DRAFT_GRUVI_SWGEO-EUVI-REQ-0005-_07-14-2026_Draft 1.pdf

SW GEO EUVI SPEC SWGEO-EUVI-REQ-0005, Revision - Effective Date: TBD ii Check https://ipdtdms.gsfc.nasa.gov/frontmenu dsp.cfm to verify that this is the correct version prior to use.

SW GEO Series Project Extreme Ultraviolet Imager (EUVI) Requirements Specification (SPEC)

Signature/Approval Page

Prepared by:

Jim Buchheit

Reviewed by:

John Deily Jeffrey Kronenwetter Gustave Comeyne Stephen Husty Gregory Yoblin Erin Lynch

Approved by:

Eugene Guerrero-martin

Electronic Approval available on-line at: TDMS https://ipdtdms.gsfc.nasa.gov/frontmenu_dsp.cfm iii Check https://ipdtdms.gsfc.nasa.gov/frontmenu dsp.cfm to verify that this is the correct version prior to use.

Preface

This document is under SW GEO Series project configuration control. Once this document is approved, SW GEO Series project-approved changes are handled in accordance with Class I and Class II change control requirements as described in the SW-GEO Configuration Management Procedures, and changes to this document shall be made by complete revision.

Any questions should be addressed to:

SW GEO Series Project Configuration Management Office

NASA/GSFC

Code 495.0 Greenbelt, MD 20771 iv Check https://ipdtdms.gsfc.nasa.gov/frontmenu dsp.cfm to verify that this is the correct version prior to use.

Change History Log

Revision Effective Date

Description of Changes (Reference the CCR & CCB/ERB Approval Date)

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10 EUVISPEC-

The observatory will be selected to operate in a TBD orbit of either:

1. A Lissajous orbit around the Sun-Earth L1 with a Sun-Earth-Vehicle (SEV) angle no greater than 13 degrees and no less than 4 degrees. Normal on-orbit operations will entail periodic station keeping maneuvers that keep the satellite within the Lissajous orbit; or

2. A geosynchronous orbit (semi-major axis of approximately 42,164 km) in a TBS longitude between 75° to 137° W longitude. Normal on-orbit operations will entail periodic station keeping maneuvers that keep the satellite within a TBD inclination about the equator and within TBD of the on-station longitude

11 EUVISPEC-

79 4.3.3

The EUVI shall survive a spacecraft attitude anomaly resulting in the sun sweeping through the field-of-view (FOV) of the instrument radiator from “horizon to horizon” at a rate of TBD°/minute, passing through the radiator normal.

12 EUVISPEC-

The SW GEO project spacecraft will monitor up to six (TBR) analog instrument health and safety parameters defined by the EUVI contractor and command the EUVI into safe mode when any of those key values have been exceeded.

13 EUVISPEC-

The SW GEO project spacecraft will monitor up to 12 (TBR) digital telemetry points that are part of the normal instrument generated data stream for instrument health and safety parameters defined by the EUVI contractor and command the EUVI into safe mode when any of those key values have been exceeded.

14 EUVISPEC-

104 4.4.8

For a Geosynchronous orbit, from the time immediately following eclipse until four hours after eclipse, the EUVI line of sight pointing knowledge shall be TBD arcseconds, 3 sigma. Refer to budget for normal (science) pointing. Need to add requirement that points to Budget.

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TBD EUVISPEC-

TBD

The EUVI shall maintain line of sight pointing knowledge of

2.5 arcseconds TBR, 3 sigma, during operational sun-pointing time, except as described in EUVISPEC-104.

15 EUVISPEC-

107 4.4.9

The EUVI shall meet all performance requirements within 300 seconds (TBR) after the spacecraft interface has returned to being within specification following spacecraft maneuvers.

16 EUVISPEC-

112 4.5

The EUVI shall limit on-orbit calibrations to no more than four (4) (TBR) calibrations per year with each calibration lasting no more than 30 minutes (TBR).

17 EUVISPEC-

149 4.8.1

The EUVI shall utilize no more than six (6) (TBR) analog signals to monitor critical temperature points when the instrument is powered off.

18 EUVISPEC-

160 4.8.2.1

The EUVI shall set the Telemetry Source Packet Time Code in the Secondary Header per CCSDS 301.0-B-4 Section 3.3 CCSDS Day Segmented Time Code T-Field format in Figure

2 (TBC).

19 EUVISPEC-

The spacecraft will point the Imager boresight to within 1.5 arcmin, 3-sigma, (TBR) of the center of the Sun during any Operational Sun-pointing Time.

20 EUVISPEC-

The spacecraft will maintain roll error between the Imager reference frame and SRF to less than 1.5 arcmin, 3-sigma, (TBR) during Operational Sun-pointing Time.

21 EUVISPEC-

The spacecraft will maintain pointing stability of the Imager reference frame to the SRF to less than 1.5 arcmin 1-sigma (TBR) over any contiguous 60-second period of Operational Sun-pointing Time.

22 EUVISPEC-

240 The spacecraft will provide pointing knowledge of < (TBD)

(1-sigma) to EUVI.

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23 EUVISPEC-

253 6.2

The EUVI shall be designed to withstand the quasi-static design limit loads defined in the mass-acceleration curve (MAC) shown in Table 3 (TBR) without damage or degradation of performance and are to be applied one axis at a time. The design loads shown below will be updated based on the results of coupled loads analysis.

24 EUVISPEC-

277 Candidate LV Shock Environment (TBR)

25 EUVISPEC-

279 Candidate LV Shock Environment (TBR)

26 EUVISPEC-

282 SW GEO Project Acoustic Design Envelope (TBR)

27 EUVISPEC-

284 SW GEO Project Acoustic Design Envelope (TBR)

28 EUVISPEC-

290 Transportation Loads (TBR)

29 EUVISPEC-

304 6.9.1

The EUVI shall meet all performance requirements after being subjected to a maximum linear acceleration due to nominal thruster firing of ±0.060 m/sec2 (TBR) in all axes.

30 EUVISPEC-

306 6.9.2

The EUVI shall meet all performance requirements after being subjected to a maximum angular acceleration of ±2.5E- 5 rad/sec2 (TBR) about all axes.

31 EUVISPEC-

During normal on-orbit operations, the spacecraft will maintain the temperature of the Imager Electronics Unit spacecraft mechanical interfaces to between -10°C to 40°C

(TBR).

