Mini-RF Requirements Overview
Mary Reden NASA/GSFC SGT, Inc. August 16-17, 2005
NASA’s Goddard Space Flight Center
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Mini-RF Overview
• Mini-RF is a NAWC/WD-provided synthetic aperture radar technology demonstration provided to the LRO spacecraft for the purpose of demonstrating new radar technology for future use in planetary resource mapping. Mini-RF is composed of the following major elements:
– Fixed planar antenna with dimensions 125 x 75 x 5.5 cm – Electronics box with dimensions 14.2 x 20.3 x 12 cm – Cable harnessing between the electronics box and the antenna, and to spacecraft electrical interfaces.
S-Omni Antenna Mini-RF E-Box
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Mini-RF Antenna
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Mini-RF is the second in a spiral technology development effort, preceded by the Forerunner radar to be placed into Lunar orbit aboard the Chandrayaan-1 satellite. Mini-RF will make a series of measurements to demonstrate enhanced technology capabilities over the Forerunner instrument.
NASA’s Goddard Space Flight Center
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Mini-RF Block Diagram
NASA’s Goddard Space Flight Center
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LRO Requirements Document Flow
Level 1 2 2 2 2 2 2 2 2 2 3 3 3 3 Document Number ESMD-RLEP-0010 431-RQMT-000004 431-RQMT-000157 431-OPS-000042 431-SPEC-000008 431-SPEC-000012 431-SPEC-000091 431-SPEC-000103 431-SPEC-000112 430-HDBK-000007 431-ICD-000152 431-ICD-000158 431-ICD-000159 431-ICD-000160 Title LRO Program Requirements Document LRO Mission Requirements Document Mini-RF Requirements and Goals Document LRO Mission Concept of Operations LRO Electrical Systems Specification LRO Mechanical Systems Specification LRO Thermal System Specification LRO SpaceWire Specification LRO Technical Resource Allocation Specification Generic Instrument Performance Assurance User's Guide Mini-RF Electrical Interface Control Document Mini-RF Mechanical Interface Control Document Mini-RF Thermal Interface Control Document Mini-RF Data Interface Control Document
NASA’s Goddard Space Flight Center
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Mini-RF Level 1 Requirements
• Mini-RF Level 2 requirements are defined, and are traceable to a single Level 1 requirement:
– LRO Program Requirements Document, #ESMD-RLEP-0010
• RLEP-LRO-P160 Technology Demonstration - The LRO shall accommodate the NAWC provided Mini-RF device in order to provide the opportunity for demonstration of this technology in the lunar orbital environment provided it does not increase the project cost, delay the launch date, adversely impact the achievement of full mission success, or increase the overall risk posture of the primary mission.
NASA’s Goddard Space Flight Center
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Mini-RF Level 2 Requirements
• Key mission requirements:
– LRO Mission Requirements Document (MRD), #431-RQMT-000004 – LRO Mission Concept of Operations Document, #431-OPS-000042 – Mini-RF Requirements and Goals Document, #431-RQMT-000157
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Key performance assurance requirements:
– Generic Instrument Performance Assurance User's Guide, #430-HDBK-000007
• Tailored for Mini-RF to specifically address those areas that may adversely impact the achievement of full mission success, increase the overall risk posture of the primary mission, or have safety implications
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Key verification requirements:
– – – – – LRO Electrical Systems Specification, #431-SPEC-000008 LRO Mechanical Systems Specification, #431-SPEC-000012 LRO Thermal System Specification, #431-SPEC-000091 LRO SpaceWire Specification, #431-SPEC-000103 LRO Technical Resource Allocation Specification, #431-SPEC-000112
NASA’s Goddard Space Flight Center
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Mini-RF Requirements Implementation
• Implementation of the Mini-RF requirements:
– – – – Mini-RF Mini-RF Mini-RF Mini-RF Spacecraft Mechanical ICD, #431-ICD-000158 to Spacecraft Thermal ICD, #431-ICD-000159 to Spacecraft Electrical ICD, #431-ICD-000152 to Spacecraft Data ICD, #431-ICD-000160
NASA’s Goddard Space Flight Center
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Driving Requirements on the Spacecraft
• Mechanical
– The spacecraft shall maintain a Mini-RF mass allocation of 12 kg, including margin – The spacecraft shall mount the Mini-RF antenna such that the antenna normal is ~45-degree off-nadir, on the anti-sun side of the spacecraft
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Thermal
– The spacecraft shall provide survival heater switch service to maintain the Mini-RF devices within the following temperature limits:
• -34 to +71 C for electronics • -160 to +100 C for antenna
NASA’s Goddard Space Flight Center
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Driving Requirements on the Spacecraft
• Electrical
– The spacecraft shall provide 2 and 5 amp 28 v power services – The spacecraft shall provide a SpaceWire interface directly to the Solid State Recorder – The spacecraft shall accommodate a data transfer rate of 8 Mbps (nominal) up to 32 Mbps (maximum) during data collections
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Operational
– The spacecraft shall provide Mini-RF with a minimum of 12, 4-minute data collection opportunities over the LRO nominal 1-year mission
• Mini-RF desires 2 successive orbits in each of 6 modes (S/X-bands, dual/quad polarization, mapping/zoom resolution) • Additional data collects at the lunar poles, bi-static radar operations and off-nadir pointing will be documented in the Concept of Operations Document as desirable targets of opportunity
NASA’s Goddard Space Flight Center
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Mini-RF Constraints
• • The Mini-RF antenna and electronics box shall be thermally isolated from the spacecraft Accommodation of Mini-RF on LRO shall not interfere with achievement of full mission success, or increase the overall risk posture of the primary mission
– Mini-RF shall not interfere with LRO S/C S-band and Ka-band operations
• Mini-RF waveform and electronics shall be designed to eliminate any interference with spacecraft S-band operations • Impact of interference shall be minimized by limiting, if necessary, the duration of Mini-RF collection intervals
– Mini-RF operations shall be deconflicted with LROC scenes and with the S/C communications timeline
• Data collection orbits will be infrequent and will be chosen to accommodate LRO mission constraints.
NASA’s Goddard Space Flight Center
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