Attachment B GXSPORD.pdf

DRAFT

Effective Date: 418-XO-GXSPORD-0118 Responsible Organization: GeoXO Flight Project/Code 418 Baseline Version 1.0

To verify the correct version of this document, please contact the GeoXO Series Configuration Management Office.

Geostationary Extended Observations (GeoXO) Flight Project Sounder (GXS)

Performance and Operational Requirements Document (PORD) Signature page

Prepared by:

Nicolaas Du Toit Date GeoXO Flight Project, Instrument Systems Engineer NASA GSFC, Code 418

Reviewed by:

Kevin J. Tewey Date GeoXO Flight Project, Instrument Manager

Steven W. Bidwell Date GeoXO Flight Project, Mission Systems Engineer

Megan Gorham Date GeoXO Flight Project, Deputy Mission Systems Engineer

Effective Date: TBD 417-R-XXX-XXXX Expiration Date: TBD Version x.x Responsible Organization: GOES-R/Code 417

Approved by:

Monica Todirita Date GeoXO Flight Project, Deputy Project Manager (DPM) NOAA GSFC, Code 418

/GeoXO Flight Project GXS Sounder

GXSPORD

418-XO-GXSPORD-0118, RM Version, GeoXO Sounder (GXS) Performance and Operational Requirements Document (PORD) Phase B

Version: 0.4 Printed by: rkhoover Printed on: Wednesday, November 30, 2022

No filter applied.

No sort applied.

Generated from DOORS 9.7.2.4

Contents

1 1Scope

1.1 1Identification

1.2 1Mission Review

1.3 1Document Overview

1.4 1Terminology

1.5 2Definitions

2 5Documents

2.1 5Applicable Documents

2.2 5Reference Documents

3 6Sensor Requirements

3.1 6Sensor Definition

3.1.1 6GXS Modes

3.1.1.1 6Safe Mode

3.1.1.2 6Normal Operational Mode

3.1.1.3 6Instrument Diagnostic Mode

3.1.1.4 7Outgas Capability

3.1.2 7On orbit Operations

3.1.2.1 7Zones of Reduced Data Quality

3.1.2.1.1 7Operational Zone

3.1.2.1.2 7Restricted Zone / Zones of Reduced Data Quality (ZRDQ)

3.1.2.2 8Scanning Across the Sun

3.1.2.3 8Eclipse

3.1.2.4 8Operations after Maneuvers

3.1.2.4.1 8Yaw Flip

3.1.2.4.2 8Other Maneuvers

3.1.2.4.3 8Post Storage Activation

3.1.2.4.4 8Detector Set-Point Temperature

3.2 9Normal Operational Mode Sensor Requirements

3.2.1 9Spectral Requirements

3.2.1.1 9Spectral Resolution

3.2.1.2 10Spectral Response

3.2.1.3 10Spectral Purity

3.2.1.4 10Spectral Knowledge, Uniformity, and Stability

Project: GeoXO Flight Project GXS Sounder Module: GXSPORD Baseline Version: 0.4

Contents ii

3.2.1.5 10Spectral Region Breaks

3.2.2 11Scan Requirements

3.2.2.1 11Coverage Rate

3.2.2.2 12Scan/Step Direction

3.2.2.3 12Flexible and Selectable Scan Pattern

3.2.2.4 13Scan Efficiency and Simultaneities

3.2.2.5 13Data Latency

3.2.3 13Spatial Sampling Requirements

3.2.3.1 14Field of Regard

3.2.3.2 14Ground Sample Distance and Angle

3.2.3.3 14Detector Sample Ground Footprint

3.2.3.3.1 14Detector / Optics Ensquared Energy

3.2.3.4 14Co-Registration

3.2.4 15Radiometric Performance Requirements

3.2.4.1 15Dynamic Range

3.2.4.2 15Measurement Precision (NEdN and NEdT)

3.2.4.2.1 16Pixel Operability

3.2.4.3 17Radiometric Accuracy

3.2.4.3.1 17Absolute Accuracy

3.2.4.3.2 18Relative Accuracy

3.2.4.3.2.1 18Scan Position to Scan Position Relative Accuracy

3.2.4.3.2.2 19Pixel-to-Pixel Relative Accuracy

3.2.4.3.2.3 20Channel-to-Channel Relative Accuracy

3.2.4.3.2.4 21Calibration-to-Calibration

3.2.4.3.3 21On-Orbit Calibration

3.2.5 21Image Navigation and Registration

3.2.5.1 21INR Scope

3.2.5.2 22INR Function

3.2.5.2.1 22Star Sensing

3.2.5.3 22INR Performance Requirements

3.2.5.3.1 22Navigation

3.2.5.3.2 22Frame-to-Frame Registration

3.2.5.3.3 23Within-Frame Registration

3.2.6 23Data Compression

4 24Design Requirements

4.1 24Reliability

4.2 24Redundancy

4.2.1 24Redundant Component Selectabiltiy

Contents iii

4.2.2 24Interchangability of Flight Model Units

4.2.3 24Cryocooler Operation

4.3 24Mechanical Requirements

4.3.1 24Design Limit Loads

4.3.2 25Yield Strength

4.3.3 26Ultimate Strength

4.3.4 26Unit Stiffness

4.3.5 26Critical Members Design Values

4.3.6 26Redundant Members Design Values

4.3.7 26Selective Design Values

4.3.8 26Fracture Control

4.3.9 27Mechanisms

4.3.10 28Pressurized Units

4.3.11 28Alignment Reference

4.3.12 28Precision Component Assembly

4.4 28Thermal Requirements

4.4.1 28Mission Allowable Temperatures

4.4.2 29Thermal Gradients

4.4.3 29Non-Operational Temperatures

4.4.4 29Thermal Control Hardware

4.4.5 29Detector Cooling Margin

4.4.6 30Radiator

4.4.7 30Heat Pipe (Two-phase Heat Transfer Device)

4.5 30Power Requirements

4.5.1 30Power Regulators and Supplies

4.5.2 30Fuses

4.5.3 30Covers for test Connectors

4.5.4 31Keyed Connectors

4.6 31Onboard Processors Requirements

4.6.1 31Flight Load Non-Volatile Memory

4.6.2 31Commandable Reinitialization

4.6.3 31Deterministic Power-on Configuration

4.6.4 31Fail-safe Recovery Mode

4.7 31Flight Software Requirements

4.7.1 31Language and Methodology

4.7.2 31Flight Software Upload

4.7.3 31Flexibility and Ease of Software Modification

4.7.4 32Version Identifiers

Contents iv

4.7.5 32Flight Processor Resource Sizing

4.7.6 33Software Event Logging

4.7.7 33Warm Restart

4.7.7.1 33Processor Re-Start

4.7.7.2 33Autonomous Re-Start

4.7.8 33Memory Integrity

4.7.8.1 33Memory Verification

4.7.8.2 33Bit Error Detection and Correction

4.7.9 33Memory Dump

4.7.10 34Telemetry Cadence and Dwell Control

4.7.11 34Long-Duration Test

4.7.12 34Unnecessary and Unreachable Software

5 35Ground Support Equipment and Development

5.1 35Electrical System Test Equipment

5.2 35Flight Software Development Environment

5.3 35Ground Processing Demonstration System

5.4 36FM and GSE Shipping Containers

6 37GXS Simulators

6.1 37GXS Instrument Hardware Simulator (GXS-IHS)

