![](media/image1.pct){width="6.0in" height="0.6798611111111111in"}

DRAFT

**Operational Land Imager Requirements Document**

**Landsat Data Continuity Mission**

**November 2, 2006**

**Revision - Draft**

![](media/image2.pct){width="1.625in" height="1.375in"}

**CM FOREWORD**

This document is a Landsat Data Continuity Mission (LDCM) 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 LDCM 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:

LDCM Configuration Management Office

Mail Stop 427

Goddard Space Flight Center

Greenbelt, Maryland 20771

# Signature Page {#signature-page .Style-Heading-1}

+--------------------------+-------+---------------------------+-------+
| Prepared by:             | Date  | Prepared by:              | Date  |
|                          |       |                           |       |
| Ted Grems                |       | Jim Storey                |       |
|                          |       |                           |       |
| LDCM Mission Systems     |       | LDCM Systems Engineer     |       |
| Engineer                 |       |                           |       |
|                          |       | SAIC, contractor to USGS  |       |
| a.i. Solutions,          |       | EROS                      |       |
| contractor to GSFC       |       |                           |       |
+--------------------------+-------+---------------------------+-------+
| Reviewed by:             | Date  |                           |       |
|                          |       |                           |       |
| Jeanine Morris-Murphy    |       |                           |       |
|                          |       |                           |       |
| LDCM OLI Manager         |       |                           |       |
|                          |       |                           |       |
| NASA GSFC Code 427       |       |                           |       |
+--------------------------+-------+---------------------------+-------+
| Reviewed by:             | Date  |                           |       |
|                          |       |                           |       |
| LDCM Mission Systems     |       |                           |       |
| Manager                  |       |                           |       |
|                          |       |                           |       |
| Evan Webb                |       |                           |       |
|                          |       |                           |       |
| NASA GSFC Code 427       |       |                           |       |
+--------------------------+-------+---------------------------+-------+
| Reviewed by:             | Date  |                           |       |
|                          |       |                           |       |
| LDCM Observatory Manager |       |                           |       |
|                          |       |                           |       |
| William Anselm           |       |                           |       |
|                          |       |                           |       |
| NASA GSFC Code 427       |       |                           |       |
+--------------------------+-------+---------------------------+-------+
| Approved by:             | Date  | Approved by:              | Date  |
|                          |       |                           |       |
| William Ochs             |       | USGS / EROS               |       |
|                          |       |                           |       |
| LDCM Project Manager     |       |                           |       |
|                          |       |                           |       |
| NASA GSFC Code 427       |       |                           |       |
+--------------------------+-------+---------------------------+-------+

#  Document Revision History {#document-revision-history .Style-Heading-1}

This document is controlled by the LDCM Project Management. Changes
require approval of the LDCM Project Manager, LDCM OLI Manager, and the
LDCM Mission Assurance Manager. Proposed changes shall be submitted to
LDCM Systems Engineering Manager.

  ------------- ---------- ---------- ----------------------------------------
  **RELEASE**   **DATE**   **BY**     **DESCRIPTION**

  −                                   Initial Version
  ------------- ---------- ---------- ----------------------------------------

# List of TBD's/TBC's/TBR's {#list-of-tbdstbcstbrs .Style-Heading-1}

This document contains information that is complete as possible. Items
that are not yet defined are annotated with TBD (To Be Determined).
Where final numerical values or data are not available, best estimates
are given and annotated TBC (To Be Confirmed). If there is an
inconsistency between two requirements then the best estimate is given
and annotated with a TBR (To Be Resolved). The following table
summarizes the TBD/TBC/TBR items in the document and supplements the
revision history.

  ---------- --------------- -------------------------------------------------
  **ITEM**   **REFERENCE**   **DESCRIPTION**

                             Data not supplied

                             

                             
  ---------- --------------- -------------------------------------------------

# Table of Contents {#table-of-contents .Style-Heading-1}

[Signature Page iii](#signature-page)

[Document Revision History iv](#document-revision-history)

[List of TBD's/TBC's/TBR's iv](#list-of-tbdstbcstbrs)

[Table of Contents v](#table-of-contents)

[List of Figures vii](#list-of-figures)

[List of Tables vii](#list-of-tables)

[1 Introduction 8](#introduction)

[1.1 Scope 8](#scope)

[1.2 Mission Overview and Requirements Flow
8](#mission-overview-and-requirements-flow)

[2 Applicable and Reference Documents
10](#applicable-and-reference-documents)

[2.1 Applicable Documents 10](#applicable-documents)

[2.2 Reference Documentation 11](#reference-documentation)

[2.3 Literature References 11](#literature-references)

[3 Functional Overview 12](#functional-overview)

[3.1 Functional Description 12](#functional-description)

[3.2 OLI Functional Element 12](#oli-functional-element)

[3.3 Mass Memory Functional Element 13](#mass-memory-functional-element)

[4 OLI System Level 13](#oli-system-level)

[4.1 General 13](#general)

[4.2 OLI System Lifetime 18](#oli-system-lifetime)

[4.3 Mission Phases 19](#mission-phases)

[4.4 Operational Orbit 20](#operational-orbit)

[4.5 Redundancy Requirements 20](#redundancy-requirements)

[4.6 Autonomy 21](#autonomy)

[4.7 Availability 22](#availability)

[4.8 Ground Support Equipment 22](#ground-support-equipment)