32 EUVISPEC-

311 6.10 The conducted heat transfer between the EUVI electronics unit and the spacecraft shall be limited to 4 Watts (TBR).

33 EUVISPEC-

314 6.10 The EUVI flight operation interface shall meet a temperature range of -10 to +40 degrees C (TBR).

34 EUVISPEC-

315 6.10 The EUVI flight survival interface shall meet a temperature range of -25 to +50 degrees C (TBR).

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35 EUVISPEC-

327 6.10.1

For a Geosynchronous orbit, thermal analysis shall be based on a Solar Flux range between 1317 W/m2 and 1419 W/m2

(TBR).

36 EUVISPEC-

621 8.3.3.1

The instrument electric field emissions shall not exceed the mission unique limits of Figure 26 nor the default limits of Figure 27 (TBC) when tested per the MIL-STD-461G RE102 test method as defined in GSFC-STD-7000B, section 2.5.2.3.2.

37 EUVISPEC-

623 Unit Level RE102 Radiated Electric Field Emission

Limits (TBR)

38 EUVISPEC-

625 Default Radiated Emissions Electric Field Limit (TBC)

39 EUVISPEC-

630 RS103 Radiated Susceptibility Levels (TBR)

40 EUVISPEC-

41 EUVISPEC-

651 8.6.1 The instrument shall be designed for a 3-year (TBR) ground storage period.

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Table of Contents

1 INTRODUCTION

1.1 General Information

1.2 Scope

2 APPLICABLE DOCUMENTS

3 CONTRACT DESCRIPTION

3.1 EUVI Description

4 FUNCTIONAL/PERFORMANCE REQUIREMENTS

4.1 EUVI Performance Requirements

4.1.1 Requirements for Extreme Ultraviolet Imagery

4.1.1.1 Scene Coverage

4.1.1.2 Spatial Resolution

4.1.1.3 Temperature Range of Imaged Plasma

4.1.1.4 Solar Feature Identification

4.1.1.5 Signal to Noise Ratio

4.1.1.6 Refresh Rate

4.1.1.7 Data Latency

4.2 Resource Allocations

4.2.1 Mass

4.2.2 Physical Envelope

4.2.3 Operational Power Allocation

4.2.4 Peak Operational Power Allocation

4.2.5 Survival Heater Power

4.2.6 Telemetry

4.2.7 Transient Magnetic Field (TBC)

4.2.8 Static Magnetic Field (TBC)

4.3 Operational Concepts

4.3.1 Pre-Launch

4.3.2 Launch

4.3.3 On-Orbit Concept

4.4 EUVI Operating Modes

4.4.1 In-Flight Calibration

4.4.2 Mode Transitions

4.4.3 Deterministic Power-on Configuration

4.4.4 Safe Mode

4.4.4.1 Entry into Safe Mode

4.4.5 Fail-safe Recovery Mode

4.4.6 Normal Operational Mode

4.4.7 On-Orbit Operations

4.4.8 Eclipse

4.4.9 Station Keeping

4.4.10 Activation

4.5 Instrument Data Availability

4.6 Power

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4.6.1 Voltage Range

4.6.2 Abnormal Voltages

4.6.3 Sudden Removal of Power

4.6.4 Over-Current Protection

4.6.5 Primary Power Return Ground

4.7 Electrical Grounding

4.7.1 Primary Power DC Isolation

4.7.2 Survival Power Isolation

4.7.3 Internally Generated Secondary to Primary DC Isolation

4.7.4 Internally Generated Secondary Return

4.7.5 Mechanical Contact Resistance

4.7.6 Grounding

4.7.7 Connector DC Resistance

4.8 Signal And Data Interfaces

4.8.1 Passive Analog Telemetry

4.8.2 Data Signal Interface

4.8.2.1 Telemetry Source Packet Format

4.8.2.2 Command Source Packet Format

4.8.3 Clock Signal Interface

4.8.4 Command and Housekeeping telemetry

4.8.5 Commands for Autonomous Functions

4.8.6 Limits and Triggers

4.8.7 On-Board Processor Reset

4.8.8 Microswitches

4.9 Flight Software

4.9.1 Flight Load Non-volatile Memory

4.9.2 Software Updates

4.9.3 Software Table Updates

4.9.4 Flexibility and Ease of Software Modification

4.9.5 Version Identifiers

4.9.6 Warm Restart

4.9.7 Memory Tests

4.9.8 Memory Dump

4.9.9 Fault Detection and Correction Control

4.9.10 Health and Safety Monitoring

5 PHYSICAL REQUIREMENTS

5.1 Interface and Design Units and Exclusions

5.2 Mass Properties Accuracy

5.2.1 EUVI Instrument Mass Accuracy

5.2.2 Center of Mass Location

5.2.3 Center of Mass Accuracy

5.2.4 Determination of Moments and Products of Inertia

5.3 Mounting

5.3.1 Surface Flatness

5.3.2 Method

5.4 Coordinate System and Alignment

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6 ENVIRONMENTAL REQUIREMENTS

6.1 Mechanical Factors of Safety

6.2 Quasi-Static Acceleration

6.3 Frequency Requirement

6.3.1 Fundamental Launch Frequencies

6.4 Vibration

6.4.1 Sinusoidal Vibration

6.4.2 Random Vibration

6.5 Shock

6.6 Acoustics

6.7 Transportation

6.7.1 Transportation Cleanliness

6.8 Pressure

6.8.1 Operating Pressure Range

6.8.2 Maximum Depressurization Rate

6.8.3 Launch Vehicle (LV) Environmental Control System (ECS) Impingement

6.9 On-Orbit Dynamic Environment

6.9.1 Dynamic Linear Acceleration

6.9.2 Dynamic Angular Acceleration

6.10 Thermal Requirements

6.10.1 Flight Interface Design Temperature Limits

6.11 Eclipse

6.12 Lunar Eclipse

6.13 Charged Particle Radiation Requirements

6.13.1 Definitions

6.13.2 Radiation Hardness Assurance

6.13.2.1 Destructive SEE Requirement

6.13.2.1.1 Single-Event Latchup Requirement

6.13.2.1.2 Single-Event Burnout and Single-Event Gate Rupture Requirements

6.13.2.2 Non-Destructive SEE Requirement

6.13.2.3 TID/DDD Requirement

6.13.3 Charging Environment

6.13.3.1 Surface Charging Environment

6.13.3.2 Internal Charging Environment

6.13.3.3 Solar Photon Environment

6.13.4 Total Ionizing Dose

6.13.5 Displacement Damage Dose

6.13.6 Single Event Effects

6.13.6.1 Solar Cycle Performance

6.13.6.2 Solar Particle Event Operations

6.13.6.3 Single-Event Effect Rate Calculations

6.13.7 Solar Flare Survival

7 CONTAMINATION CONTROL

7.1 EUVI Surface Cleanliness Requirements

7.2 Contamination Generation

7.2.1 Particulate Generation

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7.2.2 Molecular Contamination Generation

