1. Section Number - 1 NASA’s Goddard Space Flight Center Communication Systems Jason A. Soloff NASA/GSFC Code 567 August 16-17, 2005

2. Section Number - 2 NASA’s Goddard Space Flight Center Level 2 431-SPEC-000008LRO Electrical Systems Specification 431-OPS-000042LRO Mission Concept of Operations 431-REQT-000004LRO Mission Requirements Document 431-SPEC-000091General Thermal Systems Specification Level 3 431-REQT-000137Communication System Requirements for the Lunar Reconnaissance Orbiter 451-RFICD-LRO/LNRadio Frequency Interface Control Document (RFICD) Between the Lunar Reconnaissance Orbiter (LRO) and the Lunar Network (LN) Derived (Level 4) 431-SPEC-000121Performance Specification for the LRO S-Band Transceiver Subsystem 431-SPEC-000138Performance Specification for the LRO Ka-Band Modulator 431-SPEC-000178Performance Specification for the LRO Ka-Band Traveling Wave Tube Amplifier 431-SPEC-000179Performance Specification for the LRO High Gain Antenna System 431-SPEC-TBDPerformance Specification for the LRO Ka-Band Isolator 431-SPEC-TBDPerformance Specification for the LRO Omnidirectional Antennas 431-SPEC-TBDPerformance Specification for the LRO S-Band Hybrid 431-SPEC-TBDPerformance Specification for the LRO S-Band Isolator Derived (ICD) 431-ICD-TBDLRO High Gain Antenna ICD 431-ICD-TBDLRO Omnidirectional Antenna Mechanical ICD 431-ICD-TBDLRO S-Band Subsystem ICD 431-ICD-TBDLRO Ka-Band Subsystem ICD Derived (I&T Procedures & Plans) 431-PLAN-TBDLRO S-Band Subsystem Integration & Test Procedure 431-PLAN-TBDLRO Ka-Band Subsystem Integration & Test Procedure Lunar Reconnaissance Orbiter (LRO) Communication System Document List

3. Section Number - 3 NASA’s Goddard Space Flight Center Level 2 Req. 431-REQT-000137 Communication System Requirements for the Lunar Reconnaissance Orbiter Concept/Compliance ParagraphRequirement MRD-119 (TT&C) MRD-123 (TLM D/L) CONOPS-9.2.2 CSR-3The spacecraft shall include a S-Band transmit system capable of supporting S-Band telemetry in all flight conditions. Provides S-Band downlink data capability for telemetry function MRD-119 (TT&C) MRD-121 (Radiometrics) MRD-123 (TLM D/L) CSR-1The spacecraft shall include a S-Band transmitter with an output frequency of 2091.3967 MHz +/- 2.5 MHz. Frequency assignment per GSFC Spectrum Management office. MRD-119 (TT&C) MRD-121 (Radiometrics) MRD-122 (CMD U/L) CSR-2The spacecraft shall include a S-Band receiver with an operating frequency of 2271.2 MHz +/- 2.5 MHz Frequency assignment per GSFC Spectrum Management office. MRD-119 (TT&C) MRD-121 (Radiometrics) CSR-10The spacecraft transponder shall support STDN compatible operation.STDN provides S-Band TT&C, including the capability for radiometric measurement. Lunar Reconnaissance Orbiter (LRO) Communication System Level 2 Flow Down Key Requirements

4. Section Number - 4 NASA’s Goddard Space Flight Center Level 2 Req. 431-REQT-000137 Communication System Requirements for the Lunar Reconnaissance Orbiter Concept/Compliance ParagraphRequirement MRD-119 (TT&C) MRD-123 (TLM D/L) CONOPS-9.2.2 CSR-15The spacecraft transponder shall support downlink subcarrier modulation of data at rates up to 273 kbps (791.7 Kilo-symbols/sec after FEC coding). Telemetry data shall be PSK modulated on a 1.7 (TBD) MHz subcarrier. Provides S-Band downlink data capability for LRO nominal and unusual attitude telemetry data rates per CONOPS. MRD-119 (TT&C) MRD-123 (TLM D/L) CONOPS-9.2.2 CSR-16The spacecraft transponder shall support direct carrier modulation of data at rates up to 2.186 Mbps (5 Msps). Telemetry data shall be OQPSK modulated at baseband on the downlink carrier. Provides S-Band downlink data capability for LRO telemetry data rates during high rate contingencies per CONOPS MRD-119 (TT&C) MRD-122 (Radiometrics) CSR-11The spacecraft transponder receiver shall receive and demodulate command uplink data at a rate of 4 kbps. Command data shall be PSK modulated on a 16 kHz subcarrier. Provides S-Band uplink capability for TT&C function at LRO command data rates per CONOPS Lunar Reconnaissance Orbiter (LRO) Communication System Level 2 Flow Down Key Requirements