[4.9 Software Simulator 26](#software-simulator)

[4.10 Software Development and Verification Facility
28](#software-development-and-verification-facility)

[5 Imagery Requirements 28](#imagery-requirements)

[5.1 General 28](#general-1)

[5.2 Data Compression and Non-uniformity Correction
29](#data-compression-and-non-uniformity-correction)

[5.3 Data Processing Algorithms 29](#data-processing-algorithms)

[5.4 Spectral Bands 33](#spectral-bands)

[5.5 Spatial Performance 36](#spatial-performance)

[5.6 Radiometry 41](#radiometry)

[5.7 LDCM Geometric Precision, Geolocation, and Cartographic
Registration
48](#ldcm-geometric-precision-geolocation-and-cartographic-registration)

[5.8 In-Flight Calibration 50](#in-flight-calibration)

[6 Structural and Mechanical Systems
51](#structural-and-mechanical-systems)

[7 Thermal Control 52](#thermal-control)

[8 Electrical System 53](#electrical-system)

[9 Flight Software 53](#flight-software)

[9.1 General 53](#general-2)

[9.2 Event Logging 55](#event-logging)

[9.3 Initialization 55](#initialization)

[9.4 Failure Detection, Protection and Correction
56](#failure-detection-protection-and-correction)

[9.5 Hardware Commands 57](#hardware-commands)

[10 Solid State Recorder (SSR) 57](#solid-state-recorder-ssr)

[10.1 Data Flow 57](#data-flow)

[10.2 Operational Modes 57](#operational-modes)

[10.3 Data Storage 60](#data-storage)

[10.4 Data Playback 61](#data-playback)

[10.5 SSR Fault Detection and Correction
63](#ssr-fault-detection-and-correction)

[10.6 SSR Simulator 63](#ssr-simulator)

[11 Command & Data Handling 63](#command-data-handling)

[11.1 General 63](#general-3)

[11.2 Telemetry 63](#telemetry)

[11.3 Command Capability 64](#command-capability)

[12 Technical Resource Margins 65](#technical-resource-margins)

[13 Launch Services 67](#launch-services)

[13.1 Payload Processing Facility Compatibility
67](#payload-processing-facility-compatibility)

[13.2 Launch Site Support 67](#launch-site-support)

[13.3 Launch Vehicle 67](#launch-vehicle)

[14 Science and Mission Requirements Document (SMRD) Traceability
67](#science-and-mission-requirements-document-smrd-traceability)

[15 Verification Cross Reference Matrix (VCRM)
67](#verification-cross-reference-matrix-vcrm)

# List of Figures {#list-of-figures .Style-Heading-1}

[Figure 1.2‑1 LDCM Requirements Flow 9](#__RefHeading___Toc150245782)

[Figure 5.5‑1 Relative Edge Response 38](#__RefHeading___Toc150245783)

[Figure 5.6‑1 Top of Atmosphere Spectra for Uniformity Analyses
45](#__RefHeading___Toc150245784)

[Figure 5.6‑2 Coherent Noise Threshold Curve
46](#__RefHeading___Toc150245785)

[Figure 5.8‑1 Diffuser Panel Relative Geometry
50](#__RefHeading___Toc150245786)

# List of Tables {#list-of-tables .Style-Heading-1}

[Table 2.1‑1 Applicable Documents 11](#__RefHeading___Toc150245787)

[Table 2.2‑1 Reference Documents and Standards
11](#__RefHeading___Toc150245788)

[Table 5.4‑1 Spectral Bands 33](#__RefHeading___Toc150245789)

[Table 5.4‑2 Spectral Edge Slope Intervals for Reflective Bands
36](#__RefHeading___Toc150245790)

[Table 5.5‑1 GSD, Minimum Edge Slope and Maximum Half Edge Extent
Specifications 37](#__RefHeading___Toc150245791)

[Table 5.6‑1 Absolute Radiometric Uncertainty Requirements
41](#__RefHeading___Toc150245792)

[Table 5.6‑2 Radiance Levels for Signal-to-Noise Ratio (SNR)
Requirements and Saturation Radiances 41](#__RefHeading___Toc150245793)

[Table 5.6‑3 SNR Requirements 42](#__RefHeading___Toc150245794)

[Table 5.7‑1 Image Requirement to Processing Algorithm Verification
Mapping 48](#__RefHeading___Toc150245795)

# Introduction

## Scope 

The Operational Land Imager Requirements Document (OLIRD) establishes
the Level 3 procurement requirements for the reflective band sensor for
the Landsat Data Continuity Mission (LDCM). As a level 3 document it
contains the functional and performance requirements.

## Mission Overview and Requirements Flow

The OLI provides Landsat multi-spectral image acquisition. The inherent
goal of the OLI is to serve as a "standard Operational Land Imager"
which will be integrated on the LDCM observatory.

OLI will be required to operate nominally on the observatory acquiring
multi-spectral scenes (180km x 185km) on a 16 day repeat cycle, on the
Worldwide Reference System -- 2 with a descending node of 10:00am at a
nominal orbit altitude of 705km at the equator.

The general structure of the LDCM Program requirements is shown in
Figure 1-1. The flow down represented in this figure identifies which
organization controls a set of requirements and who has the authority to
change those requirements.