7.2.2.1 Molecular Material Restrictions

7.3 Vacuum Bakeouts

7.4 Contamination Analyses

7.5 Venting Requirements

7.6 Instrument Purging

7.7 Cleanability and Protection

7.8 Electrostatic Cleanliness

7.8.1 Exposed Harness Specific Requirements

8 DESIGN & CONSTRUCTION REQUIREMENTS

8.1 Electrical

8.1.1 Test Sensors

8.1.2 MGSE Grounding

8.1.3 Connector Specifications

8.1.3.1 Contact Derating

8.1.3.2 Redundant Contact Derating

8.1.3.3 Signal Segregation

8.1.3.4 Test and Flight Signal Isolation

8.1.4 Test Interfaces

8.1.4.1 Facility-Induced Noise

8.1.4.2 Facility-Induced ESD GSE Malfunction

8.1.4.3 Facility-Induced GSE Malfunction

8.1.5 Mitigation of Internal Charging

8.1.5.1 Mitigation Strategies for Internal Charging

8.2 Safety

8.3 Electromagnetic Compatibility

8.3.1 Conducted Emissions

8.3.1.1 Applicability of Conducted Emissions

8.3.1.2 CE101 – Differential Mode Current Emission Limits

8.3.1.3 CE03 – Differential Mode Current Emission Limits

8.3.1.4 CMBCE - Common Mode Bulk Conducted Emissions Limits

8.3.2 Conducted Susceptibility

8.3.2.1 Applicability of Conducted Susceptibility

8.3.2.2 CS101 – Conducted Susceptibility Limit

8.3.2.3 CS114 – Conducted Susceptibility, Power Leads, 150 kHz to 50 MHz

8.3.2.4 CS114 – Conducted Susceptibility, Common Mode, Power

8.3.2.5 CS06 - Conducted Susceptibility, Transients, Power Leads

8.3.2.6 CS115 - Conducted Susceptibility, Bulk Cable Injection, Impulse Excitation ... 71

8.3.3 Radiated Emissions

8.3.3.1 RE102 - Radiated Emissions, Electric Field

8.3.4 Radiated Susceptibility

8.3.4.1 RS103 - Radiated Susceptibility, Electric Field, Launch

8.3.4.2 RS103 - Radiated Susceptibility, Electric Field, On-orbit (TBR)

8.4 Identification and Marking

8.5 Workmanship

8.5.1 Connectors

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8.6 Reliability and Mission Lifetime

8.6.1 Mission Life

8.6.2 Operating Time

8.6.3 Trouble-Free Time

8.7 Ground Handling

8.7.1 Ground Support Equipment (GSE) Design

8.7.2 Lifting Hardware

8.7.3 Manual Lifting Hardware

8.7.4 GSE Cleanliness

8.7.5 GSE Bakeout

8.7.6 Test Harness

8.8 Interface Documentation

8.8.1 Mechanical Interface

8.8.2 Electrical Interface

8.8.3 Data Interface

9 MECHANICAL DESIGN REQUIREMENTS

9.1 Structural Requirements

9.1.1 Component Fatigue

9.1.2 Fracture Control Requirements

9.2 Fastening Systems

9.2.1 Factors of Safety

9.2.2 Fitting Factor

9.2.3 Ultimate Design Loads

9.2.4 Yield Design Loads

9.2.5 Design Separation Load

9.2.6 Fastener Locking and Retention

9.2.6.1 Thread Engagement

9.2.6.2 Locking Feature Verification

9.2.6.3 Locking Feature Installation

9.2.6.4 Snap Ring & Cotter Pin Use Limitation

9.2.6.5 Snap Ring & Cotter Pin Use

9.2.6.6 Liquid Locking Compounds

9.2.6.6.1 Verification

9.2.6.7 Locking Features

9.2.6.7.1 Specification

9.2.6.7.2 Validation

9.2.7 Installation Torque Specification and Control

9.2.7.1 Installation Torque Range

9.2.7.2 Running Torque Identification

9.2.8 Fastened Joints Criteria

9.2.8.1 Minimum and Maximum Preload

9.2.8.2 Analysis Addressing Potential Rupture

9.2.8.3 Ultimate Strength Analysis

9.2.8.3.1 Applied Shear Loading

9.2.8.3.2 Shear Loading

9.2.8.4 Simultaneous Applied Tensile and Shear Loads

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9.2.8.5 Allowable Yield Tensile Load

