Attachment C GIRD 418 XO GIRD 0041 Version 2.3.pdf

Effective Date: February 10, 2022 418-XO-GIRD-0041 Responsible Organization: GeoXO Flight Project/Code 418 Version 2.3

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

Geostationary Extended Observations (GeoXO) Flight Project

General Interface Requirements Document (GIRD) Signature page

Prepared by:

Electronically approved by:

05/03/2022

Derrick A. Early Date GeoXO Flight Project, Systems Engineer NASA GSFC, Code 418

Reviewed by:

06/06/2022

Steven W. Bidwell Date GeoXO Flight Project, Mission Systems Engineer NASA GSFC, Code 599

06/07/2022

Michelle P. Rizzo Date GeoXO Flight Project, Observatory Manager

Approved by:

Christopher A. Wheeler electronically approved for:

06/08/2022

Candace C. Carlisle Date GeoXO Flight Project, Project Manager NASA GSFC, Code 418

/GeoXO Flight Project Systems Engineering

GIRD

418-XO-GIRD-0041, RM Version, Geostationary eXtended Observations (GeoXO) General Interface Requirements Document (GIRD)

Version: 2.3 Printed by: hlhedger Printed on: Thursday, June 29, 2023

No filter applied.

No sort applied.

Generated from DOORS 9.7.2.4

Contents

1 1Scope

1.1 1Introduction

1.2 1Requirements Terminology

1.3 1Order of Precedence

1.4 1Definitions

2 4Documents

2.1 4Applicable Documents

2.2 4Reference Documents

3 6Requirements

3.1 6General Requirements

3.1.1 6Instrument Modes

3.1.1.1 6Power Off Mode

3.1.1.2 6Instrument Safe Mode

3.1.1.2.1 6Instrument Safe Mode Command

3.1.1.2.2 6Instrument Safe Mode Timeout

3.1.1.3 6Survival and Storage Modes

3.1.2 6Operational Concepts

3.1.2.1 6Pre-Launch

3.1.2.2 6Launch and Orbit Raising

3.1.2.3 6On-Orbit Concept

3.1.3 7Dimension Standard

3.1.4 7Coordinates

3.1.5 8Yaw Flip

3.2 8Interface Requirements

3.2.1 8Mechanical

3.2.1.1 8Envelope Documentation

3.2.1.2 8Critical Clearances

3.2.1.3 8Fields of View

3.2.1.4 9Mass Properties

3.2.1.4.1 9Center of Mass

3.2.1.4.2 9Inertia Properties

3.2.1.5 9Mounting

3.2.1.5.1 9Mounting Hardware

Project: GeoXO Flight Project Systems Engineering Module: GIRD Baseline Version: 2.3

Contents ii

3.2.1.5.2 9Mounting Method

3.2.1.5.3 10Handling Fixtures

3.2.1.5.4 10Interface

3.2.1.5.5 10Location

3.2.1.5.6 10Drill Templates

3.2.1.6 11Alignment

3.2.1.6.1 11Instrument Alignment (CCR-X00080A)

3.2.1.6.1.1 11Alignment References

3.2.1.6.1.2 11Alignment Responsibilities

3.2.1.6.1.3 11Instrument Placement

3.2.1.6.1.4 12Initial Alignment Knowledge

3.2.1.6.1.5 12Alignment Rate of Change

3.2.1.7 12Instrument Access

3.2.1.8 12Attitude and Disturbances (CCR-X00080A)

3.2.1.8.1 12Spacecraft Attitude and Disturbances

3.2.1.8.1.1 12Attitude Error

3.2.1.8.1.2 13Attitude Rate Error

3.2.1.9 13Flight and Non-Flight Equipment

3.2.2 13Thermal

3.2.2.1 13Thermal Control Concept

3.2.2.1.1 14Independent Unit - Net Heat Transfer

3.2.2.1.2 14Coupled Unit – Heat Transfer

3.2.2.1.3 14Coupled Unit - Heat Transfer Flux Density

3.2.2.2 14Interface Temperatures

3.2.2.3 14Temperature Monitoring

3.2.2.3.1 14Mechanical Interface Temperature Monitoring

3.2.2.3.2 15Instrument Critical Temperatures

3.2.2.3.3 15Instrument Non-Critical Temperatures

3.2.2.4 15Thermal Interfaces

3.2.2.4.1 15Mounting Details

3.2.2.4.2 15Contact Area

3.2.2.4.3 15Interstitial Materials

3.2.2.5 15Multi-layer Insulation

3.2.3 16Instrument Electrical Power

3.2.3.1 16Electrical Power Interfaces

3.2.3.2 16Power Specifications

3.2.3.2.1 16Power Definitions

3.2.3.2.2 17Power Characteristics

Contents iii

3.2.3.2.2.1 17Voltage

3.2.3.2.2.1.1 17Instrument Voltage

3.2.3.2.2.1.2 17Voltage Transients

3.2.3.2.2.1.3 17Abnormal Operation Voltage Limits

3.2.3.2.2.1.4 17Spacecraft Unpowered Voltage

3.2.3.2.2.1.5 17Voltage Power Source Impedance

3.2.3.2.2.2 18Current

3.2.3.2.2.2.1 18Operational Power Transients

3.2.3.2.3 18Power Distribution, Control, and Status

3.2.3.2.3.1 18Operational Power Lines

3.2.3.2.3.2 19Operational Power ON/OFF Functionality

3.2.3.2.3.3 19Operational Power Overcurrent Protection

3.2.3.2.3.4 20Survival Heater Power Lines

3.2.3.2.3.5 20Survival Heater Power On/Off Functionality

3.2.3.2.3.6 20Survival Heater Power Overcurrent Protection

3.2.3.2.3.7 21Abnormal Survival Power Voltage Limits

3.2.4 21Instrument Electrical Power Grounding

3.2.4.1 21Instrument Operational Power Grounding

3.2.4.2 22Instrument Survival Heater Power Grounding

3.2.4.3 23Instrument Secondary Power Grounding

3.2.4.4 23Instrument Electrical Signal Grounding

3.2.4.4.1 23Instrument Command Grounding

3.2.4.4.1.1 23Instrument Pulse Command Grounding

3.2.4.4.1.2 23Instrument Serial Command Grounding

3.2.4.4.1.3 23Instrument Electro-Explosive Device (EED) Command Grounding

3.2.4.4.2 23Instrument Telemetry Grounding

3.2.4.4.2.1 23Instrument Analog Telemetry Grounding

3.2.4.4.2.2 24Instrument Serial Telemetry Grounding

3.2.4.5 24Instrument Electrical Accommodations

3.2.4.5.1 24Spacecraft/Instrument Interface Harnessing

3.2.4.5.2 24Spacecraft/Instrument Telemetry and Command Interface Harnessing

3.2.5 24Command and Data Handling

3.2.5.1 24Data Transfer Between the Instrument and Spacecraft utilizing SpaceWire

