LNEXT-SYS-REQ-0005 Rev C Landsat Next Environmental Requirements Document (LNERD) 20250124.pdf

DOORS EXPORT

National Aeronautics and Space Administration

Goddard Space Flight Center Greenbelt, Maryland

LNEXT-SYS-REQ-0005, Revision C

Landsat Next, Code 426

Landsat Next Environmental Requirements Document (LNERD)

LNext Reviewed – Not Subject to Export Control

1/24/2025

LNERD LNEXT-SYS-REQ-0005 Revision C iv

CM Foreword This document is a Landsat Next Project Configuration Management (CM)-controlled document.

Changes to this document require prior approval of the applicable Configuration Control Board (CCB) Chairperson or designee. Proposed changes shall be submitted to the Landsat Next CM Office (CMO), along with supportive material justifying the proposed change. Changes to this document will be made by complete revision.

Questions or comments concerning this document should be addressed to:

NASA/Goddard Space Flight Center Landsat Next Project Office, Code 426 Attention: Configuration Management Office Greenbelt, Maryland 20771 v

Change History Log vi

Table of Contents SIGNATURE/APPROVAL PAGE ................................................................................................ II

CM FOREWORD ......................................................................................................................... IV

CHANGE HISTORY LOG ............................................................................................................ V

LIST OF TBDS/TBRS ............................................... ERROR! BOOKMARK NOT DEFINED.

TABLE OF CONTENTS .............................................................................................................. VI

LIST OF FIGURES .................................................................................................................... VIII

LIST OF TABLES ...................................................................................................................... VIII

1.0 GENERAL INFORMATION

1.1 Purpose

1.2 Mission Overview

1.2.1 Mission Statement

1.2.2 Mission Background

1.2.3 Mission Objectives

1.2.4 Mission Implementation

1.2.4.1 Space Segment

1.2.4.2 Ground Segment

1.2.4.3 Launch Segment

1.3 Applicability and Limitations

1.4 The Landsat Next Verification Approach

1.5 Other Assurance Requirements

1.6 Responsibility for Administration

1.7 Landsat Next Configuration Control and Distribution

1.8 Applicable and Reference Documents

1.8.1 Applicable Documents

1.8.1.1 Project Applicable Documents

1.8.2 Reference Documents

1.9 Criteria for Unsatisfactory Performance

1.10 Testing of Spare Hardware

1.10.1 "One-Shot" Items

1.11 Test Facilities, Calibration

1.12 Test Condition Tolerances

1.13 Test Measurement Considerations

2.0 VERIFICATION PROGRAM

2.1 System Performance Verification

2.2 General Verification Requirements

2.2.1 Test Sequence and Level of Assembly

2.2.2 Verification Program Tailoring

2.2.3 Qualification of Hardware by Similarity

2.2.4 Test Factors/Durations

2.2.5 Structural Analysis/Design Factors of Safety

vii

2.3 Function and Performance Test Requirements

2.3.1 Hardware Performance Testing

2.3.2 Long Duration and Failure Free System Level Test of Flight Software

2.4 Structural and Mechanical Verification Requirements

2.4.1 Structural Loads Qualification

2.4.1.1 Coupled Load Analysis

2.4.1.2 Modal Survey

2.4.1.3 Design Strength Qualification

2.4.1.4 Structural Reliability (Residual Strength Verification)

2.4.1.5 Acceptance Requirements

2.4.2 Vibroacoustic Qualification

2.4.2.1 Fatigue Life Considerations

2.4.2.2 Acoustic Testing

2.4.2.3 Observatory Random Vibration Tests

2.4.2.4 Subsystem Vibroacoustic Tests

2.4.2.5 Component/Unit Vibroacoustic Tests

2.4.2.6 Acceptance Requirements

2.4.2.7 Retest of Reworked Hardware

2.4.3 Sinusoidal Sweep Vibration Qualification

2.4.3.1 Mission Payload / System Sine Sweep Vibration Tests

2.4.3.2 Subsystem and Component Sine Sweep Vibration Tests

2.4.3.3 Sine Vibration Acceptance Requirements

2.4.4 Mechanical Shock Qualification

2.4.4.1 Subsystem Mechanical Shock Tests

2.4.4.2 Dispenser / Observatory Mechanical Shock Tests

2.4.4.3 Acceptance Requirements

2.4.5 Mechanical Function Verification

2.4.5.1 Life Testing of Mechanisms

2.4.5.2 Demonstration of Mechanical Function

2.4.5.3 Torque/Force Margin

2.4.5.4 Acceptance Requirements

2.4.6 Pressure Profile Qualification

2.4.6.1 Pressure Profile Test Demonstration

2.4.6.2 Acceptance Requirements

2.4.7 Mass Properties Verification

2.4.7.1 Mass Properties Test Demonstration

2.4.7.2 Acceptance Requirements

2.5 Electromagnetic Compatibility (EMC) Requirements

2.5.1 General EMC Requirements

2.5.1.1 Requirements Applicability

2.5.1.2 Safety and Controls

2.5.1.3 Test Facility and Equipment Requirements

2.5.1.4 Class R Bonding Verification

2.5.1.5 Power Grounding Verification

2.5.2 Detailed EMC Requirements

2.5.2.1 Conducted Emissions, Time Domain, Transients

viii

2.5.2.2 Conducted Emissions Requirements

2.5.2.3 Conducted Susceptibility Requirements

2.5.2.4 Radiated Emissions Requirements

2.5.2.5 Radiated Susceptibility Requirements

2.5.2.6 Self-Compatibility

2.6 Thermal Verification Testing

2.6.1 General Requirements

2.6.2 Unit Test

2.6.3 Subsystem/Instrument Test

2.6.4 System/Observatory Test

2.6.5 Flight Spares

2.6.6 Flight Unit Retest

2.7 Cryogenic Requirements

2.7.1 Cryogenic Systems Vacuum and Thermal Verification Requirements

2.7.2 Cryo-Thermal-Vacuum Qualification

2.7.2.1 Special Considerations

2.7.2.2 Level of Testing

2.7.2.3 Test Parameters

2.7.2.4 Test Setup

2.7.2.5 Demonstration

2.7.2.6 Special Tests

2.7.3 Leak Checking

2.7.4 Thermal Balance Qualification

APPENDIX A ABBREVIATIONS AND ACRONYMS

APPENDIX B DEFINITIONS

List of Figures Figure 1.2.4-1 Triplet Constellation Observatory Spacing On-Orbit Figure 1.2.4-2 Landsat Next Mission Architecture Figure 2.4.2.5-1 Determination of Qualification and Acceptance Random Verification

