625-205 GLL-4-2023 PLASMA WAVE SUBSYSTEM TABLE OF CONTENTS TITLE PAGE 1.0 SCOPE 2.0 APPLICABLE DOCUMENTS 3.0 FUNCTIONAL REQUIREMENTS 4.0 FUNCTIONAL DESCRIPTION 5.0 INTERFACE DEFINITION 6.0 PERFORMANCE PARAMETERS 7.0 PHYSICAL CHARACTERISTICS AND CONSTRAINTS 8.0 SAFETY CONSIDERATIONS 9.0 SPECIAL Tables Table 1. Spectrum Analyzer Filter Characteristics Table 2. Sweep Frequency Receiver Filter Characteristics Table 3. Wideband Waveform Receiver Operating Modes Table 4. High Frequency Receiver Filter Characteristics Table 5. Position of High Frequency Receiver Data in PWS Low-Rate Science Format Table 6. Position of Sweep Frequency Receiver Data in Low-Rate Science Format Table 7. Maximum EMI Levels REVISION PAGE Requirements 625-205 GLL-4-2023 PLASMA WAVE SUBSYSTEM (Insert in 625-205, Galileo Orbiter Functional Requirements Book) Custodian: G. W. McSmith APPROVED; System: . N. Yarnell Principal Investigator: . D. A. Gurnett Subsystem: . G. W. McSmith JET PROPULSION LABORATORY No. GLL-4-2023, Rev. B 2 May 1989 SUPERSEDES: GLL-4-2023, Rev. A. 18 February 1981 FUNCTIONAL REQUIREMENT GALILEO ORBITER FLIGHT EQUIPMENT PLASMA WAVE SUBSYSTEM 1.0 SCOPE This document establishes the functional requirements of the Galileo Orbiter plasma wave subsystem (PWS) which is used to investigate electric and magnetic waves in space plasmas. 2.0 APPLICABLE DOCUMENTS The following documents form a part of this Functional Requirement. NOTE GLL-3-100, Galileo Orbiter Requirements and Constraints applies to this document. Requirements of other Galileo level-three 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-three documents, as well as with the material contained herein. Requirements Jet Propulsion Laboratory GLL-3-100 Functional Requirements, Galileo Orbiter Requirements & Constraints GLL-3-110 Functional Requirements, Galileo Orbiter Functional Block Diagram & Interface Listings GLL-3-170 Functional Requirements, Galileo Orbiter Functional Accuracies & System Capabilities GLL-3-180 Functional Requirements, Galileo Orbiter Configuration GLL-3-190 Functional Requirements, Galileo Orbiter Structural Design Criteria GLL-3-200 Functional Requirements, Galileo Orbiter Inertial Properties GLL-3-210 Functional Requirements, Galileo Orbiter GLL-3-220 Functional Requirements, Galileo Orbiter Electronic Equipment Design GLL-3-230 Functional Requirements, Galileo Orbiter Equipment List and Mass Allocations GLL-3-240 Functional Requirements, Galileo Orbiter Environmental Design Requirements GLL-3-250 Functional Requirements, Galileo Orbiter Power Profile & Allocation GLL-3-260 Functional Requirements, Galileo Orbiter Electrical Grounding & Interfacing GLL-3-270 Functional Requirements, Galileo Orbiter Data System Intercommunication Description & Requirements GLL-3-280 Functional Requirements, Galileo Orbiter Telemetry Measurements & Data Formats GLL-3-0290 Functional Requirements, Galileo Orbiter Command Structure & Assignments GLL-3-1110 Functional Requirement, Galileo Orbiter Support Equipment Functional Block Diagram & Interface Listings DRAWINGS Jet Propulsion Laboratory 10085825 Circuit Data Sheet Index and Guide 10086759 PWS Interface Control Drawing 10086769 PWS Interface Control Drawing Jet Propulsion Laboratory PD625-50 Galileo Orbiter Science Requirements Document PD625-52 Project Galileo Policies and Requirements for Orbiter Science Investigations PD625-232 Galileo Orbiter System Configuration Management Plan 3.0 FUNCTIONAL REQUIREMENTS GENERAL The function of the PWS shall be to measure the characteristics of wave electric and magnetic fields in the Jovian magnetospheric plasma. The scientific objectives of this investigation are to study the characteristics and origin of plasma waves in Jupiter's magnetosphere. The measurements obtained with the PWS will be used to analyze wave-particle interactions that play important roles in controlling the dynamics of the Jovian magnetosphere and to study satellite- magnetosphere interactions. As a secondary objective a study will be made of Jovian radio emissions. 