Attachment B PORD1.pdf

Effective Date: October 21, 2021 418-XO-LMXPORD-0066 Expiration Date: Five years from date of last signature Baseline Version 1.0 Responsible Organization: GeoXO Flight Project/Code 418

Geostationary Extended Observations (GeoXO) Lightning Mapper (LMX)

Performance and Operational Requirements Document (PORD) Signature page

Prepared by:

Electronically approved 10/22/2021

Ruth W. Cholvibul Date GeoXO Flight Project, Instrument Systems Engineer NASA GSFC, Code 418

Reviewed by:

Electronically approved 10/13/2021

Monica Todirita Date GeoXO Flight Project, Deputy Instrument Manger NOAA GSFC, Code 418

Approved by:

Electronically approved by Monica Todirita for: 10/21/2021

Jason H. Hair Date GeoXO Flight Project, Project Manager NASA GSFC, Code 418

/GeoXO Flight Project LMX Lightning Mapper

LMXPORD

418-XO-LMXPORD-0066, RM Version, Geostationary eXtended Observations (GeoXO) Lightning Mapper (LMX) Performance and Operational Requirements Document (PORD)

Version: 1.0 Printed by: rkhoover Printed on: Thursday, October 21, 2021

No filter applied.

No sort applied.

Generated from DOORS 9.6.1.11

Contents

1 1Scope

1.1 1Identification

1.2 1Mission Review

1.3 1Document Overview

1.4 1Terminology

1.5 2Definitions

1.6 4Requirements Applicability

2 5Documents

2.1 5Applicable Documents

2.2 5Reference Documents

3 7Sensor Requirements

3.1 7Functional Requirements

3.1.1 7LMX Modes

3.1.1.1 7Safe Mode

3.1.1.2 7Normal Operational Mode

3.1.1.3 7Diagnostic Mode

3.1.1.4 8Survival Mode

3.1.1.5 8Mode Transitions and Commands

3.1.2 9On-Orbit Operations

3.1.2.1 9Operational Zone

3.1.2.1.1 9Zones of Reduced Data Quality (ZRDQ)

3.1.2.2 9Imaging the Sun

3.1.2.3 9Eclipse

3.1.2.4 9Operations After Maneuvers

3.1.2.4.1 9Yaw Flip

3.1.2.4.2 9Station Keeping

3.1.2.4.3 9Post Storage Activation

3.1.2.5 10Outgas Period

3.2 10Performance Requirements

3.2.1 10Coverage

3.2.1.1 10Coverage Rate

3.2.1.2 11Simultaneity

3.2.1.3 11Data Latency

Project: GeoXO Flight Project LMX Lightning Mapper Module: LMXPORD Baseline Version: 1.0

Contents ii

3.2.1.4 11Data Collection Output

3.2.1.5 12Lightning Detection

3.2.1.6 13Spectral Response

3.2.1.7 13SNR

3.2.1.8 14Saturation

3.2.1.9 14Ringing from a Sharp Edge

3.2.1.10 14Spatial Resolution

3.2.2 14Event Navigation

3.2.2.1 14Navigation Performance Requirements

3.2.2.2 15Star Sensing

3.2.2.3 15Quantization Step Size

3.2.2.4 15Lossless Data Compression

3.3 15Design Requirements

3.3.1 15Reliability

3.3.2 16Mechanical Requirements

3.3.2.1 16Design Limit Loads

3.3.2.2 16Nonlinear Loads

3.3.2.3 16Yield Strength

3.3.2.4 17Ultimate Strength

3.3.2.5 17Structural Stiffness

3.3.2.6 17Unit Stiffness

3.3.2.7 18Material Properties

3.3.2.8 18Critical Members Design Values

3.3.2.9 18Redundant Members Design Values

3.3.2.10 18Selective Design Values

3.3.2.11 18Structural Reliability

3.3.2.12 18Mechanisms

3.3.2.13 19Pressurized Units

3.3.2.14 19Alignment Reference

3.3.3 19Thermal Requirements

3.3.3.1 19Temperature Limits

3.3.3.2 19Non Operational Temperature

3.3.3.3 20Thermal Control Hardware

3.3.4 20Onboard Processors Requirements

3.3.4.1 20Flight Load Non-Volatile Memory

3.3.4.2 20Commandable Reinitialization

3.3.4.3 20Deterministic Power-on Configuration

3.3.4.4 20Fail-safe Recovery Mode

Contents iii

3.3.5 20Flight Software Requirements

3.3.5.1 20Language and Methodology

3.3.5.2 20Flight Software Upload

3.3.5.3 21Flexibility and Ease of Software Modification

3.3.5.4 21Version Identifiers

3.3.5.5 21Flight Processor Resource Sizing

3.3.5.6 21Software Event Logging

3.3.5.7 22Processor Re-Start

3.3.5.7.1 22Warm Re-Start

3.3.5.7.2 22Autonomous Re-Start

3.3.5.8 22Memory Integrity

3.3.5.8.1 22Memory Verification

3.3.5.8.2 22Bit Error Detection and Correction

3.3.5.9 22Memory Dump

3.3.5.10 22Telemetry

3.3.6 23Power Requirements

3.3.6.1 23Power Regulators and Supplies

3.3.6.2 23Fuses

3.3.6.3 23Test Connectors

3.3.7 23(Reserved)

3.3.8 23(Reserved)