3.2.5.2 24Guaranteed Delivery

3.2.5.3 25SpaceWire Data Bus

3.2.5.3.1 25SpaceWire Redundancy

3.2.5.4 25Source Packet Format

3.2.5.4.1 25Source Packet Length

Contents iv

3.2.5.4.2 25Secondary Header Flag

3.2.5.4.3 26Source Packet Secondary Header

3.2.5.4.4 26Sequence Flags

3.2.5.4.5 26User Defined Flags

3.2.5.5 26SpaceWire Data Rate

3.2.5.6 26Pulse Per Second (PPS)

3.2.5.6.1 26SpaceWire Time Code Support

3.2.5.6.2 26PPS Signal Drift

3.2.5.6.3 26Time Message

3.2.5.6.4 27Time Code Format

3.2.5.6.5 27Epoch

3.2.5.6.6 27Distribution Timing

3.2.5.7 27Reserved (CCR-X00080A)

3.2.5.8 27Control and Monitoring

3.2.5.8.1 27Critical Telemetry

3.2.5.8.2 27Critical Telemetry Analog Signals

3.2.5.8.3 28Critical Telemetry Analog Signal Resolution

3.2.5.8.4 28Discrete Signals

3.2.5.8.5 28Critical Telemetry Signal Characteristics

3.2.5.8.6 28Instrument Configuration Commands

3.2.5.8.6.1 28Configuration Command Definition

3.2.5.8.7 28Stored Command Processing

3.2.6 28Environmental Conditions

3.2.6.1 29On-Orbit Radiation Environment

3.2.6.2 29Launch Environment

3.2.6.2.1 29Thermal Environment During Launch

3.2.6.2.2 29Pressure Profile

3.2.6.2.3 29Flight Acceleration

3.2.6.2.4 31Flight Random Vibration

3.2.6.2.5 34Flight Sinusoidal Vibration

3.2.6.2.6 36Shock

3.2.6.2.7 37Flight Acoustics

3.2.6.3 39On-Orbit Environment

3.2.6.3.1 39Acceleration

3.2.6.3.2 39Orbital Heat Flux

3.2.6.3.2.1 39Direct Solar Flux

3.2.6.3.2.2 39Solar Eclipse

3.2.6.3.2.3 40Extended Solar Eclipse

Contents v

3.3 40Attitude and Orbit Data

3.3.1 40Attitude Knowledge

3.3.1.1 40Attitude Knowledge Representation

3.3.1.2 40Attitude Knowledge Accuracy

3.3.1.3 40Attitude Knowledge Update Rate

3.3.1.4 40Attitude Knowledge Latency

3.3.2 41Spacecraft Angular Rate

3.3.2.1 41Angular Rate Representation

3.3.2.2 41Angular Rate Accuracy

3.3.2.3 41Angular Rate Bandwidth

3.3.2.4 41Angular Rate Update Rate

3.3.2.5 41Angular Rate Latency

3.3.3 42Spacecraft Orbit

3.3.3.1 42Spacecraft Orbit Representation

3.3.3.2 42Spacecraft Orbit Accuracy

3.3.3.3 42Spacecraft Orbit Update Rate

3.3.3.4 42Spacecraft Orbit Latency

3.3.3.5 42Spacecraft Orbit Stability

3.4 42Instrument GSE to Spacecraft I&T GSE Interface

3.5 43Contamination Control

3.5.1 43Instrument and Spacecraft Ground Processing

3.5.1.1 43Facility Requirements

3.5.1.2 43Ground Support Equipment Requirements

3.5.1.3 44Purge Requirements

3.5.1.4 44Ground Storage/Transportation Requirements

3.5.2 45Mission Contamination Considerations

3.5.2.1 45Thermal Blanket Design

3.5.2.2 45Particulate Contamination

3.5.2.3 45Molecular Contamination

4 47Requirements Verifications

4.1 47EMC – General

4.2 47Conducted Emissions

4.3 48Common Mode Noise

4.4 48Conducted Susceptibility

4.5 51Operational Power Voltage Ripple

4.6 52Radiated Susceptibility and Emissions

4.6.1 52Radiated Susceptibility, Spacecraft/Launch Environment

4.6.2 54Radiated Emissions

Contents vi

5 57Acronyms

Contents vii

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418-XO-GIRD-0041, RM Version, Geostationary eXtended Observations (GeoXO) General Interface Requirements Document

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1 Scope

1.1 Introduction

This General Interface Requirements Document (GIRD) sets forth the general, mechanical, thermal, electrical power, command and data handling and contamination control interface requirements imposed on both the instruments and spacecraft for the GeoXO Series System. It also defines the general environments to which the satellite will be subjected. The spacecraft contractor and the instrument contractor will each meet their respective interface requirements defined in this document.

The Unique Instrument Interface Document (UIID) for an instrument defines the specific resource allocations, documents exceptions to the GIRD requirements and constraints, and defines the special requirements not specifically covered in the GIRD.

The instrument contractor will create and maintain, with government approval, an Instrument Descriptive Document (IDD) which describe the detail instrument design and unique interface requirements. The GIRD, in conjunction with the UIID and the IDD establishes the instrument-to-spacecraft interface requirements.

Interface Control Documents (ICDs) will define the specific details of the complete spacecraft to instrument interface information (i.e., mechanical, electrical power, command and data handling, and thermal interfaces). These will be developed by the spacecraft contractor to document the Instrument-Spacecraft interface. The spacecraft contractor will control the ICDs and the ICDs will replace the related IDDs.

1.2 Requirements Terminology

The following requirements terminology is used throughout this document:

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

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

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

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

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

1.3 Order of Precedence

The order of precedence of interface requirements documents is the UIID at the highest level, followed in order by the GIRD, ICD, and IDD.

1.4 Definitions

Architecture and Design - A description of the mission elements, their interfaces, their logical and physical layout, and the analysis of the design to determine expected performance and margins, including System Design Synthesis, System Design Analysis, and System Design Validation products.