3.2 Sensing and Analog Processing The PWS shall use sensors capable of detecting wave electric fields and wave magnetic fields. 3.2.1 Frequency Coverage The PWS shall measure wave phenomena at frequencies between 5 Hz and 160 kHz. The PWS shall also measure wave electric fields at frequencies in selected narrow band passes in the frequency range 100 kHz to 5.6 MHz. 3.3.2 Frequency Resolution The PWS shall measure wave phenomena in four filter channels between 5 Hz and 50 Hz. Nominal bandwidths shall be + 15 Percent of the center frequency. The PWS shall have 112 filter channels between 40 Hz and 160 kHz with bandwidths of approximately + 2 percent of the center frequency. The PWS shall also have 42 channels with 3 kHz bandwidths at frequencies between 100 kHz and 5.6 MHz. m e Galileo 2.4 kHz power supply frequency shall be notched in each of these filter channels at frequencies above 400 kHz. The PWS shall also make high frequency resolution measurements with a wideband waveform receiver that will sample wave phenomena rapidly enough to enable reconstruction of the waveform in selectable bandwidths of 5 Hz to 1 kHz, 50 Hz to 10 kHz, and 50 Hz to 80 kHz. 3.2.3 Dynamic Range The PWS shall make measurements over a dynamic range greater than 90 dB with spurious free response over a dynamic range greater than 70 dB. 3.2.4 Amplitude Resolution The PWS shall resolve the amplitude of wave phenomena measured to within +/- 2 dB. 3.3 Data Processing The instrument shall cycle through various filters, collecting, compressing, A to D converting, and formatting data for output. The output shall be in 1 of 4 fixed formats 3.4 Signal Interfacing The instrument shall contain a data interface with the command and data subsystem (CDS). This interface shall condition signals for communication with the CDS to provide instrument synchronization, mode selection, and data readout. 3.5 Power Conversion The PWS shall accept 2.4 kHz power form the power/pyro subsystem (PPS) and convert it to the necessary voltages for circuit operation. 4.0 FUNCTIONAL DESCRIPTION 4.1 Major Functional Elements The PWS shall consist of a four channel frequency spectrum analyzer, a 112 channel sweep frequency receiver, a wideband waveform receiver, a 42- channel high frequency receiver, a data processing unit, and electric dipole antenna assembly, a search coil magnetic antenna assembly, input electronics, a calibration generator, a search coil preamplifier supplemental heater, and a power supply. The PWS functional block diagram shall be as shown in Figure 1. 4.1.1 Four Channel frequency Spectrum Analyzer The four channel frequency spectrum analyzer shall measure the amplitude of signals in four filter channels with a logarithmic compressor. m e center frequencies and the nominal bandwidth of these four channels are shown in Table 1. Table 1. Spectrum Analyzer Filter Characteristics Compressor Filter Center Frequency (Hz)* Frame Number 4 5.62 1, 5, 9, 13, 17, 21 25 2, 6 10, 14, 18, 22, 26 3, 7, 11, 15, 19, 23, 27 4, 8, 12, 16, 20, 24, 28 *Nominal bandwidth of + 15% 4.1.2 One-Hundred Twelve Channel Sweep Frequency Receiver The 112 channel sweep frequency receiver shall measure the amplitude of signals in 112 filter channels with four logarithmic compressors. The center frequencies and bandwidth of these 112 channels are shown in Table 2. 