X-Band_Performance Specification.pdf

Volatiles Investigating Polar Exploration Rover

(VIPER)

X-Band Communication System Performance Specification

Revision: RFP Baseline

Dated: May 4, 2020

National Aeronautics and Space Administration

Johnson Space Center, Houston Texas

Table of Contents

1 INTRODUCTION

Purpose

Background

Scope

2 APPLICABLE DOCUMENTS

Applicable Documents

Reference Documents

3 REQUIREMENTS

System Characteristics Concurrent Transmit and Receive

Transmit Characteristics Transmit General Transmit Frequency Transmit Output Power Frequency Stability Transmit Symbol Rates Transmit Filtered OQPSK Modulation Transmit PCM/PSK/PM Modulation Transmit EVM Transmit Forward Error Correction Code Transmit Line Encoding Transmit ASM Transmit Randomization Transmit Data Link Framing Transmit Encapsulation Transmit Encryption Transmit Bandwidth Pseudo Random Binary Code Harmonic and Spurious Emissions Transmit NTIA Spectral Emissions Mask Transmit SFCG Spectral Emissions Mask

Receive Characteristics Receive General Receive Frequency

Receive Levels Receive Noise Figure Receive Bandwidth Receive Carrier Lock Receive Symbol Rates Receive BPSK Demodulation Receive PCM/PSK/PM Demodulation Receive Adaptive Baseband Equalization Receive Decoding Receiver Line Decoding Receive CLTU Start Sequence Receive CLTU Tail Sequence Receive Acquisition Sequence Receive Idle Sequence Receive Randomization Receive Data Link Framing Receive Frame Rejection Rate Receive Frame Undetected Error Rate Receiver Desensization – Diplexer Isolation Receive Decryption

Decryption Bypass Receive Authenticated Decryption Receive Crypto Module Validation Receive Crypto Key Interface Load FIRE Code Commands Receive FIRE Command Decode Capability FIRE Code Discrete Operation

Rover Electrical Interfaces Power

Voltage Transmit and Receive Mode Power Receive Mode Power Connector

Transceiver Reset Electrical Format Connector

Transmit (Downlink) Interface to Avionics Transmit Data Interface Transmit Clock Transmit CADU Pulse Connector

Receive (Uplink) Interface to Avionics Uplink Data Interface Uplink Clock Uplink Enable

Connector Transceiver Control

3.2.1.1 Electrical

Format Connector

Transceiver Monitor Electrical Format Connector

Status Discrete Signals Electrical Status Signals Format Connector

FIRE Code Discretes Electrical Connector

Temperature Monitoring Electrical Temperature Signals Format Connector

RF Input Electrical Connector

RF Output Electrical Connector

Mechanical Requirements Form Factor Mass Mounting Fasteners Labeling Conformal Coating and Staking Thermal Analysis Materials & Cleanliness

EEE Parts Parts Grade Parts Process

Life Requirements Mission Life Shelf Life

Environmental Requirements Static Loads Dynamic Loads

Random Vibration Sine Vibration Ground Handling and Shipping Vibration and Shock

Shock Thermal Vacuum Radiation Humidity Venting Multipaction Magnetic Dipole

EMC

Bonding and Grounding

Primary Power DC Isolation Electrical Bonding

EMI

CS101

CS103

CS104

CS114

CE101

CE102

CE106

RE101

RE102

RE103

RS101

RS103

VERIFICATION REQUIREMENTS

Inspection Visual Inspection Physical Measurement Documentation Search

Analysis

Test

Test Restrictions Failure During Tests Modification of Hardware Re-Test Requirements

Test Requirements Definitions Test Factors Test Tolerances Test Article Types

Protoflight Qualification Testing Acceptance Testing

Required Tests Performance Testing Mass Properties Measurement Static Load / Strength Test Sine Sweep Survey Sine Vibration Random Vibration Shock Electromagnetic Compatibility Thermal Vacuum Bakeout Thermal Vacuum

APPENDIX A ABBREVIATIONS AND ACRONYMS

APPENDIX B VIPER SPACE RADIATION ENVIRONMENT

1 Introduction

Purpose The purpose of this document is to establish the requirements associated with the X-band subsystem for a lunar rover. This is in support of NASA’s Volatiles Investigating Polar Exploration Rover (VIPER) program.

Background VIPER is a lunar volatiles detection and measurement mission that will be launched to a lunar polar region to characterize the nature of the volatiles in the area and extrapolate this data to create global lunar water resource maps. Utilizing lunar resources to produce oxygen and propellants could enable new mission architectures for human exploration to a number of different targets. VIPER will also utilize Commercial Lunar Payload Services (CLPS), where commercial entities provide the service of delivering NASA hardware directly to the lunar surface. Once on the moon, the expected lunar surface mission duration is up to four lunar days, with active surface operations completed during the periods when both sun exposure and X-Band direct to Earth (DTE) communication conditions overlap.

Scope Figure 1.3-1 illustrates the basic conceptual block diagram for VIPER’s X-Band subsystem. The scope of this document includes requirements typical of a crypto module, transceiver (including framing and coding), power amplifier, and diplexer/filter. The supplier can choose to integrate any or all of the functions in a single chassis or provide multiple components to satisfy the requirement set described herein. The RF switch and antennas will be subject to separate requirement documents and separate procurements.

Scope of this document

Figure 1.3-1 X-Band Subsystem Block Diagram

2 Applicable Documents All applicable and reference documentation identified in this document shall apply in the situations where they are specifically referenced. In the event of a conflict due to differing versions of the document, the document version that is in force and effect on the effective date of the contract take precedence, unless specifically stated otherwise by NASA. In the event of a conflict between the “Performance Specification” (this document) and other documents, with the exception of the “Statement of Work (SOW) (VIPER X-Band Communication System Statement of Work)” the Specification shall take precedence.

