voltage power supply, and temperature sensor. 4.2.2.1 Analog and Digital Processing Circuits The analog and digital processing circuits shall consist of two separate chains, one channel for the odd anodes and one channel for the even numbered anodes. 4.2.2.1.1 Integraters The charge pulse integrators shall provide a voltage output proportional to the total charge accumulated during one array scan interval. They shall hold that voltage while the analog-to-digital conversion takes place. GLL-4-2024 4.2.2.1.2 Analog-to-Digital Converters (ADC) The outputs of the integrators shall be digitized to 7 levels by 3-bit ADC's when in the pulse integration mode. In the pulse counting mode, the detector pulses shall be level-discriminated in the ADC's. 4.2.2.1.3 Adders The adders are 16-bit presetable counters which are preset to the existing value in the accumulator and are incremented by clock pulses gated by the ADC's. 4.2.2.1.4 Accumulators The accumulators shall consist of thirty-two, 64-bit shift registers arranged to provide storage for 128, 16 bit words.Each of the 128 words shall correspond to a particular anode and accumulate the ADC word corresponding to that anode during each scan interval. 4.2.2.1.5 Output Registers The two output registers shall be 16 bit parallel entry serial output shift registers. Their inputs are transferred from the accumulators by logic resulting from receipt of the register load gate command from CDS. The output register's 16 bit words are transferred into the CDS by the 14.4 KHz shift clock. 4.2.2.2 Timing and Control The output data words are buffered such that the data words may be extracted at 2.5 ms intervals are multiples thereof. This timing is provided by the register load gate command. Load gate commands shall be counted by a word address counter from which a word sequencer signal is generated for control of word loading into the output registers. The register load gate command shall inhibit the 14.4 KHz shift clock from transferring science data to the CDS while words are being loaded into the output registers. A word address reset command from the CDS resets the word address counter to word pair 1. 4.2.2.3 Low Voltage Power Supply (LVPS) The two LVPS's shall be DC to DC converters capable of accepting 30 VDC regulated power from PPS and converting it to the voltages required to operate the EUV. GLL-4-2024 4.2.2.4 High Voltage Power Supply The high voltage power supply shall be powered by a low voltage power supply dc output and supplies operating voltages for the detector. High voltage control signals from the CDS shall set the high voltage to one of seven levels or zero for the detector gain control. The high voltage converter frequency shall be synchronized to the 14.4 KHz shift clock. 4.2.2.5 Temperature Sensor A temperature sensor shall be provided to indicate the temperature in the detector assembly. 4.2.3 Logic Module 4.2.4 Data System The digital output shall consist of 12-8 bit words per telemetry request (minor frame). These data shall be organized into 12 bit rate words. Timing shall be controlled by telemetry requests sent by the CDS. A complete sequence shall consist of 16 minor sequences. Each minor sequence shall consist of 3 minor frames, as illustrated in GLL-3-270, Data System Intercommuni- cation. The word formats shall be as described in GLL- 3-270. The data rate shall be 144 bits per second as referenced in GLL-3-270. 4.2.5 Modes of Operation The EUV will have (TBD) major states, as described in Figure (TBD) 4.2.5.1 Power-On-Reset When initially energized, all circuits in the EUV shall assume a predetermined state. High voltage shall be off. Time synchronization and data identification shall be established following receipt of the first telemetry request from the CDS. A power-on-reset occurs when the supply voltage drops to approximately 20 V for approximately 0.5 seconds. GLL-4-2024 4.2.5.2 On Mode With receipt of the high voltage on command, the instrument shall go into the normal operating mode. 5.0 INTERFACE DEFINITIONS 5.1 Electrical Interfaces 1) Basic requirements for electrical grounding, electrical bonding, electrical interface circuits and electromagnetic compatibility are contained in GLL-3-260, Electrical Grounding and Interfacing. 2) Specific system-level requirements for electrical interface circuits and grounding are contained in the applicable circuit data sheets. See JPL Drawing 10085825, Circuit Data Sheet Index and Guide. 3) All spacecraft flight and umbilical interface circuits, e.g., subsystem-subsystem, subsystem- launch vehicle, and subsystem-support equipment through the umbilical connector are listed in GLL- 3-110, Functional Block Diagrams and Interface Listings. 4) All spacecraft non-flight circuits, including direct access circuits, are listed in GLL-3-110, Functional Block Diagrams and Interface Listings, if applicable. 5.1.1 Power/Pyro Subsystem (PPS) 5.1.1.1 EUV Primary Power The PPS will provide a commandable ON/OFF 30Vdc power to the EUV over a single interface. 5.1.1.2 EUV Optics Cover Deploy The PPS will provide a commandable pyro event to the EUV optics cover release mechanism over a redundant interface. GLL-4-2024 5.1.2 Command and Data Subsystem (CDS) The EUV interface with the CDS shall be as specified in IRD 512335, Galileo Command and Data Subsystem Interface Control Document. EUV communication with the CDS shall be as specified in GLL-3-270, Data System Intercommuni- cation Requirements. Refer to GLL-3-280, Telemetry Measurements and Data Formats, and GLL-3-290, Command Structure and Assignments, for formats and descriptions. 