3.3.9 23Ground Support Equipment and Development Facilities

3.3.9.1 23Electrical System Test Equipment

3.3.9.2 24Flight Software Development Environment

3.3.9.3 24Shipping Container

3.3.9.4 24Instrument Emulator

4 26Design Verification Requirements

4.1 26Performance Operating Time and Trouble-Free Performance Testing

4.2 26Structural and Mechanical Verification Requirements

4.2.1 26Mechanical Test Factors and Duration

4.2.2 26Minimum Workmanship

4.2.3 27Testing in Flight Configuration

4.2.4 27Structural Proof Testing

4.2.5 27Modal Survey Characterization

4.2.6 28Structural Qualification

4.2.7 30Deployment and Articulation Verification

4.2.8 30Life Test

Contents iv

4.2.9 30Mechanical Clearance Verification

4.3 30Electromagnetic Compatibility Requirements

4.3.1 30General

4.3.2 30Electrostatic Arc-Discharge Susceptibility

4.3.2.1 30External Surface-to-Surface direct discharge

4.3.2.2 30Deep Dielectric Charging

4.3.2.3 31ESD Characteristics

4.4 31(Reserved)

4.5 31Thermal Requirements

4.5.1 31General

4.5.1.1 31Test Chronology

4.5.1.2 31Thermal Test Chronology

4.5.1.3 31Pressure

4.5.2 32Thermal Vacuum

4.5.2.1 32Transition Rates

4.5.2.2 32Corona Operation

4.5.2.3 32Hot and Cold Start Demonstrations

4.5.2.4 32Heater Verification

4.5.2.5 32Flight Temperature Sensor Verification

4.5.3 32Thermal Cycling

4.5.3.1 33Spacecraft Level TV Test

4.5.3.2 33Cumulative Cycles

4.5.3.3 33Instrument Level TV Cycling

4.5.3.4 33Unit Level TV Cycling

4.5.3.5 33Ambient Pressure Thermal Cycling Substitution

4.5.3.6 34Test Temperatures

4.5.3.6.1 34Mission Allowable Temperatures

4.5.3.6.2 34Qualification, Protoflight and Acceptance Temperatures

4.5.3.6.3 34Non-operating Temperatures

4.5.3.7 35Temperature test tolerances

4.5.3.8 35Plateau Criteria

4.5.4 35Thermal Balance (TB)

4.5.4.1 35TB Applicability

4.5.4.2 35Balance Points

4.5.4.3 35TB-Instrument Configuration

4.5.4.4 35TB Accuracy and Knowledge

4.5.4.5 36TB Steady State Criteria

4.6 36Test Condition Tolerances

Contents v

4.6.1 36General

4.7 37Filtering Capacity Requirement

5 39Appendix A: Acronyms

Contents vi

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Operational Requirements Document (PORD)

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) GeoXO (Geostationary and Extended Observations) Lightning Mapper (LMX) instrument.

1.2 Mission Review

The LMX is a single spectral channel instrument used to measure the location and intensity of optical transients produced by lightning as part of a 3-axis stabilized, geostationary satellite system. The LMX remotely collects data over the Earth disk visible from geostationary orbit for severe weather forecasting, hazard warning, and public safety alerts.

The LMX objective is to provide NOAA Lightning Mapper operational data that will be used by NOAA and other public and private agencies to produce forecasts of severe weather and to issue warnings for public safety.

The LMX provides data to the Ground System via the spacecraft communication system. The Ground System takes the LMX data, spacecraft telemetry data, orbit determination data and other required information and autonomously generates radiometrically calibrated and navigated data (Level 1b data) for the NOAA users.

The Ground System will be procured by the Government but will implement algorithms developed by the LMX contractor to satisfy performance requirements. The Ground System will calibrate and then resample the data to generate the fixed grid. Resampling requires that the raw imagery be adequately sampled to maintain radiometric accuracy after resampling.

1.3 Document Overview

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

1.4 Terminology

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

The use of “should” designates good practice.

The use of “will” is a statement of fact.

The use of “may” designates permission by the Government.

The term “(TBD)” means “to be determined” and is used when no value is available, and subsequent vendor study will be needed to obtain it.

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Operational Requirements Document (PORD)

The term “(TBR)”, which means “to be refined/reviewed”, means that the requirement is subject to review for appropriateness and subject to revision.

The contractor is liable for compliance with the requirement as if the “TBR” notation did not exist. The “TBR” merely provides an indication that the value is more likely to change in a future modification than requirements not accompanied by a “TBR”.

The term “(TBS)”, which means “to be supplied”, means that the government 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.

1.5 Definitions

Throughout this document, the following definitions apply:

Accuracy: Refers to the error in a measurement that 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.

Albedo: Refers to the fraction of the solar spectrum taken from the default MODTRAN solar irradiance file, version 4V1R1 (newkur.dat) that is reflected by the Earth at the top of the atmosphere assuming a Lambertian surface.

Background: Best estimate of the current mean radiometric value of a detector sample.

Background Image: A scene composed of the background from all detector elements in the focal plane.

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

Collection: The set of all frames from all telescopes for a single integration period.

Detector noise: 1-sigma noise level required to meet the Signal-to-Noise Ratio (SNR) specification.

Detector sample or element: Refers to the output of a physical detector after the Analog-to-Digital converter (ADC).

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

Event: The occurrence of a detector sample exceeding the threshold (not to be confused with event logging or event messages) due to a signal transient.