4.1.3 Wideband Waveform Receiver The wideband waveform receiver shall sample and convert to digital form with 4- bit accuracy the waveform of the signal received by an automatic gain control (AGC) receiver rapidly enough to allow reconstruction of the waveform in one of three bandpasses: 50 Hz to 10 kHz, 40 Hz to 80 kHz, or 5 Hz to 1 kHz. This hi- rate data shall be supplied, serially to the bulk memory through a special purpose interface, similar to the SSI hi-rate data. The waveform receiver shall operate in one of three hi-rate modes and a waveform survey mode (data included in LRS format) as listed in Table 3. 4.1.4 Forty-two Channel High Frequency Receiver The forty-two channel high frequency receiver shall measure the amplitude of signals in forty-two filter channels with one logarithmic compressor. The center frequencies of these forty-two channels are shown in Table 4. The nominal bandwidth of these channels is 3 kHz. 4.1.1 Four Channel frequency Spectrum Analyzer The four channel frequency spectrum analyzer shall measure the amplitude of signals in four filter channels with a logarithmic compressor. m e center frequencies and the nominal bandwidth of these four channels are shown in Table 1. Table 1. Spectrum Analyzer Filter Characteristics Compressor Filter Center Frequency (Hz)* Frame Number 4 5.62 1, 5, 9, 13, 17, 21 25 2, 6 10, 14, 18, 22, 26 3, 7, 11, 15, 19, 23, 27 4, 8, 12, 16, 20, 24, 28 *Nominal bandwidth of + 15% 4.1.2 One-Hundred Twelve Channel Sweep Frequency Receiver The 112 channel sweep frequency receiver shall measure the amplitude of signals in 112 filter channels with four logarithmic compressors. The center frequencies and bandwidth of these 112 channels are shown in Table 2. 4.1.3 Wideband Waveform Receiver The wideband waveform receiver shall sample and convert to digital form with 4- bit accuracy the waveform of the signal received by an automatic gain control (AGC) receiver rapidly enough to allow reconstruction of the waveform in one of three bandpasses: 50 Hz to 10 kHz, 40 Hz to 80 kHz, or 5 Hz to 1 kHz. This hi- rate data shall be supplied, serially to the bulk memory through a special purpose interface, similar to the SSI hi-rate data. The waveform receiver shall operate in one of three hi-rate modes and a waveform survey mode (data included in LRS format) as listed in Table 3. 4.1.4 Forty-two Channel High Frequency Receiver The forty-two channel high frequency receiver shall measure the amplitude of signals in forty-two filter channels with one logarithmic compressor. The center frequencies of these forty-two channels are shown in Table 4. The nominal bandwidth of these channels is 3 kHz. Table 2. SWEEP FREQUENCY RECEIVER FILTER CHARACTERISTICS Band No. Channel No. Center Frequency (Hz)Bandwidth (Hz) Band No. Channel No. Center Frequency (Hz)Bandwidth (Hz) Band No. Channel No. Center Frequency (kHz)Bandwidth (Hz) 1 2 42.1 45.6 42 43 900 965 83 84 18.59 20.10 1 3 4 5 6 7 8 9 10 11 12 13 14 15 49.0 52.5 56.0 59.6 66.7 70.4 77.7 81.5 89.0 96.7 104.5 112.5 120.6 +/- 5.2 2 44 45 46 47 48 49 50 51 52 53 54 55 56 1031 1098 1201 1272 1380 1491 1606 1724 1887 2013 2144 2325 2513 +/- 15 85 86 87 88 89 90 91 92 93 94 95 96 97 21.6 23.3 25.1 26.9 28.7 30.5 34.2 36.0 39.8 41.7 45.6 49.5 53.5 16 17 18 19 20 21 22 23 24 25 26 27 28 128.9 137.3 150.2 158.9 172.5 186.4 200.7 215.5 235.9 251.7 268.0 290.6 314.1 57 58 59 60 61 62 63 64 65 66 67 68 69 2.70 kHz 2.91 3.14 3.36 3.58 3.81 4.27 4.50 4.98 5.21 5.70 6.19 6.69 4 98 99 100 101 102 103 104 105 106 107 108 