6.2 37GXS Instrument Software Simulator (GXS-ISS)

7 39FM Design Verification Requirements

7.1 39Powered-on Operating Time and Trouble-Free Performance Testing

7.2 39Structural and Mechanical Verification Requirements

7.2.1 39Mechanical Test Factors and Duration

7.2.2 41Minimum Workmanship

7.2.3 41Testing in Flight Configuration

7.2.4 42Structural Proof Testing

7.2.5 42Modal Survey Characterization

7.2.6 42Structural Qualification

7.2.7 42Deployment and Articulation Verification

7.2.8 42Life Test

7.2.9 43Mechanical Clearance Verification

7.3 43Electromagnetic Compatibility Verification

7.3.1 43General

7.3.2 43Electrostatic Arc-Discharge Susceptibility

7.3.2.1 43External Surface-to-Surface direct discharge

Contents v

7.3.2.2 43Deep Dielectric Charging

7.3.2.3 43ESD Characteristics

7.4 44Thermal Test Requirements

7.4.1 44General

7.4.1.1 44Thermal Test Chronology

7.4.1.2 44Pressure

7.4.2 45Thermal Vacuum

7.4.2.1 45Transition Rates

7.4.2.2 45Corona Operation

7.4.2.3 45Hot and Cold Start Demonstrations

7.4.2.4 45Heater Verification

7.4.2.5 45Flight Temperature Sensor Verification

7.4.3 46TV Thermal Cycling

7.4.3.1 46Cumulative Cycles

7.4.3.2 46Ambient Pressure Thermal Cycling Substitution

7.4.3.3 46Qualification, Protoflight and Acceptance Temperatures

7.4.3.4 47Survival Heater Verification

7.4.3.5 47Temperature test tolerances

7.4.3.6 47Plateau Criteria

7.4.4 47Thermal Balance (TB)

7.4.4.1 47Balance Points

7.4.4.2 48Instrument Configuration

7.4.4.3 48Accuracy and Knowledge

7.4.4.4 48Steady State Criteria

7.5 48Test Condition Tolerances

8 50Acronyms

Contents vi

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ID

GXSPORD1

GXSPORD2

GXSPORD3

GXSPORD4

GXSPORD5

GXSPORD6

GXSPORD7

GXSPORD8

GXSPORD9

GXSPORD10

GXSPORD11

Object Number

1.1

1.1.0-1

1.2

1.2.0-1

1.2.0-2

1.2.0-3

1.3

1.3.0-1

1.4

1.4.0-1

418-XO-GXSPORD-0118, RM Version, GeoXO Sounder (GXS) Performance and Operational Requirements Document (PORD)

Phase B

1 Scope

1.1 Identification

This Performance and Operational Requirements Document (PORD) sets forth the performance requirements for the National Oceanic and Atmospheric Administration (NOAA) next generation Geostationary (GEO) - eXtended Observations (GeoXO) hyperspectral radiometric Sounder (GXS). Note that the GXS may incorporate additional capabilities described in the Appendix.

1.2 Mission Review

The GXS is a hyperspectral infrared passive radiometric sounder used to collect environmental data as part of a 3-axis stabilized geostationary (GEO) weather satellite system of the GEO-eXtended Observations (GeoXO) program. The GXS will collect radiance observations of the earth's atmosphere with both spectral and horizontal resolution that will yield vertical temperature and moisture information.

Winds can also be derived from rapid mesoscale observations. GXS will provide hyperspectral geostationary operational observations for soundings of the western hemisphere for the first time. GXS data will enhance convective storm nowcasting as well as improve numerical weather prediction (NWP) in short range weather forecasting and longer range weather prediction.

The GXS mission objectives are to:

1. Provide radiance data that will be used by NOAA and other public and private agencies to produce routine meteorological analyses and forecasts of temperature, moisture, and winds.

2. Provide radiance data to expand knowledge of mesoscale and synoptic scale storm development and improve forecasting of severe weather events.

3. Provide radiance data for the measurement and trending of longer term climate change.

The GXS instrument, designated as GXS in this document, provides data to the GeoXO Ground System via the spacecraft communication system. The GeoXO Ground System takes the GXS data, spacecraft telemetry data, orbit determination data and other required information and autonomously generates radiometrically calibrated and navigated data (level 1b) that will be used by NOAA to generate end-products for users. The GeoXO Ground System will implement algorithms developed by the GXS contractor to satisfy GXS performance requirements.

1.3 Document Overview

This document contains all performance requirements for the GXS instrument and Ground Support Equipment (GSE). This document, the General Interface Requirements Document (GIRD), and the GXS Unique Instrument Interface Document (UIID) define all instrument to spacecraft interfaces for the GXS instrument.

1.4 Terminology

The use of "shall" designates a requirement that must be met.

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ID

GXSPORD12

GXSPORD13

GXSPORD14

GXSPORD15

GXSPORD16

GXSPORD17

GXSPORD18

GXSPORD19

GXSPORD20

GXSPORD659

GXSPORD22

GXSPORD23

GXSPORD24

GXSPORD25

GXSPORD26

GXSPORD27

Object Number

1.4.0-2

1.4.0-3

1.4.0-4

1.4.0-5

1.4.0-6

1.4.0-7

1.5

1.5.0-1

1.5.0-2

1.5.0-3

1.5.0-4

1.5.0-5

1.5.0-6

1.5.0-7

1.5.0-8

1.5.0-9

418-XO-GXSPORD-0118, RM Version, GeoXO Sounder (GXS) Performance and Operational Requirements Document (PORD)

Phase B

The use of "should" designates good practice.

The use of "will" designates a statement of fact or intention of the government.

The use of "may" designates that permission has been granted by the government.

The term "(TBS)", which means "to be specified", means that the contractor will supply the missing information in the course of the contract. These serve as a placeholder for future requirements. The contractor is not liable for compliance with these "placeholder" requirements, as insufficient information is provided on which to base a design.

The term "(TBR)" means "to be refined/reviewed" for a value that is subject to review for appropriateness and is subject to revision. The vendor is liable for compliance with the information marked "TBR" as if the "TBR" notation did not exist.

The term "(TBD)" means, "to be determined" and is used when no value is available with subsequent study needed to obtain it.