Events may include but are not limited to:

a) Optical lightning events

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Object Number

1.5.0-11

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b) Radiation-induced events

c) Surface glint-induced events

d) Electronic noise-induced events

e) Jitter-Induced events

Fixed Grid Format: Refers to the idealized georeferenced positions for pixel locations. The fixed grid has the following characteristics:

a) The fixed grid is rectified to a GRS80 geoid viewed from the idealized geostationary position.

b) The pixels have the same angular separation for East/West and North/South.

c) From the viewpoint of a right-hand coordinate system of the idealized geostationary satellite with its x-axis in the direction of the velocity and the z-axis pointed at nadir, the North/South angle is determined by a rotation about the x-axis and the East/West angle is determined by a rotation about the rotated y-axis.

d) The angular separation is 112 by 112 microradians for 4 by 4 km resolution at nadir.

e) The ideal sub-satellite point is at the corner of a pixel on the 112 microradians grid.

f) The ideal geostationary satellite position vector uses the ideal satellite as the viewpoint.

Fully Functional Configuration: Being able to perform the following functions:

Lightning optical pulse detection, sensor health and status data acquisition, CCSDS packet generation (science, health and status data) plus command reception and execution.

Frame: The set of all samples from one focal plane array for a single integration period.

Full Disk: The entire Earth disk as observed from geostationary orbit.

Geolocation: Determination of sample locations on the Earth surface (GRS80 geoid) in terms of latitude and longitude.

Level 1b Data: Optical lightning events that have been calibrated, navigated (to the fixed grid) and time tagged.

Navigation: Refers to the determination of the location of each pixel relative to a fixed reference, such as fixed-grid angle coordinates.

Navigation Error: Refers to the angular error of locations in the resampled fixed-grid frame.

Pixel: Applies to data samples after resampling during the ground processing.

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

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Pulse: An optical signal generated by lightning whose nominal duration is on the order of 1 ms. A pulse, as viewed by the LMX, can generate one or more optical events, distributed spatially and or temporally.

Radiant Energy: The integral of object radiance at the entrance aperture over the instrument integration time. The preferred units are joules (J).

Registration: Refers to maintaining the spatial relationship between pixels within frames, between frames, across multiple telescopes.

SNR: Signal-to-Noise Ratio

Threshold: Minimum amount which a detector sample must exceed the mean value of the background signal for an event to be detected.

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.

1.6 Requirements Applicability

The requirements in this LMX PORD pertain to the LMX ‘system’, which include optics, detectors, electronics, software, and ground processing.

All requirements apply over the entire life of the instrument.

The initial phase of ground processing (Level 1b) is to discriminate optical transient signals (lightning events) from the totality of events.

Data performance requirements, such as event navigation, decompression, and calibration apply to data after Level L1b ground processing.

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Operational Requirements Document (PORD)

2 Documents

2.1 Applicable Documents

The following documents form a part of this specification to the extent specified herein.

1. LMX Unique Instrument Interface Document, NASA-GSFC, 418-XO-

LMXUIID-0067

2. General Interface Requirements Document, NASA-GSFC, 418-XO-

GIRD-0025

3. CCSDS Recommended Standard for Lossless Data Compression, CCSDS 121.0-B-3, August 2020

4. CCSDS Recommended Standard for Image Data Compression, CCSDS 122.0-B-2, September 2017.

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

6. General Environmental Verification Specification for GSFC Flight Programs and Projects, GSFC-STD-7000A, April 22, 2013.

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

2.2 Reference Documents

The following documents provide reference material for part of this document.

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

2. Space Mechanisms Handbook, Document Number NASA

TP-1999-206988

3. CCSDS Informational Report Concerning Lossless Data Compression, Green Book, CCSDS 120.0-G-2 April 2013

4. Dual Geostationary Lightning Mapper Observations, S.D. Rudlosky, K.S.

Virts, AMS Monthly Weather Review, Volume 149 Issue 4, https://doi.org/10.1175/MWR-D-20-0242.1, pp. 979–998, April 2021

5. Algorithmic Chain for Lightning Detection and False Event Filtering Based on the MTG Lightning Imager”, Pierre Kokou et al., IEEE Transactions on Geoscience and Remote Sensing, vol. 50, no. 9, 5115 – 5124, 2018

6. Optical Observations of Lightning from a High-Altitude Airplane, H.J.

Christian and S.J. Goodman, J. of Atmospheric and Oceanic Technology, vol. 4, December 1987, pp. 701-711

7. The Detection of Lightning From Geostationary Orbit, Hugh J. Christian, Richard J. Blakeslee and Steven J. Goodman, J. of Geophysical Research, vol. 94, no. D11, September 1989, pp. 13329-13337

8. Laboratory Calibration of the Optical Transient Detector and the Lightning Imaging Sensor, William J. Koshak, Mike F. Stewart, Hugh J.

Christian, James W. Bergstrom, John M. Hall, and Richard J. Solakiewicz, J. of Atmospheric and Oceanic Technology, vol. 17, July 2000, pp.

905-915.

9. Lightning optical pulse statistics from storm overflights during the Altus Cumulus Electrification Study, D.M. Mach, R.J. Blakeslee, J.C. Bailey, W.M. Farrell, R.A. Goldberg, M.D. Desch, and J.G. Houser, Atmospheric Research 76 (2005), pp. 386-401

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10. Airborne radiometric validation of the geostationary lightning mapper using the Fly’s Eye GLM Simulator, Mason G. Quick, Hugh J. Christian, Katrina S. Virts, and Richard J. Blakeslee, J. Appl. Remote Sens. 14(4), 044518 (2020).

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3.1

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3 Sensor Requirements

3.1 Functional Requirements

3.1.1 LMX Modes

The contractor may propose additional modes and add additional capabilities and functions.

3.1.1.1 Safe Mode

The LMX shall implement a Safe Mode which is a thermally, electrically and optically safe configuration that protects the instrument from the spacecraft and the environment.