9.2.8.6 Separation Analysis

9.2.8.7 Seal Analysis

10 LOGISTICS

10.1 I&T Deliverables

10.2 Ground Support Equipment

10.2.1 Electrical System Test Equipment

10.2.2 Instrument Emulator

10.3 Transportation Equipment

10.3.1 Shipping Container

11 VERIFICATION REQUIREMENTS

11.1 Verification Methods

11.1.1 Inspection

11.1.2 Analysis

11.1.3 Test

11.1.4 Demonstration

11.2 Inspection Requirements

11.2.1 Visual Inspection

11.2.2 Physical Measurement

11.2.3 Documentation Search

11.3 Analysis Requirements

11.4 Test Requirements

11.4.1 Definitions

11.4.2 Test Factors

11.4.3 Test Tolerances

11.4.4 Test Restrictions

11.4.4.1 Failure During Tests

11.4.4.2 Modification of Hardware

11.4.4.3 External Adjustment

11.4.4.4 Re-Test Requirements

11.4.4.5 Configuration

11.5 Required Tests

11.5.1 Performance Tests

11.5.1.1 Comprehensive Performance Test

11.5.1.2 Limited Performance Test

11.5.1.3 Abbreviated Functional Test

11.5.2 Mass Properties Measurement

11.5.3 Static Loads/Strength Test

11.5.3.1 Sine Burst

11.5.3.2 Static Pull

11.5.4 Sine Sweep Survey

11.5.5 Sine Vibration

11.5.6 Random Vibration

11.5.7 Acoustic Test

11.5.8 Shock

11.5.9 Thermal Vacuum Bake-out

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11.5.10 Thermal Vacuum Test

11.5.10.1 Thermal Vacuum Test Parameters

11.5.10.2 Thermal Vacuum Test Profile

11.5.11 Magnetics Test

11.5.12 Harness Tests

11.5.13 EMI/EMC Tests

ABBREVIATIONS AND ACRONYMS

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List of Figures

Figure 1. Telemetry Source Packet Definition Figure 2. Time Code Format Figure 3. Command Source Packet Figure 4. Spacecraft Time Message Packet Figure 5. Spacecraft Reference System Figure 6. Sine Vibration Environment Figure 7. Random Vibration Environment Figure 8. Candidate LV Shock Environment (TBR) Figure 9. SW GEO Project Acoustic Design Envelope (TBR) Figure 10. Allowable Analytical, Flight Operation, Flight Acceptance Test, and Qualification

(Protoflight or Prototype) Test Temperature Ranges Figure 11. Direction Axes Used in L1 Plasma Flux Environments Figure 12. Integral Electron Fluence vs Energy for L1 Transfer Trajectory Figure 13. Geomagnetic Sub-storm Bulk Charging Integral Electron Flux vs Energy Figure 14. Total ionizing dose-depth curve in Silicon for a 7-year mission Figure 15. Silicon displacement damage dose-depth in Silicon curve for a 7-year mission Figure 16. LET Flux Spectra for Near Earth Interplanetary (GEO & L1) behind 100mils(Al) .. 53 Figure 17. CE101/CE03 Differential Mode Current Emission Limits Figure 18. Common Mode Bulk Conducted Emissions Limit Figure 19. Power Lead Conducted Susceptibility (CS101) Voltage Limit Figure 20. Conducted Susceptibility Power Limit (30 Hz to 150 kHz) Figure 21. Conducted Susceptibility, Power Leads, 150 kHz to 50 MHz Voltage Limit Figure 22. Conducted Susceptibility, Power Leads, 150 kHz to 50 MHz Current Limits Figure 23. Common Mode Conducted Susceptibility Calibration Limit Figure 24. Conducted Susceptibility Transient Waveform Figure 25. CS115 Default Limit Figure 26. Unit Level RE102 Radiated Electric Field Emission Limits (TBR) Figure 27. Default Radiated Emissions Electric Field Limit (TBC) Figure 28. Thermal Vacuum Profile

List of Tables

Table 1. Applicable and Reference Documents (TBR) Table 2. Factors of Safety1,2 Table 3. EUVI Design Limit Loads Table 4. Candidate LV Shock Environment (TBR) Table 5. SW GEO Project Acoustic Design Envelope (TBR) Table 6. Transportation Loads (TBR) Table 7. Orbit Thermal Parameters ............................................... Error! Bookmark not defined.

Table 8. Geomagnetic Sub-storm Region Surface Charging Environment Model Parameters –

ISO 19923 SCATHA-Mullen1 Round Robin Worst Case Table 9. Plasma Moments for L1 Solar Wind Environment Surface Charging Table 10. Directionality for L1 Surface Charging Analysis xix Check https://ipdtdms.gsfc.nasa.gov/frontmenu dsp.cfm to verify that this is the correct version prior to use.

Table 11. Geomagnetic Sub-storm Bulk Charging (Energetic Electron) Environment for L1 Transfer Trajectory

Table 12. Geomagnetic Sub-storm Bulk Charging Integral Electron Flux vs Energy Table 13. (E) Solar Photon Flux Density Environments Table 14. Total Ionizing Dose (GEO) Table 15. Total Ionizing Dose (L1) Table 16. Displacement Damage (GEO) Table 17. Displacement Damage (L1) Table 18. Lifetime Contamination Requirements Table 19. Emission and Susceptibility Requirements Table 20. RS103 Radiated Susceptibility Levels (TBR) Table 21. Locking Feature Torque Verification Table 22. Test Factors and Durations Table 23. Sine Sweep Parameters Table 24. Thermal Vacuum Test Parameters

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1 INTRODUCTION

1.1 General Information

1.2 Scope

This specification describes the performance and electrical, mechanical, environmental, and verification testing requirements for a space-qualified Extreme Ultraviolet Imager (EUVI) for the Space Weather Geostationary (SW GEO) Series project.

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2 APPLICABLE DOCUMENTS

The following documents and drawings in effect on the day this specification was signed shall apply to the fabrication and to the electrical, mechanical, and environmental requirements of the EUVI to the extent specified herein. In the event of conflict between this specification and any referenced document, this specification will govern, with the exception of the SWGEO-EUVI- SOW-0002, Statement of Work (SOW), in which case the SOW takes precedence.

In lieu of formal interface control documents, basic instrument suite interfaces definitions and requirements are provided in the following requirements.

Refer to the accompanying Instrument Mission Assurance Requirements (IMAR), SWGEO- EUVI-REQ-0004, for the risk-based application for this SW GEO Series project, Class C mission.

The following is a list of the applicable specifications and publications.

Table 1. Applicable and Reference Documents (TBR)

Document Number Title

SWGEO-EUVI-SOW-

Space Weather GEO Extreme Ultraviolet Imager (EUVI) Phase A Study Statement of Work (SOW)

SWGEO-EUVI-CDRL-

Extreme Ultraviolet Imager (EUVI)) Contract Deliverables Requirements List (CDRL)

SWGEO-EUVI-REQ-

Space Weather GEO Imager Phase A Study Mission Assurance Requirements (MAR)

ANSI/TIA/EIA-422

Revision -B

Electrical Characteristics of Balanced Voltage Digital Interface Circuits

ECSS-E-ST-50-12C-rev.1 SpaceWire – Links, nodes, routers and networks NFPA 70 National Fire Protection Association National Electric Code NASA-STD-5001B Structural Design and Test Factors of Safety for Spaceflight