Applicable Documents Doc #

CCSDS 401.0-B-30

Revision

Feb 2020 Description

Radio Frequency and Modulation Systems CCSDS 131.0-B-3 September 2017 TM Synchronization and Channel Coding CCSDS 732.0-B-3 September 2015 AOS Space Data Link Protocol CCSDS 133.1-B-2 October 2009 Encapsulation Service CCSDS 355.0-B-1 September 2015 Space Data Link Security Protocol CCSDS 352.0-B-2 August 2019 CCSDS Cryptographic Algorithms CCSDS 231.0-B-3 Sept 2017 TC Synchronization and Channel Coding CCSDS 232.0-B-3 Sept 2015 TC Space Data Link Protocol TBD Draft 3 VIPER Mission EEE Parts Control Plan

MIL-STD-461G Rev G Requirements for the Control of Electromagnetic Interference Characteristics

ITU-T-O.151 1992 Error Performance Measuring Equipment Operating at the Primary Rate and Above

PRC-9002 Rev H Process Specification for Part Marking MIL-DTL-5541 Rev F Chemical Conversion Coatings on Aluminum Alloys ARC-STD-8070.1 Dec 18, 2018 Space Flight system Design and Environmental Test GSFC-STD-7000A Rev A General Environmental Verification Standard

Reference Documents Document

TIA-422 Electrical Characteristics of Balanced Voltage Differential Interface Circuits

Doc #

ANSI/TIA/EIA-

422-B

Revision # B

Communication Frequency Allocations in the Lunar Region

SFCG 32-2R2 NA

International Communication System Interoperability Standards

ICSIS Baseline March 2019

CCSDS 230.1-G-2 Nov 2012 TC Synchronization and Channel Coding

– Summary

VIPER Environment Specification VIPER-MSE- SPEC-001 Draft

3 REQUIREMENTS

System Characteristics

Concurrent Transmit and Receive

The X-band system shall receive the uplink and transmit the downlink concurrently.

Rationale: Mission conops requires concurrent operation of the uplink and downlink to complete the mission objectives.

Transmit Characteristics

Transmit General The X-Band system shall receive NRZ-L Data and Clock over an input on an interface as defined in section 3.4.3 and process the data as defined in section 3.2 for transmission over the RF output over an RF interface defined in section 3.4.10.

Transmit Frequency The X-Band system shall transmit at 8459 MHz ± 3 ppm.

Rationale: Space Frequency Coordination Group recommendation SFCG 32-2R2 constrains lunar to earth comm to X-Band, S-Band, or Ka-Band. X-band has been selected for this mission with this particular frequency assigned..

Transmit Output Power The X-Band system shall output no less than 10 Watts as measured at the output of the Power Amplifier.

Rationale: This is the power necessary to provide the intended system performance.

Frequency Stability

a) Temperature Stability: The transmitter frequency will not vary more than ± 3 ppm from the set value over the temperature range of -20°C to +55°C or more than ±5 ppm over the temperature range of - 30°C to +65°C.

b) Short Term Stability: The transmitter rms fractional frequency deviation over a 10 minute period , measured with a 10 second integration time , will not exceed ±3 ppm at any constant temperature (±0.5 °C) in the range from -20 °C to + 55 °C .

Transmit Symbol Rates The X-Band system shall transmit symbol rates of 250 sps, 4 ksps, 512 ksps, 1 Msps, 2 Msps, 4 Msps, and 8 Msps.

Rationale: The transmit symbol rate is defined as the input to the downlink modulator. These correspond to data rates (information rates) of approximately: 121 bps, 2 kbps, 248 kbps, 484 kbps, 0.97 Mbps, 1.94 Mbps, and 3.8 Mbps. A variety of data rates are needed to support the possible scenarios the rover may experience. 230 kbps is the minimum rate necessary to support the speed-make-good goal of 0.7 cm/sec. Higher rates will be used when the link allows. Lower rates will be used for contingency and other scenarios where 248 kbps is not achievable. The information data rate is defined as the rate at the input to the LDPC Encoder.

Transmit Filtered OQPSK Modulation The X-Band system shall transmit with filtered OQPSK modulation as described in CCSDS 401.0-B-30, RF and Modulation Systems, Section 2, with modulation characteristics shown in Table 3-1 Transmit OQPSK Modulation Parameters, on downlinks with symbol rates greater than or equal to 1 Msps.

Rationale: Filtered OQPSK is selected because it is a common mode supported by existing DSN services, it is bandwidth efficient (i.e. BPSK is insufficient for the higher required rates), radiometric measurements are not necessary, and this modulation scheme is consistent with the recommendations in the International Communication System Interoperability Specification.

Table 3-1 Transmit OQPSK Modulation Parameters

Parameter Value Q sinusoid phase relative to I sinusoid 90 deg delay Q data delay relative to I data ½ symbol I:Q power ratio 1:1

Transmit PCM/PSK/PM Modulation

The X-band system shall transmit with PCM/PSK/PM modulation as described in CCSDS 401.0- B-30, RF and Modulation Systems Section 2, with modulation characteristics shown in Table 3-2 Transmit PCM/PSK/PM Modulation Parameters, on downlinks with symbol rates less than 1 Msps.

Rationale: PCM/PSK/PM is selected because it allows the ground station to track a residual carrier.

Table 3-2 Transmit PCM/PSK/PM Modulation Parameters

Parameter Value Subcarrier Frequency 1024 kHz

Subcarrier type Squarewave Carrier Modulation Index Variable (Default 75 degrees RMS)

Transmit EVM

The X-Band system shall transmit the OQPSK signal with an Error Vector Magnitude (EVM) of less than 10%.

Rationale: the EVM is a measure of the difference between the reference waveforms and the measured waveform. This difference is called the error vector.

Transmit Forward Error Correction Code The X-Band system shall transmit using a rate ½ (2048, 1024) Low Density Parity Check (LDPC) Code as specified in CCSDS 131.0-B-3.

Rationale: LDPC provides more coding gain than a concatenated coding system. This encoding scheme is consistent with the recommendations in the International Communication System Interoperability Specification (ICSIS) and provides sufficient coding gain for the X-band system.

ICSIS specifies two codeword sizes, 256 octets for rates < 60 kbps and 4096 octets for rates > 60 kbps. To minimize data latency for the rover and to reduce the number of formats that need to be supported, which requires ground user interaction to ‘drive’ it, the 4096 octet version will not be implemented for this X-Band system.

Transmit Line Encoding The X-Band system shall transmit using NRZ-L encoding.