The LMX shall enter Safe Mode upon receipt of a ground command, receipt of an autonomous safe mode command from the observatory, or detection of internal faults that could cause damage to the instrument.

The LMX shall be maintainable in Safe Mode for an indefinite period of time.

Rationale: The LMX needs a Safe Mode for contingency operations.

3.1.1.2 Normal Operational Mode

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

Rationale: Normal mode is used for observations that require full functionality.

The LMX 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 Diagnostic Mode

The LMX shall implement a Diagnostic Mode.

The LMX shall enter Diagnostic Mode only on command.

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

Rationale: Diagnostic mode is needed for diagnosing anomalies.

The LMX shall by command send background images at increased cadence not to exceed the maximum data rate specified in the LMX UIID while in Diagnostic Mode.

Rationale: Diagnostic mode will afford commandable sampling engagement for diagnosing anomalies. Fill data bandwidth with background images, no events.

Or downlink specific detector sample from every data frame.

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If the data is compressed, LMX shall by command send the same data both compressed and uncompressed while in Diagnostic Mode.

Rationale: Diagnostic mode will send compressed and uncompressed to help in validation and in assessing anomalies.

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

Rationale: Diagnostic mode dwell data will help in validation and in assessing anomalies.

3.1.1.4 Survival Mode

The LMX shall implement a Survival Mode in which all power is off (except for spacecraft provided survival heater power) and only passive telemetry is available.

3.1.1.5 Mode Transitions and Commands

The LMX shall transition from any defined mode to any other defined mode upon command.

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

Rationale: Autonomous capability needs to be able to be disengaged as well.

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

Rationale: Mode transitions should occur rapidly for operators.

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

Rationale: Autonomous functions should be controlled by operators if there is a special need to do so.

The LMX shall transition from its current mode to any other mode without causing permanent damage to itself.

Rationale: Mode transitions should occur without damage.

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

Rationale: Knowledge of instrument modes is needed for data processing.

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

Rationale: Command and housekeeping telemetry is necessary for monitoring instrument health at all times.

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Receipt and processing of commands and data shall not interfere with LMX data collection in any mode.

The LMX shall provide an event detection threshold that is adjustable by command.

3.1.2 On-Orbit Operations

3.1.2.1 Operational Zone

The LMX shall meet all operational and performance requirements over the full field of view, except for ZRDQ.

3.1.2.1.1 Zones of Reduced Data Quality (ZRDQ)

The LMX shall meet all performance requirements for all samples whose distance from any part of the uneclipsed Sun and any part of the uneclipsed Sun rotated 180° about the instrument boresight is greater than 5° (TBR).

3.1.2.2 Imaging the Sun

The LMX shall survive imaging of the sun without sustaining damage.

Rationale: imaging of the sun or unexpected loss of pointing control that points at the sun must not result in damage to the instrument.

3.1.2.3 Eclipse

The LMX shall operate continuously through eclipse periods.

3.1.2.4 Operations After Maneuvers

3.1.2.4.1 Yaw Flip

The LMX shall meet all SNR, coverage and navigation requirements after spacecraft attitude has been within specification for 30 minutes 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 Station Keeping

The LMX shall meet all SNR, coverage and navigation requirements after spacecraft attitude has been within specification for 30 minutes following a station-keeping maneuver.

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

Page 10 of 40 Printed Thursday, October 21, 2021

ID

LMXPORD102

LMXPORD103

LMXPORD104

LMXPORD105

LMXPORD106

LMXPORD107

LMXPORD108

LMXPORD109

LMXPORD110

Object Number

3.1.2.4.3.0-1

3.1.2.4.3.0-2

3.1.2.5

3.1.2.5.0-1

3.1.2.5.0-2

3.2

3.2.1

3.2.1.0-1

3.2.1.1

418-XO-LMXPORD-0066, RM Version, Geostationary eXtended Observations (GeoXO) Lightning Mapper (LMX) Performance and

Operational Requirements Document (PORD)

The LMX shall meet all requirements within 2 days (TBR) of LMX turn-on after being in on-orbit storage, except navigation.

Navigation shall meet all requirements after 3 days (TBR) of LMX turn-on after being in on-orbit storage.

Rationale: After activation, spectral filters require thermal stabilization.

Navigation may require coastline identification or landmarking data.

3.1.2.5 Outgas Period

The LMX will sublimate and evaporate contaminants from hardware to prevent contamination from jeopardizing performance.

The post-launch outgas period shall be no longer than 14 days.

Rationale: Outgassing should occur relatively quickly to afford time for PLT testing in 6 months.

3.2 Performance Requirements

3.2.1 Coverage

LMX shall view the entire Earth disk as observed from geostationary orbit.

Rationale: Coverage of the Earth’s full disk is needed to meet user needs, although there are manufacturing complexities associated with achieving full disk coverage, fast array readout, and 4 km spatial resolution at nadir. The instrument design may use up to four quadrants to achieve the full disk coverage.

3.2.1.1 Coverage Rate

Page 11 of 40 Printed Thursday, October 21, 2021

ID

LMXPORD111

LMXPORD112

LMXPORD113

LMXPORD114

LMXPORD115

LMXPORD116

Object Number

3.2.1.1.0-1

3.2.1.2

3.2.1.2.0-1

3.2.1.3

3.2.1.3.0-1

3.2.1.4

418-XO-LMXPORD-0066, RM Version, Geostationary eXtended Observations (GeoXO) Lightning Mapper (LMX) Performance and

Operational Requirements Document (PORD)

The LMX shall provide continuous optical transient pulse detection over full-disk at a cadence between 500 Hz to 1000 Hz.