Hardware NASA-STD-8719.24 NASA Expendable Launch Vehicle Payload Safety Requirements NASA-STD-8719.9C Lifting Standard NASA-STD-6016C Standard Materials and Processes Requirements for Spacecraft NASA-HDBK-7005 Dynamic Environment Criteria NASA-STD-7001 Payload Vibroacoustic Test Criteria IEST-STD-CC-1246E Product Cleanliness Levels and Contamination Control Program EEE-INST-002 Instructions for EEE Parts Selection, Screening, Qualification, and Derating MIL-STD-461G Military Standard, Electromagnetic Emission and Susceptibility

Requirements for the Control of Electromagnetic Interference

(EMI)

GSFC-STD-7000B General Environmental Verification Standard (GEVS) NASA-STD-5020B Requirements for Threaded Fastening Systems in Spaceflight

Hardware NASA-HDBK-4002B Mitigating In-Space Charging Effects—A Guideline

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NASA-HDKB-4001 Electrical Grounding Architecture for Unmanned Spacecraft NHB-8071.1 Fracture control requirements for payloads using the National

Space Transportation System (NSTS) FAA AC 20-71 Federal Aviation Administration Advisory Circular (AC) 20-71, “Dual Locking Devices on Fasteners".

NASM 33540 Safety Wiring, Safety Cabling, Cotter Pinning, General Practices for SAE AS567 Safety Cable, Safety Wire, Key Washers, and Cotter Pins for

Propulsion Systems, General Practices for Use of MSFC-STD-3029A Guidelines for the Selection of Metallic Materials for Stress

Corrosion Cracking Resistance in Sodium Chloride Environments MIL-STD-462, Notice 4 Electromagnetic Interference Characteristics, Measurement of, 1

May 1970 MIL-PRF-27401G Propellant Pressurizing Agent, Nitrogen ISO-JCGM 200:2008 International vocabulary of metrology CCSDS 133.0-B-2 Space Packet Protocol, Blue Book, Issue 2, June 2020 CCSDS 301.0-B-4 Time Code Formats. Blue Book. November 2010

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3 CONTRACT DESCRIPTION

3.1 EUVI Description

The EUVI will be capable of producing line of sight (LOS) imaging of the Sun’s hot outer atmosphere, or corona. EUV photons are created in the million-degree plasma of the corona.

Continual high-resolution observations of solar EUV emission aids in the early detection of solar flares, coronal mass ejections (CMEs), and other phenomena that impact the geospace environment.

EUV photons travel at the speed of light and are the first indication we receive at Earth of solar magnetic eruptions and associated flares. These high-energy photons cause changes to the Earth’s ionosphere and can result in significant degradation of radio communications, including complete black outs at some frequencies. The impacts begin only 8 minutes (time for light to travel from the Sun to Earth) after a flare.

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4 FUNCTIONAL/PERFORMANCE REQUIREMENTS

This section defines the functional and performance requirements for the SW GEO Series project

EUVI.

The requirements in this Specification pertain to the EUVI “system,” which may include all instrument hardware, software, and ground processing algorithms. The EUVI vendor is not responsible for the operational ground system, but certain data products may require ground processing between data collection and data distribution; the vendor is responsible for defining, developing, and delivering the associated ground processing algorithms that will provide measurements within specifications. Specifications for each measurement can be found below.

4.1 EUVI Performance Requirements

Extreme Ultraviolet imagery measurement requirements.

4.1.1 Requirements for Extreme Ultraviolet Imagery

4.1.1.1 Scene Coverage

EUVISPEC-23: The EUVI shall capture Extreme Ultraviolet imagery with a sun-centered and solar north-aligned view.

EUVISPEC-24: The EUVI shall capture Extreme Ultraviolet imagery with observational extent from 0 to 1.5 Rsun.

EUVISPEC-TBD: The EUVI shall maintain line of sight pointing knowledge of 2.5 arcseconds TBR, 3 sigma, during operational sun-pointing time, except as described in EUVISPEC-104.

4.1.1.2 Spatial Resolution

EUVISPEC-25: The EUVI shall produce Extreme Ultraviolet imagery with a spatial resolution of 5 arcsec or better. Note: The resolution refers to the resolution of the calibrated imagery product rather than the native instrument resolution.

4.1.1.3 Temperature Range of Imaged Plasma

EUVISPEC-26: The EUVI shall produce Extreme Ultraviolet imagery of solar plasma with temperatures of 10^4.9 K to 10^7.2 K.

4.1.1.4 Solar Feature Identification

EUVISPEC-27: The EUVI shall produce image data to identify the following solar features:

Coronal holes, Filaments / Prominences, Active Regions, CMEs, X10 Class Solar Flares.

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4.1.1.5 Signal to Noise Ratio

EUVISPEC-28: The EUVI shall produce Extreme Ultraviolet imagery with a signal to noise ratio of at least10.

4.1.1.6 Refresh Rate

EUVISPEC-29: The EUVI shall produce Extreme Ultraviolet imagery with a refresh rate of equal to or less than 2 minutes.

4.1.1.7 Data Latency

EUVISPEC-30: The processing of a completed on-orbit data collection by the EUVI instrument and the transmission to the spacecraft shall contribute ≤ 2 seconds TBD to the overall latency of the Extreme Ultraviolet imagery data product.

4.2 Resource Allocations

The EUVI instrument consists of all flight hardware needed to take measurements that meet the performance requirements above. It includes the physical imaging module or telescope, any electronics or power supply box (if separate from the imaging module), any intra-instrument harnesses, and thermal blankets. The EUVI flight hardware must meet the resource requirements in this section.

4.2.1 Mass

EUVISPEC-52: The EUVI instrument shall have a combined mass of less than or equal to 39.4 kg (includes margin).

4.2.2 Physical Envelope

EUVISPEC-55: The Telescope Module and Electronics unit—including mounts, sensor standoff bracket (if required), intra-instrument harness, thermal blankets, and connectors—in both stowed and operational configurations shall have dimensions that do not exceed spacecraft defined Imager Reference Frame (IRF) dimensions of 25 cm (XIRF) x 25 cm (ZIRF) x 25 cm (YIRF) (TBR—all 3 dimensions). These dimensions pertain to both static and dynamic envelopes of the instrument.

EUVISPEC-56: Reserved

4.2.3 Operational Power Allocation

EUVISPEC-58: The EUVI average operational EOL power, including operational heater power, shall not exceed 62.5 Watts when averaged over any 15-minute period.

