80GSFC25R0001 - Attachment C (SPEC).pdf

Effective Date: May 22, 2025 Expiration Date: May 22, 2030

Check https://ipdtdms.gsfc.nasa.gov to verify that this is the correct version prior to use.

SWGEO-PHOMI-REQ-0003, Revision - Space Weather Geostationary (SW GEO) Series, Code 495.0

Attachment C

SW GEO Series Project PHOtospheric Magnetograph Imager

(PHOMI)

Requirements Specification (SPEC)

U.S. Department of Commerce (DOC) National Oceanic and Atmospheric Administration (NOAA) National Environmental Satellite, Data, and Information Service (NESDIS) National Aeronautics and Space Administration (NASA)

GSFC SW GEO CMO

05/30/2025 Released

SW GEO PHOMI SPEC SWGEO-PHOMI-REQ-0003, Revision -ii

Space Weather Geostationary (SW GEO) Series Project

PHOtospheric Magnetograph Imager (PHOMI) Requirements Specification (SPEC)

Review/Signature/Approval Page

Prepared by:

Originally signed by on behalf of:

Robin Minor SW Next Program Systems Engineer NASA Goddard Space Flight Center

Approved by:

Originally signed by:

Eugene Guerrero-Martin SW GEO Series Project Manager NASA Goddard Space Flight Center iii

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

Change History Log

Revision Effective

Date Description of Changes

Revision - 05/22/2025 Baseline Release following the approval of SWGEO-CCR-0008 v

Deviations/Waivers Record

Section # / Rqmt.

Deviation / Waiver #

CCR # Date Approved Description vi

Table of Contents

1 INTRODUCTION

1.1 General Information

1.2 Scope

2 APPLICABLE DOCUMENTS

3 CONTRACT DESCRIPTION

3.1 PHOMI Description

4 FUNCTIONAL/PERFORMANCE REQUIREMENTS

4.1 PHOMI Performance Requirements

4.1.1 Requirements for Photospheric Magnetograph Imagery

4.1.1.1 Scene Coverage

4.1.1.2 Spatial Resolution

4.1.1.3 Measurement Range

4.1.1.4 Measurement Accuracy

4.1.1.5 Sensitivity

4.1.1.6 Zero Point Error

4.1.2 Requirements for Photospheric Doppler Velocity Field Imagery

4.1.2.1 Scene Coverage

4.1.2.2 Spatial Resolution

4.1.2.3 Measurement Accuracy

4.1.3 Refresh Rate

4.1.4 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 PHOMI 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

vii

4.4.8 Eclipse

4.4.9 Station Keeping

4.4.10 Activation

4.5 Instrument Data Availability

4.6 Power

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 PHOMI Instrument Mass Accuracy

5.2.2 Center of Mass Location

5.2.3 Center of Mass Accuracy

viii

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

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

ix

6.13.7 Solar Flare Survival

7 CONTAMINATION CONTROL

7.1 PHOMI Surface Cleanliness Requirements

7.2 Contamination Generation

7.2.1 Particulate Generation

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 Conductive Surface Ground Path

7.8.2 Conductive Surface Resistivity

7.8.3 Closeout of Gaps and Apertures

7.8.4 Exposed Harness Specific Requirements

7.8.5 Thermal Blankets

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

8.1.5.2 Floating Conductors

8.1.5.3 Dielectric Structures

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 x

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 ... 69

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

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

9.2.6.6.1.1 Torque Measurement

9.2.6.6.1.2 Witness Coupons

xi

9.2.6.6.1.3 Cure Samples

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

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

xii

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

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

Appendix A Abbreviations and Acronyms

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) .. 51 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 xiii

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. PHOMI 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 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 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. Thermal Blanket Area vs. Grounding Tabs Table 20. Emission and Susceptibility Requirements Table 21. RS103 Radiated Susceptibility Levels (TBR) Table 22. Locking Feature Torque Verification Table 23. Test Factors and Durations Table 24. Sine Sweep Parameters Table 25. Thermal Vacuum Test Parameters

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 PHOtospheric Magnetograph Imager (PHOMI) for the Space Weather Geostationary (SW GEO) Series project.