Rationale: The LMX revisit of the entire region occurs continuously with a rapid cadence to the optical transients associated with lightning. The average temporal variation of a lightning pulse is shown in the Lightning Pulse Duration Figure (Figure 1) below.

-500 0 500 1000 1500 2000

Time ( sec)

0.2

0.4

0.6

0.8

R el at iv e A m pl itu de

FWHM

450 sec

10-10%: 1100 sec

Figure 1 Lightning Pulse Duration Figure

3.2.1.2 Simultaneity

The LMX shall time tag each event to an accuracy of 0.5 msec.

Rationale: Precision is needed for lightning event clustering.

3.2.1.3 Data Latency

The LMX shall contribute no more than 10 seconds to the total data latency from event detection through generation of Level 1b products.

Rationale: Data latency is measured from the time the instrument acquires all samples for a scene to the time the events are available for dissemination on the ground. The LMX contribution to data latency includes delay of delivery of data to the spacecraft and delay due to ground algorithm processing (i.e., 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.

3.2.1.4 Data Collection Output

Page 12 of 40 Printed Thursday, October 21, 2021

ID

LMXPORD117

LMXPORD118

LMXPORD119

LMXPORD120

LMXPORD121

LMXPORD122

Object Number

3.2.1.4.0-1

3.2.1.5

3.2.1.5.0-1

3.2.1.5.0-2

3.2.1.5.0-3

3.2.1.5.0-4

418-XO-LMXPORD-0066, RM Version, Geostationary eXtended Observations (GeoXO) Lightning Mapper (LMX) Performance and

Operational Requirements Document (PORD)

The LMX shall collect each pixel from multiple detector frame samples contained within a single collection.

Rationale: Identify same events in overlap region. Need one report per event, even if sample from multiple detectors. A collection is the set of all frames from all telescopes for a single integration period. A frame is the set of all samples from one detector for a single integration period.

3.2.1.5 Lightning Detection

The LMX shall provide the radiant energy of each event with associated data needed by ground processing to detect each event.

Rationale: Provide detection threshold, surrounding pixels, background, detector element, false event filter data, etc.

The event detection probability shall be greater than 70% (TBR) after Level 1b processing per the Table 1 lightning distribution spectrum. The time span for this computation is 24 hours.

Table 1 Lightning Distribution Spectrum

Minimum Detectable Event

Energy Density

(µJ/m2/sr)

Cumulative Percent

Lightning Detected

3.8 (extrapolated) 95

4.5 90

5.1 85

5.9 80

6.7 75

7.6 70

8.7 65

9.9 60

11.3 55

12.9 50

16.6 45

18.1 40

Rationale: Table 1 shows that the ability to detect fainter lightning events leads to higher levels of lightning detection. As an example, if the instrument detects lightning events having an energy density of 5.9 µJ/m2/sr, then the instrument is capable of detecting 80% of the lightning.

The false event probability shall be less than 5% (TBR) after Level 1b processing. This includes radiation (cosmic rays), cross talk. The time span for this computation is 24 hours.

The readout of a background image (if applicable) shall not interfere with the detection and reporting of events.

Page 13 of 40 Printed Thursday, October 21, 2021

ID

LMXPORD123

LMXPORD124

LMXPORD125

LMXPORD126

LMXPORD127

LMXPORD128

Object Number

3.2.1.5.0-5

3.2.1.6

3.2.1.6.0-1

3.2.1.7

3.2.1.7.0-1

3.2.1.7.0-2

418-XO-LMXPORD-0066, RM Version, Geostationary eXtended Observations (GeoXO) Lightning Mapper (LMX) Performance and

Operational Requirements Document (PORD)

The LMX shall be able to detect events in the same detector element in consecutive frames.

3.2.1.6 Spectral Response

The LMX system spectral response shall have a spectral range sufficient to collect the lightning signal associated with the oxygen triplet centered near 777.4 nm per Table 2.

Table 2. Oxygen emission line spectral locations and relative intensities associated with lightning to be detected by the LMX instrument.

λ

(nm, air) λ

(nm, vac)

Normalized

Relative

Intensities

Oxygen triplet

777.196 777.408 0.358

777.418 777.630 0.333

777.540 777.753 0.309

Mean

Wavelength

777.376 777.589

Rationale: LMX must discriminate a small lightning signal on top of a large background signal, so the spectral response envelope must be large enough to collect the lightning signal (nominally from the entire triplet in order to maximize signal), and small enough to avoid collecting too much background signal.

3.2.1.7 SNR

The LMX shall observe daytime lightning events with a minimum SNR of 4 across the field of view for:

- Dim lightning signal level of 3.44x1013 photons/m2/sr. This photon energy density is equal to 8.8 µJ/m2/sr.

- Background of 1.47x1021 photons/s/m2/sr/µm. This photon radiance is equal to a Lambertian reflector with solar illumination at 777.4 nm.

The LMX shall observe nighttime lightning events with a minimum SNR of 4 across the field of view for:

- Dim lightning signal level of 2.51x1013 photons/m2/sr. This photon energy density is equal to 6.4 µJ/m2/sr.

- Background of 0 photons/s/m2/sr/µm.

Rationale: These SNR values are needed to detect radiance associated with lightning under daytime and nighttime conditions. Driver is daytime. Need nighttime prediction. Impulse for lightning signal is less than 1 msec. Lightning line spectra is integrated in the spectral dimension. Background is a continuum.