![](media/image3.pct){width="7.026388888888889in"
height="4.483333333333333in"}

[]{#__RefHeading___Toc150245782 .anchor}Figure 1.2‑1 LDCM Requirements
Flow

# Applicable and Reference Documents

## Applicable Documents

The OLI-RD is consistent with, and responsive to, the following
applicable documents of the revision and release date shown. Unless
otherwise stated in this document, all inconsistencies in the OLI-RD
will be resolved in the following order:

1.  LDCM Operational Land Imager Contract

2.  LDCM Operational Land Imager SOW

3.  LDCM Mission Assurance Requirements

4.  LDCM Environmental Verification Requirements Document (LEVR)

+--------------+---------------+---+---------------------------------------+
| **Document   | **Revision/   |   | **Document Title**                    |
| Number**     | Release       |   |                                       |
|              | Date**        |   |                                       |
+==============+===============+===+=======================================+
| 42 U. S. C., | Sept. 13,     |   | National Environmental Policy Act of  |
| 4321 et seq. | 1982          |   | 1969                                  |
| NEP          |               |   |                                       |
+--------------+---------------+---+---------------------------------------+
| AFSPCMAN     | July 1, 2004  |   | Air Force Space Command Manual 91-710 |
| 91-710 (Vol. |               |   | Range Safety User Requirements        |
| 1-7)         |               |   |                                       |
+--------------+---------------+---+---------------------------------------+
| CCSDS        | Blue Book,    |   | Recommendation For Space Data System  |
| 122.0--B--1  | November 2005 |   | Standards Image Data Compression      |
+--------------+---------------+---+---------------------------------------+
| CCSDS        | September     |   | Recommendation for Space Data Systems |
| 133.0--B-1   |               |   | Standards TM Space Packet Protocol.   |
|              | 2003          |   | Blue Book. Issue 1.                   |
+--------------+---------------+---+---------------------------------------+
| CCSDS        | September     |   | Recommendation for Space Data Systems |
| 231.0--B--1  |               |   | Standards. TC Synchronization and     |
|              | 2003          |   | Channel Coding. Blue Book. Issue 1.   |
+--------------+---------------+---+---------------------------------------+
| CCSDS        | September     |   | Recommendation for Space Data Systems |
| 232.0--B--1  |               |   |                                       |
|              | 2003          |   | TC Space Data Link Protocol. Blue     |
|              |               |   | Book. Issue 1.                        |
+--------------+---------------+---+---------------------------------------+
| CCSDS        | September     |   | Recommendation for Space Data Systems |
| 232.1--B--1  |               |   | Standards. Communications Operations  |
|              | 2003          |   | Procedure-1. Blue Book. Issue 1.      |
+--------------+---------------+---+---------------------------------------+
| CCSDS        | June 2001     |   | Recommendation for Space Data Systems |
| 202.0--B--3  |               |   | Standards. Telecommand, Part 2: Data  |
|              |               |   | Routing Service. CCSDS                |
|              |               |   | Recommendation, Blue Book             |
+--------------+---------------+---+---------------------------------------+
| CCSDS        | January 2002  |   | Time Code Formats                     |
| 301.0-B-3    |               |   |                                       |
+--------------+---------------+---+---------------------------------------+
| CCSDS        | June 2005     |   | CCSDS File Delivery Protocol (CFDP),  |
| 727.0-B-3    |               |   | Blue Book Issue 3                     |
+--------------+---------------+---+---------------------------------------+
| KNPR 8715.3  |               |   | KSC Safety Requirements               |
+--------------+---------------+---+---------------------------------------+
| NIMA         | 3^rd^         | D |                                       |
| TR8350.2     | Edition,      | e |                                       |
|              | Amendment 1,  | p |                                       |
|              | dated 3       | a |                                       |
|              | January 2000  | r |                                       |
|              |               | t |                                       |
|              |               | m |                                       |
|              |               | e |                                       |
|              |               | n |                                       |
|              |               | t |                                       |
|              |               | o |                                       |
|              |               | f |                                       |
|              |               | D |                                       |
|              |               | e |                                       |
|              |               | f |                                       |
|              |               | e |                                       |
|              |               | n |                                       |
|              |               | s |                                       |
|              |               | e |                                       |
|              |               | W |                                       |
|              |               | o |                                       |
|              |               | r |                                       |
|              |               | l |                                       |
|              |               | d |                                       |
|              |               | G |                                       |
|              |               | e |                                       |
|              |               | o |                                       |
|              |               | d |                                       |
|              |               | e |                                       |
|              |               | t |                                       |
|              |               | i |                                       |
|              |               | c |                                       |
|              |               | S |                                       |
|              |               | y |                                       |
|              |               | s |                                       |
|              |               | t |                                       |
|              |               | e |                                       |
|              |               | m |                                       |
|              |               | 1 |                                       |
|              |               | 9 |                                       |
|              |               | 8 |                                       |
|              |               | 4 |                                       |
+--------------+---------------+---+---------------------------------------+
| NASA         | Rev. B, Sept. | G |                                       |
| STD-5005     | 15, 2003      | r |                                       |
|              |               | o |                                       |
|              |               | u |                                       |
|              |               | n |                                       |
|              |               | d |                                       |
|              |               | S |                                       |
|              |               | u |                                       |
|              |               | p |                                       |
|              |               | p |                                       |
|              |               | o |                                       |
|              |               | r |                                       |
|              |               | t |                                       |
|              |               | E |                                       |
|              |               | q |                                       |
|              |               | u |                                       |
|              |               | i |                                       |
|              |               | p |                                       |
|              |               | m |                                       |
|              |               | e |                                       |
|              |               | n |                                       |
|              |               | t |                                       |
+--------------+---------------+---+---------------------------------------+
| NPD 8010.2   | Rev. D, May   | U |                                       |
|              | 14, 2004      | s |                                       |
|              |               | e |                                       |
|              |               | o |                                       |
|              |               | f |                                       |
|              |               | t |                                       |
|              |               | h |                                       |
|              |               | e |                                       |
|              |               | S |                                       |
|              |               | I |                                       |
|              |               | ( |                                       |
|              |               | M |                                       |
|              |               | e |                                       |
|              |               | t |                                       |
|              |               | r |                                       |
|              |               | i |                                       |
|              |               | c |                                       |
|              |               | ) |                                       |
|              |               | S |                                       |