5. Section Number - 5 NASA’s Goddard Space Flight Center Level 2 Req. 431-REQT-000137 Communication System Requirements for the Lunar Reconnaissance Orbiter Concept/Compliance ParagraphRequirement MRD-39 (Radiometric Tracking) MRD-41 (Orbit Determination) MRD-121 (Radiometric) MRD-146 (Mission Planning) CSR-18The spacecraft transponder shall support radiometric measurement. Radiometric measurement provides range and range-rate (Doppler) data to the FDF and LRO Flight Dynamics team. MRD-119 (TT&C) MRD-123 (TLM D/L) CSR-5The spacecraft shall include a S-Band transmit system with a radiated EIRP of not less than 34 dBm through the omnidirectional antennas. Sufficient EIRP to meet LRO telemetry requirements during off- nominal flight as described in CONOPS MRD-119 (TT&C) MRD-123 (TLM D/L) CSR-9The S-Band transmit gain over of the combined omnidirectional antenna system shall not be less than 0 dBi over 90% (TBD) of the spherical radiation pattern, including losses due to the omnidirectional antenna hybrid. Provides antenna visibility for TLM/CMD during off-nominal attitudes & spacecraft contingencies. MRD-119 (TT&C) MRD-123 (TLM D/L) CSR-4The spacecraft shall include a S-Band transmit system with a radiated EIRP of not less than 55 dBm through the high gain antenna. Sufficient EIRP to meet LRO telemetry requirements during nominal flight as described in CONOPS Lunar Reconnaissance Orbiter (LRO) Communication System Level 2 Flow Down Key Requirements

6. Section Number - 6 NASA’s Goddard Space Flight Center Level 2 Req. 431-REQT-000137 Communication System Requirements for the Lunar Reconnaissance Orbiter Concept/Compliance ParagraphRequirement MRD-119 (TT&C) MRD-123 (TLM D/L) MRD-124 (High Rate D/L) CSR-25The spacecraft downlink telemetry shall be FEC coded using concatenated CCSDS Reed-Solomon, interleave level 8, and rate ½ convolutional codes. FEC coding provides necessary coding gain to ensure required link BER and link margin. MRD-119 (TT&C) MRD-121 (Radiometrics) MRD-122 (Command Link) CSR-31Ground stations in the LRO Ground System shall provide an S-Band transmit EIRP of not less than 79 dBW. Allocation to ground station in link budget. MRD-119 (TT&C) MRD-121 (Radiometrics) MRD-123 (TLM D/L) CSR-32Ground stations in the LRO Ground System shall provide a station S- Band G/T of not less than 20.3 dB/K, including full lunar noise. Allocation to ground station in link budget. Lunar Reconnaissance Orbiter (LRO) Communication System Level 2 Flow Down Key Requirements

7. Section Number - 7 NASA’s Goddard Space Flight Center Level 2 Req. 431-REQT-000137 Communication System Requirements for the Lunar Reconnaissance Orbiter Concept/Compliance ParagraphRequirement MRD-124 (High Rate D/L) CONOPS-9.2 CSR-33The spacecraft shall include a transmitter with an output frequency of 25.650 GHz +/- 200 MHz. Frequency assignment per GSFC Spectrum Management office. MRD-124 (High Rate D/L) CONOPS-9.2.1.3 CSR-34The Ka-Band transmitter shall modulate a Ka-Band carrier using OQPSK, direct carrier modulation, at data rates up to 100 Mbps (229 Mega-symbols per second including all FEC encoding). OQPSK is required to support LRO’s downlink data volume within the allocated spectrum. MRD-124 (High Rate D/L) CSR-35The spacecraft shall include a Ka-Band transmit system with an EIRP of not less than 54 dBW. Sufficient EIRP to meet LRO high rate telemetry requirements during nominal flight as described in CONOPS MRD-124 (High Rate D/L) CSR-40The high speed science data shall be encoded using concatenated CCSDS Reed-Solomon, with interleave level 8, and rate ½ convolutional encoding. FEC coding provides necessary coding gain to ensure required link BER and link margin. MRD-124 (High Rate D/L) CSR-49Ground stations in the LRO Ground System shall have a Ka-Band receive G/T of not less than 45 dB/K in the presence of full lunar noise under clear sky conditions. Allocation to ground station in link budget. Lunar Reconnaissance Orbiter (LRO) Communication System Level 2 Flow Down Key Requirements

8. Section Number - 8 NASA’s Goddard Space Flight Center Lunar Reconnaissance Orbiter (LRO) Communication System Block Diagram S-Band TT&C Subsystem

9. Section Number - 9 NASA’s Goddard Space Flight Center Lunar Reconnaissance Orbiter (LRO) Communication System Block Diagram Ka-Band High Rate Downlink Subsystem

10. Section Number - 10 NASA’s Goddard Space Flight Center Lunar Reconnaissance Orbiter Communication System Preliminary Verification Approach Communication System Analysis –S-Band frequency spectrum interference analysis –S-Band link budget calculation –Ka-Band link budget calculation –HGA RF field calculation and modeling –Omnidirectional antenna RF phasing analysis –Navigation signal accuracy analysis –Mini-RF interference analysis Flight Module Testing –Performed at vendor and as part of LRO I&T Comm System Verifications –RF compatibility test (RF Compat Lab, TURFTS) –Antenna radiation pattern measurement (GEMAC) –End-to-end communication link BER measurement –EMI/EMC compliance testing with Mini-RF

11. Section Number - 11 NASA’s Goddard Space Flight Center Lunar Reconnaissance Orbiter Communication System Summary LRO Communication driving requirements are defined –COMM preliminary architecture developed in accordance with defined driving requirements –COMM system functional allocation of requirements completed –COMM system component specifications in development –Interfaces being defined between the following elements at Level 3 S-Band / C&DH interface Ka-Band / C&DH interface HGA / Mechanisms interface –Driving requirements still in development Information assurance based on no encryption requirement The Comm Subsystem is ready for Preliminary Design