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 PHOMI 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-PHOMI- 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- PHOMI-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-PHOMI-SOW-

Space Weather GEO Photospheric Magnetograph Imager (PHOMI) Phase A Study Statement of Work (SOW)

SWGEO-PHOMI-CDRL-

Photospheric Magnetograph Imager (PHOMI)) Contract Deliverables Requirements List (CDRL)

SWGEO-PHOMI-REQ-

Space Weather GEO Magnetograph 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-1000H GSFC Rules for the Design, Development, Verification, and Operation of Flight Systems

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 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

3 CONTRACT DESCRIPTION

3.1 PHOMI Description

The PHOMI will be capable of producing line of sight (LOS) measurements of the photospheric magnetic field that meet the specifications in the requirements below. LOS magnetograph imagery provides important information about the magnetic field strength and polarity of the solar magnetic field, the complexity of active regions, the emergence of new flux, and the location where the magnetic field polarity switches sign. Continual high-resolution mapping of the solar photospheric magnetic field is required to accurately model the solar wind velocity, density, and magnetic polarity values that cause both minor to moderate geomagnetic storming and influence Coronal Mass Ejection (CME) arrival time.

4 FUNCTIONAL/PERFORMANCE REQUIREMENTS

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

PHOMI.

The requirements in this Specification pertain to the PHOMI “system,” which may include all instrument hardware, software, and ground processing algorithms. The PHOMI 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 PHOMI Performance Requirements

Magnetograph imagery and photospheric Doppler velocity field imagery measurement requirements.

4.1.1 Requirements for Photospheric Magnetograph Imagery

4.1.1.1 Scene Coverage

PHOMISPEC-001: The PHOMI shall capture photospheric magnetograph imagery with a sun-centered and solar north-aligned view.

PHOMISPEC-002: The PHOMI shall capture photospheric magnetograph imagery with observational extent from 0 to 1 Rsun.

4.1.1.2 Spatial Resolution

PHOMISPEC-003: The PHOMI shall produce photospheric magnetograph imagery with a spatial resolution of 2 arcsec.

4.1.1.3 Measurement Range

PHOMISPEC-004: The PHOMI shall produce photospheric magnetograph imagery with a measurement range of ±3 kilogauss.

4.1.1.4 Measurement Accuracy

PHOMISPEC-005: The PHOMI shall produce photospheric magnetograph imagery with a measurement accuracy of ±20%.

Note: Measurement accuracy is defined as the closeness of agreement between a measured quantity value and a true quantity value of a measurand (i.e., the quantity intended to be measured) (ISO-JCGM 200:2008), and is often limited by calibration errors.

4.1.1.5 Sensitivity

PHOMISPEC-006: The PHOMI shall produce photospheric magnetograph imagery with an image sensitivity of 10 G/pxl (TBR).

4.1.1.6 Zero Point Error

PHOMISPEC-007: The PHOMI shall produce photospheric magnetograph imagery with a zero point error of 0.1 G.

Rationale: The zero point error refers to the disk-averaged line-of-sight field zero point noise and drives the exposure duration accuracy requirement.

4.1.2 Requirements for Photospheric Doppler Velocity Field Imagery

4.1.2.1 Scene Coverage

PHOMISPEC-008: The PHOMI shall capture photospheric Doppler velocity field imagery with a sun-centered and solar north-aligned view.

PHOMISPEC-009: The PHOMI shall capture photospheric Doppler velocity field magnetograph imagery with observational extent from 0 to 1 Rsun.

4.1.2.2 Spatial Resolution

PHOMISPEC-010: The PHOMI shall produce photospheric Doppler velocity field imagery with a spatial resolution of 2 arcsec.

4.1.2.3 Measurement Accuracy

PHOMISPEC-011: The PHOMI shall produce photospheric Doppler velocity field imagery with a measurement accuracy of ±20%.

4.1.3 Refresh Rate

PHOMISPEC-012: The PHOMI shall produce an image during normal operations at a refresh rate of ≤ one (1) hour.

4.1.4 Data Latency

PHOMISPEC-013: The processing of a completed on-orbit data collection by the PHOMI instrument and the transmission to the spacecraft shall contribute ≤ one (1) hour to the overall latency of the imagery product(s).

4.2 Resource Allocations

The PHOMI 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 PHOMI flight hardware must meet the resource requirements in this section.

4.2.1 Mass

PHOMISPEC-014: The PHOMI instrument shall have a combined mass of less than or equal to

67.8 kg (includes margin).

PHOMISPEC-015: The PHOMI instrument mass margin shall comply with GSFC-STD-1000H Rule 1.06.

4.2.2 Physical Envelope

PHOMISPEC-016: The Telescope Module—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 Magnetograph Reference Frame (MRF) dimensions of 82 cm (XMRF) x 90 cm (ZMRF) x 30 cm

(YMRF) (TBR—all 3 dimensions). These dimensions pertain to both static and dynamic envelopes of the instrument.