|              |               | y |                                       |
|              |               | s |                                       |
|              |               | t |                                       |
|              |               | e |                                       |
|              |               | m |                                       |
|              |               | o |                                       |
|              |               | f |                                       |
|              |               | M |                                       |
|              |               | e |                                       |
|              |               | a |                                       |
|              |               | s |                                       |
|              |               | u |                                       |
|              |               | r |                                       |
|              |               | e |                                       |
|              |               | m |                                       |
|              |               | e |                                       |
|              |               | n |                                       |
|              |               | t |                                       |
|              |               | i |                                       |
|              |               | n |                                       |
|              |               | N |                                       |
|              |               | A |                                       |
|              |               | S |                                       |
|              |               | A |                                       |
|              |               | P |                                       |
|              |               | r |                                       |
|              |               | o |                                       |
|              |               | g |                                       |
|              |               | r |                                       |
|              |               | a |                                       |
|              |               | m |                                       |
|              |               | s |                                       |
+--------------+---------------+---+---------------------------------------+
| NPD 8710.3   | Rev. B, April | N |                                       |
|              | 28, 2004      | A |                                       |
|              |               | S |                                       |
|              |               | A |                                       |
|              |               | P |                                       |
|              |               | o |                                       |
|              |               | l |                                       |
|              |               | i |                                       |
|              |               | c |                                       |
|              |               | y |                                       |
|              |               | f |                                       |
|              |               | o |                                       |
|              |               | r |                                       |
|              |               | L |                                       |
|              |               | i |                                       |
|              |               | m |                                       |
|              |               | i |                                       |
|              |               | t |                                       |
|              |               | i |                                       |
|              |               | n |                                       |
|              |               | g |                                       |
|              |               | O |                                       |
|              |               | r |                                       |
|              |               | b |                                       |
|              |               | i |                                       |
|              |               | t |                                       |
|              |               | a |                                       |
|              |               | l |                                       |
|              |               | D |                                       |
|              |               | e |                                       |
|              |               | b |                                       |
|              |               | r |                                       |
|              |               | i |                                       |
|              |               | s |                                       |
|              |               | G |                                       |
|              |               | e |                                       |
|              |               | n |                                       |
|              |               | e |                                       |
|              |               | r |                                       |
|              |               | a |                                       |
|              |               | t |                                       |
|              |               | i |                                       |
|              |               | o |                                       |
|              |               | n |                                       |
+--------------+---------------+---+---------------------------------------+
| NPR 2810.1A  | May 16, 2006  | N |                                       |
|              |               | A |                                       |
|              |               | S |                                       |
|              |               | A |                                       |
|              |               | P |                                       |
|              |               | r |                                       |
|              |               | o |                                       |
|              |               | c |                                       |
|              |               | e |                                       |
|              |               | d |                                       |
|              |               | u |                                       |
|              |               | r |                                       |
|              |               | a |                                       |
|              |               | l |                                       |
|              |               | R |                                       |
|              |               | e |                                       |
|              |               | q |                                       |
|              |               | u |                                       |
|              |               | i |                                       |
|              |               | r |                                       |
|              |               | e |                                       |
|              |               | m |                                       |
|              |               | e |                                       |
|              |               | n |                                       |
|              |               | t |                                       |
|              |               | , |                                       |
|              |               | S |                                       |
|              |               | e |                                       |
|              |               | c |                                       |
|              |               | u |                                       |
|              |               | r |                                       |
|              |               | i |                                       |
|              |               | t |                                       |
|              |               | y |                                       |
|              |               | o |                                       |
|              |               | f |                                       |
|              |               | I |                                       |
|              |               | n |                                       |
|              |               | f |                                       |
|              |               | o |                                       |
|              |               | r |                                       |
|              |               | m |                                       |
|              |               | a |                                       |
|              |               | t |                                       |
|              |               | i |                                       |
|              |               | o |                                       |
|              |               | n |                                       |
|              |               | T |                                       |
|              |               | e |                                       |
|              |               | c |                                       |
|              |               | h |                                       |
|              |               | n |                                       |
|              |               | o |                                       |
|              |               | l |                                       |
|              |               | o |                                       |
|              |               | g |                                       |
|              |               | y |                                       |
+--------------+---------------+---+---------------------------------------+

[]{#__RefHeading___Toc150245787 .anchor}Table 2.1‑1 Applicable Documents

## Reference Documentation

The OLI-RD is consistent with the following documents. If the OLI-RD
conflicts with the any of these listed documents, the OLI-RD takes
precedence.