Test Levels Figure 2.4.4.1.3-1 Shock Response Spectrum (SRS) for assessing Component Test

Requirements Figure 2.5.2.2.1-1 Conducted Emission Limits on Power Lines Figure 2.5.2.2.2-1 Common Mode Bulk Cable Emission Limits Figure 2.5.2.3.1-1 CS101 Power Line Conducted Susceptibility Voltage Limits Figure 2.5.2.3.1-2 CS101 Power Line Conducted Susceptibility Power Limits Figure 2.5.2.3.3-1 Conducted Susceptibility, Power Leads, 150 kHz to 50 MHz

Precalibrated Current Limits Figure 2.5.2.3.4-1 Common Mode Conducted Susceptibility Precalibrated Limit

List of Tables

Table 1.2.4.1-1 Mission Parameters Table 1.12-1 Test Condition Tolerances Table 2.2.1-1 Flight System Hardware Levels of Assembly ix

Table 2.2.4-1 Test Factors/Durations/Margins Table 2.2.5-1 Flight Hardware Design/Analysis Factors of Safety Applied to Limit Loads

Table 2.4.1-1 Structural and Mechanical Verification Test Requirements Table 2.4.1-2 Minimum Probability-Level Requirements for Flight Limit (maximum expected) Level Table 2.4.2.6-1 Generalized Random Vibration Test Levels Components 22.7-kg (50-lb) or less Table 2.4.2.6-2 Component Minimum Workmanship Random Vibration Test Levels 45.4-kg (100-lb) or less Table 2.4.3.2-1 Component/Subsystem Acceptance Sine Environment (All Axes) Table 2.4.5.3-1 Torque/Force Margins By Project Phase Table 2.5.1.1-1 Component/Subsystem Level EMI Test Summary Table 2.5.2.4.1-1 Mission Payload Radiated Emissions Electric Field Limits Table 2.5.2.5.1-1 Launch Site Radiated Susceptibility Electric Field Exposure Table 2.6.1-1 Environmental Verification Test Level Temperature Ranges Table 2.6.2-1 Thermal Cycling Options for Mechanical and Propulsion Hardware Table 2.7.1-1 Cryogenic Vacuum, Thermal, Electrical and Mechanical Requirements ..104 Table 2.7.2.3-1 Margin as a function of Phase In Project Life Cycle

1.0 GENERAL INFORMATION

1.1 PURPOSE

This document provides requirements and guidelines for the environmental verification program for the Landsat Next (LNext) constellation, payload, observatories, instruments, spacecraft buses, subsystems and components and describes methods for implementing those requirements.

It contains a baseline for demonstrating by test or analysis the satisfactory performance of hardware in the expected mission environments, and that minimum workmanship standards have been met. It elaborates on those requirements, gives guideline test levels, provides guidance in the choice of test options, and describes acceptable test and analytical methods for implementing the requirements. There will be environmental verification plans to address requirements specified within this document at the instrument and observatory levels. (The term payload as used in this document refers to the ready to launch collection of Landsat Next observatories, their separation adapters, and any other hardware that is together mounted atop or within the upper stage of the launch vehicle.)

This document, nicknamed the LNERD, is directly based on the General Environmental Verification Standard (GEVS) for GSFC Flight Programs and Projects, GSFC-STD-7000. GEVS has been tailored to create the many Landsat Next Project specific environmental verification requirements within this document. For the purposes of environmental verification of Landsat Next Project flight hardware, GEVS is not a formally applicable document in its entirety, but instead, portions are referenced herein for numerous purposes including the clarification of testing rationale and for specific test guidance.

1.2 MISSION OVERVIEW

1.2.1 Mission Statement

Landsat Next, consistent with United States (U.S.) law and government policy, will continue the Landsat program's acquisition, archival, and distribution of multi-spectral imagery, affording global, synoptic, and repetitive coverage of the Earth's land surfaces and coastal regions at a scale where natural and human-induced changes can be detected, differentiated, characterized, and monitored over time.

1.2.2 Mission Background

Following the successful launch of Landsat 8 (formally named Landsat Data Continuity Mission, LDCM) in February 2013, and during the development of Landsat 9, the United States Geological Survey (USGS) and the National Aeronautics and Space Administration (NASA) recognized the need to assemble a team of experts from within both agencies to evaluate and inform an acquisition strategy for the Landsat mission to follow Landsat 9. The NASA-USGS Joint Agency Sustainable Land Imaging (SLI) Architecture Study Team (AST) was formed in September 2018 and was tasked with investigating how to best satisfy the diverse set of user needs collected in the USGS User Needs for the Sustainable Land Imaging Program July 2018, Release 2.0. These investigations resulted in a set of recommendations to the headquarters of both agencies, delivered in December 2019. The highest-recommended “Roadmap 1” architecture described a small constellation of “superspectral” space-based sensors that would substantially improve the spectral, spatial, and temporal capabilities of previous Landsat missions, while continuing to satisfy the primary goal of ensuring a highly calibrated data set that maintains compatibility with the legacy data of the Earth’s land surfaces and coastal regions held in the National Satellite Land Remote Sensing Data Archive at the USGS’s Earth Resources and Observation Science (EROS) Center. In April 2020 NASA/Goddard Space Flight Center (GSFC) received authorization to initiate the Landsat Next project consistent with the AST’s “Roadmap 1” recommendation.