PHOMISPEC-017: If a separate Electronics Unit is required, it—including mounts, brackets, thermal blankets, and connectors shall have dimensions that do not exceed contractor defined MRF dimensions of 23 cm (XMRF) x 11 cm (ZMRF) x 19 cm (YMRF) (TBR—all 3 dimensions).

4.2.3 Operational Power Allocation

PHOMISPEC-018: The PHOMI average operational EOL power, including operational heater power, shall not exceed 63 Watts when averaged over any 15-minute period.

4.2.4 Peak Operational Power Allocation

PHOMISPEC-019: The PHOMI 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

PHOMISPEC-020: The PHOMI survival heater power shall not exceed 22.5 (TBR) Watts when averaged over any 72-minute period.

4.2.6 Telemetry

PHOMISPEC-021: The PHOMI 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 160 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)

PHOMISPEC-022: The PHOMI 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)

PHOMISPEC-023: The PHOMI 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.

The PHOMI will be in Survival Mode during launch. The PHOMI 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.

PHOMISPEC-026: The PHOMI 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 PHOMI Operating Modes

PHOMISPEC-027: The PHOMI current operating mode shall be identified by a flag in its telemetry stream.

4.4.1 In-Flight Calibration

PHOMISPEC-028: The PHOMI shall provide an in-flight calibration mode that provides a test input to support calibration and testing both on the ground and in space.

PHOMISPEC-029: The PHOMI in-flight calibration shall be both self-terminating and able to be terminated by a ground command.

4.4.2 Mode Transitions

PHOMISPEC-030: The PHOMI instrument shall transition from the current mode to any other mode without causing damage to itself.

4.4.3 Deterministic Power-on Configuration

PHOMISPEC-031: The PHOMI shall initialize into a predetermined configuration.

4.4.4 Safe Mode

PHOMISPEC-032: The PHOMI 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.

PHOMISPEC-033: 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

PHOMISPEC-034: The PHOMI 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 PHOMI contractor and command the PHOMI 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 PHOMI contractor and command the PHOMI into safe mode when any of those key values have been exceeded.

4.4.5 Fail-safe Recovery Mode

PHOMISPEC-035: The PHOMI 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

PHOMISPEC-036: In normal operational mode, the PHOMI instrument shall be in a fully functional configuration in which measurements are made in accordance with the performance requirements listed in Section 4.1 (PHOMI Performance Requirements) of this document and are available to be sent to the spacecraft for downlink.

4.4.7 On-Orbit Operations

PHOMISPEC-037: The PHOMI 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

PHOMISPEC-038: For a Geosynchronous orbit, the PHOMI shall be capable of continuous operation through eclipse periods.

PHOMISPEC-039: For a Geosynchronous orbit, from the time immediately following eclipse until four hours after eclipse, the PHOMI line of sight pointing knowledge shall be TBD arcseconds, 3 sigma.

4.4.9 Station Keeping

PHOMISPEC-040: The PHOMI instrument shall continuously operate during all spacecraft maneuvers.

PHOMISPEC-041: The PHOMI 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 PHOMI radiator during the maneuver.

4.4.10 Activation

PHOMISPEC-042: The PHOMI 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

PHOMISPEC-043: The PHOMI shall limit on-orbit calibrations to no more than four (4) calibrations per year with each calibration lasting no more than 30 minutes.

PHOMISPEC-044: The PHOMI shall be capable of maintaining nominal observation mode without ground interaction for a minimum of 4 days.

PHOMISPEC-045: The PHOMI 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 Magnetograph Imagery High Availability Product (HAP) be less than 5 min and any instrument’s pre-planned event has the potential to impact Magnetograph Imagery HAP acquisition. The expected cadence and duration of NWS-declared Critical Space Weather Days could last between 3 and 21 consecutive days.

PHOMISPEC-046: The PHOMI 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.

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

PHOMISPEC-047: The PHOMI 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).

PHOMISPEC-048: The PHOMI 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

PHOMISPEC-049: The PHOMI 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

PHOMISPEC-050: The PHOMI shall meet its performance requirements without degradation after exposure to an abrupt, unannounced removal of power.

4.6.4 Over-Current Protection

PHOMISPEC-051: The PHOMI shall not use non-resetting over-current protection (i.e., fuses) internal to the unit.