  --------------------------------------------------------------------------
  **Document      **Revision/   **Document Title**
  Number**        Release       
                  Date**        
  --------------- ------------- --------------------------------------------
  427-xx-xx                     Level 1 Requirements for the LDCM Mission

  427-xx-xx                     Science and Mission Requirements Document

  427-xx-xx                     OLI Statement of Work

  427-xx-xx                     Mission Assurance Requirements

  427-xx-xx                     LDCM Lexicon

  427-xx-xx       Rev. -, ,     LDCM Environmental Verification Requirements
                  2006          Document (LEVR)

  427-xx-xx                     LDCM Operations Concept Document

  427-xx-xx                     Special Calibration Test Requirements (SCTR)

  427-xx-xx                     LDCM Worldwide Reference System-2 Memorandum

  427-XX-XX                     Top of Atmosphere Radiance Values Assessment
  --------------------------------------------------------------------------

[]{#__RefHeading___Toc150245788 .anchor}Table 2.2‑2 Reference Documents
and Standards

## Literature References

For additional clarification reference is made to documents in the open
literature. These documents should be used for clarification and
understanding of the requirement. These documents do not constitute
additional requirements on the bidder.

  ---------------------------------------------------------------------------
  **Authors**        **Document   **Revision/   **Document Title**
                     Number**     Release       
                                  Date**        
  ------------------ ------------ ------------- -----------------------------
  \[1\] S. K. Park                1983          "Image reconstruction by
  and R. A.                                     parametric cubic
  Schowengerdt,                                 convolution," Computer
                                                Vision, Graphics, and Image
                                                Processing, vol. 23, pp.
                                                258-272.

  \[2\] A. Berk,     01731-3010   1 June 1999   MODTRAN4 User's Manual, Air
  G.P. Anderson,                                Force Research Laboratory,
  P.K. Acharya, J.H.                            Space Vehicles Directorate
  Chetwynd, L.S.                                Air Force Materiel Command,
  Bernstein, E.P.                               Hanscom AFB, MA
  Shettle, M.W.                                 
  Matthew, and S.M.                             
  Adler-Golden                                  
  ---------------------------------------------------------------------------

# Functional Overview 

## Functional Description

The Operational Land Imager (OLI) is required to provide Landsat
multi-spectral image acquisition onboard the LDCM spacecraft for a
period of 5 years within the prescribed requirements. The OLI consists
of the 9 band reflective sensor. The OLI provides Visible and Near
Infrared / Short Wave Infrared (VNIR/SWIR) imagery consistent with
Landsat spectral, spatial, radiometric and geometric qualities as
specified in Section 5 of this document.

## OLI Functional Element

The OLI includes the optical telescope, Focal Plane Array / Focal Plane
Electronics (FPA/FPE) and instrument control electronics. The optical
telescope includes the optical bench assembly, baffles and mirrors to
gather and focus the optical beam onto the FPA. The FPA/FPE converts
photon energy into electrical voltage signals and converts the voltage
signals into digital signals. The OLI is specified to provide nine
spectral bands with a maximum ground sampling distance, both in-track
and cross track, of 30m for all bands except the panchromatic band,
which is specified to have a 15m ground sampling distance. The OLI will
have a 185km cross track swath width at the mission nominal orbit of 716
± 12 km altitude and 98.2 ± .05° inclination sun synchronous orbit. The
OLI provides both internal calibration sources such as lamps to ensure
radiometric accuracy as well as capabilities to perform solar and lunar
calibrations within the field of view constraints. The on-board
electronics provide the necessary band ordered, data compression
necessary to meet the total data rate and data volume of the OLI.

## Mass Memory Functional Element

The Mass Memory or Solid State Recorder (SSR) provides all of the
functions necessary to store and as required compress digital image data
from the LDCM instruments. The SSR provides the capacity to ingest high
rate data streams from the LDCM instruments and data from the spacecraft
bus. The SSR will need to temporarily store up to 400 WRS-2 scenes of
Mission Data and observatory housekeeping data before this data must be
overwritten. Ancillary data includes such items as spacecraft attitude,
navigation, timing data and key telemetry values from the sensor and
spacecraft. Instrument ancillary data packets provide all necessary
image reconstruction information for later ground processing.

The SSR is assumed to be an onboard device that can simultaneously
store, process and output the LDCM instrument data streams.
Mechanically, the SSR is separate from the other instruments and is
likely mounted to the spacecraft bus. This separation is to provide
environmental isolation from the LDCM instruments. SSR is expected to
ingest image and ancillary data packets and store the data in a
time-correlated fashion such that the ancillary data and image data
remain time synchronized. Using root filenames assigned by the ground.
The ground assigned root filenames will be used for image data,
ancillary data (spacecraft and instrument). Mission Data and observatory
data stored on the SSR will take advantage of the CCSDS File Delivery
Protocol (CFDP). The SSR provides the ability to concurrently store and
playback data as necessary to meet the LDCM data collection and downlink
requirements. Playback of data will be controlled by ground command. The
SSR is expected to provide any necessary error detection and correction
to the stored data to prevent degradation due to Single Event Upsets
(SEUs) or other space environmental factors. Additionally, the DSAP will
provide self-test modes to exercise internal data paths.

# OLI System Level

## General

The LDCM OLI shall be comprised of the sensor module, all associated
sensor control electronics and power modules, all required control,
signal processing and data formatting and compression electronics, all
required hardware and software to meet sensor performance requirements.