109 110 57.6 61.7 66.0 70.3 76.9 81.4 88.3 95.4 102.8 110.3 120.7 128.9 137.2 +/- 720 2 29 30 31 32 33 34 35 36 37 38 39 40 41 337 364 392 420 448 476 534 563 622 652 712 774 836 3 70 71 72 73 74 75 76 77 78 79 80 81 82 7.20 7.72 8.25 8.78 9.61 10.17 11.04 11.93 12.85 13.79 15.09 16.11 17.15 +/- 90 111 112 148.8 160.8 4.1.5 Data Processing Unit The data processing unit shall perform sampling, 8-bit analog-to- digital conversion, storage, and routing of data from the spectrum analyzer, the sweep frequency receiver, and the high frequency receiver. The data processing unit shall generate clocking and timing pulses from signals received on the CDS bus. The data processing unit shall provide a bus adapter to interface between the CDS bus and the PWS. The data processing unit shall also collect and route sampled data from the wideband waveform receiver in two bandpasses, 50 Hz to 10 kHz and S Hz to l Hz, when it is in the Waveform Survey Mode. A fixed number (280) of these samples shall be collected at a rate of 100.8 or 12.6 kb/s, stored in the data processing unit, and clocked into the low rate science format at an effective rate of 120 b/s. Table 3. Wideband Waveform Receiver Operating Modes Mode Bandwidth Hi-Rate Data Rate Mode 1 50 Hz - 10 kHz 100.8 kb/s Mode 2 50 Hz - 80 kHz 806.4 kb/s Mode 3 5 Hz - l kHz 12.6 kb/s Waveform Survey Mode (Mode 4) 50 Hz -10 kHz 100.8 kb/s, 12. 6 kb/s alternating every 9.3 sec. (14 LRS frames) Note: Data rate is rate at which data is clocked into the CDS bulk memory. Effective data rates in spacecraft telemetry will be less than or equal to these rates, depending on how much data is clocked into the telemetry stream. Table 4. High Frequency Receiver Filter Characteristics 1 F Filter Channel Number Center Frequency (MHz) (MHz) 0.10- 0.18 1 2 3 4 5 6 7 0.1008 0.1134 0.1260 0.1386 0.1512 0.1638 0.1764 0.20- 0.35 8 9 10 11 12 13 14 0.2016 0.2268 0.2520 0.2772 0.3024 0.3276 0.3528 0.40- 0.71 15 16 17 18 19 20 21 0.4032 0.4536 0.5040 0.5544 0.6048 0.6552 0.7056 0.81- 1.41 22 23 24 25 26 27 28 0.8060 0.9070 1.008 1. 109 1.210 1.310 1.411 1.61 2.82 29 30 31 32 33 34 35 1.613 1.814 2.016 2.218 2.419 2.621 2.822 3.23 5.65 36 37 38 39 40 41 42 3.226 3.629 4.032 4.435 4.838 5.242 5.645 4.1. 6 Electric DiPole Antenna Assembly The electric dipole antenna assembly shall receive plasma wave electric fields with two deployable elements. Two preamplifiers integral with the assembly shall be used between the antenna elements and the main electronics package. 4.1.7 Magnetic Antenna Assembly The magnetic antenna assembly shall receive plasma wave magnetic fields with two search coil magnetometers covering the frequency ranges 70 Hz to 3.5 kHz and 1 to 50 kHz. A preamplifier shall be used between each search coil and the main electronics package. 4.1.8 Input Electronics Input electronics consisting of differential amplifiers, analog switches, notch filters, and drivers shall route and condition the signal between the two antenna assemblies and the major subassemblies within the main electronics package. 4.1.9 Calibration Generator A calibration generator shall be provided to supply a calibration signal to the search coil magnetic antennas. This calibration signal shall consist of a one volt peak-to-peak square wave at 960 Hz. Calibration data will be processed by the PWS similar to normal science data. 4.1.10 Power Supply The power supply shall convert the +50 volt, 2.4 kHz power for the Orbiter into regulated voltages required by the instrument. 4.1.11 Search Coil Preamplifier Supplemental Heater To maintain suitable temperature for the search coil preamplifier, a supplemental electrical heater shall be provided. This heater will be switched by the CDS and powered from the S/C 30 VDC supply. 