Rationale: NRZ-L symbol format encoding has better Energy per Bit-to-Noise Power Spectral Density Ratio (Eb/No) performance than differential symbol format encoding like Non-Return-to-Zero-Mark (NRZ-M). It also minimizes degradation to LDPC decoder performance as described by Note 7.2.1.2 in CCSDS 131.0-B-3. Phase ambiguity resolution will be resolved using a frame ASM rather than using differential encoding like NRZ-M.

Transmit ASM The X-Band system shall transmit using a 64 bit attached sync marker (ASM) of 0x034776C7272895B0 in accordance with CCSDS 131.0-B-3, TM Synchronization and Channel Coding, Section 9.

Rationale: CCSDS 131.0-B-3 recommends use of a 64 bit ASM for rate ½ LDPC codes. This ASM is consistent with the recommendations in the International Communication System Interoperability Specification (ICSIS).

Transmit Randomization The X-Band system shall transmit using bit randomization techniques in accordance with CCSDS 131.0-B-3, TM Synchronization and Channel Coding, Section 10.

Rationale: Use of bit randomization techniques as specified in CCSDS 131.0-B-3 will ensure the proper bit synchronization process and interoperability. This is also consistent with the recommendations in the International Communication System Interoperability Specification.

Transmit Data Link Framing The X-Band system shall transmit data using CCSDS AOS Data Link Framing per CCSDS 732.0-B-3. The AOS transfer frame is defined in Table 3-3 Transmit Data Structure

Table 3-3 Transmit Data Structure

Framing Lengths AOS Transfer Frame length 1024 bits Encoded AOS Transfer Frame length 2048 bits ASM length 64 bits CADU length 2112 bits

Rationale: AOS framing is currently supported by existing DSN services and is also consistent with the recommendations in the International Communication System Interoperability Specification.

Transmit Encapsulation The X-Band system shall transmit data using CCSDS Encap Service with Space Packets per

CCSDS 133.1-B-2.

Rationale: Encap Services are currently supported by existing DSN services and is also consistent with the recommendations in the International Communication System Interoperability Specification.

Transmit Encryption N/A. Encryption is not required on the downlink.

Transmit Bandwidth The X-Band system shall transmit all signals with a maximum bandwidth less than or equal to 8 MHz.

Rationale: The maximum bandwidth is defined as the width of a frequency band that contains 99 percent of the total mean power of a given emission. The 8 MHz bandwidth accommodates the highest rate downlink signal and was allocated by JSC Spectrum Management to reduce interference with other users.

Pseudo Random Binary Code The X-Band system shall generate a Pseudo Random Binary Code (PRBS) 215-1 test pattern, per ITU-T O.151 recommendation.

Rationale: Added as a commandable mode, this feature is used during bit error rate testing or troubleshooting of the transceiver. The test pattern is inserted at the input to the modulator

(bypassing the framing and randomization). The PRBS test sequence is generated by the degree of the polynomial: PRBS15 = x15 + x14 + 1. This polynomial is an element of the Galois Field of two elements (2n). PRBS bit-pattern is generated in a linear feed-back shift-register. This is a shift-register with a XORed- feedback of the output-values of specific flip-flops to the input of the first flip-flop. Generation of the sequence 215-1 is depicted in the figure below. At start time of the PRBS sequence, all flip flops are set to ‘1’.

Harmonic and Spurious Emissions The X-Band system shall maintain harmonic and spurious emissions less than -60 dBc (outside of the necessary bandwidth), where dBc is relative to the unmodulated carrier power of the emission or in the cases which do not have a carrier, is relative to the mean signal power.

Rationale: Limiting harmonic and spurious emissions is necessary to ensure that transmitting systems do not cause harmful interference to other systems.

Transmit NTIA Spectral Emissions Mask The X-Band system shall comply with the NTIA Spectral Emissions Mask limits shown in Table 3-4 Transmit NTIA Mask Definition. The NTIA Necessary Bandwidth for each data rate is defined in Table 3-5 NTIA Necessary Bandwidth Definition.

Table 3-4 Transmit NTIA Mask Definition

Frequency Offset NTIA Emissions Mask (f – fc) < 0.5 BN 0 dBsd

0.5 BN < (f – fc) < 10

BN

- 40 log10 [2 (f – fc)/BN] - 8 dBsd

(f – fc) > 10 BN -60 dBsd

Table 3-5 NTIA Necessary Bandwidth Definition

Bit Rate BN 250 sps 2.0485 MHz 4 ksps 2.056 MHz 512 ksps 3.072 MHz 1 Msps 1.00 MHz 2 Msps 2.00 MHz 4 Msps 4.00 MHz

8 Msps 8.00 MHz

Rationale: This requirement ensures that the RF communications system is compliant with the regulatory limits established by the NTIA. The mask is defined in dBsd, which is the attenuation in Decibels relative to the maximum value of the power spectral density within the transmit signal’s necessary bandwidth. The calculation for the necessary bandwidth can be found in the NTIA Red Book Annex J. The symbol rates definition includes coding bits from the LDPC encoder, as well as the ASM.

Transmit SFCG Spectral Emissions Mask The X-Band system shall comply with the SFCG Spectral Emissions Mask limits shown in the following tables.

Table 3-6 Transmit SFCG Spectral Emissions Mask

SFCG Spectral Emission Mask for symbol Rates ≥ 2 Msps Frequency Offset SFCG Emissions Mask (f – fc) < 0.5 Rs 0 dBsd

0.5 Rs < (f – fc) < 1.4 Rs - 33.33 (f – fc)/ Rs + 16.67 dBsd

1.4 Rs < (f – fc) < 3 Rs - 18.75 (f – fc)/Rs -3.75 dBsd

(f – fc) > 3 Rs -60 dBsd

Table 3-7 Transmit SFCG Spectral Emissions Mask (<2 Msps)

SFCG Spectral Emission Mask for symbol Rates < 2 Msps Frequency Offset SFCG Emissions Mask (f – fc) < 0.5 Rs 0 dBsd

0.5 Rs < (f – fc) < 3 Rs - 12 (f – fc)/Rs + 6 dBsd

3 Rs < (f – fc) < 8 Rs - 6 (f – fc)/Rs -12 dBsd (f – fc) > 8 Rs -60 dBsd

Rationale: This requirement facilitates efficient spectrum utilization by limiting the occupied bandwidths and reduces potential for interference to other users. Compliance with SFCG recommendations is compulsory per NASA Procedural Requirements (NPR) 2570.1. Note, the SFCG emissions mask scales in frequency depending on the coded symbol rate, Rs, which is defined as the symbol rate after error correction coding but before modulation.