1.5 Definitions

Throughout this document, the following definitions apply:

Accuracy: Refers to the error in a measurement, which is the difference between the measurement result and the object to be measured (the measured or true value). It includes both systematic and random errors. Systematic errors must be estimated from an analysis of the experimental conditions and techniques. Random errors can be determined, and reduced, through repeated measurements under identical conditions.

Absolute accuracy is traceable to NIST, where traceability is defined by NIST as the "property of the result of a measurement or the value of a standard whereby it can be related to stated references, usually national or international standards, through an unbroken chain of comparisons all having stated uncertainties." (ISO VIM, 2nd.

Ed., 1993, definition 6.10). This includes instituting a measurement insurance program and use of NIST practices in radiance and irradiance determinations including quality programs detailing measurement procedures and reproducibility and using trained personnel.

All requirements/all performance requirements/all operational requirements: Refers to any performance characteristic or requirement in the GXS PORD, GXS UIID, and the GIRD.

Band: A set of channels.

Channel: A measurement that is an aggregate of one or more spectral samples that meets or exceeds GXS requirements.

Derived Noise Equivalent Delta Radiance (NEdN): Refers to the NEdN required to meet the NEdN specification, or the Signal-to-Noise Ratio (SNR) specification.

Detector sample or element: Digitized output from a single detector element.

Eclipse: Defined as when the solar disk is completely occulted by the Earth or Moon, as viewed from the GeoXO satellite.

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ID

GXSPORD1336

GXSPORD28

GXSPORD29

GXSPORD30

GXSPORD31

GXSPORD32

GXSPORD33

GXSPORD1330

GXSPORD1331

GXSPORD1332

GXSPORD1333

GXSPORD34

GXSPORD35

Object Number

1.5.0-10

1.5.0-11

1.5.0-12

1.5.0-13

1.5.0-14

1.5.0-15

1.5.0-16

1.5.0-17

1.5.0-18

1.5.0-19

1.5.0-20

1.5.0-21

1.5.0-22

418-XO-GXSPORD-0118, RM Version, GeoXO Sounder (GXS) Performance and Operational Requirements Document (PORD)

Phase B

Fixed-Grid Angles: Refers to North/South (NS) and East/West (EW) Euler angles defined as follows. Starting with the orbit reference frame (ORF) in GIRD62 at the ideal satellite location, a positive NS angle is a rotation of the ORF about its +x axis, and a positive EW angle is a subsequent rotation of the rotated frame about its +y axis. The +z axis of the final frame is the line of sight (LOS) represented by the EW and NS fixed-grid angles.

Frame: Collection of pixels from a contiguous region as commanded by a minimum bounding rectangle or one of the predefined regions such as Superregional, 62 degree LZA Disk, etc.

Fourier Transform Spectrometer (FTS) System: One approach to spectroscopy that, in contrast to a Grating System, relies on time-domain interference measurements that are converted into spectral data using a Fourier Transform.

Full Disk: Defined as a 17.4 degree diameter circle centered at nadir.

Fully Functional Configuration: Being able to perform the following functions: scene radiance measurement; radiometric calibration; star sensing; on-orbit monitoring of calibration sources and instrument response changes; acquisition of sensor health and status data; generation of the following data streams: sensor, calibration, monitoring, health and status; and reception and execution of command and control data.

Grating System: One approach to spectroscopy that, in contrast to an FTS System, relies on spectral dispersion by means of an optical grating.

Launch: The time between lift off and the separation of the GeoXO satellite from the launch vehicle.

Level 0 data: Raw data reconstructed to unprocessed instrument data at full space-time resolution with all available supplemental information to be used in subsequent processing (e.g., ephemeris, health and safety) appended.

Level 1a data: Unpacked, reformatted, and resampled Level 0 data with all supplemental information to be used in subsequent processing appended. Data generally presented as full space/time resolution. A wide variety of sub-level products are possible.

Level 1b data: Unpacked, reformatted, and resampled Level 0 data with all supplemental information to be used in subsequent processing appended.

Radiometric and geometric correction applied to produce parameters in physical units. Data generally presented as full space/time resolution. (This is identical to the earth-referenced instrument data with radiometric calibration applied and all calibration data appended).

Level 2+ data: Retrieved environmental variables (e.g., sea surface temperature) and higher products.

Mesoscale: Defined as the equivalent of a 1000 km x 1000 km nadir-viewed area.

Navigation: Refers to the determination of the location of each pixel relative to a fixed reference, namely for the GXS, the GRS80 geoid viewed from the idealized geostationary position, with latitude and longitude information appended in the L1b product.

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ID

GXSPORD36

GXSPORD37

GXSPORD38

GXSPORD39

GXSPORD40

GXSPORD41

GXSPORD42

GXSPORD43

GXSPORD44

GXSPORD45

Object Number

1.5.0-23

1.5.0-24

1.5.0-25

1.5.0-26

1.5.0-27

1.5.0-28

1.5.0-29

1.5.0-30

1.5.0-31

1.5.0-32

418-XO-GXSPORD-0118, RM Version, GeoXO Sounder (GXS) Performance and Operational Requirements Document (PORD)

Phase B

Pixel: All spectral channels associated with a given spatial resolution element after processing, including calibration and navigation. (Level 1b)

Precision: Refers to the standard deviation of a statistically meaningful number of samples of a measurement.

Registration: Refers to maintaining the spatial relationship between pixels within frames, between frames, and between channels.

Sounding Disk (SD): Defined as a collection of spatial resolution elements viewing the earth where the local zenith angle (LZA) to a GOES satellite is less than 62 degrees and the local zenith angle is less than or equal to the local zenith angle to the neighboring GOES satellite.

Spectral Sample: A measurement within a channel that may or may not be aggregated for transmission to the ground.

Superregional: Defined as the equivalent of a 5000 km East/West x 3000 km North/South nadir-viewed area.

Swath: Refers to any set of detector samples that are collected during a continuous scan or stepping of the detectors over the scene, in a horizontal fashion, which covers the entire horizontal extent of the scene.

Task: Repeating data collection pattern providing coverage of one or more observing regions.

Threshold Channel: A channel with the GXS required spectral resolution element width.

Unit: A functional subdivision of a subsystem and generally a self-contained combination of items performing a function necessary for the subsystem's operation.

Examples are electronics unit and sensor unit.

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ID

GXSPORD46

GXSPORD47

GXSPORD49

GXSPORD50

GXSPORD53

GXSPORD648

GXSPORD650

GXSPORD56

GXSPORD48

GXSPORD664

GXSPORD662

GXSPORD54

GXSPORD52

GXSPORD665

GXSPORD51

GXSPORD57

GXSPORD58

Object Number

2.1

2.1.0-1

2.1.0-2

2.1.0-3

2.1.0-4

2.1.0-5

2.1.0-6

2.1.0-7

2.1.0-8

2.1.0-9

2.1.0-10

2.1.0-11

2.1.0-12

2.1.0-13

2.2

2.2.0-1

418-XO-GXSPORD-0118, RM Version, GeoXO Sounder (GXS) Performance and Operational Requirements Document (PORD)

Phase B

2 Documents

2.1 Applicable Documents

A New Distortion Measure for Video Coding Blocking Artifacts. Wu, H. R., Proceedings from the 1996 International Conference on Communication Technology.