The LDCM OLI shall meet the requirements of the LDCM Observatory
Interface Requirements Document, 427-XX-XXX.

The LDCM OLI shall provide the capability to selectively disable any
on-orbit processing operation that combines or compresses raw Mission
data in any manner.

Rationale: To support early orbit checkout, and for anomaly resolution,
by the instrument contractor. Examples of such processing operations
are: spatial aggregation of detector samples; temporal aggregation of
detector samples; averaging of detector data acquired while viewing
calibration sources; averaging of calibration instrumentation data such
as source temperature measurements; and data compression.

The LDCM OLI shall meet LDCM imaging requirements at all points
throughout the orbit.

Rationale: Take an image anywhere within the orbit sunlit or eclipse.

The LDCM OLI shall acquire mission data equivalent to 400 individual
WRS-2 Scenes, including the in-situ calibration data, per 24 hours.

Rationale: The LDCM OLI will be capable of acquiring sensor image data
equivalent to 400 WRS-2 scenes per day plus any necessary calibration
data. The 400 WRS-2 scenes account for all image collections in a
24-hour period. Vicarious, lunar, and solar, calibration images are part
of the 400 WRS-2 equivalent scenes. In-situ calibration data includes
internal sources and blackbody imaging results and is in addition to the
400 scenes. The WRS-2 scenes are actually generated on the ground and
not on-orbit.

The LDCM OLI shall operate within the designed operational parameters
when the LDCM Observatory points up to 15 degrees, off-nadir, to either
side of the current orbit plane.

Rationale: The OLI instrument must remain thermally stable, and fully
function in off-nadir pointing attitudes. The image acquisition in this
attitude is in lieu of an equivalent amount of nadir WRS-2 path image
acquisition.

The LDCM OLI shall acquire up to 5 off-nadir image intervals per day as
part of the 400 WRS-2 equivalent OLI instrument data.

Rationale: For rapidly changing conditions on the earth LDCM will be
able to image either WRS-2 scenes or off-nadir scenes. These may or may
not be a priority interval.

The LDCM OLI shall acquire up to 77 contiguous, sun-lit scenes during
any orbit.

Rationale: See the design reference missions in the Operations Concept
document which provides the longest possible daylight contiguous land
pass.

The LDCM OLI shall acquire up to 38 contiguous, night scenes during any
orbit.

Rationale: See the design reference missions in the Operations Concept
document which provides a possible lunar imaging scenario for
calibration using the moon.

The LDCM OLI shall be commanded by the ground into any operational mode.

Rationale: Operational flexibility but also should not be possible to
command the instrument into non-operational (ground test, storage, etc.)
modes.

The LDCM OLI shall be in compliance with NASA Policy Directive 8010.2,
Use of the SI (Metric) System of Measurement in NASA Programs.

### OLI Operational Modes 

The LDCM OLI shall implement the following modes and functionalities, as
defined herein.

Rationale: This document uses the following definition of OLI modes.
Though the OLI contractor is not required to use these same definitions;
a mapping of the contractor's OLI modes to these is required.

#### Survival Mode

The LDCM OLI shall implement an Instrument Survival Mode.

Rationale: Survival Mode is entered when a critical power shortage has
been identified by the spacecraft. In this low power mode only those
functions required for satellite safety, diagnostics and recovery to
full operational status will be powered. All instruments on the
spacecraft will be reactivated by ground command upon spacecraft
recovery.

The LDCM OLI shall enter Instrument Survival Mode without receiving a
command from the spacecraft.

Rationale: Survival mode is basically a power off mode and as such the
instrument maybe commanded into this mode without any warning. Clearly,
it would be better to have the OLI pass through Safe Mode first but that
may not always happen.

The LDCM OLI shall receive no external power in the Survival Mode.

Rationale: In this mode the spacecraft will supply survival heater power
but that power does not go through any OLI electronics.

The LDCM OLI shall meet all performance specifications after power up
following an indefinite period of time in Instrument Survival Mode.

Rationale: The OLI survival is contingent upon power being supplied to
the OLI survival heaters. However, it is the OLI contractor who is
responsible for sizing and installing OLI survival heaters.

The LDCM OLI shall transition from Instrument Survival Mode to Safe Mode
within 45 minutes \[TBC\].

Rationale: The OLI transition from Instrument Survival Mode to Safe Mode
in as short a time as possible within reason to not damage the
instrument. This is to maximize the availability of the imaging time.

The LDCM OLI Survival mode shall be used for ground storage and
transportation, launch, and spacecraft power crisis situations.

Rationale: The Survival mode is basically the power-off mode for the
instrument.

#### OFF Mode 

#### Activation Mode

The LDCM OLI shall implement an Activation Mode for instrument turn-on,
and subsequent instrument component warm up, or cool down, to its
operating temperature.

The LDCM OLI Activation mode shall terminate when all instrument
temperatures, biases, and currents have stabilized within specified
operational limits.

Rationale: Activation mode includes any deployments and opening of
covers or shutters. It is used for the initial power on of the
instrument electronics and can be performed while the OLI is in the
survival temperature range.

The LDCM OLI shall use the Activation Mode for to enable the command and
telemetry functions, and provide for orderly turn-on based on commands
to the instrument.