Page 14 of 40 Printed Thursday, October 21, 2021

ID

LMXPORD129

LMXPORD130

LMXPORD131

LMXPORD132

LMXPORD133

LMXPORD134

LMXPORD135

LMXPORD136

LMXPORD137

LMXPORD138

Object Number

3.2.1.8

3.2.1.8.0-1

3.2.1.9

3.2.1.9.0-1

3.2.1.10

3.2.1.10.0-1

3.2.2

3.2.2.0-1

3.2.2.0-2

3.2.2.1

418-XO-LMXPORD-0066, RM Version, Geostationary eXtended Observations (GeoXO) Lightning Mapper (LMX) Performance and

Operational Requirements Document (PORD)

3.2.1.8 Saturation

The LMX shall not saturate any detector element with a radiance (from Reference Document 4) of:

- Bright background of 1.78x1021 photons/s/m2/sr/µm. This photon radiance is equal to 1.21 times the radiance of a Lambertian reflector.

Rationale: This radiance value encompasses a background radiance of 1.1 times the radiance of a Lambertian reflector and includes 90-percentile of all lightning event energy densities. Earth scene signals need to be observed without saturation. Extreme Lightning cases outside of the radiance above is rare and might generate rare saturation events.

3.2.1.9 Ringing from a Sharp Edge

The LMX shall not overshoot the top of an edge or undershoot the bottom of scene edges by more than 5% (TBR) of the height of the edge where:

a) The height and the overshoot/undershoot are measured in radiance units.

b) The edge delineates a 10% albedo region from a 90% albedo.

c) The overshoot is averaged over all resampling phases of the detector sample grid to fixed-grid and edge position to detector sample grid.

Rationale: Requirement limits ringing response or overshoot near a sharp edge in scene.

3.2.1.10 Spatial Resolution

The LMX shall have a ground sample resolution of 112 µrad.

Rationale: 112 µrad is 4 km ground sample distance at nadir.

3.2.2 Event Navigation

All event navigation requirements listed herein apply to optical lightning events and refer to location error of the fixed-grid pixels. The requirements apply to the end-to-end system, taking all instrument, spacecraft, and ground processing effects into account. Unless otherwise specified, all navigation requirements in this document are specified as North/South and East/West angles, in microradians, 3-sigma, and refer to all hours of operation as defined by the operational zones.

In the context of LMX, 3-sigma error is defined to be equal to the 99.73rd percentile of the absolute values of all navigation error observations collected over each 24-hour period from local noon to local noon. When navigation 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.

3.2.2.1 Navigation Performance Requirements

Page 15 of 40 Printed Thursday, October 21, 2021

ID

LMXPORD139

LMXPORD140

LMXPORD141

LMXPORD142

LMXPORD143

LMXPORD144

LMXPORD145

LMXPORD146

LMXPORD147

LMXPORD148

LMXPORD149

LMXPORD150

LMXPORD151

LMXPORD152

LMXPORD153

Object Number

3.2.2.1.0-1

3.2.2.1.0-2

3.2.2.1.0-3

3.2.2.2

3.2.2.2.0-1

3.2.2.3

3.2.2.3.0-1

3.2.2.4

3.2.2.4.0-1

3.3

3.3.1

3.3.1.0-1

3.3.1.0-2

3.3.1.0-3

3.3.1.0-4

418-XO-LMXPORD-0066, RM Version, Geostationary eXtended Observations (GeoXO) Lightning Mapper (LMX) Performance and

Operational Requirements Document (PORD)

The LMX shall navigate each optical lightning event.

The LMX navigation error shall not exceed 42 µrad (TBR), 3-sigma, per axis, except during eclipse periods.

The LMX navigation error shall not exceed 63 µrad (TBR), 3-sigma, per axis, for up to a four hour period (TBR) that includes partial and/or total eclipse of the sun during eclipse periods. The phasing of the four hour relaxation relative to the eclipse may be design-specific.

Rationale: Navigation error is allocated as portion of pixel size.

3.2.2.2 Star Sensing

If autonomous star sensing is required to meet navigation requirements, the LMX shall have an on-board star catalog provided by the LMX 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.

3.2.2.3 Quantization Step Size

The quantizing step size for all detector samples shall be less than half the detector noise.

Rationale: Signal quantization by the analog to digital converter should not be the driver in the noise budget in order to avoid having discrete jumps in signal level that can lead to digital artifacts (blocky) data.

3.2.2.4 Lossless Data Compression

If compression is employed, lossless data compression shall be in accordance with Applicable Document 4.

3.3 Design Requirements

3.3.1 Reliability

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

Rationale: Reliability of 0.6 at 10 years is equivalent of MMD of 8.4 years.

The LMX shall demonstrate by analysis a Mean Mission Duration (MMD) of 8.4 years for a design life of 10 years.

No credible single-point failure in the LMX instrument electronics unit or power supply shall permanently preclude the LMX from supporting the mission.

Single string and selectively redundant design approaches may be used outside of electronics unit and power supply design.

Page 16 of 40 Printed Thursday, October 21, 2021

ID

LMXPORD154

LMXPORD155

LMXPORD156

LMXPORD157

LMXPORD158

LMXPORD159

LMXPORD160

LMXPORD161

LMXPORD162

LMXPORD163

LMXPORD164

LMXPORD165

LMXPORD166

Object Number

3.3.1.0-5

3.3.1.0-6

3.3.1.0-7

3.3.1.0-8

3.3.2

3.3.2.0-1

3.3.2.1

3.3.2.1.0-1

3.3.2.1.0-2

3.3.2.2

3.3.2.2.0-1

3.3.2.3

3.3.2.3.0-1

418-XO-LMXPORD-0066, RM Version, Geostationary eXtended Observations (GeoXO) Lightning Mapper (LMX) Performance and

Operational Requirements Document (PORD)

The LMX shall have redundancy to eliminate all credible single-point failures in motor windings, heaters and temperature sensors.