Assembly - A functional subdivision of a component consisting of parts or subassemblies that perform functions necessary for the operation of the component as a whole. Examples are power amplifier and gyroscope.

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1.4.0-3

1.4.0-4

1.4.0-5

1.4.0-6

1.4.0-7

1.4.0-8

1.4.0-9

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Component - A functional subdivision of a subsystem and generally a self-contained combination of items performing a function necessary for subsystem operation. A functional unit viewed as an entity for purpose of analysis, manufacturing, testing, or record keeping.

Element - A complete, integrated set of subsystems capable of accomplishing an operational role or function.

Field of Regard – the total object space that can be sampled by a movable sensor field of view (FOV). (CCR-X00080A)

Field of View – the object space sampled with the sensor scanner at a fixed position.

If the Instrument does not include a scanning mechanism, the Field of View is equivalent to the Field of Regard. (CCR-X00080A)

Part - A hardware element, which is not normally subject to further subdivision or disassembly without destruction of designated use.

Subsystem - A functional grouping of components that combine to perform a major function within an element.

Satellite - The GeoXO Satellite consists of the Spacecraft and Government Furnished Equipment (GFE) science instrument payload. (CCR-X00080A)

Spacecraft - The Spacecraft consists of the flight hardware and software required to accommodate the science instrument payload. For the east and west stations, the Spacecraft includes the Data Collection Platform Report (DCPR) auxiliary communication. (CCR-X00080A)

Spacecraft Bus - Satellite without instruments and DCPR auxiliary communication.

System - A composite of hardware, software, skills, personnel, and techniques capable of performing and/or supporting an operational role. A complete system includes related facilities, equipment, materials, services, software, technical data, and personnel required for its operation and support to the degree that it can be considered a self-sufficient unit in its intended operational and/or support environment.

The system is what is employed operationally and supported logistically. (More than one system may be needed to conduct a mission)

Unit - Defined to be a functional subdivision of an instrument, such as an Electronics Box or Power Supply Box or cryocooler.

Validation - Proof that the Operations Concept, Requirements, and Architecture and Design will meet Mission Objectives, that they are mutually consistent, and that the “right system” has been designed.

Validation Basis - A set of requirements that provide the success criteria for a system or system element.

Verification - Proof of compliance with requirements and that the system has been “Designed and Built Right.” May be determined by a combination of test, analysis, and inspection.

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Critical telemetry - telemetry points that are required to monitor the instrument in powered OFF state.

Non-critical telemetry - telemetry points that are required to monitor the instrument in powered ON state.

Engineering telemetry - data required to process instrument sensor data to higher level products.

Housekeeping telemetry - data required to monitor instrument operation, health, and safety.

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2 Documents

2.1 Applicable Documents

The following documents of the exact issue shown form a part of this GIRD to the extent specified herein. In the event of conflict between the documents referenced and the contents of this GIRD the latter shall be the superseding requirement.

1. 418-XO-RPT-0039 - GOES Reliable Data Delivery Protocol (GRDDP).

2. 418-XO-RPT-0042 - Radiation Environment for Electronic Devices on the

GeoXO Series Satellites.

3. CCSDS 133.0-B-2 Space Packet Protocol, Blue Book, Issue 2, June 2020.

4. CCSDS 301.0-B-4 - Time Code Formats. Blue Book. Issue 4, November 2010.

5. CCSDS 660.0-B-2 – XML Telemetric and Command Exchange, Version 1.2, February 2020.

6. ECSS-E-ST-50-12C Rev.1 – European Cooperation for Space Standardization

(ECSS), SpaceWire – Links, nodes, routers and networks, 15 May 2019.

7. ECSS-E-ST-50-14C - Spacecraft discrete interfaces, 31 July 2008.

8. GSFC-STD-7000B – General Environmental Verification Standard (GEVS) for

GSFC flight Programs and Projects, 28 April 2021.

9. IEEE/ASTM SI-10 - American National Standard for Metric Practice, 2016.

10. ISO 14644-1:2015 Cleanrooms and associated controlled environments - Part

1: Classification of air cleanliness by particle concentration, December 15, 2015.

11. ISO 14644-3:2019 Cleanrooms and associated controlled environments - Part 3: Test methods, September 1, 2019.

12. MIL-STD-461C – Electromagnetic Emission and Susceptibility Requirements for the Control of Electromagnetic Interference, 4 August 1986.

13. MIL-STD-461G – Requirements for the Control of Electromagnetic Interference Characteristics of Subsystems and Equipment, 11 December 2015.

14. MIL-PRF-27401G – Propellant Pressurizing Agent, Nitrogen, 7 August 2013.

15. PRC-5001 Rev G – Process Specification for Cleaning Hardware, June 2020.

16. USNO Circular 179 - The IAU Resolutions on Astronomical Reference Systems, Time Scales, and Earth Rotation Models 20 October 2005.

17. ITU-R RA.769-2 – Protection criteria used for radio astronomical measurements, 2003.

(CCR-X00080A) (CCR-X00153A)

2.2 Reference Documents

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1. CCSDS 701.0-B-3 - Recommendations for Advanced Orbiting Systems, Networks and Data Links, Architectural Specification, June 1, 2001

2. CCSDS 660.1-G-1 – XML Telemetric and Command Exchange (XTCE) – Element Description, May 2012.

3. Farrenkopf, R.L., "Analytic Steady-State Accuracy Solutions for Two Common Spacecraft Attitude Estimators," Journal of Guidance and Control (Reston, VA:

American Institute of Aeronautics and Astronautics), July-August, 1978, Vol.1, No.4, pp.282-284.

4. Markley, F. Landis, and R.G. Reynolds, "Analytic Steady-State Accuracy of a Spacecraft Attitude Estimator," Journal of Guidance, Control, and Dynamics (Reston, VA: American Institute of Aeronautics and Astronautics), November- December, 2000, Vol.23, No.6, pp.1065- 1067.

5. Wertz, J.R., Spacecraft Attitude Determination and Control, edited by James R.

Wertz (Boston: Reidel, 1978), pp.268-270.

(CCR-X00080A)

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418-XO-GIRD-0041, RM Version, Geostationary eXtended Observations (GeoXO) General Interface Requirements Document

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3 Requirements

3.1 General Requirements

3.1.1 Instrument Modes

3.1.1.1 Power Off Mode

The Instrument Power OFF Mode shall not draw operational power.