The goal of Landsat Next is to continue the acquisition, archival, and distribution of multi-spectral imagery affording global, synoptic, and repetitive coverage of the Earth's land surfaces and coastal regions at a scale where natural and human-induced changes can be detected, differentiated, characterized, and monitored over time. This goal is in keeping with the Landsat programmatic goals stated in both the Commercial Space Act of 1998, Public Law #105-303 and the Land Remote Sensing Policy Act of 1992, Public Law #102-555. This policy requires that the Landsat Program provide data into the future that is sufficiently consistent with previous Landsat data to allow the detection and quantitative characterization of changes in or on the land surface of the globe.

Landsat Next continues the long-running partnership of NASA and the USGS, with NASA providing the space and launch segments and the USGS providing the ground system (GS), providing the longest continuous global record of the Earth’s land surface and coastal regions.

The Landsat series of satellites have continuously acquired multispectral images of the global land surface since the launch of the Earth Resources Technology Satellite (ERTS, later renamed Landsat 1) in 1972.

1.2.3 Mission Objectives

Landsat Next has these major mission objectives:

· Collect and archive moderate resolution Visible to Shortwave-Infrared (VSWIR) reflective and Thermal Infrared (TIR) emissive image data affording seasonal coverage of the global landmass for a continuous period of not less than five (5) years.

· Ensure that Landsat Next data are sufficiently consistent with data from the earlier Landsat missions in terms of relative acquisition geometry, calibration, coverage characteristics, spectral characteristics, output product quality, and data availability; all of which permit scientific studies, management of land cover and land use change, along with associated inland and coastal water resources, over multi-decadal periods.

· Ensure Landsat Next is responsive to documented emerging user needs and applications as characterized by periodic assessment, currently the User Needs for the SLI Program July 2018, Release 2.0, and identified by the operational requirements for acquisition, processing, archiving, and distribution of Earth’s image data to the United States Government and other users.

· Distribute Landsat Next data products to the public freely on a nondiscriminatory basis.

1.2.4 Mission Implementation

The Landsat Next mission is a constellation of three identical Observatories, referred to as “triplets” with equal orbit spacing. Each observatory images the full swath required to achieve global coverage, with the use of three observatories used to reduce revisit time for any scene.

The Figure below illustrates the 120 degree separation of the Observatories.

Figure 1.2.4-1 Triplet Constellation Observatory Spacing On-Orbit

This selected architecture of three observatories has been endorsed by the Landsat user communities and improves all temporal, spectral, and spatial capabilities by approximately twofold, while maintaining the historical Landsat data continuity. With all three observatories operating, imaging revisit will be every six (6) days, at the equator.

Each agency has specific responsibilities and will deliver major elements to the overall mission.

NASA will provide the Space and Launch Segments of Landsat Next and the USGS will provide the Ground System and Operations. NASA/Goddard Space Flight Center (GSFC) will provide overall Landsat Next project management, mission system engineering and mission assurance during development and will transition the mission to USGS for science operations following on-orbit commissioning. Each agency in addition to specific responsibilities, will deliver the three major segments to the overall mission.

The three segments are the Space Segment (SS), the Ground Segment (GS), and the Launch Services Segment (LSS). They are described in more detail in the following sections and shown in the Landsat Next Operations Concept below.

Figure 1.2.4-2 Landsat Next Mission Architecture

(Generated from Landsat Next Common Mission Architecture Diagram LNEXT-SYS-DESC-0022 Rev A)

1.2.4.1 Space Segment

NASA/GSFC will provide the Space Segment via competitive procurements for the science instrument suite and the spacecraft bus. The Space Segment will consist of a constellation of three observatories flying in sun-synchronous, polar orbits at 653km altitude, each with nominally identical spacecraft and instrument suites. The three observatories will be launched on a single launch vehicle with a single dispenser provided by the spacecraft bus provider. The observatories will be transitioned to their final orbit alignments during commissioning. In aggregate, they provide a six-day ground repeat period at the equator. The spacecraft and instrument will be Class C. The Mission Class B is accomplished by providing redundancy at the Observatory level. The overall mission parameters needed to achieve global coverage are shown below in the Mission Parameters Table.

Table 1.2.4.1-1 Mission Parameters

A single Observatory will consist of the spacecraft and imaging sensors, referred to as the Landsat Next Instrument Suite (LandIS). Each observatory operates independently, and unique coordination is conducted by the ground as the observatories do not communicate with each other directly.

The LandIS instrument suite is a whiskbroom scanner which provides 26 spectral bands with a maximum ground sampling distance of 10m-60m dependent on the spectral band, covering a swath on the ground of approximately 164km on a ground track defined by a world-wide reference system known as WRS-3. The instrument suite will be capable of acquiring raw detector data for all spectral bands within 15 second to minimize the illumination changes within the observations. Data will be generated at a rate no greater than 1.8 Gbps. The LandIS provides internal calibration sources such as blackbody, a space port, stim lamps and solar diffuser. LandIS instrument suite provides compression prior to packaging the data for transfer to the spacecraft storage.

The Space Segment will also provide simulators for mission, ground system and interface testing during the development phase of the mission and in support of long-term maintenance of systems. Space Segment simulator types include spacecraft, instrument suite, spacecraft and the LandIS instrument suite interface, launch vehicle interface and a combination of simulators integrated to be an Observatory. These simulators will have varying fidelity and capabilities to meet the mission needs.