4.2 Data Processing and Format PWS commands from CDS for instrument control will be shown in GLL-3- 290, Command Structure and Assignments. Telemetry will be shown in GLL-3- 280, Telemetry Measurements and Data Formats. Data bus protocol will be as shown in GLL-3-270, Galileo Orbiter Data System Intercommunication Requirements. 4.2.1 Lo-Rate Data Data processing for the PWS lo-rate data shall consist of performing analog-to- digital conversions of data from the spectrum analyzer, sweep frequency receiver, the waveform receiver, and the high frequency receiver; storing the digitized data; and sending data to the CDS through the bus adapter. All PWS lo- rate science data shall be clocked serially to the CDS bus in one block of 18 eight-bit words. One 8-bit digital status word and one 8-bit analog engineering word will also be provided immediately preceding this 18-word block of science data. This results in a total block of 20 8-bit words at an effective data rate of 240 bits per second. The CDS will provide commands to enable the PWS to control the switching, sampling, and routing of these data. The format for the PWS science and engineering words is shown in Figure 2. The position of the high frequency receiver channels in the lo-rate science format is shown in Table 5. The position of the sweep frequency receiver channels in the lo- rate science format is shown in Table 6. 4.2.2 Hi-Rate Data Data processing for the PWS hi-rate data shall consist of performing an analog- to-digital conversion of sampled data from the waveform receiver and routing that data to the CDS bulk memory via the hi-rate data interface. Appropriate synchronizing words shall be provided to enable the CDS to clock the data into the bulk memory. The Format for the hi-rate data is shown in Figure 3. 4.2.3 PWS Digital Status The PWS shall make status measurements in the PWS digital status word as shown in Figure 4 and GLL-3-280. 4.2.1 Lo-Rate Data Data processing for the PWS lo-rate data shall consist of performing analog-to- digital conversions of data from the spectrum analyzer, sweep frequency receiver, the waveform receiver, and the high frequency receiver; storing the digitized data; and sending data to the CDS through the bus adapter. All PWS lo- rate science data shall be clocked serially to the CDS bus in one block of 18 eight-bit words. One 8-bit digital status word and one 8-bit analog engineering word will also be provided immediately preceding this 18-word block of science data. This results in a total block of 20 8-bit words at an effective data rate of 240 bits per second. The CDS will provide commands to enable the PWS to control the switching, sampling, and routing of these data. The format for the PWS science and engineering words is shown in Figure 2. The position of the high frequency receiver channels in the lo-rate science format is shown in Table 5. The position of the sweep frequency receiver channels in the lo- rate science format is shown in Table 6. 4.2.2 Hi-Rate Data Data processing for the PWS hi-rate data shall consist of performing an analog- to-digital conversion of sampled data from the waveform receiver and routing that data to the CDS bulk memory via the hi-rate data interface. Appropriate synchronizing words shall be provided to enable the CDS to clock the data into the bulk memory. The Format for the hi-rate data is shown in Figure 3. 4.2.3 PWS Digital Status The PWS shall make status measurements in the PWS digital status word as shown in Figure 4 and GLL-3-280. Table 5. Position of High Frequency Receiver Data in PWS Low-Rate Science Format Frame No.