3.1.1.2 Instrument Safe Mode

3.1.1.2.1 Instrument Safe Mode Command

The instrument shall enter Instrument Safe Mode upon receipt of a safing command from the spacecraft.

3.1.1.2.2 Instrument Safe Mode Timeout

The instrument shall enter Instrument Safe Mode upon the detection of 10 consecutive missing time messages.

3.1.1.3 Survival and Storage Modes

The spacecraft shall provide survival heater power in Survival and Storage modes.

The instrument shall not draw operational power while in Survival and Storage modes.

3.1.2 Operational Concepts

3.1.2.1 Pre-Launch

The satellite will be transported to the launch site where final vehicle preparations and checkout will be accomplished.

The Spacecraft and Instrument contractors will conduct final system verification tests prior to launch. (CCR-X00080A)

Instrument testing and inspection to be accomplished at the launch site will be documented in the ICD.

3.1.2.2 Launch and Orbit Raising

The instrument will be in Survival Mode during launch.

The instrument contractor will identify in the IDD 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.

3.1.2.3 On-Orbit Concept

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The satellite will operate in a geosynchronous orbit (Semi-major axis of approximately 42,164 km) located between 75 degrees and 137 degrees west longitude. Normal on-orbit operations entail periodic station keeping maneuvers that keep the satellite within a 0.05 degrees inclination about the equator and within 0.05 degrees of the on-station longitude.

The instrument with associated ground processing algorithms shall meet all functional and performance requirements when stationed in geostationary orbit within +/- 0.5 degrees of the spacecraft’s reference longitude and with an inclination up to 0.5 degrees.

The spacecraft and instrument shall operate at any reference longitude between 5 degrees West and 148 degrees West longitude.

Instrument products shall be generated from the viewpoint of a satellite at the designated longitude at zero inclination. (CCR-X00080A)

Instruments shall survive an anomaly resulting in a static instrument line-of-sight (LOS) such that the sun passes through the LOS at orbit rate.

Instruments, while operational, shall survive a spacecraft attitude anomaly resulting in the sun being at an arbitrary fixed location within the instrument field of regard (FOR) for an indefinite period of time.

Instruments shall survive the sun sweeping through the field-of-view (FOV) of the instrument radiator from “horizon to horizon” at a rate of 6 degrees per minute, passing through radiator normal.

3.1.3 Dimension Standard

For all documents related to Instrument interfaces, the Spacecraft and Instrument contractors shall use the International System of Units (SI) for all measurement units in accordance with IEEE/ASTM SI-10 [9]. The contractor may include English units in parenthesis for clarification. (CCR-X00080A)

3.1.4 Coordinates

The orbit reference frame (ORF) shall be defined as follows:

The ORF is orthogonal and right-handed.

The ORF origin is at the spacecraft center of mass.

The ORF +z axis points toward the center of the Earth.

The ORF +y axis points along the negative orbit normal.

The ORF +x axis completes the triad.

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The body reference frame (BRF) shall be defined as follows:

The BRF is orthogonal and right-handed.

The BRF is fixed to the body of the spacecraft.

The location of the BRF origin will be specified by the spacecraft contractor.

The BRF axes are nominally parallel to the ORF axes when spacecraft attitude is in its nominal Earth-pointing, upright yaw attitude with zero attitude error.

The roll, pitch, and yaw axes are defined to be parallel to the BRF x, y, and z axes, respectively.

The reference coordinate system of each instrument unit shall be nominally parallel to the spacecraft BRF coordinate system.

The origin of the coordinate system of each instrument unit shall be located and defined inside the mechanical envelope of the instrument unit.

3.1.5 Yaw Flip

Instruments shall meet all performance requirements whether or not the spacecraft performs a yaw flip.

3.2 Interface Requirements

All instrument-to-spacecraft interfaces shall be single fault tolerant. This does not include primary mechanical load paths for kinematic mounts.

3.2.1 Mechanical

3.2.1.1 Envelope Documentation

The instrument contractor will document the instrument unit envelopes in the IDD by engineering drawings with a set of “not to exceed” dimensions. The instrument envelopes will be inclusive of the thermal blankets.

The instrument contractor will ensure that the swept or deployed volume includes tolerances, distortions and misalignments.

The instrument contractor will include any harness constraints including bend radiuses in the IDD.

3.2.1.2 Critical Clearances

The spacecraft contractor will position the instrument units on the spacecraft to ensure that the stowed, deploying, and final deployed positions of the instrument units clear all obstacles including obstacles on the spacecraft, and other instruments.

The spacecraft shall maintain a minimum of 2.5 cm clearance between the instrument units and surrounding structure.

The spacecraft contractor will implement a critical clearance analysis to ensure that the clearance rule is not violated.

3.2.1.3 Fields of View

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ID

GIRD81

GIRD82

GIRD83

GIRD84

GIRD85

GIRD86

GIRD87

GIRD88

GIRD89

GIRD90

GIRD566

GIRD91

GIRD92

GIRD93

GIRD94

GIRD95

GIRD96

GIRD97

GIRD98

Object Number

3.2.1.3.0-1

3.2.1.4

3.2.1.4.0-1

3.2.1.4.0-2

3.2.1.4.1

3.2.1.4.1.0-1

3.2.1.4.1.0-2

3.2.1.4.2

3.2.1.4.2.0-1

3.2.1.4.2.0-2

3.2.1.4.2.0-3

3.2.1.4.2.0-4

3.2.1.5

3.2.1.5.1

3.2.1.5.1.0-1

3.2.1.5.1.0-2

3.2.1.5.1.0-3

3.2.1.5.1.0-4

3.2.1.5.2

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(GIRD)

The instrument contractor will document the instrument field-of-view requirements in the IDD.

3.2.1.4 Mass Properties

Each Instrument unit measured mass shall have an accuracy of 0.5 kg. (CCR- X00080A)

The nominal launch mass with tolerances of each instrument unit will be provided to the spacecraft contractor for documentation in the ICD.

3.2.1.4.1 Center of Mass

Each Instrument unit’s measured center of mass relative to the instrument unit coordinate system shall have an accuracy of 5 mm for both launch and deployed configurations. (CCR-X00080A)

The launch and deployed centers of mass with tolerances of each instrument unit will be provided to the spacecraft contractor for documentation in the ICD, referenced to the instrument coordinate axes.

3.2.1.4.2 Inertia Properties

The instrument unit moment of inertia will be defined using the instrument unit coordinate frame passing through the instrument center of mass.