Volume 2, May 5-7, 1996, Beijing, China. pp 658-651.

CCSDS Recommendation for Space Data System Standards, Image Data Compression, CCSDS 122.0-B-2, September 2017.

General Environmental Verification Standard (GEVS) for GSFC Flight Programs and Projects, Document Number GSFC-STD-7000B, April 28, 2021

General Specification for Assemblies, Moving Mechanical, for Space and Launch Vehicles, Document Number MIL-A-83577B, February 1, 1988.

Geostationary and eXtended Observations (GeoXO) Flight Project Instrument Mission Assurance Requirements (IMAR), 418-XO-IMAR-0026, February 03, 2021.

Geostationary Extended Observations (GeoXO) Sounding Radiances Upwelling, 418-

XO-RPT-0093.

Geostationary Extended Observations (GeoXO) hyperspectral radiometric Sounder (GXS) Unique Instrument Interface Document (UIID), 418-XO-GXSUIID-0030.

Lossless Multispectral and Hyperspectral Image Compression, Document Number

CCSDS 120.2-G-1

Low-complexity Lossless and Near-Lossless Multispectral and Hyperspectral Image Compression, Document Number CCSDS 123.0-B-2

NASA-STD-8719.24 NASA Expendable Launch Vehicle Payload Safety Requirements (Base + Annex), June 2018.

Space Mechanisms Handbook, Document Number NASA TP-1999-206988.

Spectral Preprocessing Transform for Multispectral and Hyperspectral Imager Compression, Document Number CCDS 122.1-B-1

Structural Design and Test Factors of Safety for Spaceflight Hardware, NASA, Document Number NASA-STD-5001B, August 6, 2014.

2.2 Reference Documents

Geostationary Extended Observations (GeoXO) General Interface Requirements Document (GIRD), 418-XO-GIRD-0041.

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ID

GXSPORD59

GXSPORD60

GXSPORD61

GXSPORD62

GXSPORD63

GXSPORD64

GXSPORD65

GXSPORD66

GXSPORD67

GXSPORD68

GXSPORD69

GXSPORD70

GXSPORD71

GXSPORD72

GXSPORD661

GXSPORD73

GXSPORD74

GXSPORD75

GXSPORD76

GXSPORD77

Object Number

3.1

3.1.1

3.1.1.0-1

3.1.1.0-2

3.1.1.0-3

3.1.1.0-4

3.1.1.0-5

3.1.1.1

3.1.1.1.0-1

3.1.1.1.0-2

3.1.1.1.0-3

3.1.1.2

3.1.1.2.0-1

3.1.1.2.0-2

3.1.1.3

3.1.1.3.0-1

3.1.1.3.0-2

3.1.1.3.0-3

3.1.1.3.0-4

418-XO-GXSPORD-0118, RM Version, GeoXO Sounder (GXS) Performance and Operational Requirements Document (PORD)

Phase B

3 Sensor Requirements

3.1 Sensor Definition

3.1.1 GXS Modes

The GXS shall execute commands to individually enable and disable each autonomous function.

The GXS shall initiate all commanded mode transitions in no more than 20 seconds after receipt of command.

The GXS shall make limits and triggers of autonomous functions changeable by command.

The GXS shall indicate the mode of the instrument in housekeeping telemetry.

The GXS shall provide command and housekeeping telemetry functions in all powered modes.

3.1.1.1 Safe Mode

The GXS shall implement a Safe Mode.

The GXS shall be in a thermally and optically safe configuration for an indefinite period of time while in Safe Mode.

The GXS shall enter Safe Mode upon detection of internal faults capable of causing permanent damage to the instrument.

3.1.1.2 Normal Operational Mode

The GXS shall be in a fully functional configuration while in Normal Operational Mode.

The GXS shall meet all performance requirements while in Normal Operational Mode without receiving commands or data loads for a minimum of 7 days.

Rationale: Autonomy is required for a period of 7 days, without impacting performance.

3.1.1.3 Instrument Diagnostic Mode

The GXS shall implement an Instrument Diagnostic Mode.

The GXS shall be in a fully functional configuration while in Instrument Diagnostic Mode.

The GXS shall by command send selected channels while in Instrument Diagnostic Mode.

The GXS shall by command send the individual measurement in those cases where TDI data is digitally processed off the focal plane while in Instrument Diagnostic Mode.

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ID

GXSPORD78

GXSPORD79

GXSPORD80

GXSPORD81

GXSPORD82

GXSPORD83

GXSPORD84

GXSPORD85

GXSPORD86

GXSPORD87

GXSPORD88

GXSPORD89

GXSPORD90

GXSPORD91

GXSPORD1334

Object Number

3.1.1.3.0-5

3.1.1.3.0-6

3.1.1.3.0-7

3.1.1.3.0-8

3.1.1.4

3.1.1.4.0-1

3.1.2

3.1.2.1

3.1.2.1.1

3.1.2.1.1.0-1

3.1.2.1.2

3.1.2.1.2.0-1

3.1.2.1.2.0-2

3.1.2.1.2.0-3

3.1.2.1.2.0-4

418-XO-GXSPORD-0118, RM Version, GeoXO Sounder (GXS) Performance and Operational Requirements Document (PORD)

Phase B

The GXS shall by command send data from all detectors while in Instrument Diagnostic Mode.

The GXS shall by command send all bits from the A to D converter while in Instrument Diagnostic Mode.

The GXS shall by command perform electronic in-flight calibration while in Instrument Diagnostic Mode.

The GXS shall by command send dwell data (increased samples per second of a particular telemetry measurand) while in Diagnostic Mode.

3.1.1.4 Outgas Capability

The post-launch outgas period shall be no longer than 30 days.

3.1.2 On orbit Operations

3.1.2.1 Zones of Reduced Data Quality

3.1.2.1.1 Operational Zone

The GXS shall meet all operational sounding requirements for all pixels that are greater than 10 degrees in angular distance from the center of the uneclipsed sun.

Rationale: Measurement Precision, on-orbit calibration, and accuracy are met outside of the Zones of Reduced Data Quality.

3.1.2.1.2 Restricted Zone / Zones of Reduced Data Quality (ZRDQ)

The GXS shall meet all sounding requirements, except as noted below concerning Measurement Precision (GXSPORD90), Radiometric Accuracy (GXSPORD91), and Image Navigation and Registration (GXSPORD1334), for all pixels between 10 degrees and 3 degrees in angular distance from the center of the uneclipsed Sun.