4.6.5 Primary Power Return Ground

PHOMISPEC-052: The PHOMI shall provide a dedicated Primary Power return in the same connector as the primary power.

4.7 Electrical Grounding

4.7.1 Primary Power DC Isolation

PHOMISPEC-054: The PHOMI 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

PHOMISPEC-055: The PHOMI 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

PHOMISPEC-056: 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

PHOMISPEC-057: The PHOMI 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

PHOMISPEC-058: The PHOMI 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

PHOMISPEC-059: The DC resistance between the PHOMI chassis and the observatory chassis shall be ≤ 2.5 milliohms.

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

PHOMISPEC-060: The PHOMI shall provide a ground lug for a grounding strap to be attached from the PHOMI 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

PHOMISPEC-062: PHOMI 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

PHOMISPEC-063: The PHOMI 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 two 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.

PHOMISPEC-064: The PHOMI operational data transfer interface to the spacecraft shall be SpaceWire (ECSS-E-ST-50-12C-rev.1) data bus. For command and telemetry, the instrument may use either SpaceWire or a serial Universal Asynchronous Receiver Transmitter (UART) using ANSI/TIA/EIA-422-B Electrical Characteristics of Balanced Voltage Differential Interface Circuits.

Rationale: SpaceWire, LVDS, and RS-422 are the preferred standard high-rate data interfaces.

4.8.2.1 Telemetry Source Packet Format

PHOMISPEC-065: The PHOMI 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.

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

PHOMISPEC-066: The PHOMI 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.

PHOMISPEC-067: The PHOMI 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.

PHOMISPEC-068: The PHOMI 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.

PHOMISPEC-069: The PHOMI 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

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.

4.8.2.2 Command Source Packet Format

PHOMISPEC-070: The PHOMI 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

PHOMISPEC-071: The PHOMI 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.

PHOMISPEC-072: The PHOMI 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.

PHOMISPEC-073: The PHOMI 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.

4.8.3 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.

PHOMISPEC-074: The PHOMI 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.

PHOMISPEC-075: The PHOMI 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

4.8.4 Command and Housekeeping telemetry

PHOMISPEC-076: The PHOMI shall provide command and housekeeping telemetry functions in all powered modes.

4.8.5 Commands for Autonomous Functions

PHOMISPEC-077: The PHOMI shall execute commands to individually enable and disable each autonomous function.

4.8.6 Limits and Triggers

PHOMISPEC-078: The PHOMI autonomous limits and triggers shall be changeable by command.

4.8.7 On-Board Processor Reset

PHOMISPEC-079: The PHOMI On-Board Processor shall be reset by command.

PHOMISPEC-080: 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.

4.8.8 Microswitches

PHOMISPEC-081: 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

PHOMISPEC-082: The PHOMI flight software image shall be contained in its entirety in non-volatile memory at launch.

4.9.2 Software Updates

PHOMISPEC-083: The PHOMI flight software modules shall be reprogrammable.

4.9.3 Software Table Updates

PHOMISPEC-084: Instrument configuration data (e.g., Table Loads or Configuration Parameters) shall be reprogrammable during integration and test phases and on-orbit without computer restart.

PHOMISPEC-085: 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

PHOMISPEC-086: The instrument flight software shall be deterministic in terms of scheduling and prioritization of critical processing tasks to ensure their timely completion.

PHOMISPEC-087: 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.

PHOMISPEC-088: 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.

4.9.5 Version Identifiers

PHOMISPEC-089: 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.

PHOMISPEC-090: This software identifier shall be configuration management controlled.

4.9.6 Warm Restart

PHOMISPEC-091: The instrument flight software shall provide a restart by command with preservation of instrument configuration data and memory tables.

4.9.7 Memory Tests

PHOMISPEC-092: The instrument flight software shall provide a mechanism to verify the contents of all memory areas.

4.9.8 Memory Dump

PHOMISPEC-093: The instrument flight software, and associated on-board computer hardware shall provide the capability to dump any memory location.

PHOMISPEC-094: The flight software memory dump capability shall not disturb normal operations and instrument data processing.

4.9.9 Fault Detection and Correction Control

PHOMISPEC-095: The instrument shall provide the capability to enable and disable any internal Fault Detection and Correction (FDC) features.

4.9.10 Health and Safety Monitoring

PHOMISPEC-096: The instrument flight software shall provide health and safety monitoring, including memory checksum and watchdog timer.