The instrument unit’s reported moments and products of inertia at the center of mass shall have an accuracy of 5% of the maximum principal moment of inertia for both stowed and deployed configurations. (CCR-X00080A)

The Instrument measured rotating moments of inertia for all scan mechanisms shall have an accuracy of 5.0 percent. (CCR-X00080A)

The launch and deployed moments and products of inertia with tolerances of each separately mounted instrument unit, referenced to the instrument coordinate axes, will be provided to the spacecraft contractor for documentation in the ICD.

3.2.1.5 Mounting

3.2.1.5.1 Mounting Hardware

The spacecraft contractor will define and document all mounting hardware in the ICD and indicate the hardware provider.

Unless otherwise specified, the spacecraft contractor will provide all mounting hardware for the instrument units.

The instrument contractor will provide all kinematic mounts.

The instrument units will be delivered to the spacecraft contractor with flight mounts installed.

3.2.1.5.2 Mounting Method

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ID

GIRD99

GIRD100

GIRD101

GIRD102

GIRD103

GIRD104

GIRD105

GIRD106

GIRD107

GIRD108

GIRD109

GIRD110

GIRD111

GIRD112

GIRD113

GIRD114

GIRD115

GIRD116

Object Number

3.2.1.5.2.0-1

3.2.1.5.2.0-2

3.2.1.5.2.0-3

3.2.1.5.2.0-4

3.2.1.5.2.0-5

3.2.1.5.3

3.2.1.5.3.0-1

3.2.1.5.3.0-2

3.2.1.5.3.0-3

3.2.1.5.4

3.2.1.5.4.0-1

3.2.1.5.4.0-2

3.2.1.5.5

3.2.1.5.5.0-1

3.2.1.5.5.0-2

3.2.1.5.6

3.2.1.5.6.0-1

3.2.1.5.6.0-2

418-XO-GIRD-0041, RM Version, Geostationary eXtended Observations (GeoXO) General Interface Requirements Document

(GIRD)

The Instrument units and Spacecraft, excluding the sensor unit, shall accommodate mounting the Instrument units onto the Spacecraft with the Spacecraft mounting surface in the vertical or with the Spacecraft mounting surface normal pointing up.

(CCR-X00080A)

The Instrument sensor unit and Spacecraft shall accommodate mounting the Instrument sensor unit onto the Spacecraft with the Spacecraft mounting surface normal pointing up. (CCR-X00080A)

For instrument units with a mass greater than 15 kg, a minimum of three lifting points shall be provided.

The Instrument lifting points shall allow handling with an overhead crane including when the unit is in its launch or deployed configuration. (CCR-X00080A)

The method by which each instrument unit is mounted to the spacecraft will be defined in the ICD.

3.2.1.5.3 Handling Fixtures

The instrument contractor will provide proof tested handling fixtures for each unit with a mass greater than 15 kg.

The Instrument handling fixtures shall be designed to 5 times limit load for ultimate strength and 3 times limit load for yield strength. (CCR-X00080A)

The Instrument handling fixtures shall survive 2 times the working load as demonstrated by proof load testing. (CCR-X00080A)

3.2.1.5.4 Interface

The Spacecraft and Instrument mounting surfaces shall be flat to less than 0.83 mm per meter peak to peak. (CCR-X00080A)

The spacecraft contractor working with the instrument contractor will define the mechanical mounting interface requirements for each instrument unit in the ICD.

Requirements include surface flatness, finish, mounting bolt size, number, material, and torque limits.

3.2.1.5.5 Location

The spacecraft contractor working with the instrument contractor will define and document the location and orientation of instrument units on the spacecraft in the ICD.

Coordinates and dimensions of the holes for mounting hardware will be specified at the mechanical interface and defined in the ICD.

3.2.1.5.6 Drill Templates

The Spacecraft and Instrument unit mounting design shall allow like Instrument units to be interchanged. (CCR-X00080A)

Instrument unit, spacecraft, and test fixture interfaces shall be drilled using templates to correctly establish the pattern of the mounting holes.

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ID

GIRD117

GIRD118

GIRD119

GIRD120

GIRD121

GIRD123

GIRD124

GIRD125

GIRD126

GIRD127

GIRD128

GIRD129

GIRD130

GIRD131

GIRD132

GIRD133

GIRD134

GIRD135

Object Number

3.2.1.5.6.0-3

3.2.1.5.6.0-4

3.2.1.5.6.0-5

3.2.1.6

3.2.1.6.0-1

3.2.1.6.0-2

3.2.1.6.0-3

3.2.1.6.1

3.2.1.6.1.1

3.2.1.6.1.1.0-1

3.2.1.6.1.1.0-2

3.2.1.6.1.1.0-3

3.2.1.6.1.1.0-4

3.2.1.6.1.1.0-5

3.2.1.6.1.2

3.2.1.6.1.2.0-1

3.2.1.6.1.2.0-2

3.2.1.6.1.3

418-XO-GIRD-0041, RM Version, Geostationary eXtended Observations (GeoXO) General Interface Requirements Document

(GIRD)

The Instrument unit drill template shall include appropriate alignment, orientation and location reference information and alignment cubes if required. (CCR-X00080A)

The spacecraft contractor will document functional requirements, and orientation information for the drill templates in the ICD.

The instrument contractor will provide an alignment drill template labeled with appropriate alignment, orientation, location reference information, and alignment cubes if necessary.

3.2.1.6 Alignment

The instrument contractor will measure the alignment between the sensor line-of-sight and the instrument alignment reference frame and deliver the results to the spacecraft contractor.

The spacecraft contractor will document all alignment measurements in an alignment report.

The spacecraft and instrument contractors will negotiate and document in the ICD any relevant alignment requirements not specified in this document (GIRD).

3.2.1.6.1 Instrument Alignment (CCR-X00080A)

3.2.1.6.1.1 Alignment References

The instrument shall include a permanent alignment reference on the instrument sensor unit composed of a minimum 2.54 cm alignment cube with a flight cover and a mounting surface datum. The instrument alignment cube defines the instrument alignment reference frame.

The spacecraft inertial reference unit (IRU) shall include an alignment cube mounted with a flight cover on the IRU. This alignment cube defines the IRU reference frame. The IRU reference frame is the navigation reference frame of the spacecraft and is nominally parallel to the BRF.

The spacecraft IRU and instrument alignment cube pairs shall be viewable from two orthogonal directions.

The instrument contractor will document the location of all instrument optical alignment cubes in the IDD.