* (Filter No.) (Filter No.) 1 15 1 2 22 1 3 29 8 4 36 8 5 16 2 6 23 2 7 30 9 8 37 9 9 17 3 10 24 3 11 31 10 12 38 10 13 18 4 14 25 4 15 32 1 16 39 11 17 19 5 18 26 5 19 33 12 20 40 12 21 20 6 22 27 6 23 34 13 24 41 13 25 21 7 26 28 7 27 35 14 28 42 14 *See Figure 2 & Figure 4. Table 6. Position of Sweep Frequency Receiver Data in Low-Rate Science Format Frame SFR 1 SFR 2 SFR 3 SFR 4 No. (Filter No.) (Filter No.) (Filter No.) (Filter No.) 1 1 29 57 85 2 2 30 58 86 3 3 31 59 87 4 4 32 60 88 5 5 33 61 89 6 6 34 62 90 7 7 35 63 91 8 8 36 64 92 9 9 37 65 93 10 10 38 66 94 11 11 39 67 95 12 12 40 68 96 13 13 41 69 97 14 14 42 70 98 15 15 43 71 99 16 16 44 72 100 17 17 45 73 101 18 18 46 74 102 19 19 47 75 103 20 20 48 76 104 21 21 49 77 105 22 22 50 78 106 23 23 51 79 107 24 24 52 80 108 25 25 53 81 109 26 26 54 82 110 27 27 55 83 111 28 28 56 84 112 MSB ANT SW POS. 0 - 27 COUNTER CMD STATUS BIT12345678 LSB BITS 1-6 DIGITAL PERFORMANCE PARAMETERS BIT 1 Antenna Switch Position 0 = E 1 = B BITS 2-6 0-27 counter 0-27 counter increments once per LRS frame; 0-27 counter- frame No. Minus one (1). Waveform survey data: frame No. 1-14 is waveform survey low frequency range (5Hz - 1 kHz), frame No. 15-28 is waveform survey high frequency range (50Hz - 10 kHz). Other science data: see Table 1, Table 5, and Table 6. BITS 7-8 COMMAND STATUS Frame 1 CMD WORD, BITS 1-2 frame 2 CMD WORD, BITS 3-4 Frame 3 CMD WORD, BlTS 5-6 Frame 4 CMD WORD, BITS 7-8 (SEE FIGURE 6 FOR CMD WORD DEFINITION) Figure 4. PWS Status Word 4.3 Operating Modes The PWS shall operate in the operating modes shown in the PWS state diagram shown in Figure 5. The PWS command format is shown in Figure 6 and GLL-3- 290. Commands are issued by the CDS and may be either around commands or sequenced commands. 5.0 INTERFACE DEFINITION 5.1 Electrical Interfaces 5.1.1 General a. Basic requirements for electrical grounding, electrical bonding, electrical interface circuits, and electromagnetic compatibility are contained in GLL-3-260, Electrical Grounding and Interfacing. b. Specific system-level requirements for electrical interface circuits and ground are contained in the applicable circuit data sheets. See JPL Drawing 10085825, Circuit Data Sheet Index and Guide. c. All spacecraft flight and umbilical interface circuits, e.g., sub-system-system, subsystem-launch vehicle, and subsystem- support equipment through the umbilical connector, are listed in GLL-3-110, Functional Block Diagram and Interface Listings. d. All spacecraft non-flight circuits, including direct access circuits, are listed in GLL-3-1110, Support Equipment Functional Block Diagrams and Interface Listings. 5.1 2 Power/Pyro Subsystem (PPS) 5.1.2.1 2.4 kHz Power (PPS) The PPS will provide commandable on-off control of the 2.4 kHz, 50 V rms power. 5.1.2.2 30V DC Power The PPS will provide commandable on-off control over a single interface for the search coil preamplifier supplemental heater. 5.1.3 PWS - PWS Sensor Interface 5.1.3.1 Electric Antenna Preamplifier - Main Electronics The interface between the electric antenna preamplifiers and the main electronics includes positive and negative 11 volt power and signals from-- both preamplifiers. 5.1.3.2 Magnetic Antenna Preamplifiers - Main Electronics. The interface between the magnetic antenna preamplifiers and the main electronics includes positive and negative 11 volt power, signals from.. both preamplifiers, calibration signal to the search coils, and preamp temperature. 