1.2.4.2 Ground Segment

The Landsat Ground Segment consists of the Ground System and its external interfaces, including NASA institutional services. The GS includes the Mission Operations Center (MOC), the Ground Network (GN), and the Data Processing and Archive System (DPAS). External interfaces include NASA's Near Space Network (NSN), GSFC Conjunction Assessment and Risk Analysis (CARA) and its Flight Dynamics Facility, along with other external interfaces.

The Landsat Next MOC functionality will be used for command and control, health and status monitoring, orbit and attitude maintenance, performance analysis, onboard memory management, and flight and ground software maintenance. The MOC will support onboard autonomy for mission planning and scheduling. The MOC ingests, processes and archives data delivered via the GN. The Landsat Next Flight Operations Team (FOT) located at the MOC performs these functions and is responsible for monitoring the Observatories, detecting, investigating and resolving spacecraft anomalies and monitoring the instrument image collections and special image collections.

The GN provides geographically dispersed ground station resources for mission execution; it includes the Landsat Ground Network (LGN) and a wideband data routing capability to the Landsat Cloud. The LGN provides communication capability for each observatory of the constellation for commanding and housekeeping data via the S-Band and will receive science mission data from each observatory over a Ka-band downlink. The LGN is used to transfer commands and receive telemetry from each Observatory within the constellation and deliver it to the MOC.

The DPAS ingests, processes, and archives science data returned from each satellite via the GN.

The DPAS also provides a long-term archive capability for raw data and allows the user community to query, download, and directly interact in the cloud with Landsat Next data products, via a public-facing web portal for receiving data products.

The USGS will lead overall Landsat Next GS development. The USGS will also lead integration of the GS and ensure timely completion of ground readiness testing in preparation for NASA-led mission readiness activities. The MOC will support Landsat Next mission readiness activities.

1.2.4.3 Launch Segment

The Launch Segment will provide the assets and services associated with the Launch Vehicle (LV) and the Mission Payload-to-LV integration. The Launch Segment will include the LV; all Launch Vehicle-Ground Support Equipment (LV-GSE), property, and facilities to integrate the Mission Payload to the LV and verify its integration; and perform prelaunch testing with ground-based functions. The launch vehicle and launch site have not been specified and will not be until closer to Mission Phase C. The three observatories comprising the Landsat Next Mission Payload, including the Observatory dispenser, will be launched together on the same launch vehicle.

The candidate launch vehicles for the launch of the Landsat Next Mission Payload are the Falcon 9 Full Thrust, the United Launch Alliance Vulcan Centaur and the Blue Origin New Glenn. This list will be updated in the future to reflect additions and deletions to the candidate launch vehicles presently available under the NASA Launch Services II Contract.

Section 1.2 was generated using Landsat Next Common Boilerplate (LNEXT-MGMT-DESC-0005) Rev D

1.3 APPLICABILITY AND LIMITATIONS

These requirements apply to LNext hardware and associated software that is to be launched on an LNext Project designated launch vehicle.

These requirements apply to all space flight hardware (see definition of hardware, Appendix B), including Ground Support interface hardware that is developed as part of the LNext Project.

These requirements are written in accordance with the current GSFC practice of using a single protoflight observatory to qualify for space flight. The protoflight verification program, therefore, is given as the nominal test program for LNext. The second and third observatories will be a combination of protoflight and acceptance tested hardware.

1.4 THE LANDSAT NEXT VERIFICATION APPROACH

The entire LNext Constellation, at the appropriate levels of assembly, must be verified under conditions that simulate the launch operations, flight operations and flight environment as realistically as possible.

Since testing at the component (or unit) level, or lower level of assembly for large components, often becomes a primary part of the verification program, all components should be operating and monitored during all environmental tests if practicable.

Environmental verification of hardware is only a portion of the total assurance effort for LNext that establishes confidence that the constellation will function correctly and fly a successful mission. The environmental test program provides confidence that the design will perform when subjected to environments more severe than expected during the mission, and provides environmental stress screening to uncover workmanship defects.

The total verification process also includes the development of models representing the hardware, tests to verify the adequacy of the models, analyses, alignments, calibrations, functional/performance tests to verify proper operation, and finally end-to-end tests and simulations to show that the total system will perform as specified.

The level, procedure, and decision criteria for performing any additional tests will be included in the LNext system verification plan.

1.5 OTHER ASSURANCE REQUIREMENTS

In addition to the verification program, the assurance effort includes parts and materials selection and control, reliability assessment, quality assurance, software assurance, design reviews, and system safety per the Landsat Next (LNext) Instrument Mission Assurance Requirements (IMAR), LNEXT-SMA-REQ-0013 and Landsat Next Spacecraft Mission Assurance Requirements (SCMAR), LNEXT-SMA-REQ-0015.

1.6 RESPONSIBILITY FOR ADMINISTRATION

The responsibility and authority for decisions in waving the requirements rest with the GSFC LNext Project Manager.

The requirements thus derived and deviations from the requirements of this document are subject to review and approval by the GSFC Landsat Next Project.

1.7 LANDSAT NEXT CONFIGURATION CONTROL AND DISTRIBUTION

This document is controlled and maintained by the GSFC Landsat Next Project.

1.8 APPLICABLE AND REFERENCE DOCUMENTS

LNERD-25 The Contractor shall use the version of all Applicable Documents in effect at the time of procurement throughout development, except as identified in specific requirement(s).