Rationale: There are relaxations near the sun in the Zones of Reduced Data Quality.

For all pixels between 10 degrees and 3 degrees in angular distance from the center of the uneclipsed sun, the GXS shall meet the sounding requirements in the measurement precision section relaxed by a factor of two.

Rationale: Specifically the measurement precision is relaxed by a factor of 2 in the Zones of Reduced Data Quality near the sun.

For all pixels between 10 degrees and 3 degrees in angular distance from the center of the uneclipsed sun, the GXS shall have an absolute calibration accuracy of either less than 2.0 K or less than the derived NEdT, whichever is greater.

Rationale: Specifically the calibration accuracy is relaxed to 2.0 K in the Zones of Reduced Data Quality near the sun.

For all pixels between 10 degrees and 3 degrees in angular distance from the center of the uneclipsed sun, the GXS shall meet the sounding requirements in the Navigation and Registration section relaxed by a factor of 1.5 (GXSPORD210, Page 8 of 50 Printed Wednesday, November 30, 2022

ID

GXSPORD1334

GXSPORD92

GXSPORD93

GXSPORD94

GXSPORD95

GXSPORD96

GXSPORD97

GXSPORD98

GXSPORD99

GXSPORD100

GXSPORD101

GXSPORD102

GXSPORD103

Object Number

3.1.2.1.2.0-4

3.1.2.2

3.1.2.2.0-1

3.1.2.3

3.1.2.3.0-1

3.1.2.4

3.1.2.4.1

3.1.2.4.1.0-1

3.1.2.4.2

3.1.2.4.2.0-1

3.1.2.4.3

3.1.2.4.3.0-1

3.1.2.4.4

418-XO-GXSPORD-0118, RM Version, GeoXO Sounder (GXS) Performance and Operational Requirements Document (PORD)

Phase B

GXSPORD214, and GXSPORD217 only).

Rationale: Specifically, the Navigation and Registration are relaxed by a factor of 1.5 in the Zones of Reduced Data Quality near the sun.

3.1.2.2 Scanning Across the Sun

The GXS shall survive the presence of the sun within the field of regard without sustaining any permanent degradation in performance.

Rationale: The sun must not result in damage to the instrument.

3.1.2.3 Eclipse

During eclipse periods, the GXS shall meet all requirements, except the four-hour phased relaxation specified in the INR section.

Rationale: Any loss of power from the solar arrays and conversion to battery power for the Spacecraft shall not adversely impact the instrument performance.

3.1.2.4 Operations after Maneuvers

3.1.2.4.1 Yaw Flip

The GXS shall meet all requirements within 30 minutes after the spacecraft interface has returned to being within specification following a yaw flip.

Rationale: If the spacecraft executes a yaw flip, the instrument recovery will occur in this duration after the interface is restored to nominal conditions.

3.1.2.4.2 Other Maneuvers

With the exception of a yaw flip, the GXS shall meet all radiometric, coverage and INR requirements within 2 minutes after the spacecraft interface has returned to being within specification following spacecraft maneuvers.

Rationale: If the spacecraft executes a different maneuver than a yaw flip, the instrument recovery will occur in this short duration after the interface is restored to nominal conditions.

3.1.2.4.3 Post Storage Activation

The GXS shall meet all requirements within 5 days of GXS turn-on after post storage activation.

Rationale: After activation, GXS will cool for operations in this time listed here.

3.1.2.4.4 Detector Set-Point Temperature

Page 13 of 50 Printed Wednesday, November 30, 2022

ID

GXSPORD130

GXSPORD131

GXSPORD132

GXSPORD133

GXSPORD134

GXSPORD135

GXSPORD136

GXSPORD137

GXSPORD138

GXSPORD140

Object Number

3.2.2.3.0-1

3.2.2.3.0-2

3.2.2.3.0-3

3.2.2.4

3.2.2.4.0-1

3.2.2.4.0-2

3.2.2.4.0-3

3.2.2.5

3.2.2.5.0-1

3.2.3

418-XO-GXSPORD-0118, RM Version, GeoXO Sounder (GXS) Performance and Operational Requirements Document (PORD)

Phase B

The GXS sensor shall scan an area of arbitrary size anywhere within the field of regard when commanded, including Superregional and Mesoscale regions.

Rationale: Permits flexible tasking of GXS to regions of interest, likely including Superregional and Mesoscale.

The scan area and geographic location shall be selectable from one frame to the next.

Rationale: Permits flexible tasking of GXS to regions of interest, likely including Superregional and Mesoscale.

The GXS shall be designed such that the Earth-scanning patterns are fully programmable on-orbit.

Rationale: Permits flexible tasking of GXS to regions of interest, likely including Superregional and Mesoscale.

3.2.2.4 Scan Efficiency and Simultaneities

For the sounding tasks, data for all the channels obtained from any specific point on the Earth shall be coincident within 18 seconds.

Rationale: Spectrally simultaneous observations provide observations of the same features in the atmosphere and avoid artifacts in resulting data.

The time between collection of adjacent pixels within a single GXS data frame shall be less than or equal 10 minutes.

Rationale: This limits shearing in an image composed of multiple individual observations.

The data shall be time identified so that the time any detector sample in the data was acquired can be determined to within 0.1 milliseconds relative to the spacecraft provided clock information. The spacecraft clock is synchronized to Universal Time (UT) to an accuracy defined in the GIRD.

Rationale: Temporal telemetry is needed to facilitate data processing.

3.2.2.5 Data Latency

For sounding products, the GXS shall contribute to the total data latency for the Level 1b product of no more than 180 seconds for calibrated, navigated radiances.

Data latency is measured from the time the instrument collects all samples for an earth scene (or frame) to the time the data is available for dissemination on the ground as level 1b data. The GXS contribution to data latency includes delay of delivery of data to the spacecraft and delay due to ground algorithm processing (i.e., any resampling and INR).

Rationale: Latency between the last observation of the input data to the level 1b processing and the availability of the data for further processing should be as short as practical.

3.2.3 Spatial Sampling Requirements

Page 14 of 50 Printed Wednesday, November 30, 2022

ID

GXSPORD141

GXSPORD142

GXSPORD143

GXSPORD144

GXSPORD146

GXSPORD148

GXSPORD149

GXSPORD152

GXSPORD153

Object Number

3.2.3.1

3.2.3.1.0-1

3.2.3.2

3.2.3.2.0-1

3.2.3.3

3.2.3.3.1

3.2.3.3.1.0-1

3.2.3.4

3.2.3.4.0-1

418-XO-GXSPORD-0118, RM Version, GeoXO Sounder (GXS) Performance and Operational Requirements Document (PORD)

Phase B

3.2.3.1 Field of Regard

The unvignetted Field of Regard (FOR) of the instrument shall include a circle of at least 20 degrees in diameter with its center at the sub-satellite point and accounting for alignment errors as described in the GIRD.