5.1.5 Command Data Subsystem (CDS) a. Bus Sync. Bus sync is an 806.4 kHz square wave which, after being divided by two, is used to clock supervisory data into and reply data out of the PWS bus adapter. It is also used for basic timing within PWS and for clocking out high rate data. b. Bus Real Time Interrupt (RTI) Bus RTI is a 620 ns pulse occurring every 66- 2/3 ms. This pulse along with spacecraft time, broadcast over the supervisory data line, is used to synchronize the PWS with the CDS. c. Supervisory Data Supervisory data is a 403.2 kb/s, quarter duty cycle, return to zero (RZ), simplex communication line to the CDS. It is used to transmit PWS lo- rate telemetry data to the CDS. 5.1.5.1 PWS to CDS Interfaces a. Bus Reply Data. Bus reply data is a 403.2 kb/s, quarter duty cycle, RZ, simplex communication line to the CDS. It is used to transmit PWS lo-rate telemetry data to the CDS. b. High Rate Data High Nybble. This line operates at 403.2 kb/s, 50.4 kb/s, or 6.3 kb/s to send every other 4-bit word from the wideband waveform receiver directly to the CDS DMS bulk memory. c. High Rate Data Low Nybble. This line operates as above, carrying the alternate 4-bit words. CDS will assemble these two words into an 8-bit byte for further telemetry processing. d. High Rate Data Bit Sync. A PWS generated signal used to clock high rate data on the two above lines. e. High Rate Data Word Sync. A PWS generated pulse occurring every four high rate data bit syncs to synchronize CDS to the PWS high rate data words. f. PWS Search Coil Preamp Temp. A CDS transducer signal indicating the temperature in the search coil preamplifier. g. PWS Main Elect. Temp. A CDS transducer signal indicating the temperature in the PWS main electronics subchassis. 5.2 Thermal Interface Two Radio Isotope Heater Units (RHUs) are mounted on the electric antenna assembly. The one RHU is mounted in the search coil to maintain appropriate temperatures. In addition, a supplementary electrical heater will be provided for the search coil preamplified by the Galileo Orbiter for adequate thermal control at Jupiter. 5.3 Mechanical Interfaces The PWS will be mounted with the main electronics assembly on the Orbiter bus, the electric antenna assembly near the end of the MAG boom, and the search coil magnetic antenna assembly on the HGA sub- reflector as specified in GLL-3- 180, Configuration, and in accordance with PWS Interface Control Drawings 10086759 and 10086769. Alignment requirements are listed in GLL-3-170, Functional Accuracies and System Capabilities. 6.0 PERFORMANCE PARAMETERS 6.1 Frequency Range The PWS shall have a dynamic range greater than 90 dB in each log-arithmic compressor. It shall be measured at the antenna interface at frequencies of 31.1 z, 112.5 Hz, 900 Hz, 6.69 kHz, 57.6 kHz, and 1.008 MHz. The response shall be spurious free over a dynamic range of 70 dB at these frequencies. 6.3 Common Mode Rejection The PWS shall have attenuation of in-phase interference signals at the antenna elements > 20 dB 6.4 Sensitivity Approximate instrument sensitivity shall be as shown in Table 7. 7.0 PHYSICAL CHARACTERISTICS AND CONSTRAINTS 7.1 Mass The total-mass of the PWS, excluding cabling shall not exceed its allocation as specified in GLL-3-230, Galileo Orbiter Equipment List and Mass Allocations. The mass expressed herein is for information only: Electric Antenna 1.68 kg; Main Electronics, 3.94 kg; Magnetic Antenna, 1.52 kg; Total, 7.14 kg. This mass includes 3 RHUs and thermal blankets. 7.2 Power Power consumption of the PWS shall be as specified in GLL-3-250, Power Profile and Allocations. Power expressed herein is for information only: 5.92 W, waveform receiver power OFF ; 6.8 W, waveform receiver power ON . The power for the supplementary electrical heater shall be 3.00 W. 7.3 Volume The volume of the PWS shall be as specified in ICDs 10086759 and 10086769. and GLL-3-180. 