1.8.1 Applicable Documents

Document Number Title Revision Applicable Section(s)

NASA-STD-5001 Structural Design and Test Factors of Safety for Space Flight Hardware

B w/CHAN

GE 3

Section 4.2.4

NASA-STD-5009 Nondestructive Evaluation Requirements for Fracture Critical Metallic Components

C All

NASA-STD-5019 Fracture Control Requirements for Spaceflight Hardware A w/CHAN

GE 4

FCR 6 through

FCR 17

NASA-STD-7001 Payload Vibroacoustic Test Criteria B Section 4.3.4 NASA-STD-8719.24 NASA Expendable Launch Vehicle Payload Safety

Requirements A All

Annex to NASA-

STD-8719.24

Annex to NASA Expendable Launch Vehicle Payload Safety Requirements: Requirements Table

B Chapters 11 and

MSFC-STD-3029 Guidelines for the Selection of Metallic Materials for Stress Corrosion Cracking Resistance in Sodium Chloride Environments

A Tables II and

III

MIL-HDBK-17-1 Department of Defense Handbook: Composite Materials Handbook - Volume 1. Polymer Matrix Composites Guidelines for Characterizations of Structural Materials

F Section 8.1.4

MIL-STD-461 Requirements for the Control of Electromagnetic Interference Characteristics of Subsystems and Equipment

G Sections 5.4 thru 5.9, 5.12, 5.18, & 5.21

MIL-STD-462 MEASUREMENT OF ELECTROMAGNETIC

INTERFERENCE CHARACTERISTICS

Notice 2 Section:

2.5.2.2.1

In this document, citations are assumed to be the latest version unless otherwise noted.

This document table was generated from the Landsat Next Common Reference and Applicable Documents List (LNEXT-MGMT-DESC-0008) Rev E.

1.8.1.1 Project Applicable Documents

Document Number Title

LNEXT-LANDIS-PLAN-

Landsat Next Landsat Instrument Suite (LandIS) Contract Data Requirements List (CDRL) and Data Item Descriptions (DID)

LNEXT-LANDIS-REQ-

Landsat Next Instrument Suite (LandIS) GSFC-STD-1000, Goddard Open Learning Design (GOLD) Rules, Applicability Matrix

LNEXT-LANDIS-SOW-

Landsat Next Landsat Instrument Suite (LandIS) Statement of Work (SOW)

LNEXT-SC-PLAN-0055 Landsat Next Spacecraft Contract Data Requirements List (CDRL) and Data Item Descriptions (DID)

LNEXT-SC-REQ-0019 Landsat Next Spacecraft GSFC-STD-1000, Goddard Open Learning Design (GOLD) Rules Applicability Matrix

LNEXT-SC-SOW-0004 Landsat Next Spacecraft Statement of Work (SC SOW) LNEXT-SMA-REQ-0013 Landsat Next (LNext) Instrument Mission Assurance Requirements (IMAR) LNEXT-SMA-REQ-0015 Landsat Next Spacecraft Mission Assurance Requirements (SCMAR) LNEXT-SYS-DESC-0015 Landsat Next Radiation Environment Description (LRED) In this document, citations are assumed to be the latest version unless otherwise noted.

This document table was generated from the Landsat Next Common Reference and Applicable Documents List (LNEXT-MGMT-DESC-0008) Rev E.

1.8.2 Reference Documents

Document Number Title Revision NASA-HDBK-7004 Force Limited Vibration Testing D NASA-HDBK-7005 Dynamic Environmental Criteria A NASA-STD-5002 Load Analyses of Spacecraft and Payloads A NASA-STD 7002 Payload Test Requirements B NASA-STD-7003 Pyroshock Test Criteria A NASA-STD-8739.12 Metrology & Calibration - w/Change 1 GSFC-STD-1000 Rules for the Design, Development, Verification, and Operation of Flight Systems H

GSFC-STD-7000 General Environmental Verification Standard (GEVS) for GSFC Flight Programs and Projects

B

AIAA S-121A-2017 Electromagnetic Compatibility Requirements for Space Equipment and Systems

ISO/IEC 17025 General Requirements for the Competence of Testing and Calibration Laboratories

Third Edition

MIL-STD-464 ELECTROMAGNETIC ENVIRONMENTAL

EFFECTS REQUIREMENTS FOR SYSTEMS

D

In this document, citations are assumed to be the latest version unless otherwise noted.

This document table was generated from the Landsat Next Common Reference and Applicable Documents List (LNEXT-MGMT-DESC-0008) Rev E.

1.9 CRITERIA FOR UNSATISFACTORY PERFORMANCE

Deterioration or any change in performance of any test item that does or could in any manner prevent the item from meeting its functional, operational, or design requirements throughout its mission is reason to consider the test item as having failed. Further elaboration of project requirements regarding failed testing may be found in the Landsat Next (LNext) Instrument Mission Assurance Requirements (IMAR), LNEXT-SMA-REQ-0013 or Landsat Next Spacecraft Mission Assurance Requirements (SCMAR), LNEXT-SMA-REQ-0015, as appropriate.

If during a test sequence a test item is operated in excess of design life and wears out or becomes unsuitable for further testing from causes other than deficiencies, a spare may be substituted.

LNERD-3492 If the substitution of a test item that has exceeded its design life affects the significance of test results, the test during which the item was replaced and any previously completed tests that are affected shall be repeated to the extent necessary to demonstrate satisfactory performance.

1.10 TESTING OF SPARE HARDWARE

A supply of selected spares is often maintained in case of the failure of flight hardware. Sparing requirements are documented in the Instrument and Spacecraft Statements of Work.

LNERD-3496 Spares shall undergo a verification program equal to that required for follow-on hardware.

LNERD-261 The extent and type of testing shall be determined as part of the flight hardware test program.

LNERD-262 If a flight element is replaced for reasons of failure and is then repaired and re-designated as a spare, appropriate retesting shall be conducted as agreed to by the Landsat Next Project.

LNERD-263 When the need for a spare arises, immediate analysis and review of the failed hardware shall be made to determine if the failure applies to all units.

Note: If failure occurs in a hardware item of which there are others of identical design, the fault may be generic and may affect all hardware of that design.