Receive Characteristics

Receive General The X-Band system shall receive an RF signal at the RF input over an interface defined in section 3.4.9 and process the signal as defined in section 3.3 and provide NRZ-L Data and Clock on an interface as defined in section 3.4.4

Receive Frequency The X-Band system shall receive at 7199.7625 MHz ± 3 ppm.

Rationale: Space Frequency Coordination Group recommendation SFCG 32-2R2 constrains lunar to earth comm to X-Band, S-Band, or Ka-Band. Currently, Ka-band uplink is not supported by DSN and S-band is significantly less efficient, thus X-Band was selected for both the uplink and the downlink.

Receive Levels The X-Band system shall receive RF levels between -120 dBm and -30 dBm and be able to receive a level of at least +10 dBm at the receiver input without damage to the receiver.

Rationale: These are the receive levels necessary to provide the intended system performance and not damage the RF input to the receiver.

Receive Noise Figure The X-Band system shall have a noise figure of 2.3 dB or less.

Rationale: This is the noise figure necessary to provide the intended system performance.

Receive Bandwidth

The X-Band system shall receive signals with a maximum bandwidth less than 128 kHz.

Rationale: The maximum bandwidth is defined as the width of a frequency band that contains 99 percent of the total mean power of a given emission. The 128 kHz bandwidth accommodates the highest rate uplink signal and was allocated by JSC Spectrum Management to reduce interference with other users.

Receive Carrier Lock The X-Band system shall achieve carrier lock in less than 5 seconds from the time RF is present at the RF input port with a Carrier to Noise Density (C/No) of 31.8 dBHz.

Rationale: A C/No value of 31.8 dBHz provides a PLL Loop SNR of 10 dB, the minimum level recommended by DSN for residual carrier acquisition, when the PLL Loop bandwidth is 150 Hz.

Acquiring the residual carrier from the PCM/PSK/PM uplinks allows for robust carrier and data tracking in a difficult multipath environment.

Receive Symbol Rates The X-Band system shall receive (uplink) symbol rates of 145 sps, 1160 sps, 2320 sps and 75000 sps.

Rationale: The uplink symbol rate is defined as the input to the uplink modulator. It includes the overhead due to BCH encoding, the start and tail sequences for the CLTU, and the idle bits sent between the CLTUs. The symbol rates correspond to information data rates of 125.08 bps,

1000.707 bps, 2001.42 bps, and 64700.93 bps. The information data rate is defined as the rate at the input to the BCH encoder.

A variety of data rates are needed to support the possible scenarios the rover may experience including contingency commanding. 2 kbps is the minimum rate necessary to support the speed-make-good goal of 0.7 cm/sec. Higher rates will be used when the link allows. Lower rate will be used for contingency and other scenarios where 2 kbps is not achievable.

Receive BPSK Demodulation The X-Band system shall receive with BPSK modulation as described in CCSDS 401.0-B-30, RF and Modulation Systems, Section 2, for symbol rates above 2.32 ksps.

Rationale: BPSK is selected because it is a common mode supported by existing DSN services, radiometric measurements are not necessary, and this modulation scheme is consistent with the recommendations in the International Communication System Interoperability Specification. A complete set of data rates and modulation schemes are given in Table 3-9 Uplink Data Rates.

Receive PCM/PSK/PM Demodulation

The X-Band system shall receive with PCM/PSK/PM modulation as described in CCSDS 401.0- B-30, RF and Modulation Systems, Section 2, with the modulation parameters shown in Table 3-8 Receive PCM/PSK/PM Modulation Parameters, for symbol rates less than or equal to 2.32 ksps.

Rationale: PCM/PSK/PM is recommended for low rate applications and allows the receiver to track a residual carrier and offers more robust performance in the presence of multipath. A complete set of data rates and modulation schemes are given in Table 3-9 Uplink Data Rates.

Table 3-8 Receive PCM/PSK/PM Modulation Parameters

Parameter Value Subcarrier Frequency 18.65 kHz Subcarrier type Sinewave Carrier Modulation Index Variable (default: 80 degrees RMS) http:64700.93

Table 3-9 Uplink Data Rates

Link Modulation Symbol Rate (ksps) Very Low Data Rate (VLDR) PCM/PSK/PM .145 Low Data Rate 1 (LDR1) PCM/PSK/PM 1.16

Low Data Rate 2 (LDR2) PCM/PSK/PM 2.32

Medium Data Rate (MDR) BPSK 75

Receive Adaptive Baseband Equalization The X-Band system receiver shall have Adaptive Baseband Equalization with the ability to enable and disable the capability.

Rationale: Adaptive Baseband Equalization can assist with mitigating expected multipath at the receiver location.

Receive Decoding The X-Band system shall receive using a BCH Code for error detection (TED mode) as described in CCSDS 231.0-B-3.

Rationale: CCSDS 231.0-B-3 recommends use of BCH to detect errors. The BCH decoder will operate in Triple Error Detection (TED) mode to improve performance.

Receiver Line Decoding The X-Band system shall receive using NRZ-L encoding.

Rationale: NRZ-L symbol format encoding has better Energy per Bit-to-Noise Power Spectral Density Ratio (Eb/No) performance than differential symbol format encoding like Non-Return-to-Zero-Mark (NRZ-M). Phase ambiguity resolution will be resolved using the start sequence rather than using differential encoding like NRZ-M.

Receive CLTU Start Sequence The X-Band system shall receive using use a 16 bit Start Sequence of 0xEB90 in accordance with CCSDS 231.0-B-3.

Rationale: CCSDS 231.0-B-3 recommends use of a 16 bit Start Sequence when using CLTU Telecommands.

Receive CLTU Tail Sequence The X-Band system shall receive using use a 64 bit Tail Sequence of 0xC5C5C5C5C5C5C579 in accordance with CCSDS 231.0-B-3.