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4.2.4 Peak Operational Power Allocation

EUVISPEC-60: The EUVI shall have a peak (instantaneous) power consumption of less than or equal to 94.5 Watts (TBR) for a duration of 20msec @ 28Vdc.

4.2.5 Survival Heater Power

EUVISPEC-62: The EUVI survival heater power shall not exceed 22.5 (TBR) Watts when averaged over any 72-minute period.

4.2.6 Telemetry

EUVISPEC-64: The EUVI instrument operational and engineering data rate, including all overhead associated with Consultative Committee for Space Data Systems (CCSDS) packetization by the instrument at the spacecraft interface, shall not exceed 10,000 kilobits per second (kbps) (L1 orbit) or 4 Megabits per second (GEO orbit) (TBR) averaged over any 5 second period.

4.2.7 Transient Magnetic Field (TBC)

EUVISPEC-66: The EUVI shall limit varying magnetic field less than 5 Hz to less than 4 nT zero-to-peak in any axis 1 meter from any face of the unit for any operating mode and changing configurations.

4.2.8 Static Magnetic Field (TBC)

EUVISPEC-68: The EUVI shall limit the static magnetic field to less than 1 nT in any axis 1 meter from any face of the unit for any operating mode.

4.3 Operational Concepts

4.3.1 Pre-Launch

The satellite will be transported to the launch site where final vehicle preparations and checkout will be accomplished. Final inter-segment and system verification tests will be accomplished prior to launch. Instrument testing and inspection to be accomplished at the launch site will be documented in the Interface Control Document “ICD.”

4.3.2 Launch

During launch the various spacecraft subsystems may be powered on or turned off in order to provide protection from the launch and injection environments or to comply with other specified Requirements.

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The EUVI will be in Survival Mode during launch. The EUVI contractor will identify the required configuration of the instrument for the launch environment, and the power required, in the event the mode is to be anything other than OFF, and also to document required sequences leading up to the pre-launch OFF mode.

4.3.3 On-Orbit Concept

The observatory will be selected to operate in a TBD orbit of either:

1. A Lissajous orbit around the Sun-Earth L1 with a Sun-Earth-Vehicle (SEV) angle no greater than 13 degrees and no less than 4 degrees. Normal on-orbit operations will entail periodic station keeping maneuvers that keep the satellite within the Lissajous orbit; or

2. A geosynchronous orbit (semi-major axis of approximately 42,164 km) in a TBS longitude between 75° to 137° W longitude. Normal on-orbit operations will entail periodic station keeping maneuvers that keep the satellite within a TBD inclination about the equator and within TBD of the on-station longitude

The spacecraft will be 3-axis stabilized.

EUVISPEC-79: The EUVI shall survive a spacecraft attitude anomaly resulting in the sun sweeping through the field-of-view (FOV) of the instrument radiator from “horizon to horizon” at a rate of TBD°/minute, passing through the radiator normal.

4.4 EUVI Operating Modes

EUVISPEC-81: The EUVI current operating mode shall be identified by a flag in its telemetry stream.

4.4.1 In-Flight Calibration

EUVISPEC-83: The EUVI shall provide an in-flight calibration mode that provides a test input to support calibration and testing both on the ground and in space.

EUVISPEC-84: The EUVI in-flight calibration shall be both self-terminating and able to be terminated by a ground command.

4.4.2 Mode Transitions

EUVISPEC-86: The EUVI instrument shall transition from the current mode to any other mode without causing damage to itself.

4.4.3 Deterministic Power-on Configuration

EUVISPEC-88: The EUVI shall initialize into a predetermined configuration.

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4.4.4 Safe Mode

EUVISPEC-90: The EUVI shall provide a Safe Mode. Safe mode is an operating mode of the instrument during which all non-essential subsystems are shut down and only essential functions are active. Safe mode represents a configuration in which the instrument is thermally, mechanically, and optically “safe” without receiving commands from the spacecraft.

EUVISPEC-91: The instrument shall be capable of remaining in a safe configuration for at least 168 hours without ground intervention.

4.4.4.1 Entry into Safe Mode

EUVISPEC-93: The EUVI instrument shall enter Safe Mode upon detection of internal faults that are capable of causing damage to the instrument.

The SW GEO project spacecraft will monitor up to six (TBR) analog instrument health and safety parameters defined by the EUVI contractor and command the EUVI into safe mode when any of those key values have been exceeded.

The SW GEO project spacecraft will monitor up to 12 (TBR) digital telemetry points that are part of the normal instrument generated data stream for instrument health and safety parameters defined by the EUVI contractor and command the EUVI into safe mode when any of those key values have been exceeded.

4.4.5 Fail-safe Recovery Mode

EUVISPEC-97: The EUVI shall provide a failsafe recovery mode dependent on a minimal hardware configuration capable of accepting and processing a minimal command subset sufficient to load and dump memory.

4.4.6 Normal Operational Mode

EUVISPEC-99: In normal operational mode, the EUVI instrument shall be in a fully functional configuration in which measurements are made in accordance with the performance requirements listed in Section 4.1 (EUVI Performance Requirements) of this document and are available to be sent to the spacecraft for downlink.

4.4.7 On-Orbit Operations

EUVISPEC-101: The EUVI shall operate normally, within specification, while flying aboard a 3-axis stabilized spacecraft with orbital limit constraints as stated in this specification.

4.4.8 Eclipse

EUVISPEC-103: For a Geosynchronous orbit, the EUVI shall be capable of continuous operation through eclipse periods.

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EUVISPEC-104: For a Geosynchronous orbit, from the time immediately following eclipse until four hours after eclipse, the EUVI line of sight pointing knowledge shall be TBD arcseconds, 3 sigma.

4.4.9 Station Keeping

EUVISPEC-106: The EUVI instrument shall continuously operate during all spacecraft maneuvers.

EUVISPEC-107: The EUVI shall meet all performance requirements within 300 seconds (TBR) after the spacecraft interface has returned to being within specification following spacecraft maneuvers.

Note: this requirement assumes that no direct sunlight illuminates the EUVI radiator during the maneuver.

4.4.10 Activation

EUVISPEC-110: The EUVI instrument shall remain in a powered off survival configuration with no active commanding following launch without degradation or performance impact for up to 14 days.

4.5 Instrument Data Availability

EUVISPEC-112: The EUVI shall limit on-orbit calibrations to no more than four (4) (TBR) calibrations per year with each calibration lasting no more than 30 minutes (TBR).