1.10.1 "One-Shot" Items Some items may be degraded or expended during the integration and test period and replaced by spares.

LNERD-3497 The spare that is used to replace an expended “One-Shot” item shall have met the required quality control standards and passed all required flight qualification tests for items.

Note: Items may include pyrotechnic gas generators and release devices, low-shock energy release mechanisms, and elements that absorb impact energy by plastic yielding.

LNERD-3498 When the replacement of a 'One-Shot' item entails procedures that could jeopardize mission success, the replacement procedure shall be successfully demonstrated with the hardware in the same configuration that it will be in when final replacement is to be accomplished.

1.11 TEST FACILITIES, CALIBRATION

The facilities and fixtures used in conducting tests must be capable of producing and maintaining the test conditions prescribed with the test specimen installed and operating or not operating, as required.

LNERD-3499 Facility performance shall be verified prior to the test.

LNERD-3500 All measurements that require a specified level of accuracy shall be taken using equipment that has been properly calibrated, with non-expired documentation, using General Requirements for the Competence of Testing and Calibration Laboratories, ISO/IEC 17025, in accordance with Metrology & Calibration, NASA-STD-8739.12, or in accordance with Contractor's equivalent in-house standard only with Landsat Next Project approval.

1.12 TEST CONDITION TOLERANCES

LNERD-270 The values and measurement uncertainties in Table 1.12-1 shall be used unless a rationale is provided for using other test condition tolerances, subject to the approval of the Landsat Next Project Office.

Table 1.12-1 Test Condition Tolerances

Acoustics Overall Level: ≤ 1 dB l/3 Octave Band Tol: Frequency (Hz) Tolerance (dB) f ≤ 40

40 < F < 3150 f ≥ 3150

+3, -6 ±3

+3, -6 Duration: +10%, -0% Antenna Pattern Determination ± 2 dB Electromagnetic Compatibility Voltage Magnitude: ± 5% of the peak value Current Magnitude: ± 5% of the peak value RF Amplitudes: ± 2 dB Frequency: ± 2 % Distance: ± 5% of specified distance or

± 5 cm, whichever is greater Humidity ± 5% RH Loads Steady-State (Acceleration): ± 5% Sine Burst Amplitude: ± 5% Static: ± 5% Magnetic Properties Mapping Distance

Measurement:

± 1 cm

Displacement of assembly center of gravity (c.g.)

from rotation axis:

± 5 cm

Vertical displacement of single probe centerline from c.g. of assembly:

± 5 cm

Mapping turntable angular displacement:

± 3 degrees

Magnetic Field Strength: ± 1 nT Repeatability of magnetic measurements (short term):

± 5% or ± 2 nT, whichever is greater

Demagnetizing and Magnetizing Field Level:

±5% of nominal

Mass Properties Weight: ± 0.2% Center of Gravity: ± 0.15 cm (± 0.06 in.)

Moments of Inertia: ± 1.5% Mechanical Shock Response Spectrum: Frequency (Hz) Tolerance (dB) Simulated Fn ≤ 3 kHz

Fn ≥ 3kHz ± 6 +9/-6

Shaker Fn ≤ 3 kHz ± 3 Overall Spectrum > 50% of SRS magnitude above nominal test level

Time History: ± 10% Pressure Greater than 1.3e04 Pa

(Greater than 100 mm Hg):

± 5%

1.3e04 to 1.3e02 Pa (100 mm Hg to 1 mm Hg):

± 10%

1.3e02 to 1.3e01 Pa (1 mm Hg to 1 micron):

± 25%

Less than 1.3e01 Pa (less than 1 micron):

± 80%

1.13 TEST MEASUREMENT CONSIDERATIONS

LNERD-348 From the moment a test article is excited or illuminated by an environmental source until the article is returned to an ambient condition, measurements shall be collected over time at sufficient temporal resolution to capture any relevant frequency- or time-dependent effects.

Note: In the cases of an anomaly or test failure, the constant monitoring throughout the applied environment will assist in assessing the possibility that the incident was caused by overtest due to an error in process or in the test equipment itself.

2.0 VERIFICATION PROGRAM

2.1 SYSTEM PERFORMANCE VERIFICATION

This section applies to the entire Landsat Next Constellation, each Observatory including its constituents. The provisions apply to all flight hardware, and associated software.

The hardware SOWs provide the guidelines for an environmental verification program and the CDRLs detail the many associated deliverables.

2.2 GENERAL VERIFICATION REQUIREMENTS

Sections 2.3 through 2.7 cover the specific requirements for implementing the Landsat Next environmental verification program for verifying observatories and their constituents.

2.3 Function & Performance Test Requirements

2.4 Structural and Mechanical

2.5 EMC

2.6 Thermal

2.7 Cryogenics

In general, the environmental tests are not performed at the spacecraft bus level, but they can be done where beneficial for risk reduction or other purposes. Functional and performance tests are what will generally be done at the spacecraft bus level prior to LandIS integration.

The basic provisions are written assuming protoflight hardware. They are, in general, also applicable to prototype hardware. Acceptance requirements are also given for the flight acceptance of previously qualified hardware. This applies to follow-on hardware (multiple copies of the same item) developed for the program, or hardware (from another program) qualified by similarity.

2.2.1 Test Sequence and Level of Assembly

The verification activities herein are grouped by discipline; they are not all in a recommended sequence of performance. The recommended order of testing is electrical, mechanical and thermal at the end of the testing sequence. No specific environmental test sequence is required, but the test program will be arranged in a way to best disclose problems and failures associated with the characteristics of the hardware and the mission objectives.

LNERD-492 In cases where the magnetic properties of the hardware need to be controlled, the dc magnetics testing shall be performed after vibration testing.

Note: Magnetics testing after vibe testing provides an opportunity to correct for any magnetization of the flight hardware caused by fields associated with the vibration test equipment.