7.4 Environmental The PWS shall be designed to operate within specification over the qualification temperature range, which is: a. Main Electronics -20/+75 degC b. Mag Pre Amp -35/+75 degC c. Elect Pre Amp -45/+75deg C d. Search Coils -125/+75deg C e. Dipole Antenna Elements -196/+75deg C In Addition, the PWS shall be compatible with all the requirements of GLL-3- 240, Environmental Design Requirements, and GLL-3-210, Design Criteria for Temperature Control. 7.5 Packaging The PWS shall be packaged in accordance with the applicable sections of GLL- 3-220, Electronic Equipment Design. 7.6 Identification and Marking The PWS shall be identified in accordance with ICDs 10086759 and 10086769; Section VII, Part F, Configuration Management, of PD635-52, Project Galileo Policies, and Requirements for Orbiter Science Investigations; and Section VII, Equipment Identification and Marking, 625- 232, Galileo Orbiter Configuration Management Plan 7.7 Inertial Properties The PWS shall be in accordance with the applicable sections of GLL-3-200, Inertial Properties. 7.8 Structural Design The structural design of the PWS shall be in accordance with GLL-3-190, Structural Design Criteria. 8.0 SAFETY CONSIDERATIONS The PWS shall constitute no unusual safety hazard. Special handling is required for the RHUs. The search coils must be protected from large alternating magnetic fields. 9.0 SPECIAL 9.1 Oscillator Synchronization In Orbiter subsystems, all oscillator circuits and countdown circuits in the range of 5 Hz to 6 MHz will be a harmonic of the 2.4 kHz power frequency unless otherwise approved by waiver. 9.2 Electromagnetic Interference Electric and magnetic field interference from other subsystems measured at the PWS antenna assemblies should be below levels specified in PD625- 50, Galileo Orbiter Science Requirements Document. These levels are repeated in Table 7, and are approximately equivalent to the PWS instrument sensitivity. Allowable subsystem emission levels are shown in GLL-3-240. If all sub-systems meet these requirements then the maximum science data will be possible. Table 7. Maximum EMI Levels Electric Field Interference at Electric Antenna Assembly Frequency Range Integrated Electric Field 1 Hz - 4 kHz 0.5 v/m in 30% bandwidth 4 Hz - 400 kHz 0.5 v/m in 15% bandwidth 1 Hz - 2 kHz 50 v/m 250 Hz - 85 kHz 50 v/m 400 Hz - 10 kHz 0.5 v/m in 1 kHz bandwidth between harmonics of 2.4 kHz power supply frequency Magnetic Field Interference at Magnetic Antenna Assembly Frequency Range Integrated Electric Field 1 Hz - 1 kHz 40 in 30% bandwidth 1 Hz - 400 kHz 30 in 15% bandwidth 1 Hz - 2 kHz 2 250 Hz - 85 kHz 1 9.3 Equipotential Spacecraft The use of an equipotential spacecraft to control spacecraft charging will assist in controlling electromagnetic radiation from the Orbiter and possible electric interference from discharges on the surface of the Orbiter resulting from differential charging. REVISION PAGE Revision Date ECRs Comments ________________________________________________________________ __ Original 9 Oct 1979 Issue ________________________________________________________________ __ Revision A 18 Feb 1981 23408, 23438 ________________________________________________________________ __ 29 May 1981 23565 Closed by Amendment 1 23841, 23899, 24066 Closed by Amendment 2 23841, 24115, 24135 Closed by Amendment 3 24309, 24613 ________________________________________________________________ __ Revision B 2 May 1989 35275