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

3.2.1.6.1.2 Alignment Responsibilities

The spacecraft contractor will align the instrument alignment reference frame to the spacecraft IRU reference frame.

The Spacecraft contractor will measure the alignment between the Instrument alignment reference frame and the Spacecraft attitude control system reference frame. The Spacecraft contractor will define the attitude control system reference frame in the ICD. (CCR-X00080A)

3.2.1.6.1.3 Instrument Placement

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ID

GIRD136

GIRD137

GIRD138

GIRD139

GIRD140

GIRD141

GIRD142

GIRD143

GIRD144

GIRD145

GIRD146

GIRD147

GIRD148

GIRD149

GIRD150

GIRD151

GIRD152

Object Number

3.2.1.6.1.3.0-1

3.2.1.6.1.4

3.2.1.6.1.4.0-1

3.2.1.6.1.5

3.2.1.6.1.5.0-1

3.2.1.7

3.2.1.7.0-1

3.2.1.7.0-2

3.2.1.7.0-3

3.2.1.8

3.2.1.8.0-1

3.2.1.8.1

3.2.1.8.1.0-1

3.2.1.8.1.1

3.2.1.8.1.1.0-1

3.2.1.8.1.1.0-2

3.2.1.8.1.1.0-3

418-XO-GIRD-0041, RM Version, Geostationary eXtended Observations (GeoXO) General Interface Requirements Document

(GIRD)

The Spacecraft placement of the Instrument alignment reference frame with respect to the Spacecraft attitude control system reference frame shall be to within 0.25 degrees per axis, including variation over all launch and on-orbit environments. (CCR-X00080A)

3.2.1.6.1.4 Initial Alignment Knowledge

The Spacecraft prelaunch alignment knowledge of the Instrument alignment reference frame with respect to the Spacecraft attitude control system reference frame shall be 300 microradians or better per axis. (CCR-X00080A)

3.2.1.6.1.5 Alignment Rate of Change

The Spacecraft alignment change between the Instrument mounting frame and the Spacecraft attitude control system reference frame shall not exceed 100 microradians per hour per axis.

This requirement includes on-orbit environments and Spacecraft structural and thermal stability.

(CCR-X00080A)

3.2.1.7 Instrument Access

The Spacecraft mounting for the Instrument units shall leave adequate clearance between the Instrument and surrounding structures to provide access to Instrument mounting hardware, access to Instrument connectors including a view during mating, and space for Instrument interfacing harness service loops. (CCR-X00080A)

The Instrument contractor will document the Instrument access requirements in the

IDD. (CCR-X00080A)

The instrument units shall mount to the satellite with only exterior access to the instrument unit.

3.2.1.8 Attitude and Disturbances (CCR-X00080A)

The requirements in this section apply while any instrument is on orbit and operating.

(CCR-X00080A)

3.2.1.8.1 Spacecraft Attitude and Disturbances

The interface attitude error and disturbance limits include government-held reserve and all spacecraft errors, including orbit and attitude knowledge, attitude command error, and attitude control error with all instruments operating in normal operational mode.

3.2.1.8.1.1 Attitude Error

Attitude error is defined as the difference between the target attitude and the true attitude of the instrument mounting frame.

The Instrument shall meet all performance requirements while the total bias and quasi-static attitude error of the instrument mounting frame relative to the desired ORF-referenced attitude is less than 4500 microradians, 3-sigma, per axis. Quasi-static error includes variation over timeframes longer than 24 hours. (CCR-X00080A)

The Instrument shall meet all performance requirements while the total diurnal and dynamic attitude error of the instrument mounting frame relative to the desired ORF-referenced attitude is less than 325 microradians, 3-sigma, per axis. Diurnal error has a period of 24 hours. Dynamic error includes variation over timeframes shorter than 24 hours, typically much shorter. (CCR- X00080A)

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ID

GIRD153

GIRD154

GIRD155

GIRD156

GIRD157

GIRD158

GIRD159

GIRD160

GIRD161

Object Number

3.2.1.8.1.2

3.2.1.8.1.2.0-1

3.2.1.9

3.2.1.9.0-1

3.2.1.9.0-2

3.2.1.9.0-3

3.2.2

3.2.2.1

3.2.2.1.0-1

418-XO-GIRD-0041, RM Version, Geostationary eXtended Observations (GeoXO) General Interface Requirements Document

(GIRD)

3.2.1.8.1.2 Attitude Rate Error

The Instrument shall meet all performance requirements while amplitudes of the Instrument mounting frame (IMF) angular rates per axis relative to the ORF and the total Spacecraft angular rate data latency are less than the limits in Figure GIRD154. (CCR-X00080A)

Figure GIRD154: Instrument Limit for Angular Rate Error vs Latency

3.2.1.9 Flight and Non-Flight Equipment

The instrument contractor will provide information on all items to be installed or removed prior to flight for identification in the IDD.

The instrument contractor will tag all non-flight items to be removed prior to flight with a red tag stating, "Remove Before Flight".

The instrument contractor will tag all flight items to be installed prior to flight with a green tag stating, "Install Before Flight".

3.2.2 Thermal

3.2.2.1 Thermal Control Concept

The instrument units installed on the spacecraft bus fall under one of the following categories:

a) Thermally-independent units are conductively and radiatively decoupled from the spacecraft and reject their heat directly to space.

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ID

GIRD161

GIRD162

GIRD163

GIRD164

GIRD165

GIRD166

GIRD167

GIRD168

GIRD169

GIRD170

GIRD171

GIRD172

GIRD173

GIRD174

GIRD175

Object Number

3.2.2.1.0-1

3.2.2.1.1

3.2.2.1.1.0-1

3.2.2.1.2

3.2.2.1.2.0-1

3.2.2.1.3

3.2.2.1.3.0-1

3.2.2.2

3.2.2.2.0-1

3.2.2.2.0-2

3.2.2.2.0-3

3.2.2.2.0-4

3.2.2.3

3.2.2.3.1

3.2.2.3.1.0-1

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(GIRD)

b) Thermally-coupled units dissipate their heat to the spacecraft.

In general:

⦁ Instrument electronic units are thermally-coupled.

⦁ Instrument sensor units are thermally-independent.

3.2.2.1.1 Independent Unit - Net Heat Transfer

Instrument sensor units shall transfer less than 15.5 watts per meter squared averaged over its interface plane including radiation between adjacent Instrument and Spacecraft surfaces, conduction via the mechanical interface and conduction via the instrument harness. (CCR-X00080A)

3.2.2.1.2 Coupled Unit – Heat Transfer

The spacecraft shall provide a heat rejection path for thermally coupled units.