Table 2.2.1-1 provides a hierarchy of levels of assembly for the flight hardware, with examples.

These level designators are based on those used in the Space Systems Engineering Database developed by The Aerospace Corporation for the Air Force, and agreed to by NASA Headquarters, GSFC, and JPL. The LNERD environmental test requirements generally start at the “unit” level and end at the “mission payload” level. However, screening and life-tests often occur at lower levels, and overall system verification continues beyond the “mission payload” level.

Table 2.2.1-1 Flight System Hardware Levels of Assembly

2.2.2 Verification Program Tailoring

This document assumes that the observatory is of modular design and can be tested at the unit/component, subsystem/LandIS, and observatory/system levels of assembly.

The Contractor will develop a verification program as stated in the SOW that satisfies the intent of the required verification program while taking into consideration the specific characteristics of the mission and the hardware. For example:

An observatory subsystem, or instrument, may be a functional subdivision of the observatory, but it may be distributed throughout the observatory rather than being a physical entity.

In this case, the environmental tests, and associated functional tests, will be performed at a minimum at the component, subsystem/LandIS, and observatory levels. Performance tests and calibrations may still be performed on the functional subsystem or instrument.

The physical size of the system may necessitate testing at other levels of assembly. Facility limitations may not allow certain environmental tests to be performed at the system level. In this case, testing should be performed at the highest practicable level. Also, for very large systems or subsystems/instruments, tests at additional levels of assembly may be added in order to adequately verify the hardware design, workmanship and/or performance.

In some cases, because of the hardware configuration it may be reasonable to test more than one component at a time. The components may be stacked in their flight configuration and may therefore be tested as a "section." Part of the decision process must consider the physical size and mass of the hardware. The test configuration must allow for adequate dynamic or thermal stress inputs to the hardware to uncover design errors and workmanship flaws.

Some test requirements stated as subsystem/instrument requirements may be satisfied at a higher level of assembly if approved by the GSFC project. For example, externally induced mechanical shock test requirements may be satisfied at the system level by firing the environment-producing pyro. A simulation of this environment is difficult, especially for large subsystems or instruments.

Aspects of the design and/or mission may negate certain test conditions to be imposed. For example, if the on-orbit temperature variations are small, less than 5°C, the project may consider alternate testing to the thermal-vacuum cycling at the system, or instrument, level of assembly and increasing the hot and cold dwell times.

The same process must be applied when developing the test plan for an instrument. While testing is required at the instrument component and all-up instrument levels of assembly, additional test levels may be called for because of hardware complexity or physical size.

2.2.3 Qualification of Hardware by Similarity

There are cases in which hardware qualified for one flight program is to be built and used on another program. Hardware that has been previously qualified may be considered qualified for use on a new program by showing that the hardware is sufficiently similar to the original hardware and that the previous qualification program has adequately enveloped the new mission environments. The details for performing this comparison should be defined by the Contractor with approval from the LNext Project. As a minimum the following areas should be reviewed and documented:

LNERD-507 Design and test requirements of original hardware that was previously qualified shall be shown to envelope the design and test requirements of subsequent hardware that is to be qualified by similarity to include a detailed review of the test configuration and of all waivers and deviations that may have occurred during testing of the original hardware.

LNERD-508 Manufacturing information of hardware that is to be qualified by similarity shall be reviewed to determine if changes have been made that would invalidate the previous hardware qualification, covering parts, materials, packaging techniques as well as changes to the assembly process or procedures.

LNERD-509 Test experience with the previous flight build shall be reviewed to verify that no modifications were made to the hardware during testing to successfully complete the test program, or else to verify all changes to the heritage hardware as a result of testing have been implemented on the current flight hardware.

If the LNext Project review shows that the hardware is of sufficiently similar design as the first build and that the previous test requirements envelope the LNext specified environmental requirements, then the hardware can be, with LNext approval, treated as qualified and need only to be subjected to acceptance level test requirements. The review of the hardware for similarity must be documented and included as part of the Contractor verification package.

2.2.4 Test Factors/Durations

Test factors for prototype, protoflight, and acceptance are given in Table 2.2.4-1.

Table 2.2.4-1 Test Factors/Durations/Margins

Test Prototype

Qualification

Protoflight

Qualification

Acceptance

Structural Loads1 Level

Duration Centrifuge/Static Load4 Sine Burst

1.25 x Limit Load 1 minute

5 cycles @ full level per axis

1.25 x Limit Load 30 seconds

5 cycles @ full level per axis

1.0 x Limit Load 30 seconds

5 cycles @ full level per axis

Acoustics Level2 Duration

Limit Level + 3dB 2 minutes

Limit Level + 3dB 1 minute

Limit Level 1 minute

Random Vibration Level2 Duration

Limit Level + 3dB 2 minutes/axis

Limit Level + 3dB 1 minute/axis

Limit Level 1 minute/axis

Sine Vibration3 Level Sweep Rate

1.25 x Limit Level 2 oct/min

1.25 x Limit Level 4 oct/min

Limit Level 4 oct/min

Mechanical Shock Actual Device Simulated

2 actuations

1.4 x Limit Level

2 x Each Axis

2 actuations

1.4 x Limit Level

1 x Each Axis

1 actuations Limit Level

1 x Each Axis

Thermal-Vacuum Max./min.

Allowable Flight

Temperature (AFT).

± 10°C

Max./min. AFT ± 10°C

Max./min. AFT ± 5°C(vacuum)

± 20°C (ambient pressure)

EMC & Magnetics As Specified for Mission

Same Same

1 - If qualified by analysis only, positive margins are to be shown for factors of safety of 2.0 on yield and 2.6 on ultimate as directed in subsection 2.4.1.1.1. Beryllium and composite materials may not be qualified by analysis alone as covered in section 2.4.1.3.4. Test levels for weldments, beryllium, bonded and composite structure, including metal matrix, are to be 1.25 x Limit Level for acceptance testing as covered in section 2.4.1.5.