Rationale: CCSDS 231.0-B-3 recommends use of a 64 bit Tail Sequence when using CLTU Telecommands.

Receive Acquisition Sequence The X-Band System shall achieve symbol synchronization using a 22 octet length minimum acquisition sequence in accordance with CCSDS 231.0-B-3. The acquisition sequence is alternating ones and zeros.

Rationale: CCSDS 231.0-B-3 recommends use of an acquisition sequence with a minimum length of 16 octets. 22 octets provide extra time to ensure symbol synchronization is achieved.

Receive Idle Sequence

The X-Band system shall receive an idle sequence comprised of alternating ones and zeros and use it to maintain symbol synchronization in the absence of CLTUs. In accordance with CCSDS 231.0-B-3.

Rationale: The idle sequence allows for continuous operation over the RF link when there is no data being received.

Receive Randomization The X-Band system shall derandomize the received CLTUs using bit randomization techniques in accordance with CCSDS 231.0-B-3.

Rationale: Use of bit randomization techniques as specified in CCSDS 231.0-B-3 will ensure the proper bit synchronization process and interoperability. This is also consistent with the recommendations in the International Communication System Interoperability Specification.

Receive Data Link Framing The X-Band system shall process CLTU telecommands per CCSDS 231.0-B-3. The lengths of the various fields that make up the CLTU are listed in Table 3-10 CLTU Max Lengths.

Table 3-10 CLTU Max Lengths

Field Size (bits) Telecommand Transfer Frame (TCTF) 8192 (max)

Encoded TCTF 9408 (max) Start sequence 16 Tail Sequence 64 Total CLTU 9488 (max)

Rationale: Use of CLTU telecommands per CCSDS 231.0-B-3 is currently supported by existing DSN services.

Receive Frame Rejection Rate

The X-Band system shall have a Frame rejection rate no greater than 10-3 when the signal power at the receiver (Prec) is no less than the value given in Table 3-11 X-Band System Prec for Receiver Performance.

Rationale: The Frame Rejection Rate and Undetected Error rate are the appropriate performance criteria for the Telecommand Transfer Frame Service as defined in CCSDS 230.1- G-2. The specified Prec ensures the receiver meets both the frame rejection rate and frame undetected error rate requirements. The frame rejection rate is intended to be measured at the output of the BCH decoder.

Receive Frame Undetected Error Rate

The X-Band system shall have a Frame undetected error rate no greater than 10-9 when the signal power at the receiver (Prec) is no less than the value given in Table 3-11 X-Band System Prec for Receiver Performance. The specified Prec guarantees a link margin of 3 dB.

Rationale: The Frame Rejection Rate and Undetected Error rate are the appropriate performance criteria for the Telecommand Transfer Frame Service as defined in CCSDS 230.1- G-2. The specified Prec ensures the receiver meets both the frame rejection rate and frame undetected error rate requirements. The Prec table is based on performance at low temperatures and needs to be adjusted for on-ground testing.

Table 3-11 X-Band System Prec for Receiver Performance

Symbol rate (sps) Prec (dBW) 145 -163.4 1160 -143.3 2320 -151.3 75000 -138.6

Receiver Desensization – Diplexer Isolation The X-band system receiver shall not degrade more than 0.1 dB due to the transmitter operation at maximum output power.

Rationale: 0.1 dB degradation to SNR protects the receiver performance due to transmitter coexistence. This is meant to provide limits associated with the diplexer isolation between the transmit and receive channels.

Receive Decryption The X-band system shall decrypt uplink transfer frames using AES-GCM (w/ 256 bit keys) per CCSDS 352.0-B-2, NIST SP 800-38D, & CCSDS 355.0-B-1, on encrypted uplinks.

Rationale: Use of AES-GCM (w/ 256 bit keys) per CCSDS 352.0-B-2, NIST SP 800-38D, & CCSDS 355.0-B-1 meets current requirements for commanding.

Decryption Bypass The X-band system shall be able to bypass decryption upon command.

Rationale: The uplink may need to be operated without encryption for some test and contingency scenarios.

Receive Authenticated Decryption The X-band system shall perform authenticated decryption with the parameters in Table 3-12 Authenticated Encryption Parameters, in accordance with NIST Special Publication 800-38D, Recommendation for Block Cipher Modes of Operation: GCM and GMAC, on authenticated encrypted uplinks.

Rationale: The ICSIS specifies usage of GCM with the specified parameters.

Table 3-12 Authenticated Encryption Parameters

Parameter Value Block Cipher AES

Plaintext/Ciphertext The size of Plaintext/Ciphertext varies with the selection of the code, authentication, and encryption

Key Length 256 bits

Initialization Vector (IV) Length 96 bits

Authentication Tag Length 128 bits shortened to 64 bits

Receive Crypto Module Validation The X-band system Crypto Module shall meet FIPS 140-2, Level 1 or better.

Rationale: FIPS 140-2, Level 1 validation is the current accepted validation level for unmanned spacecraft. Level 2 validation would also be acceptable. As the standard shifts to FIPS 140-3 in the near future, the contractor may choose to validate their product to the updated standard which would also be acceptable.

Receive Crypto Key Interface The X-band system Crypto Module shall have an interface to allow loading of keys using DS-

101 SKL.

Rationale: Keys will need to be loaded into the crypto module. GSE may be provided to convert a product’s native interface to a SKL compatible interface.

Load FIRE Code Commands

The X-Band system shall have the capability to load two fire code commands in non-volatile memory prior to flight for use in restarting the Avionics systems.

Rationale: These stored fire code commands will be used to correlate to commands sent from the ground to initiate an Avionics reset or power cycle.

Receive FIRE Command Decode Capability The X-band system shall have the stand-alone capability of decoding two fire code commands sent from the operations center over RF.

Rationale: This capability is used to allow the ground to reset the computer or power cycle the computer.

FIRE Code Discrete Operation The X-Band system Fire Code Discrete signals shall create discrete signals with characteristics in 3.4.8 after decoding the received FIRE code commands.

Rationale: This capability is used to allow the ground to reset the computer or power cycle the computer.