EUVISPEC-113: The EUVI shall be capable of maintaining nominal observation mode without ground interaction for a minimum of 4 days.

EUVISPEC-114: The EUVI shall be capable of re-scheduling planned instrument events that occur during NWS-declared Critical Space Weather Days.

Rationale: Once the National Weather Service (NWS) declares a Critical Space Weather Day, it is expected that any pre-planned instrument activities (e.g., calibration maneuvers) will have the flexibility to be re-scheduled without impacting instrument performance. Space Weather Observations Programs Division (SWOPD) requires that the sum of daily data gaps for in situ Imager Imagery High Availability Product (HAP) be less than 5 min and any instrument’s pre-planned event has the potential to impact Imager Imagery HAP acquisition. The expected cadence and duration of NWS-declared Critical Space Weather Days could last between 3 and 21 consecutive days.

EUVISPEC-115: The EUVI shall provide a 99% or greater probability of providing all of the instrument data during S4 class solar radiation storms or solar flare conditions including class X50, verifying through analysis using the “Worst Week” October 1989 model in CREME96 or equivalent.

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Rationale: The CREME96 model includes the October 1989 solar particle event worst week model that conservatively bounds the single event effects environment in S4 and X50 solar events. It is expected that the probability of occurrence of outages as well as Bit Error Rates (BER) due to SEE will be used in the analysis that verifies this probability. Further definition of the worst week model can be found here:

https://creme.isde.vanderbilt.edu/CREME-MC/help/solar-energetic-particle-environment.

4.6 Power

The spacecraft will supply one operational power bus for normal instrument operation.

The spacecraft will supply one survival power bus for the instrument survival heaters.

4.6.1 Voltage Range

EUVISPEC-120: The EUVI shall operate over the operational bus voltage range of +26 to +34 VDC at the primary power inputs for all expected load conditions (except when turned off).

EUVISPEC-121: The EUVI survival heaters shall operate over the voltage range of +24 to +34 VDC at the power inputs for all expected load conditions.

4.6.2 Abnormal Voltages

EUVISPEC-123: The EUVI shall survive without performance degradation after indefinite exposure to an anomalous voltage range of 0 to +40 VDC.

4.6.3 Sudden Removal of Power

EUVISPEC-125: The EUVI shall meet its performance requirements without degradation after exposure to an abrupt, unannounced removal of power.

4.6.4 Over-Current Protection

EUVISPEC-127: The EUVI shall not use non-resetting over-current protection (i.e., fuses) internal to the unit.

4.6.5 Primary Power Return Ground

EUVISPEC-129: The EUVI shall provide a dedicated Primary Power return in the same connector as the primary power.

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4.7 Electrical Grounding

4.7.1 Primary Power DC Isolation

EUVISPEC-132: The EUVI primary power interfaces, primary power and primary power returns shall be isolated from the unit chassis by a DC resistance of greater than or equal to 1 Megaohms.

4.7.2 Survival Power Isolation

EUVISPEC-134: The EUVI survival heater power interfaces shall be isolated from the unit chassis by a DC resistance of greater than or equal to 1 Megaohms.

Rationale: Returning the instrument survival heater power returns to the spacecraft single point ground and isolating the survival heater power returns from the instrument chassis helps control common mode noise current and minimize magnetic field effects due to ground loops.

4.7.3 Internally Generated Secondary to Primary DC Isolation

EUVISPEC-136: Secondary power inputs shall be isolated from primary power by a DC resistance of greater than 1 Megaohms.

Rationale: Isolating the instrument secondary power returns from the instrument primary power returns helps control common mode noise currents and minimizes magnetic field effects due to ground loops.

4.7.4 Internally Generated Secondary Return

EUVISPEC-138: The EUVI shall reference its secondary returns (power and signal grounds) to the unit chassis ground by connecting them at one or more places.

Rationale: NASA-HDBK-4001 Electrical Grounding Architecture for Unmanned Spacecraft.

4.7.5 Mechanical Contact Resistance

EUVISPEC-140: The EUVI DC resistance of the mechanical contact between two conductive mating surfaces (internal to the unit) shall be less than or equal to 2.5 milliohms DC resistance.

Rationale: Low resistance contacts are essential for maintaining a zero potential ground.

4.7.6 Grounding

EUVISPEC-142: The DC resistance between the EUVI chassis and the observatory chassis shall be ≤ 2.5 milliohms.

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Rationale: Low resistance contact between instrument chassis to spacecraft structure is essential for maintaining a zero potential ground.

EUVISPEC-143: The EUVI shall provide a ground lug for a grounding strap to be attached from the EUVI chassis for connection to the spacecraft conductive structure.

Rationale: This provides a method/location for tying the instrument ground to the spacecraft conductive structure.

4.7.7 Connector DC Resistance

EUVISPEC-146: EUVI connector backshells shall be electrically connected to Electronic Unit chassis with a DC resistance ≤ 2.5 milliohms.

Rationale: Low resistance contact between instrument chassis to spacecraft structure is essential for maintaining a zero potential ground.

4.8 Signal And Data Interfaces

4.8.1 Passive Analog Telemetry

EUVISPEC-149: The EUVI shall utilize no more than six (6) (TBR) analog signals to monitor critical temperature points when the instrument is powered off.

Rationale: Common best practices for on-orbit operations deems that the spacecraft will be able to monitor health and safety of the instrument if the instrument is in any configuration other than the normal operational configuration, e.g., safe or survival mode. Six signals are also deemed reasonable given the complexity of the instrument.

4.8.2 Data Signal Interface

The spacecraft will provide one data signal interface feeds to the instrument for command and telemetry. The spacecraft will also provide an interface line for a Pulse Per Second (PPS) time pulse.

EUVISPEC-152: The EUVI operational data (operational commands, telemetry) transfer interface to the spacecraft shall be SpaceWire (ECSS-E-ST-50-12C-rev.1) data bus.

4.8.3 Telemetry Source Packet Format

EUVISPEC-154: The EUVI shall transfer all data to the spacecraft using the CCSDS 133.0-B-2 Section 4.1 Protocol Data Unit definition with mission unique customization as shown in Figure 1.

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Rationale: Use of CCSDS standards simplifies command and telemetry data handling system and interface design. Mission Unique definitions retain consistency in implementation across space weather instruments, spacecraft, and ground systems.