2 - As a minimum, the test level should be equal to or greater than the workmanship level.

3 - The sweep direction must be evaluated and chosen to minimize the risk of damage to the hardware. If a sine sweep is used to satisfy the loads or other requirements, rather than to simulate an oscillatory mission environment, a faster sweep rate may be considered, e.g., 6-8 oct/min to reduce the potential for over stress.

4 - Shorter durations may be used in static testing if necessary to protect the hardware from damage due to facility limitations. If a shorter duration is used then the dwell time at load must be sufficient to demonstrate that the target loading condition has been achieved within the specified tolerances, all test measurements have been recorded, and the structure is stable under the applied loading condition.

2.2.5 Structural Analysis/Design Factors of Safety

LNERD-514 Structural and mechanical verification testing shall be supported by structural analysis to provide confidence that the hardware will not experience failure or detrimental permanent deformation under test or launch conditions.

LNERD-3714 The factors of safety that shall be applied to limit loads in order to calculate structural margins are shown in Table 2.2.5-1.

These factors of safety have been selected to be consistent with the test factors shown in Table 2.2.4-1. The yield factor of safety ensures that a prototype or protoflight test can be conducted with low risk of the hardware experiencing detrimental yielding. The ultimate factor of safety provides adequate separation between yield and ultimate failure modes and ensures that the hardware will not experience an ultimate failure under expected loading conditions.

LNERD-515 In the case of thermally induced loads or stresses, the factors of safety shown in Table 2.2.5-1 for the static loading condition shall be used for calculating strength margins.

LNERD-3715 If the absolute value of the temperature differential between the stressed and un-stressed condition for the hardware using flight acceptance temperatures is equal to or greater than 20° C, then the static factors of safety from Table 2.2.5-1 shall be applied to the loads/stresses induced by acceptance temperatures.

Flight acceptance temperatures are defined as the maximum allowable flight temperature plus acceptance margin which is typically 5° C for thermal vacuum as defined in Table 2.2.4-1.

Survival temperatures are treated as flight acceptance temperatures for assessing strength margins as they do not include qualification margin. If the absolute value of the temperature differential between the stressed and un-stressed condition using flight acceptance temperatures is < 20°C, then the static factors of safety from Table 2.2.5-1 can be applied to the loads/stresses induced by protoflight temperatures for hardware which does not contain any heat generating components. Both hot and cold conditions should be evaluated and the factors of safety should be applied to the appropriate test temperature (acceptance or protoflight). Thermally induced loads should be combined with mechanical loading due to launch loads, gravity, or external loads due to enforced deflection if these mechanical loads occur at the same time.

Table 2.2.5-1 Flight Hardware Design/Analysis Factors of Safety Applied to Limit Loads

Type Static Sine Random/Acoustic

Metallic Yield 1.25 1.25 1.6 Metallic Ultimate 1.4 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

LNERD-605 Factors of safety for pressurized systems shall be compliant with NASA

Expendable Launch Vehicle Payload Safety Requirements, NASA-STD-

8719.24 and chapters 11 & 12 of Annex to NASA Expendable Launch Vehicle Payload Safety Requirements: Requirements Table, NASA-STD-

8719.24 (Annex).

LNERD-606 Factors of safety for glass and structural glass bonds shall be as specified in

Structural Design and Test Factors of Safety for Space Flight Hardware, NASA-STD-5001, Section 4.2.4.

LNERD-608 The random/acoustic safety factors shown in Table 2.2.5-1 shall be applied to statistically derived peak response based on RMS level and calculated as a 3-sigma value as a minimum.

Factors shown in Table 2.2.5-1 assume that qualification/protoflight testing is performed at acceptance level plus 3dB. If difference between acceptance and qualification levels is less than 3dB, then these factors may be applied to qualification level minus 3dB instead of analyzing to acceptance level.

2.3 FUNCTION AND PERFORMANCE TEST REQUIREMENTS

The SOW defines functional, performance and confidence tests that are meant to verify and validate the observatory's operation before, during, and after environmental testing. These tests along with all other calibrations, measurements/ demonstrations, alignments (and alignment verifications), end-to-end tests, simulations, etc., that are part of the overall verification program are to be described in the System Performance Verification Plan. The following requirements address the minimum times for performance tests, and for failure-free testing/simulations that are needed for the Landsat Next observatories.

2.3.1 Hardware Performance Testing

LNERD-623 One-thousand (1000) hours of operating/power-on time shall be accumulated on all flight electronic hardware, including any spares, prior to launch, in accordance with Rules for the Design, Development, Verification, and Operation of Flight Systems, GSFC-STD-1000, GOLD Rule GR-2.01.

NOTE: For electronics consisting of a prime and redundant sides, i.e. A and B sides, 1000 hours should be accumulated on each side.

LNERD-624 At the conclusion of the performance verification program, the observatory shall have demonstrated failure-free performance testing for at least the last 350 hours of operation via any combination of Comprehensive Performance Test (CPT), Limited Performance Test (LPT) and Mission Simulation testing.

NOTE: Hardware changes during or after the verification program invalidate previous demonstration.

LNERD-2109 At the conclusion of the performance verification program, all flight electronic hardware shall have demonstrated failure-free performance testing for at least the last 350 hours of operation.

The demonstration hours may be accumulated at the subsystem level or system level of assembly. Hardware changes during or after the verification program invalidate previous demonstration.

LNERD-2110 At the conclusion of the performance verification program, flight electronic hardware shall have demonstrated failure-free performance testing for at least 200 hours of operation during the thermal-vacuum test exposure, with 100 hours of the trouble-free operation being logged at the hot-dwell temperatures…