Rover Electrical Interfaces

Power

Voltage The X-band system shall operate at a nominal voltage of 28 VDC +/- 6 VDC.

Transmit and Receive Mode Power The X-Band system shall draw less than 100 Watts DC Power during Transmit and Receive Operations.

Receive Mode Power The X-Band system shall draw less than 17 Watts DC Power during Receive only Operations.

Connector Supplier can specify connector and pinouts.

Transceiver Reset

Electrical The X-Band system shall allow a reset of the transceiver using an interface conforming to the RS-422 electrical specifications not to exceed +/- 5 VDC.

Format The X-Band system shall allow a reset of the transceiver when this interface is held active low for a time period to be specified by the supplier.

Connector Supplier can specify connector and pinouts.

Transmit (Downlink) Interface to Avionics

Downlink Clock

Start of CADU Pulse

T1

T0

CADU

BIT 1

CADU

BIT 2

T2

CADU CADU

BIT n BIT 1

T0 = Bit Period

T1 = T0/2 ± 10%

T2 = Frame Period Transmit downlink data rate determined by avionics interface clock rate and must always be active.

Downlink Data

Figure 3-1 Transmit Data Input Data, Clock, and CADU Pulse Relationship

Figure 3-1 describes the intended relationship of the downlink data, clock, and pulse signal interface with Avionics. Data is latched on the rising edge of the clock. The start of the Channel Access Data Units (CADU) is high (true) for a single clock period, latched on the rising edge of the clock. The start of the CADU pulse coincides with the first bit of the ASM of each CADU to be transmitted. The CADU pulse is low (false) for the remaining bits in the CADU.

Transmit Data Interface

3.4.3.1.1 Electrical

The X-Band system shall receive telemetry data to be transmitted (Downlink) using an interface conforming to the RS-422 electrical specifications not to exceed +/- 5 VDC.

3.4.3.1.2 Line Encoding Format

The X-Band system shall receive telemetry data to be transmitted (Downlink) encoded as NRZ-L data.

3.4.3.1.3 Data Format

The X-band system shall receive (from Avionics) a CADU comprised of the 64 bit ASM, the AOS transfer frame, and a LDPC codeword field.

Rationale: The received LDPC codeword field contains dummy data of the appropriate length.

The transceiver performs LDPC encoding, replacing the codeword field, randomizes the CADU and replaces the ASM. The frame period is nominally 2112 clock cycles.

Transmit Clock

3.4.3.2.1 Electrical

The X-Band system shall receive the clock input using an interface conforming to the RS-422 electrical specifications not to exceed +/- 5 VDC.

3.4.3.2.2 Format

The X-Band system shall receive a clock signal at the bit rate to be transmitted.

Transmit CADU Pulse

3.4.3.3.1 Electrical

The X-Band system shall receive the clock input using an interface conforming to the RS-422 electrical specifications not to exceed +/- 5 VDC.

3.4.3.3.2 Format

The X-Band system shall receive a pulse (high [true] for a single clock cycle) that coincides with the first bit of the ASM of each CADU to be transmitted.

3.4.3.3.3 Fill Data

The X-Band system shall output a properly formatted CADU with a virtual ID of decimal 63 if the CADU pulse input is not active on the downlink interface.

Connector Supplier can specify connector and pinouts.

Receive (Uplink) Interface to Avionics

T3 = Minimum of 64 bits Avionics interface uplink clock fixed at 1 MHz and is independent of uplink data rate.

Uplink Clock

Uplink Data

TC TF

BIT 1

TC TF

BIT 2

Uplink Enable

TC TF

BIT n

TC TF

BIT 1

T3

Figure 3-2 RF Receive Data Output Data, Clock, & Enable Relationship

Figure 3-2 describes the intended functionality of uplink data, clock, and enable signal interface with Avionics. The rising edge of the command clock occurs in the middle of the command data bit. The command clock is continuous at 1 MHz. The uplink interface command enable is driven low (true) for a maximum of 8192 bits of decrypted data corresponding to the Telecommand (TC) Transfer Frame maximum length. The enable is high (flase) for at least 64 clock periods before sending another Telecommand (TC) Transfer Frame over the uplink interface. The length of the received TC Transfer Frame can vary on a byte boundary.

Uplink Data Interface

3.4.4.1.1 Electrical

The X-Band system shall output telecommand data received (Uplink) using an interface conforming to the RS-422 electrical specifications not to exceed +/- 5VDC.

3.4.4.1.2 Line Encoding Format

The X-Band system shall output telecommand data received (Uplink) encoded as NRZ-L data and a clock signal at the bit rate received.

3.4.4.1.3 Data Format

The X-band system shall output (to Avionics) TC Transfer Frames per CCSDS 232.0-B-3 Figure 6-2.

Rationale: Consistent with CCSDS 232.0-B-3 Figure 6-2, two basic formats are necessary: one when uplink encryption is enabled (uplink contains security header and trailer); and one when uplink encryption is bypassed (uplink does not contain security header and trailer). The X-band system sends to Avionics: the transfer frame primary header, the security header (when uplink is secured), clear-text user data (decrypted by the X-band system), and the security trailer (when uplink is secured). The frame error control field is not used in this application.

Uplink Clock

3.4.4.2.1 Electrical

The X-Band system shall output the clock using an interface conforming to the RS-422 electrical specifications not to exceed +/- 5VDC.

3.4.4.2.2 Format

The X-Band system shall output the clock signal at 1 MHz.

Uplink Enable

3.4.4.3.1 Electrical

The X-Band system shall output the uplink enable signal using an interface conforming to the RS-422 electrical specifications not to exceed +/- 5VDC.

3.4.4.3.2 Format

The X-Band system shall provide an uplink enable signal that is driven low (true) when providing the telecommand data received.

Connector Supplier can specify connector and pinouts.

Transceiver Control

3.2.1.1 Electrical

The X-Band system Transceiver Control interface shall receive commands to configure the transceiver using an interface conforming to the RS-422 electrical specifications not to exceed

+/- 5 VDC.

Format Supplier can specify.

Connector

Transceiver Monitor

Electrical The X-Band system Transceiver Monitor interface shall transmit transceiver status using an interface conforming to the RS-422 electrical specifications not to exceed +/- 5 VDC.