5.1.2.1 Signals from CDS to EUV The synchronization signal will be a 806.4 KHz square wave which shall be used by the EUV bus adapter, along with the real-time interrupt signal described below, to generate bit synchronization and word synchronization signals for use by the bus adapter logic. 5.1.2.1.1 Real-Time Interrupt The RTI signal will be a 15 Hz rectangular pulse with 0.00093 percent duty; that is, pulses 0.62 micro sec wide will occur periodically on this line with a frequency of 15 Hz. The RTI shall be used by the EUV for real-time synchronization. 5.1.2.1.2 Supervisory Data The supervisory data line will deliver serial data to the bus adapter. These data will be bus control words, recipient/source codes store/load addresses, and command data bytes. Pulses on this line will have a duration of 0.62 micro sec. 5.1.2.2 Signals from EUV to CDS 5.1.2.2.1 Reply Data The reply data line shall be used by EUV to send telemetry data bytes to the CDS. The most significant (first) bit os a byte of reply data shall be placed on the reply line during bit 1 (MSB) of supervisory data, with the subsequent seven bits os reply data being shifted onto the reply line at a rate of 403.2 KHz. All science data shall go to the CDS on this single line, which will not be shared by any other subsystem. 5.1.2.2.2 EUV Detector Temperature Measurement The temperature of the detector will be measured and included in the spacecraft engineering telemetry. GLL-4-2024 5.2 Mechanical Interfaces The EUV instrument will be mounted on the top of Bay 4 and the EUV logic module will be mounted on top of Bay 5 as specified in GLL-3-180, Configuration, and in the EUV Interface Control Drawing 10086754. 5.2.1 Alignment The instrument mounting surface will be known to within 3 degrees. 5.2.2 Field-of-View The FOV of the EUV shall be 1.0 X 0.1 degrees. 5.3 Thermal The EUV shall be thermally coupled to the mounting points provided at the top of bay 4 as shown in the EUV Interface Control Drawing 10086754. Surfaces shall be finished as shown in the drawing. 6.0 Performance Parameters (TBD) 7.0 Physical Characteristics and Constraints 7.1 Mass The mass of the EUV shall be described in GLL-3-230, Equipment List and Mass Allocations. For reference only, the current mass estimate is: Spectrometer 4.7 Kgs Logic Module 2.3 Kgs Total mass of 7.0 Kgs GLL-4-2024 7.2 Power The 30 Vdc power required by the EUV shall be as specified in GLL-3-250, Power Profile and Allocation. For reference only, the power estimate is as follows: Spectrometer 1.9 Watts Logic Module 3.0 Watts Total Power 4.9 Watts 7.3 Volume The dimensions of the EUV shall be as specified in ICD 10086754. Given here for reference only: Spectrometer 44.3 cm x 16.9 cm x 14.9 cm high Logic Module 25.4 cm x 15.2 cm x 2.4 cm high 7.4 Environmental The EUV subsystem shall be designed to operate within specifications over the type approval temperature range which is -20 to +55 degrees C. In addition, the subsystem shall be compatible with the requirements of GLL-3-240, Environmental Design Requirements, and GLL-3- 210, Design Criteria for Spacecraft Temperature Control. 7.5 Packaging The EUV shall be packaged per PD625-52, Project Policies paragraph 9.2.3, section 3.1.3 of MJS77-3-220, Electronic Equipment Design, shall also apply. The rest of MJS77-3-220 and GLL-3-220 may be used as a guideline. 7.6 Identification The EUV shall be identified per PD625-52, Project Policies paragraph 9.7.2.2 (2). 8.0 Safety Considerations 8.1 Personnel Safety High voltage is present during EUV operation, but is contained within the instrument. GLL-4-2024 8.2 Instrument Safety To avoid damage to the EUV during handling and operation, the following constraints shall apply: 1) The EUV will not be expose to relative humidities above 50 percent, or temperatures above +55 degrees C. 2) The EUV will not be operated while in the corona region, i.e., between standard atmospheric pressure and 5 x 15-5 TORR. 3) The EUV will not be exposed to an atmosphere containing hydrogen or helium in substantially larger concentrations than exist in the normal earth atmosphere to avoid diffusion of the small molecules into the detector. NOTE: After vacuum testing of the EUV, the chamber will be backfilled with dry nitrogen. 4) The EUV will be transported only in its special carrying case, except for shipment to ETR. 5) During all periods between system tests, the EUV dust cover and desiccant will be in place. During vacuum testing the dust cover must be removed. For system checks the dust cover will be replaced by the External Stimulus Unit. In final flight configuration the dust cover/desiccant will be replace by the protective flight cover. 6) When the protective flight cover is in place, a flow rate of dry nitrogen purge at (TBD) SCFH will be provided through the instrument purge fitting. After the shuttle doors are closed, purging of the instrument is no longer needed. 7) The EUV is designed to operate in atmospheric or vacuum temperature range of -30 to +40 degrees C. 8) During spacecraft solar thermal vacuum tests, the EUV aperture must be shielded from the solar lamps by the EUV stimulus unit, the flight cover or a light disc on the thermal stand offs. Exposure of the EUV optics to the solar lamps will cause severe damage. This mail session is now complete. MAIL DISCONNECTED 00 40 00:00:06:30 456 9