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

The LMX units of any Flight Model shall be interchangeable, without modification, with the equivalent units of any other Flight Model.

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

3.3.2 Mechanical Requirements

Each LMX unit structure shall possess sufficient strength, rigidity and other characteristics required to survive the critical loading conditions that exist within the envelope of handling and mission requirements.

3.3.2.1 Design Limit Loads

The structure shall be capable of withstanding all limit loads without loss of any required function.

Limit loads are defined as all worst case load conditions including 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 and on-orbit operations and storage.

3.3.2.2 Nonlinear Loads

The structures shall be capable of withstanding redistribution of internal and external loads resulting from nonlinear effects including deflections under load.

3.3.2.3 Yield Strength

The instrument shall support yield loads verified by analysis without detrimental permanent deformation. Yield load factors are defined in the Flight Hardware Design/Analysis Factors of Safety Applied to Limit Loads Table.

Flight Hardware Design/Analysis Factors of Safety Applied to Limit Loads Table1,2

Page 17 of 40 Printed Thursday, October 21, 2021

ID

LMXPORD166

LMXPORD167

LMXPORD168

LMXPORD169

LMXPORD170

LMXPORD171

LMXPORD172

LMXPORD173

LMXPORD174

LMXPORD175

Object Number

3.3.2.3.0-1

3.3.2.3.0-2

3.3.2.4

3.3.2.4.0-1

3.3.2.5

3.3.2.5.0-1

3.3.2.5.0-2

3.3.2.6

3.3.2.6.0-1

3.3.2.6.0-2

418-XO-LMXPORD-0066, RM Version, Geostationary eXtended Observations (GeoXO) Lightning Mapper (LMX) Performance and

Operational Requirements Document (PORD)

Type Static Sine Random/Acoustic 4,5

Metallic Yield 1.25 3 1.25 1.6

Metallic Ultimate 1.4 3 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.

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.

While subjected to any operational load up to yield operational loads, the resulting deformation shall not interfere with the operation of the flight units.

Operational load is defined as the expected on-orbit loads while the instrument is operating.

3.3.2.4 Ultimate Strength

The instrument shall support ultimate loads verified by analysis. Ultimate load factors are defined in the Flight Hardware Design/Analysis Factors of Safety Applied to Limit Loads Table.

3.3.2.5 Structural Stiffness

Stiffness of the structures and their attachments shall be designed by consideration of their performance requirements and their handling, transportation and launch environments.

Special stowage provisions shall be used if required to prevent excessive dynamic amplification during handling, transportation and transient flight events.

3.3.2.6 Unit Stiffness

The fundamental resonant frequency of the sensor unit shall be 50 Hz or greater when the sensor unit is rigidly constrained at its spacecraft interface and the sensor unit is in its launch configuration. The fundamental resonant frequency is defined as the lowest mode with more than 2% effective modal mass in any direction.

The fundamental resonant frequency of the electronics units shall be 50 Hz or greater when the electronics units are rigidly constrained at their spacecraft interfaces. The fundamental resonant frequency is defined as the lowest mode with more than 2% effective modal mass in any direction.

Page 18 of 40 Printed Thursday, October 21, 2021

ID

LMXPORD176

LMXPORD177

LMXPORD178

LMXPORD179

LMXPORD180

LMXPORD181

LMXPORD182

LMXPORD183

LMXPORD184

LMXPORD185

LMXPORD186

LMXPORD187

LMXPORD188

LMXPORD189

LMXPORD190

LMXPORD191

Object Number

3.3.2.6.0-3

3.3.2.7

3.3.2.7.0-1

3.3.2.7.0-2

3.3.2.8

3.3.2.8.0-1

3.3.2.9

3.3.2.9.0-1

3.3.2.10

3.3.2.10.0-1

3.3.2.11

3.3.2.11.0-1

3.3.2.11.0-2

3.3.2.11.0-3

3.3.2.12

3.3.2.12.0-1

418-XO-LMXPORD-0066, RM Version, Geostationary eXtended Observations (GeoXO) Lightning Mapper (LMX) Performance and

Operational Requirements Document (PORD)

The instrument units shall survive the spacecraft system level testing with notching of interface forces to design limits only.

3.3.2.7 Material Properties

Material properties shall be based on sufficient tests of the material meeting approved specifications to establish design values on a statistical basis.

Design values shall account for the probability of structural failures and loss of any required function due to material variability.

3.3.2.8 Critical Members Design Values

For critical members, design values shall be selected to assure strength with a minimum of 99 percent probability and 95 percent confidence. Structural members are classified as critical when their failure would result in loss of structural integrity of the flight units.

3.3.2.9 Redundant Members Design Values

For redundant members, design values shall be selected to assure strength with a minimum of 90 percent probability and 95 percent confidence. Structural members are classified as redundant when their failure would result in the redistribution of applied loads to other structural members without loss of structural integrity.

3.3.2.10 Selective Design Values

As an exception to Critical Members Design Values and Redundant Members Design Values, greater design values may be used if a representative portion of the material used in the structural member is tested before use to determine that the actual strength properties of that particular structural member will equal or exceed those used in the design.

3.3.2.11 Structural Reliability

Accounting for the presence of stress concentrations and the growth of undetectable flaws, the instrument structures shall withstand loads equivalent to four complete service lifetimes.