Format Supplier can specify.

Connector Supplier can specify connector and pinouts.

Status Discrete Signals

Electrical The X-Band system shall provide Status Discrete Signals using an interface conforming to the RS-422 electrical specifications not to exceed +/- 5 VDC.

Status Signals The X-Band system shall provide at a minimum the following discrete Signals; Carrier Lock, Receive Bit Sync Lock and Receive Frame Sync Lock.

Format The X-Band system shall provide an active low signal for all of the Status Signals.

Connector Supplier can specify connector and pinouts.

FIRE Code Discretes

Electrical The X-Band system shall provide FIRE Code Discrete Signals using an interface conforming to the RS-422 electrical specifications not to exceed +/- 5 VDC

Temperature Monitoring

Electrical The X-Band system shall provide internal temperature monitoring of key components within the system using PT1000 or AD590 compatible devices.

Temperature Signals The X-Band system shall provide Temperature monitoring of key components in the system including but not limited to; SSPA, CPUs, FPGAs.

Format Supplier shall provide details on sensors used.

Connector Supplier can specify connector and pinouts.

RF Input

Electrical The X-Band system shall be capable of receiving an RF signal at a level as defined in section 3.3 with an impedance of 50 Ω and a VSWR of less than 1.5:1.

The X-Band system RF input shall use either a TNC or SMA connector.

RF Output

Electrical The X-Band system shall be capable of transmitting an RF signal at a level as defined in section

3.2 into an impedance of 50 Ω and a VSWR of less than or equal to 1.5:1.

Connector The X-Band system RF output shall use either a TNC or SMA connectors.

Mechanical Requirements

Form Factor Supplier can specify the component configuration and volume.

Mass The X-Band system mass shall not exceed 8 kg total.

Mounting The X-Band System shall provide mounting holes to attach to the rover that do not interfere with mating connectors.

Fasteners The X-Band System structural bolts shall use a locking feature that does not rely on preload, such as self-locking nuts or inserts or patch-lock bolts.

Labeling

a) The X-Band System shall have a label placed on the assembly indicating part number, serial number and title per PRC-9002.

b) All external connectors shall have a unique reference designator marked on the outside of the component and be legible to the unaided eye under reasonable lighting conditions and viewing angles.

Conformal Coating and Staking

a) All X-Band System Flight Unit PCBAs shall be conformal coated and staked prior to delivery.

b) Conformal coating shall be a low out-gassing material, such as Arathane 5750LV or Nusil

CV-1152.

c) Staking shall be a low out-gassing material, such as EC2216 or Arathane 5753LV.

Thermal Analysis

a) The X-Band System thermal analysis shall assume a vacuum environment where heat dissipation to the chassis is due only to conduction and radiation.

Materials & Cleanliness

a) All mounting interfaces shall be chemical conversion coated per MIL-DTL-5541 Type 1 Class 3

b) All external non-faying surfaces shall have a hemispherical emissivity of less than 0.1.

c) All components shall meet general requirements of Visibly Clean Highly Sensitive (VCHS), defined as absence of surface contamination when examined under oblique white light of more than 1080 lx and from a distance of 15 cm to 45 cm using normal of magnified vision.

d) All components shall meet the Total Mass Loss (TML) of <1% and the total Collected Volatile Condensable Materials (CVCM) of <0.1%. Bakeout of the components is assumed, but supplier can suggest alternate approaches.

e) The following materials are banned by the VIPER Program unless specifically waived:

silicones; foams; non-flight adhesives; lubricants; and mold release agents.

f) A NASA approved mitigation approach must accompany the use of any of the following materials.

Material Woven textiles (cloth, lacing cord, lanyards, ropes, sewing threads, polyester/other mesh in MLI, scrim, hem. sleeving)

Particle Generation Risk Particles released from cut edges, broken or poorly captured filament strands. Also materials trap particulate contamination that can be later released.

Possible Mitigations Seal cut edges with polymer, use hot knife to cut materials. Overwrap materials with a non-particulating tape or film barrier.

Ultrasonically clean in solvents to remove trapped particular contaminants. Handle so as to minimize abrasion or damage to threads/filaments.

Woven Metallic Materials Particles released from broken Overwrap materials with a non-particulating (Wire rope, emi shielding for strands or trapped particulate tape or film barrier. Ultrasonically clean in cables, emi filters, etc) contamination dislodging solvents to remove trapped particular contaminants and damaged strands. Seal cut edges with polymers; Demonstrate that material is not shedding particles.

Woven materials with brittle Particles released from broken Overwrap materials with a non-particulating components (glass, ceramic, strands or trapped particulate tape or film barrier. Ultrasonically clean in graphite, carbon fibers, etc.) contamination dislodging solvents to remove trapped particular contaminants and damaged strands. Seal cut edges with polymers; Demonstrate that material is not shedding particles and does not have broken fibers.

Metals subject to oxidation (Bare (untreated) aluminum and magnesium, iron, non-corrosion resistant steel, etc.)

Oxide particles slough off. (Note:

aluminum particles will shed over time.)

Apply surface treatments to prevent corrosion (irridite, annodization, protective sealants, etc.). Avoid dissimilar metals from contacting each other. Keep surfaces clean and free of agents that accelerate oxidation (water (humidity), acids, bases, salts, fingerprints, etc.)

Velcro Generates particles when hook and pile are mated and demated

Clean by the following a specified process prior to installing on Flight Hardware

Paints or coatings with overspray Overspray nodules or large pigment Improve processes to prevent overspray.

nodules or large pigment or other or other particles/fillers are too large Reject surfaces with overspray or remove particle-based additives/fillers to be retained by the paint or coating overspray nodules. Avoid use of paints or (silicate based thermal coatings) matrix. Easily break off during handling.

coatings with large pigment or particle-based additives/fillers. Verify paint does not generate particles.

Flexible substrates with brittle coatings (ceramic, glass, metallic, epoxies, etc.)

Brittle coatings crack when substrates are handled, bent, or otherwise disturbed

Minimize handling. Inspect often and remove contaminants. Protect from contamination to minimize damage from cleaning. Use minimal contact methods to clean surfaces – light brushing, vacuuming (with minimal suction and soft brush tool), solvent rinsing, blowing with filtered, clean dry air/nitrogen, etc.