Rationale: A boresighted, clear FOR of 20 degrees affords sufficient star coverage in the annulus around the edge of the earth and the edge of the FOV to permit acceptable navigation, and also supports observations of the moon which is an important calibration reference sources.

3.2.3.2 Ground Sample Distance and Angle

The centroid-to-centroid distance between adjacent spatial samples on the Earth's surface, as measured at the Sub-Satellite Point, defines the ground sample distance (GSD). The ground sample angle (GSA) is the associated angle. A two-dimensional pixel is defined by the GSD in the East/West and North/South dimensions.

The GXS shall have a GSA no larger than 112 microradians (4 km at nadir) for emissive channels.

Rationale: GSA defines the spatial sampling for the Level 1b output of GXS.

3.2.3.3 Detector Sample Ground Footprint

3.2.3.3.1 Detector / Optics Ensquared Energy

The dynamic ensquared energy (EE) is a unitless figure of merit that is defined as an energy ratio. The energy ratio's numerator is the energy measured by a nominal pixel of 112 urad x 112 urad, from a projection of the nominal pixel onto the sample area of a uniform scene from an infinite plane. The energy ratio's denominator is the energy measured by the nominal pixel from the extent of the full uniform scene from an infinite plane.

The EE can be understood in terms of the scene spread function (SSF), which is the convolution of the polychromatic system point spread function (PSF) with the nominal pixel spatial response function (SRF) including, but not limited to, any jitter, scan effects, optical crosstalk, and electrical crosstalk. As a standard, the EE is always referenced to a nominal pixel of 112 urad x 112 urad. The EE requirements are presented by band. The requirement applies to all channels within each specified band.

The GXS EE shall be greater than or equal 70% for the aggregate of the channels within each band as defined in the Sounding Spectral Range Table.

3.2.3.4 Co-Registration

Between emissive channels, the channel-to-channel registration, or co-registration, is defined as the following correlation equation:

Page 15 of 50 Printed Wednesday, November 30, 2022

ID

GXSPORD153

GXSPORD154

GXSPORD156

GXSPORD157

GXSPORD158

GXSPORD161

GXSPORD162

Object Number

3.2.3.4.0-1

3.2.3.4.0-2

3.2.4

3.2.4.1

3.2.4.1.0-1

3.2.4.2

3.2.4.2.0-1

418-XO-GXSPORD-0118, RM Version, GeoXO Sounder (GXS) Performance and Operational Requirements Document (PORD)

Phase B

The co-registration between emissive channels within the same band (LWIR or MWIR) shall be greater than 95%.

Rationale: Co-registration needs to be very high to ensure that the same phenomena are being observed for all bands.

The co-registration between emissive channels from different bands shall be greater than 80%.

3.2.4 Radiometric Performance Requirements

3.2.4.1 Dynamic Range

The sounding spectral regions shall have sufficient dynamic range to measure cold space and the peak temperature for any one channel (as specified in the Dynamic Range and Precision Table) and the integrated flux for the band (as specified in the Dynamic Range and Precision Table).

Rationale: Both cold space and the earth scene need to be observed, along with a reference blackbody in order to provide sufficiently calibrated data.

3.2.4.2 Measurement Precision (NEdN and NEdT)

For the corresponding black body scene and for linear interpolation in the corresponding dimensions for regions with multiple points specified, the GXS sounder shall have a maximum Noise Equivalent Delta Radiance as specified in the Dynamic Range and Precision Table.

Notes:

1. This specification applies equally to individual channel observations and to Fourier transformed channel observations.

2. Per industry standard, the noise equivalent temperature error is reported as the error when viewing a 250K scene; however, the actual scene is not necessarily a 250K scene.

3. For data acquired at more than one sample per channel, the noise performance for terms that are uncorrelated between channels can be reduced by a factor of the inverse of the square root of the oversampling.

4. For each spectral channel, NEdN = dB/dT *NEdT, where dB/dT is the derivative of the blackbody function at 250 K for that spectral channel, and NEdT is the Noise Equivalent Delta Temperature.

D

AFT

Project: GeoXO Flight Project GXS Sounder Module: GXSPORD Baseline Version: 0.4

Page 18 of 50 Printed Wednesday, November 30, 2022

ID

GXSPORD175

GXSPORD176

GXSPORD177

GXSPORD178

GXSPORD179

Object Number

3.2.4.3.1.0-2

3.2.4.3.2

3.2.4.3.2.0-1

3.2.4.3.2.1

3.2.4.3.2.1.0-1

418-XO-GXSPORD-0118, RM Version, GeoXO Sounder (GXS) Performance and Operational Requirements Document (PORD)

Phase B

All calibration shall be traceable to National Institute of Standards and Technology (NIST) standards.

Rationale: Calibrations shall follow NIST methodologies to ensure unbreakable chain for traceability.

3.2.4.3.2 Relative Accuracy

The relative radiometric accuracy is defined as the unknown bias error between two arbitrary radiance measurements, root-sum-squared (RSS) with any random precision or repeatability component in a specific measurement period. The relative accuracy error is defined as the RMS variation in signal level, for all measurements in a large ensemble (e.g. all the pixels in a frame such that the residual temporal variation does not dominate the calculation,) illuminated by constant scene radiance and over expected geostationary environmental conditions and calibration frequency.

All relative accuracy values presented are 1-sigma.

3.2.4.3.2.1 Scan Position to Scan Position Relative Accuracy

The difference in calibrated radiance between scan positions (where scan position refers to location of a target within a swath) for the emissive channels shall be less than or equal to the derived NEdN evaluated using the scan position to scan position equation below.

Scan Position to Scan Position Equation

Page 19 of 50 Printed Wednesday, November 30, 2022

ID

GXSPORD179

GXSPORD180

GXSPORD181

Object Number

3.2.4.3.2.1.0-1

3.2.4.3.2.2

3.2.4.3.2.2.0-1

418-XO-GXSPORD-0118, RM Version, GeoXO Sounder (GXS) Performance and Operational Requirements Document (PORD)

Phase B

Illustration of Scan Position to Scan Position Evaluation

Rationale: Scan position to scan position relative accuracy limits detection errors as a function of scan position.

3.2.4.3.2.2 Pixel-to-Pixel Relative Accuracy

For each and every 3x10 region on the SD, the difference in radiance between calibrated detector samples for each emissive channel shall be less than or equal to the derived NEdN evaluated using the pixel-to-pixel equation below.

Pixel-to-Pixel Equation

DRA

Page 20 of 50 Printed Wednesday, November 30, 2022

ID

GXSPORD181

GXSPORD182

GXSPORD183

Object Number

3.2.4.3.2.2.0-1

3.2.4.3.2.3

3.2.4.3.2.3.0-1

418-XO-GXSPORD-0118, RM Version, GeoXO Sounder (GXS) Performance and Operational Requirements Document (PORD)

Phase B

Illustration of Pixel-to-Pixel Evaluation

Rationale: Pixel-to-pixel relative accuracy limits detection errors in nearby observing regions.