While subjected to any flight operational load up to limit flight operational loads, the resulting deformation of the residual structures shall not interfere with the operation of the instrument units.

After any load up to limit loads, the resulting permanent deformation of the residual instrument flight unit structures shall not interfere with the operation of the instrument units.

3.3.2.12 Mechanisms

Deployment, sensor, pointing, drive, separation mechanisms and other moving mechanical assemblies may be designed using MIL-A-83577B and NASA

TP-1999-206988.

Page 19 of 40 Printed Thursday, October 21, 2021

ID

LMXPORD192

LMXPORD193

LMXPORD194

LMXPORD195

LMXPORD196

LMXPORD197

LMXPORD198

LMXPORD199

LMXPORD200

LMXPORD201

LMXPORD202

LMXPORD203

LMXPORD204

LMXPORD205

LMXPORD206

LMXPORD207

LMXPORD208

LMXPORD209

Object Number

3.3.2.12.0-2

3.3.2.12.0-3

3.3.2.12.0-4

3.3.2.12.0-5

3.3.2.12.0-6

3.3.2.12.0-7

3.3.2.12.0-8

3.3.2.12.0-9

3.3.2.13

3.3.2.13.0-1

3.3.2.13.0-2

3.3.2.14

3.3.2.14.0-1

3.3.2.14.0-2

3.3.3

3.3.3.1

3.3.3.1.0-1

3.3.3.2

418-XO-LMXPORD-0066, RM Version, Geostationary eXtended Observations (GeoXO) Lightning Mapper (LMX) Performance and

Operational Requirements Document (PORD)

All mechanisms shall meet performance requirements while operating in an earth gravity environment with any orientation of the gravity vector.

For the on orbit operational conditions, moving mechanical assemblies shall have torque and force ratios per section 2.4.5.3 of GEV-SE using a NASA approved classification of each instrument mechanism.

For all operating points of the actuators, all rotational actuators shall have available a continuous maximum torque output greater than 7.0 milli-Newton meters.

For all operating points of the actuators, all linear actuators shall have available a continuous maximum force output greater than 0.28 N.

For mechanisms using closed-loop control, gain and phase margins shall be greater than 12 dB, and greater than 40 degrees, respectively including the effects of the dynamic properties of any flexible structure.

All mechanisms requiring restraint during launch shall be caged during launch without requiring power to maintain the caged condition.

All mechanisms requiring restraint shall be released from a caged condition by command.

All mechanisms requiring restraint shall be returned to a caged condition ready for launch by either command or by manual actuation of an accessible caging device.

3.3.2.13 Pressurized Units

Pressurized systems shall follow the requirements in accordance with NASA- STD-8719.24 for the design of pressurized systems.

The LMX shall have no open fluid reservoirs when delivered to the spacecraft contractor.

3.3.2.14 Alignment Reference

The LMX shall have a flight worthy cover for the optical alignment cube.

The sensor unit shall have fiduciary marks locating the X, Y, and Z axes of the unit.

3.3.3 Thermal Requirements

3.3.3.1 Temperature Limits

The LMX shall maintain thermally independent units and their internal components within MAT limits, maintaining at least 5 K of analytical/test uncertainty in the MAT range, during all flight operational conditions including bounding worst-case environments.

3.3.3.2 Non Operational Temperature

Page 20 of 40 Printed Thursday, October 21, 2021

ID

LMXPORD210

LMXPORD211

LMXPORD212

LMXPORD213

LMXPORD214

LMXPORD215

LMXPORD216

LMXPORD217

LMXPORD218

LMXPORD219

LMXPORD220

LMXPORD221

LMXPORD222

LMXPORD223

LMXPORD224

LMXPORD225

LMXPORD226

LMXPORD227

LMXPORD228

LMXPORD229

LMXPORD230

Object Number

3.3.3.2.0-1

3.3.3.2.0-2

3.3.3.3

3.3.3.3.0-1

3.3.3.3.0-2

3.3.3.3.0-3

3.3.4

3.3.4.1

3.3.4.1.0-1

3.3.4.2

3.3.4.2.0-1

3.3.4.3

3.3.4.3.0-1

3.3.4.4

3.3.4.4.0-1

3.3.5

3.3.5.1

3.3.5.1.0-1

3.3.5.2

3.3.5.2.0-1

3.3.5.2.0-2

418-XO-LMXPORD-0066, RM Version, Geostationary eXtended Observations (GeoXO) Lightning Mapper (LMX) Performance and

Operational Requirements Document (PORD)

The Non-Operational Temperatures (NOT) range shall extend at least 20 K warmer than the hot MAT and at least 20 K colder than the cold MAT.

The cold NOT shall be 248 K or colder.

3.3.3.3 Thermal Control Hardware

There shall be two or more serial and independent controls for disabling any heater where any failed on condition would cause over-temperature conditions or exceed the instrument power budget.

The LMX heaters shall be sized to have 25% margin for worst case conditions.

The LMX survival heaters shall be thermostatically controlled.

3.3.4 Onboard Processors Requirements

3.3.4.1 Flight Load Non-Volatile Memory

The entire flight software image shall be contained in non-volatile memory at launch.

3.3.4.2 Commandable Reinitialization

The On-board Processor shall provide for reset by command.

3.3.4.3 Deterministic Power-on Configuration

The On-Board Processor shall initialize upon power-up into a predetermined configuration.

3.3.4.4 Fail-safe Recovery Mode

The Instrument shall provide a fail-safe recovery mode dependent on a…