3.2.2.1.3 Coupled Unit - Heat Transfer Flux Density

The Instrument electronics units shall transfer less than 0.25 watts per square centimeter on average across the spacecraft interface plane with an allowable peak of

3.0 watts per square centimeter. (CCR-X00080A) (CCR-X00176)

3.2.2.2 Interface Temperatures

The instrument units shall operate with spacecraft interface temperatures defined in the operate columns of Table GIRD169.

Table GIRD169: Instrument operational and survival spacecraft interface temperatures operate survive min max min max units C C C C electronic 0 40 -10 50 sensor -15 35 -30 50

The instrument units shall survive with spacecraft interface temperatures defined in the survive columns of Table GIRD169.

The instrument units shall survive power ON at the minimum survival temperatures defined in Table GIRD169.

The spacecraft shall maintain the instrument interface temperatures within the operate range defined in Table GIRD169.

3.2.2.3 Temperature Monitoring

3.2.2.3.1 Mechanical Interface Temperature Monitoring

The instrument contractor will select a unit attachment point for interface temperature monitoring device and identify it on the IDD.

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ID

GIRD176

GIRD177

GIRD178

GIRD179

GIRD180

GIRD181

GIRD182

GIRD183

GIRD184

GIRD185

GIRD583

GIRD186

GIRD187

GIRD188

GIRD189

GIRD190

GIRD191

GIRD192

GIRD193

GIRD567

Object Number

3.2.2.3.1.0-2

3.2.2.3.2

3.2.2.3.2.0-1

3.2.2.3.2.0-2

3.2.2.3.2.0-3

3.2.2.3.3

3.2.2.3.3.0-1

3.2.2.4

3.2.2.4.1

3.2.2.4.1.0-1

3.2.2.4.1.0-2

3.2.2.4.1.0-3

3.2.2.4.1.0-4

3.2.2.4.2

3.2.2.4.2.0-1

3.2.2.4.3

3.2.2.4.3.0-1

3.2.2.5

3.2.2.5.0-1

3.2.2.5.0-2

418-XO-GIRD-0041, RM Version, Geostationary eXtended Observations (GeoXO) General Interface Requirements Document

(GIRD)

The spacecraft shall have a temperature sensor adjacent to this attachment point (on the spacecraft side) to serve as the interface temperature sensor.

3.2.2.3.2 Instrument Critical Temperatures

The instrument units shall contain critical temperature sensors to allow monitoring the thermal safety of the instrument while the instrument is OFF.

The spacecraft shall convey instrument critical temperatures via the spacecraft telemetry stream.

The instrument contractor will furnish temperature calibration coefficients for the critical temperature sensors and document them in the IDD.

3.2.2.3.3 Instrument Non-Critical Temperatures

The instrument shall report instrument non-critical temperatures in telemetry.

3.2.2.4 Thermal Interfaces

3.2.2.4.1 Mounting Details

The instrument shall be designed to perform during Spacecraft level Thermal Vacuum with the Spacecraft +Y BRF axis aligned with gravity and pointed down. (CCR- X00153A)

The Spacecraft shall be designed to perform during Spacecraft level Thermal Vacuum with the Spacecraft +Y BRF axis aligned with gravity and pointed down. (CCR-

X00080A) (CCR-X00153A)

Reserved (CCR-X00198A)

The spacecraft contractor will document in the ICD properties of any thermally conductive or isolating materials used at the interface of the instrument unit.

3.2.2.4.2 Contact Area

The Instrument and Spacecraft mounting contact areas shall be unpainted for thermally coupled Instrument units. (CCR-X00080A)

3.2.2.4.3 Interstitial Materials

The spacecraft contractor will integrate the instrument units onto the spacecraft including application of any interstitial materials as conductive enhancements.

Selection and application of any interface materials require the concurrence of the instrument contractor and spacecraft contractor.

3.2.2.5 Multi-layer Insulation

The Instrument multi-layer insulation (MLI) shall have provisions for electrical grounding to prevent ESD. (CCR-X00080A)

The Spacecraft shall ground the Instrument multi-layer insulation. (CCR-X00080A)

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ID

GIRD194

GIRD195

GIRD196

GIRD197

GIRD198

GIRD199

GIRD200

GIRD201

GIRD202

GIRD203

GIRD204

GIRD205

GIRD206

GIRD207

GIRD208

GIRD209

GIRD210

Object Number

3.2.2.5.0-3

3.2.3

3.2.3.0-1

3.2.3.1

3.2.3.1.0-1

3.2.3.1.0-2

3.2.3.1.0-3

3.2.3.1.0-4

3.2.3.1.0-5

3.2.3.1.0-6

3.2.3.1.0-7

3.2.3.1.0-8

3.2.3.1.0-9

3.2.3.1.0-10

3.2.3.1.0-11

3.2.3.2

3.2.3.2.1

418-XO-GIRD-0041, RM Version, Geostationary eXtended Observations (GeoXO) General Interface Requirements Document

(GIRD)

The Instrument MLI vents shall be located and oriented consistent with Satellite contamination requirements as documented in the ICD. (CCR-X00080A)

3.2.3 Instrument Electrical Power

The Instrument and Spacecraft electrical power interface requirements shall be specified at the Instrument input power connectors. (CCR-X00080A)

3.2.3.1 Electrical Power Interfaces

The Spacecraft shall supply functionally independent, primary and redundant operational power buses to each Instrument for normal Instrument operation.

Functionally independent operational power buses includes supplying primary or redundant operational power to one Instrument while supplying primary or redundant operational power to any other Instrument. (CCR-X00080A)

The spacecraft shall supply either primary or redundant operational power buses for any instrument.

The instrument shall operate using either the primary or redundant operational power buses.

The instrument shall survive for an hour the application of power simultaneously on both primary and redundant operation buses.

The Spacecraft shall supply functionally independent, primary and redundant survival power buses to each Instrument to power the Instrument survival heaters. Functionally independent survival power buses includes supplying primary or redundant survival power to one Instrument while supplying primary or redundant survival power to any other Instrument. (CCR-X00080A)

The spacecraft shall energize both primary and redundant survival power buses for all the instruments.

The thermally independent instrument units shall only utilize survival heater power for heaters and associated passive control circuitry which maintains the instrument above its minimum turn-on temperature.