#### Decontamination Mode 

The LDCM OLI shall implement a Decontamination Mode in which the
instrument is configured to periodically evaporate contaminants which
may have been deposited on critical optical surfaces.

Rationale: The LDCM OLI Decontamination Mode is utilized to outgas and
evaporate contaminants from the OLI hardware to prevent contamination
from jeopardizing performance. In this mode, initial out gassing during
the Launch and Early Orbit Phase will occur.

The LDCM OLI Decontamination Mode shall collect and transfer health and
status data, but not mission or calibration data.

The LDCM OLI Decontamination Mode shall be exercised at any time during
the mission when decontamination is required.

#### Operational Mode

The LDCM OLI shall implement an Operational Mode in which all data
collection needed to satisfy the full functional and performance
requirements for the instrument are performed.

Rationale: This is the nominal operational mode of the instrument.

The LDCM OLI Operational Mode shall generate the normal mission data,
instrument housekeeping telemetry, and periodic calibration information.

Rationale: All allocated spacecraft resources will be available to the
instrument in this mode.

The LDCM OLI shall remain in the Operational Mode without damage while
the LDCM Observatory performs orbit correction maneuvers.

Rationale: The instrument is not required to meet performance
requirements during orbit correction but is not to be damaged by
spacecraft maneuvers.

#### Diagnostic Mode

The LDCM OLI shall implement a Diagnostic Mode.

The LDCM OLI Diagnostic Mode shall be used to update or change the fight
software.

The LDCM OLI Diagnostic Mode shall be used to update or make changes to
housekeeping telemetry format and content.

The LDCM OLI Diagnostic Mode shall be used to update or make changes to
different telemetry sampling rates as documented in the LDCM OLI to LDCM
Spacecraft ICD.

#### Safe Mode

The LDCM OLI shall implement an Instrument Safe Mode in which OLI is in
a fully functional configuration without any science data being
collected.

Rationale: This is a safe mode of operations where all instrument
constraints (thermal, pointing, etc.) are maintained

The LDCM OLI in Safe Mode shall maintain the design operational
environments.

Rationale: This mode maintains operational temperatures and other
environment ready for nominal operations.

The LDCM OLI shall transition upon command from Safe Mode to any
operational mode or vice versa within 20 seconds.

Rationale: To limit the time needed for OLI transition from various
modes. This allows startup and shut down in a reasonable period of time.

The LDCM OLI shall autonomously enter into Safe Mode when an OLI
detected failure could result in damage to the OLI.

The LDCM OLI shall notify the spacecraft that it has placed itself into
the Safe Mode and await specific further commands via the spacecraft.

The LDCM OLI shall continue to collect and transmit housekeeping data to
the spacecraft when in Safe Mode

Rationale: Mission or calibration data would not be automatically
transferred to the spacecraft, but it could be if commanded to send the
data.

The LDCM OLI shall configure itself such that no damage will occur if
the next action from the spacecraft is to turn off the instrument.

Rationale: The contractor may, by choice, utilize this mode as an
intermediate state between [Operational]{.underline} and
[Survival]{.underline} [Modes]{.underline}.

The LDCM OLI shall enter the Safe Mode by command from the spacecraft.

Rationale: For example this command could be a forwarded ground command,
or generated by the spacecraft in response to a power system anomaly.
The instrument may also be commanded to enter Safe Mode when the
spacecraft is performing scheduled thruster activity, such as for orbit
maintenance.

The LDCM OLI shall not over ride or ignore a command to enter Safe Mode.

Rationale: A command to force entry into Safe Mode is not over-ride able
by the instrument. The command may originate from the S/C or from the
ground

The LDCM OLI shall be capable of autonomously (TBD) transitioning from
Safe Mode to the Survival Mode.

Rationale: OLI should be able to power off if there is a problem

The LDCM OLI shall enter Safe Mode upon receipt of a command to enter
Safe Mode.

Rationale: There is no autonomous override of the Safe Mode command any
conflicts are better resolved after the OLI has been safed.

The LDCM OLI shall enter Safe Mode failing to receive the stored number
of consecutive time code data packets from the spacecraft.

Rationale: The OLI will be continuously receiving a time code message
unless the S/C C&DH system is down. If the C&DH is down then OLI should
be safed.

The LDCM OLI stored number of missed time code packets which result in
Safe Mode shall be alterable on-orbit over the range of 1 (TBC) up to a
maximum of 63 (TBC) consecutive time code data packets.

Rationale: The value selected to enter Safe Mode will depend on
instrument and S/C design.

The LDCM OLI shall enter Safe Mode upon deploying protection for direct
solar illumination.

Rationale: In the event the sun is about to enter the OLI aperture the
instrument would be most protected in Safe Mode

## OLI System Lifetime

The LDCM OLI shall be designed to operate and meet all design
specifications for 5 years beginning after the NASA completes acceptance
of the OLI on orbit.

Rationale: Design life starts after acceptance, so instrument
commissioning is in addition to the 5 years of operations.

The LDCM OLI shall be designed for an overall Probability of Mission
Success of 0.85 \[TBC\] or greater at the end of design life.

Rationale: End of design life Mission Success is defined as meeting 100%
of the minimum mission success requirements at the end of the
observatory design life.

## Mission Phases

### Storage Phase

The LDCM OLI shall be capable of being placed in a state that does not
require intervention by personnel, excluding anomalous events and
telemetry monitoring, for 30 day periods.