3.2.4.3.2.3 Channel-to-Channel Relative Accuracy

The difference in calibrated radiance between emissive channels shall be less than or equal to the derived NEdT evaluated using the channel-to-channel equation below.

Channel-to-Channel Equation

Page 21 of 50 Printed Wednesday, November 30, 2022

ID

GXSPORD183

GXSPORD184

GXSPORD185

GXSPORD187

GXSPORD188

GXSPORD197

GXSPORD198

Object Number

3.2.4.3.2.3.0-1

3.2.4.3.2.4

3.2.4.3.2.4.0-1

3.2.4.3.3

3.2.4.3.3.0-1

3.2.5

3.2.5.1

418-XO-GXSPORD-0118, RM Version, GeoXO Sounder (GXS) Performance and Operational Requirements Document (PORD)

Phase B

Illustration of Channel-to-Channel Relative Accuracy

Rationale: Channel-to-Channel relative accuracy limits detection errors between spectral channels.

3.2.4.3.2.4 Calibration-to-Calibration

The difference in calibrated radiance between calibrations for each emissive band shall be less than or equal to the derived NEdN evaluated using the calibration-to-calibration equation below.

Blackbody Calibration-to-Calibration Equation

Rationale: Calibration-to-calibration relative accuracy limits detection errors between calibrations.

3.2.4.3.3 On-Orbit Calibration

The GXS shall have on-board, full aperture and full system calibration for all emissive channels; i.e., the clear aperture of every component in the optical train is subject to calibration.

Rationale: Best practice for calibration of instrument.

3.2.5 Image Navigation and Registration

3.2.5.1 INR Scope

Page 22 of 50 Printed Wednesday, November 30, 2022

ID

GXSPORD199

GXSPORD200

GXSPORD201

GXSPORD202

GXSPORD203

GXSPORD205

GXSPORD206

GXSPORD207

GXSPORD208

GXSPORD209

GXSPORD210

GXSPORD212

GXSPORD213

Object Number

3.2.5.1.0-1

3.2.5.2

3.2.5.2.0-1

3.2.5.2.1

3.2.5.2.1.0-1

3.2.5.3

3.2.5.3.0-1

3.2.5.3.0-2

3.2.5.3.0-3

3.2.5.3.1

3.2.5.3.1.0-1

3.2.5.3.1.0-2

3.2.5.3.2

418-XO-GXSPORD-0118, RM Version, GeoXO Sounder (GXS) Performance and Operational Requirements Document (PORD)

Phase B

Image navigation refers to the determination of the location of each image pixel relative to a fixed reference coordinate system. Image registration refers to maintaining the spatial relationship between pixels within image frames and between image frames. Mission-level Image Navigation and Registration (INR) requirements apply to pixels and encompass the combined system performance of the GXS, spacecraft and ground processing system.

3.2.5.2 INR Function

This section defines several INR-related functions to be included in the GXS and associated GeoXO ground system.

3.2.5.2.1 Star Sensing

If autonomous star sensing is required to meet navigation requirements, the GXS shall have an on-board star catalog provided by the GXS vendor, which is loadable and modifiable from the ground and covers a span of two weeks.

Rationale: If employed, star sensing will require a star catalog and not rely on operators.

3.2.5.3 INR Performance Requirements

All INR requirements listed herein apply to the end-to-end system, taking all instrument, spacecraft, and ground processing effects into account. INR errors for any given pixel(s) can be determined through analysis and simulation, while on-orbit verification will require using landmarks in an image.

Unless otherwise specified, all INR requirements in this document are specified in terms of North/South and East/West fixed-grid angles, in microradians, 3-sigma, and refer to all hours of operation. In the context of sounder INR, 3-sigma error is defined to be equal to the 99.73rd percentile of the absolute values of all INR error observations collected over each 24-hour period from local noon to local noon. When INR requirements are temporarily suspended, due to Sun/Earth geometry or maneuver outages (including recovery time), the raw errors during the requirements suspension period should be ignored.

In this section, "frame" refers to any programmed scan area data set ranging from a full disk down through the mesoscale in pixel space, as opposed to detector sample space.

3.2.5.3.1 Navigation

Navigation error is the angular location knowledge error of pixels or features in a frame. For emissive channels, the navigation error shall not exceed 42 microradians for pixels on the Earth's disk, except during eclipse periods.

For up to a four-hour period that includes an eclipse of the Sun, the GXS navigation error shall not exceed 64 microradians for emissive channels. The phasing of the four-hour relaxation relative to the eclipse may be design-specific and will be recommended by the GXS contractor.

3.2.5.3.2 Frame-to-Frame Registration

Page 23 of 50 Printed Wednesday, November 30, 2022

ID

GXSPORD214

GXSPORD216

GXSPORD217

GXSPORD219

GXSPORD220

GXSPORD221

GXSPORD222

GXSPORD223

Object Number

3.2.5.3.2.0-1

3.2.5.3.3

3.2.5.3.3.0-1

3.2.6

3.2.6.0-1

3.2.6.0-2

3.2.6.0-3

3.2.6.0-4

418-XO-GXSPORD-0118, RM Version, GeoXO Sounder (GXS) Performance and Operational Requirements Document (PORD)

Phase B

Frame-to-frame registration error is the difference in navigation error for any given pixel in two consecutive frames. "Any given pixel in two consecutive frames" refers to the nearest pixel to any given Earth-fixed location in two consecutive frames.

Since frames may be 60 minutes apart, these requirements apply over 60 minute periods.

For emissive channels, frame-to-frame registration errors shall not exceed 35 microradians.

3.2.5.3.3 Within-Frame Registration

Within-frame registration error is the difference between the estimated and nominal distance between any two pixels in a frame. "Estimated distance" refers to the distance between the navigated pixel locations as reported in the level 1b data.

"Nominal distance" refers to the distance between the actual locations of the scene elements sampled by the pixels.

For emissive channels, the within-frame registration error shall not exceed 42 microradians.

3.2.6 Data Compression

The GXS may perform lossy data compression in order to satisfy the GXS requirements.

If performed, lossy compression shall not prevent the GXS from meeting requirements.

Rationale: Constraint on application is not to degrade data beyond performance levels.

Command activation of lossy compression capability shall be on a channel-by-channel basis.

All calibration data shall be lossless compressed or uncompressed.

Rationale: Calibration data needs to be a high quality so nominally it should not be compressed as it may impact performance.