Figure 1. Telemetry Source Packet Definition

EUVISPEC-157: The EUVI telemetry Source packet data field shall be a minimum length of 10 and maximum length of 8192 octets including Secondary Header.

Rationale: Set standard of telemetry packets consistent with heritage space weather observatory and ground implementations.

EUVISPEC-158: The EUVI shall set the telemetry source packet Secondary Header Flag to the value one (1).

Rationale: The Secondary Header Flag, Bit 4 of the Packet Primary header, indicates the presence or absence of the packet Secondary Header within this space packet. A value of ‘1’ indicates the Packet Secondary Header is present.

EUVISPEC-159: The EUVI shall set the Telemetry Source Packet Sequence Flags to the value of 11.

Rationale: The Sequence Flags, bits 16-17 of the Packet Primary header, is a mandatory field for this mission unique application. It is used to indicate that the User Data contained within the Space Packet is a segment of a larger set of application data. A value of ‘11’ indicates the Space Packet contains unsegmented User Data and is required if an Octect String service may be invoked within the managed data path.

EUVISPEC-160: The EUVI shall set the Telemetry Source Packet Time Code in the Secondary Header per CCSDS 301.0-B-4 Section 3.3 CCSDS Day Segmented Time Code T-Field format in Figure 2 (TBC).

Figure 2. Time Code Format

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Note: The P-Field is not included in the actual time message. It is shown in the figure above to imply the mission unique format of the T-Field. An Extension Flag (bit 0) of ‘0’ indicates that the P-field definition is only 1 octet. A Timecode ID (bits 1-3) of ‘100’ indicates this is a Day Segmented Time Code. An Epoch (bit 4) of ‘1’ indicates usage of a mission unique epoch (set here as 1/1/2000). A Day Segment Length (bit 5) of ‘1’ indicates 24-bit day segments. A Submillisecond Segment length (bits 6-7) of ‘01’ indicates 16-bit (microsecond) resolution.

4.8.3.1 Command Source Packet Format

EUVISPEC-165: The EUVI shall receive all data from the spacecraft formatted per CCSDS 133.0-B-2 Section 4.1 Protocol Data Unit definition with mission unique customization as shown in Figure 3.

Rationale: Use of CCSDS standards simplifies command and telemetry data handling system and interface design. Mission Unique definitions retain consistency in implementation across space weather instruments, spacecraft, and ground systems.

Figure 3. Command Source Packet

EUVISPEC-168: The EUVI Command Source packet data field shall be variable length with a minimum length of one (1) and maximum length of 1013 octets.

Rationale: Set standard of command packets consistent with heritage space weather observatory and ground implementations.

EUVISPEC-169: The EUVI shall receive Command Source Packet with Secondary Header Flag set to the value 0.

Rationale: The Secondary Header Flag, Bit 4 of the Packet Primary header, indicates the presence or absence of the packet Secondary Header within this space packet. A value of ‘0’ indicates the Packet Secondary Header is not present.

EUVISPEC-170: The EUVI shall receive Command Source Packet with the Sequence Flags set to the value of 11.

Rationale: The Sequence Flags, bits 16-17 of the Packet Primary header, is a mandatory field for this mission unique application. It is used to indicate that the User Data contained within the Space Packet is a segment of a larger set of application data. A value of ‘11’ indicates the Space Packet contains unsegmented User Data and is required if an Octect String service may be invoked within the managed data path.

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4.8.4 Clock Signal Interface

The spacecraft will maintain spacecraft time correlation to within +/- 0.95 sec of UTC and will provide the instrument a 1 PPS with a time code message.

EUVISPEC-173: The EUVI shall receive a Pulse Per Second (PPS) time pulse from spacecraft clock line by the interface defined in section 4.8.2 (Data Signal Interface) of this document.

EUVISPEC-174: The EUVI shall receive from the spacecraft a time code message on the data line as defined in Figure 4. The time code message is the time applicable to receipt of the 1 PPS.

Figure 4. Spacecraft Time Message Packet

4.8.5 Command and Housekeeping telemetry

EUVISPEC-178: The EUVI shall provide command and housekeeping telemetry functions in all powered modes.

4.8.6 Commands for Autonomous Functions

EUVISPEC-180: The EUVI shall execute commands to individually enable and disable each autonomous function.

4.8.7 Limits and Triggers

EUVISPEC-182: The EUVI autonomous limits and triggers shall be changeable by command.

4.8.8 On-Board Processor Reset

EUVISPEC-184: The EUVI On-Board Processor shall be reset by command.

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EUVISPEC-185: An autonomous power-on reset occurrence shall be unambiguously identifiable via telemetry.

Note: This does not imply real-time telemetry as the reset is occurring.

4.8.9 Microswitches

EUVISPEC-188: Instrument micro-switches shall be used for information only and not used to initiate on-board autonomous activity or as an on-board interlock.

4.9 Flight Software

4.9.1 Flight Load Non-volatile Memory

EUVISPEC-191: The EUVI flight software image shall be contained in its entirety in non-volatile memory at launch.

4.9.2 Software Updates

EUVISPEC-193: The EUVI flight software modules shall be reprogrammable.

4.9.3 Software Table Updates

EUVISPEC-195: Instrument configuration data (e.g., Table Loads or Configuration Parameters) shall be reprogrammable during integration and test phases and on-orbit without computer restart.

EUVISPEC-196: Modified instrument configuration data (e.g., Table Loads or Configuration Parameters) shall be committed to operational use by ground command.

4.9.4 Flexibility and Ease of Software Modification

EUVISPEC-198: The instrument flight software shall be deterministic in terms of scheduling and prioritization of critical processing tasks to ensure their timely completion.

EUVISPEC-199: Instrument configuration data (e.g., Table Loads or Configuration Parameters) shall be referenced such that data can be loaded and dumped by the ground without reference to memory address.

EUVISPEC-200: The definition of instrument commands within the ground database (excluding memory diagnostic/load commands) shall not be dependent on physical memory addresses within the flight software.

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4.9.5 Version Identifiers

EUVISPEC-202: The instrument software and firmware versions shall each have an internal identifier (embedded in the executive program) that can be included in the instrument engineering data.

EUVISPEC-203: This software identifier shall be configuration management controlled.

4.9.6 Warm Restart

EUVISPEC-205:…