The thermally independent instrument units shall maintain turn-on temperatures using either the primary or redundant survival heater buses.

The spacecraft power system shall accommodate instrument operational bus turn-on and peak survival bus loading simultaneously for each instrument.

The spacecraft power system shall accommodate the sequential turn-on/activation of all instruments.

Following the initial thermal transition from survival mode following instrument turn-on, the instrument shall not use power from the survival heater buses when operational power is active.

3.2.3.2 Power Specifications

3.2.3.2.1 Power Definitions

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ID

GIRD211

GIRD212

GIRD213

GIRD214

GIRD215

GIRD571

GIRD216

GIRD573

GIRD217

GIRD218

GIRD219

GIRD220

GIRD221

GIRD581

GIRD222

GIRD582

GIRD223

GIRD224

GIRD575

GIRD225

Object Number

3.2.3.2.1.0-1

3.2.3.2.2

3.2.3.2.2.1

3.2.3.2.2.1.1

3.2.3.2.2.1.1.0-1

3.2.3.2.2.1.1.0-2

3.2.3.2.2.1.1.0-3

3.2.3.2.2.1.1.0-4

3.2.3.2.2.1.2

3.2.3.2.2.1.2.0-1

3.2.3.2.2.1.3

3.2.3.2.2.1.3.0-1

3.2.3.2.2.1.3.0-2

3.2.3.2.2.1.3.0-3

3.2.3.2.2.1.3.0-4

3.2.3.2.2.1.3.0-5

3.2.3.2.2.1.4

3.2.3.2.2.1.4.0-1

3.2.3.2.2.1.4.0-2

3.2.3.2.2.1.5

418-XO-GIRD-0041, RM Version, Geostationary eXtended Observations (GeoXO) General Interface Requirements Document

(GIRD)

The following definitions shall be used when calculating average power, and maximum power values.

Average Power (Operational) - The total power into an instrument averaged over any 5 minute period.

Average Power (Survival) - The total power into an instrument averaged over any 72 minute period.

Maximum Power (Operational or Survival) - The total power into an instrument averaged over any 20 ms period.

3.2.3.2.2 Power Characteristics

3.2.3.2.2.1 Voltage

3.2.3.2.2.1.1 Instrument Voltage

The spacecraft shall supply DC voltage of 28 +/- 2.0 volts at the instrument operational power input connector for any condition of instrument load current including transients.

The Instrument shall meet all performance requirements with the operational voltage range defined in GIRD215. (CCR-X00080A)

The spacecraft shall supply a DC voltage of 100 (TBR) +/- 3.0 volts at the instrument survival heater power input connector. (CCR-X00153A)

The Instrument shall survive with the survival voltage range defined in GIRD216. (CCR- X00080A)

3.2.3.2.2.1.2 Voltage Transients

The spacecraft shall control the voltage rate of rise in the range of 7 – 30 Volts/millisecond when powering ON instrument operational power interfaces. (CCR-X00198A)

3.2.3.2.2.1.3 Abnormal Operation Voltage Limits

The Spacecraft shall limit an operational power supply over voltage to less than 40 volts for less than 30 minutes. (CCR-X00080A)

The Spacecraft shall limit an operational power supply over voltage to less than 50 volts for less than 10 ms. (CCR-X00080A)

The Instrument shall survive operational power over voltage events to the voltages and durations specified in GIRD220 and GIRD221. (CCR-X00080A)

The instrument shall limit the operational power supply undershoot to minus 3 volts following removal of power.

The Spacecraft shall survive an operational power under voltage event with the voltage specified in GIRD222. (CCR-X00080A)

3.2.3.2.2.1.4 Spacecraft Unpowered Voltage

The spacecraft operational power OFF voltage shall be zero to 1.5 volts at the instrument interface.

The Instrument shall remain OFF with the operational voltage range defined in GIRD224. (CCR-

3.2.3.2.2.1.5 Voltage Power Source Impedance

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ID

GIRD226

GIRD227

GIRD228

GIRD229

GIRD230

GIRD231

GIRD232

GIRD233

GIRD234

Object Number

3.2.3.2.2.1.5.0-1

3.2.3.2.2.1.5.0-2

3.2.3.2.2.1.5.0-3

3.2.3.2.2.2

3.2.3.2.2.2.1

3.2.3.2.2.2.1.0-1

3.2.3.2.3

3.2.3.2.3.1

3.2.3.2.3.1.0-1

418-XO-GIRD-0041, RM Version, Geostationary eXtended Observations (GeoXO) General Interface Requirements Document

(GIRD)

The spacecraft shall control its instrument operational power source impedance to the levels specified in Figure GIRD226.

Figure GIRD226: Spacecraft’s Instrument Operational Power Source Impedance

The actual source impedance the instrument will see at the instrument/spacecraft interface will be the source impedance in Figure GIRD226 modified by the additional impedance of the spacecraft power distribution hardware and the additional impedance of the harness unique to each instrument. These instrument unique spacecraft source impedance values will be documented in the spacecraft to instrument ICDs.

The input impedance of the instrument will be coordinated with the spacecraft provider and documented in the spacecraft to instrument ICD. The instrument supplier should consider input filter design, DI/DT requirements, and negative impedance loading of the instrument power conditioning hardware to mitigate potential stability concerns.

3.2.3.2.2.2 Current

3.2.3.2.2.2.1 Operational Power Transients

The instrument shall limit any change in operational power current at any time including initial power turn-on to no more than 0.2 A/usec.

3.2.3.2.3 Power Distribution, Control, and Status

3.2.3.2.3.1 Operational Power Lines

The Spacecraft shall supply single fault tolerant operational power distribution to the Instrument for primary and redundant Instrument operational power sources as specified in Figure GIRD234.

Rationale: The Spacecraft can power each Instrument side independently. The Spacecraft primary (A) side and redundant (B) side are independent for each Instrument.

Page 19 of 58 Printed Thursday, June 29, 2023

ID

GIRD234

GIRD235

GIRD236

GIRD237

GIRD238

GIRD239

GIRD240

GIRD241

GIRD242

Object Number

3.2.3.2.3.1.0-1

3.2.3.2.3.1.0-2

3.2.3.2.3.1.0-3

3.2.3.2.3.1.0-4

3.2.3.2.3.2

3.2.3.2.3.2.0-1

3.2.3.2.3.2.0-2

3.2.3.2.3.2.0-3

3.2.3.2.3.3

418-XO…