Page 24 of 50 Printed Wednesday, November 30, 2022

ID

GXSPORD1000

GXSPORD1001

GXSPORD1002

GXSPORD1003

GXSPORD1004

GXSPORD1005

GXSPORD1006

GXSPORD1007

GXSPORD1008

GXSPORD1009

GXSPORD1010

GXSPORD1011

GXSPORD1012

GXSPORD1013

GXSPORD1014

GXSPORD1015

GXSPORD1016

GXSPORD1017

GXSPORD1018

Object Number

4.1

4.1.0-1

4.1.0-2

4.1.0-3

4.1.0-4

4.1.0-5

4.1.0-6

4.2

4.2.1

4.2.1.0-1

4.2.2

4.2.2.0-1

4.2.3

4.2.3.0-1

4.3

4.3.0-1

4.3.0-2

4.3.1

418-XO-GXSPORD-0118, RM Version, GeoXO Sounder (GXS) Performance and Operational Requirements Document (PORD)

Phase B

4 Design Requirements

4.1 Reliability

The GXS shall demonstrate by analysis a Reliability (R) of at least 0.6 after 10 years of on-orbit operations, preceded by ground storage, and up to 5 years of on-orbit storage.

Rationale: The design life of at least 10 years extends from commencement of on-orbit operations until Reliability falls to 0.6.

The GXS shall demonstrate by analysis a Mean Mission Duration (MMD) of at least

8.4 years by integrating under the Reliability curve for 10 years of on-orbit operations, preceded by the storage periods.

No credible single-point failure in GXS flight heater components shall permanently preclude the Instrument from supporting the mission.

No credible single-point failure in GXS flight temperature-sensing components shall permanently preclude the Instrument from supporting the mission.

To satisfy the Reliability and Design Life Requirements, the Instrument may choose selectively redundant approaches beyond those explicitly required in GXSPORD1004 and GXSPORD1005.

The GXS shall withstand without damage the sudden removal of operational power.

4.2 Redundancy

4.2.1 Redundant Component Selectabiltiy

The GXS redundant components shall be selectable by external command only.

4.2.2 Interchangability of Flight Model Units

The GXS units of any Flight Model (FM) shall be interchangeable, without modification, with the equivalent units of any other FM

4.2.3 Cryocooler Operation

The GXS shall operate either the primary or the redundant cryocooler from either electronics side of the instrument.

4.3 Mechanical Requirements

Compliance with the requirements in this section ensures that the GXS unit structures possess sufficient strength, rigidity, and other characteristics required to survive the critical loading conditions that are expected during the GeoXO mission.

All threaded fasteners shall employ a locking feature.

4.3.1 Design Limit Loads

Page 25 of 50 Printed Wednesday, November 30, 2022

ID

GXSPORD1019

GXSPORD1020

GXSPORD1021

GXSPORD1022

GXSPORD1023

GXSPORD1024

Object Number

4.3.1.0-1

4.3.1.0-2

4.3.1.0-3

4.3.2

4.3.2.0-1

4.3.2.0-2

418-XO-GXSPORD-0118, RM Version, GeoXO Sounder (GXS) Performance and Operational Requirements Document (PORD)

Phase B

Limit loads are defined as all worst-case load conditions enveloping temperature effects from the environments expected during all phases of the structure's service life including manufacturing, ground handling, transportation, environmental testing, integration, pre-launch, launch, on-orbit operations, and storage.

The GXS Instrument units not mounted on the spacecraft nadir deck shall survive a limit static positive and negative acceleration load applied at the spacecraft interface in each axis individually to the values shown in the Mass Acceleration Table and Mass Acceleration Curve in GIRD385, multiplied by the Static load factors from the GeoXO Flight Hardware Design/Analysis Factors of Safety Applied to Limit Loads Table listed in GXSPORD1024.

The GXS Instrument units mounted on the spacecraft nadir deck shall survive a limit static positive and negative acceleration load applied at the spacecraft interface in each axis individually to the values shown in the Table GIRD387 Nadir Deck Mass Acceleration multiplied by the Static load factors from the GeoXO Flight Hardware Design/Analysis Factors of Safety Applied to Limit Loads Table listed in

GXSPORD1024.

4.3.2 Yield Strength

The GXS structures shall support yield loads without detrimental permanent deformation with load factors from the Flight Hardware Design/Analysis Factors of Safety Applied to Limit Loads Table listed in GXSPORD1024.

GeoXO Flight Hardware Design/Analysis Factors of Safety Applied to Limit Loads1,2

Table

Type Static Sine Random/Acoustic4,5

Metallic-Yield 1.253 1.25 1.6

Metallic Ultimate 1.43 1.4 1.8

Stability Ultimate 1.4 1.4 1.8

Beryllium Yield 1.4 1.4 1.8

Beryllium Ultimate 1.6 1.6 2

Composite/Glass Ultimate

1.5 1.5 1.9

Bonded Inserts/Joints Ultimate

1.5 1.5 1.9

1 - Factors of safety for pressurized systems to be compliant with AFSPCMAN 91-710 (Range Safety).

2 - Factors of safety for pressurized bonded glass and glass joints specified in NASA-

STD-5001.

3 - If qualified by analysis only, positive margin must be shown for factors of safety of 2.0 on yield and 2.6 on ultimate. Project approval required for analysis only.

4 - Factors shown should be applied to statistically derived peak response based on RMS level.

As a minimum, the peak response shall be calculated as a 3-sigma value.

Page 26 of 50 Printed Wednesday, November 30, 2022

ID

GXSPORD1024

GXSPORD1025

GXSPORD1026

GXSPORD1027

GXSPORD1028

GXSPORD1029

GXSPORD1030

GXSPORD1031

GXSPORD1032

GXSPORD1033

GXSPORD1034

GXSPORD1035

GXSPORD1036

GXSPORD1037

Object Number

4.3.2.0-2

4.3.3

4.3.3.0-1

4.3.4

4.3.4.0-1

4.3.4.0-2

4.3.4.0-3

4.3.5

4.3.5.0-1

4.3.6

4.3.6.0-1

4.3.7

4.3.7.0-1

4.3.8

418-XO-GXSPORD-0118, RM Version, GeoXO Sounder (GXS) Performance and Operational Requirements Document (PORD)

Phase B

5 - Factors shown assume that qualification/protoflight testing is performed at acceptance level plus 3dB. If difference between acceptance and qualification levels is less than 3dB, then above factors may be applied to qualification level minus 3dB instead of analyzing to acceptance level.

4.3.3 Ultimate Strength

The GXS structures shall support ultimate loads without collapse or rupture when subjected to loads with the applied ultimate load factors from the GeoXO Flight Hardware Design/Analysis Factors of Safety Applied to Limit Loads Table listed in

GXSPORD1024.

4.3.4 Unit Stiffness

The fundamental resonant frequency of the GXS Sensor Unit shall be 45 Hz or greater when the sensor unit is rigidly constrained at its spacecraft interface and the sensor unit is in its launch configuration.