Carbon Loaded Materials (conductive Kapton, graphite, conductive Teflon, coatings, paints, etc.)

Carbon particles can be released if not contained with matrix. Cut edges of materials can shed particles.

Test material for release of particle as a result of handling and/or abrasion. One test is to rub the material on paper and see if it leaves marks (crayoning) on the paper. Encapsulate cut edges of material if they are shedding particles.

Highly textured surfaces Contain crevices that can trap particles and impede cleaning.

Particles may be released especially in a vacuum microgravity environment

Rigorously clean and protect cleanliness by covering or encapsulating except when exposure is absolutely necessary.

Dry lubricants Can generate particles if applied in excess. Can become cross contamination hazard if applied to areas that can be contacted by personnel or GSE.

Remove excess. Perform tests and inspections after exercising flight hardware throughout the range of motion of the flight article.

EEE Parts

Parts Grade The X-band System shall utilize NPSL Level 2 parts or better.

Parts Process The X-Band System shall comply with the VIPER Mission EEE Parts Control Plan.

Life Requirements

Mission Life The X-Band System orbit and lunar life shall be 210 days with a goal to survive 365 days.

Shelf Life The X-Band System shall not suffer any degradation in performance when stored for ten years when packaged using agreed-to procedures.

Environmental Requirements The X-Band System shall be designed to withstand (without degradation of performance) the operational and non-operational environments specified in the following section. All testing shall be conducted at the protoflight test levels and test durations.

Static Loads The X-Band System shall demonstrate the ability to survive the quasi static loads described by the physical Mass Acceleration Curve (MAC) in the figure below. Loads are considered to act in any direction, individually.

Given the criteria provided in the figure, the MAC value loads are applicable to hardware that has first modes below 80 Hz or mounts to hardware with first modes below 80 Hz. Further refinement of secondary structures quasi-static loads are updated by the CLA when available. Random Vibration Testing can satisfy the MAC analysis if the random vibration loads can be shown to meet or exceed the MAC loads.

Rationale: Limits defined by VIPER-MSE-SPEC-001, VIPER Environment Specification

Dynamic Loads

Random Vibration The X-Band System shall be capable of withstanding the random vibration levels shown in the following table. These spectra shall be applied in each of three orthogonal axes at the mounting interface of the assembly.

Table – Assembly Random Vibration

Frequency (Hz) ASD Level (g2/Hz) for items 22.7-kg or less

Qualification / Protoflight Acceptance

20 0.026 0.013

20-50 +6 dB/oct +6 dB/oct

50-800 0.16 0.08

800-2000 -6 dB/oct -6 dB/oct

2000 0.026 0.013

Overall 14.1 grms 10.0 grms

2) The slopes shall be maintained at ±6dB/oct for components weighing up to 59-kg (130 lb). Above 59-kg, the shapes shall be adjusted to maintain an ASD of 0.01 g2/Hz at 20-2,000 Hz.

Rationale:

Limits defined by VIPER-MSE-SPEC-001, VIPER Environment Specification

A force limit spectrum may be used to notch the input acceleration to an assembly. The force limit values may be modified based on information gathered during shaker vibration testing (See NASA-HDBK-7004C for more information on force limiting).

For assemblies with fundamental resonances below 80 Hz, the peak acceleration of the assembly c.g. should be limited to the assembly’s limit load value times an appropriate test factor and sigma value. [Ref: APR 8070.2] Class D Spacecraft Design and Environmental Test

Sine Vibration The X-Band System shall be capable of withstanding the sine vibration levels described in the figures below.

Axial Sine Environment

Lateral equivalent Sine Environment

Rationale: Limits defined by VIPER-MSE-SPEC-001, VIPER Environment Specification

Ground Handling and Shipping Vibration and Shock The X-Band System shall be capable of withstanding the ground handling limit loads as defined in the following table.

Table 2.6.11 – Ground Handling Loads

Event Design Limit Load, DLL (g)

Vertical Lateral Longitudinal

S/C Dolly / Stand Interface -1.6 +/- 0.5 +/- 0.5

S/C Lift-sling Interface 1.6 +/- 0.25 +/- 0.25

S/C Transportation in shipping container -3.6 / +1.6 +/- 1.0 +2.0 / -1.5

Notes

1. Loads to be applied separately, single direction at a time.

2. Vertical loads act in the gravity gradient, Lateral loads act perpendicular to the direction of travel, and Longitudinal loads act in the direction of travel.

3. Positive vertical loads impart a tension at the S/C MGSE I/F

Rationale: Limits defined by VIPER-MSE-SPEC-001, VIPER Environment Specification

Shock The X-Band System shall be capable of withstanding the shock environment shown in the table below:

Frequency (Hz) SRS (g) a SV Sep Plane 100 80 625 500 10,000 500

Verification of the shock requirements may be deferred if the hardware is not considered to be shock sensitive.

Thermal The X-band System shall comply with the thermal limits described in Table 3-13 Thermal Limits.

Table 3-13 Thermal Limits

Mode Design Acceptance Protoflight

Min Max Min Max Min Max Operating -25 °C +60 °C -30 °C +65 °C -35°C +71°C Non-

Operational -40 °C +70 °C -45 °C +75 °C -50 °C +80 °C

Rationale: The VIPER thermal summit provided the maximum and minimum predicted temperature limits for the communication hardware. Non-operational levels were further defined by the transportation environment defined in VIPER-MSE-SPEC-001, VIPER Environment Specification. Consistent with ARC-STD-8070.1 section 3.1.3, the component thermal design provides a margin ≥ 5˚C to those predicted temperature limits. Also consistent with ARC-STD- 8070.1, the acceptance test limits apply an additional ±5˚C margin, while the protoflight test limits apply an additional ±10˚C margin to the thermal design values.

Vacuum The X-band System shall be capable of meeting all performance at ambient pressure (760 Torr) as well as when exposed to a vacuum (tested to <10-5 Torr in Thermal Vacuum Test).

The X-Band System will be powered off during launch and ascent.

The X-band System shall operate as specified after…