5 PHYSICAL REQUIREMENTS

5.1 Interface and Design Units and Exclusions

PHOMISPEC-097: The contractor shall use metric units to design the instrument and for developing interfaces with the spacecraft including any drawings, documents, models, except for the following cases:

Heritage Component or unit: Components or units that has been previously qualified, or of similar design heritage, may be specified in English units where use of metric equivalents would lead to additional cost to the program.

Fasteners: Although bolt patterns will be defined using metric dimensioning, use of English fasteners (with hole dimensioning and tolerancing) is permitted.

Angular Measurement: Angular measurement may be expressed in degree of arc or in an appropriate subdivision of degree of arc such as second of arc (arc-sec) when advantageous to application.

5.2 Mass Properties Accuracy

5.2.1 PHOMI Instrument Mass Accuracy

PHOMISPEC-098: The mass of the PHOMI shall be measured to within ±0.1 kg.

5.2.2 Center of Mass Location

PHOMISPEC-099: The contractor shall define the center of mass in the Mechanical ICD.

5.2.3 Center of Mass Accuracy

PHOMISPEC-100: The PHOMI Telescope Module and Electronics Unit (if applicable) center of mass shall be determined to within ±5 mm relative to a reference that will be defined in the

MICD.

5.2.4 Determination of Moments and Products of Inertia

PHOMISPEC-101: The contractor shall determine by analysis the launch and on-orbit moments and products of inertia to an accuracy of ±5.0 percent of the maximum principal moment of inertia, referenced to the coordinate axes with an origin at the center of gravity.

5.3 Mounting

5.3.1 Surface Flatness

PHOMISPEC-102: Mounting interface flatness, and co-planarity requirements for The PHOMI side of the interface (including brackets, if any, and shims) shall be as defined in the MICD.

5.3.2 Method

The method by which The PHOMI is mounted to the spacecraft will be defined in the Spacecraft to PHOMI Interface Control Document (ICD).

5.4 Coordinate System and Alignment

PHOMISPEC-390: The instrument shall use the spacecraft on-orbit coordinate system which uses a right-hand orthogonal, body-fixed XYZ coordinate system, Spacecraft Reference Frame (SRF), as follows: the +X-axis is aligned with the nominal direction of the spacecraft to Sun vector pointing towards the Sun, the +Y-axis nominal to normal of the ecliptic plane and pointing to celestial North, and the Z-axis is obtained from the right-hand rule. The roll, pitch and yaw rotations are defined about the X, Z, and Y axes, respectively. The origin of the coordinate system is at the center of the Launch Vehicle separation ring attachment plane. See Figure 5.

In the Magnetograph Reference Frame (MRF) which is parallel to the SRF: the +X-axis is aligned with the instrument line of sight, the Y-axis is perpendicular to the instrument mounting plane, and the Z-axis completes the triad.

Figure 5. Spacecraft Reference System

The spacecraft will point the Magnetograph boresight to within (TBD) 3-sigma, of the center of the Sun during any Operational Sun-pointing Time.

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

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

The spacecraft will provide pointing knowledge of < (TBD) (1-sigma) to PHOMI.

PHOMISPEC-103: The instrument shall have clear fiducial marks and/or optical alignment devices, including flight covers as applicable, to enable alignment during integration with spacecraft.

The instrument unit mounting frame is an orthogonal reference frame defined by the locations of the spacecraft side of the instrument unit mounting points. A rigorous definition of this frame will be documented in the ICD.

6 ENVIRONMENTAL REQUIREMENTS

Environmental design requirements for the PHOMI Instrument are specified in this section.

PHOMISPEC-104: The PHOMI shall meet its performance requirements in section 4 (Functional/Performance Requirements) after exposure to the environments specified in this section.

6.1 Mechanical Factors of Safety

PHOMISPEC-105: The PHOMI flight hardware shall demonstrate positive Margins of Safety under limit loads for all yield and ultimate failures using the Factors of Safety (FS) defined in Table 2. Margin of Safety (MS) is defined as follows:

MS = (Allowable Stress (or Load) / (Applied Limit Stress (or Load) x FS)) -1

Table 2. Factors of Safety1,2

Type Static Sine Random/Acoustic 4,5 Metallic Yield 1.253 1.25 1.6 Metallic Ultimate 1.43 1.4 1.8 Stability Ultimate 1.4 1.4 1.8 Beryllium Yield 1.4 1.4 1.8 Beryllium Ultimate 1.6 1.6 2.0 Composite 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 glass and structural glass bonds 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. See section 2.4.1.1.1 GSFC-STD-7000B 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.

PH…