Rationale: This mode allows for storage of the instrument in the event
of delays. This requirement does not preclude the use of N2 or some
other purge gas during storage to ensure cleanliness.

### Pre-Launch Phase

The LDCM OLI shall be designed for a launch from Vandenberg AFB, CA.

The LDCM OLI shall be compatible with a government furnished payload
processing facility at Vandenberg AFB, CA.

Rationale: What ever covers, bagging, purges, etc. are necessary to
ensure cleanliness needs to be incorporated in the design.

The LDCM OLI and its Ground Support Equipment used at the launch site
shall comply with the US Air Forces Space Command Manual 91-710 Range
Safety User Requirements, dated July 1, 2004.

Rationale: Any hazardous systems on the OLI must be in compliance with
the Western Range. This includes things like the use of pyrotechnics,
pressurized systems, radiation sources, mechanical lift equipment,
electrical equipment, etc.

The LDCM OLI shall be designed to be compatible with the Delta II
Visible Cleanliness Level -- 6.

Rationale: The OLI must meet all performance specifications after
exposure to the environments within the launch vehicle fairing. If
special protection is required it is the responsibility of the OLI
contractor to provide that protection.

The LDCM OLI shall perform aliveness tests while mated to the launch
vehicle.

Rationale: To ensure the instrument is ready for launch on pad testing
will be performed.

### Launch and Early Orbit Phase

The LDCM OLI shall be --launched and remain in the Survival Mode during
Launch and Early Orbit Phase of the mission.

Rationale: OLI operations should not interfere with the initial turn-on
of the observatory; therefore there should be no need for checking the
OLI during the first week of the mission.

The LDCM OLI shall have a launch readiness capability once every 24
hours.

Rationale: To support a launch opportunity every day of the year there
should not be any instrument constraints to attempting a launch once
every 24 hours.

### Commissioning Phase

The LDCM OLI shall be capable of completing commissioning within 30
days.

### Operational Phase

Reserved

### Decommissioning Phase

The LDCM OLI shall be compliant with NASA Policy Directive NPD 8710.3,
NASA Policy for Limiting Orbital Debris Generation.

Rationale: The NPD provides guidelines for minimizing orbital debris. It
also invokes NASA Safety Standard NSS 1740.14 for assessing debris and
mission survivability. Aperture covers, doors, etc. will not be released
as orbital debris and material selection will consider the effects on
the re-entry foot print.

## Operational Orbit

The LDCM OLI shall have a 185 km cross track swath width at the mission
nominal orbit of 716 ± 12 km altitude and 98.25 ± .05° inclination.

Rationale: The WRS-2 orbit has a nominal equatorial altitude of 705 km.
Earth flattening causes the altitude of a circular orbit to vary from
705 km at the equator to just over 726 km at the maximum latitude.
Designing the sensor to operate over a range of altitudes from 704 km to
728 km accounts for the effects of Earth flattening and a small amount
(\~1 km) of orbital variation.

## Redundancy Requirements

The LDCM OLI requirements identified in section 4.5 shall only apply to
redundant systems within OLI.

The LDCM OLI shall be designed such that no single credible failure
permanently precludes the LDCM OLI from meeting the minimum mission
success requirements throughout the observatory design life.

The LDCM OLI shall identify and have compensating provisions for
Non-credible single points of failure.

Rationale: This may include such items as design factors of safety,
graceful degradation, functional redundancy, etc. Cable harness and
pin/socket connections are considered credible failure mechanisms, where
an open circuit would result in a single point failure of any required
instrument function.

The LDCM OLI shall have no single command that could cause loss of OLI,
assuming no OLI components have previously failed.

The LDCM OLI shall provide status of redundant components following
processor restart, processor failover, RAM memory loss, or bus
under-voltage.

Rationale: This is to prevent the instrument from switching to
previously failed components.

The LDCM OLI shall be capable of switching from the prime to the backup
unit for redundant systems by ground command.

Rationale: Be able to switch back and forth between prime and backup
units through ground commands

The LDCM OLI shall be capable of switching from the backup to the prime
unit for redundant systems by ground command.

Rationale: Be able to switch back and forth between prime and backup
units through ground commands

The LDCM OLI shall provide status telemetry for all powered redundant
systems.

The LDCM OLI shall provide indication for redundant systems of which
unit is operating in housekeeping data.

## Autonomy

The LDCM OLI shall autonomously complete transition to its Safe Mode
within 45 seconds (TBC) after receiving the command to enter Safe Mode.

The LDCM OLI shall inhibit autonomous Safe Mode entry through a ground
command.

Rationale: Ground generated commands can be used to turn-off the
automatic transition into Safe Mode by the instrument or from the
spacecraft or by other mechanisms documented in the ICD.

The LDCM OLI shall transition out of the OFF Mode, Safe Mode and
Survival Mode to an operational mode only via ground command.

Rationale: The instrument can transition to safer modes automatically
but up to more complex modes.

The LDCM OLI shall be capable of operating safely without ground
intervention for a complete 16-day repeat cycle.

Rationale: In the event there is a failure the OLI can safe its self
including power off if necessary. There might not be an imaging schedule
but the instrument would survive fine.

The LDCM OLI shall have the ability to autonomously perform
reconfiguration of redundant components as required to enter into the
Safe Mode or Survival Mode.

Rationale: Ensure that a failure does not propagate or prevent safing of
the instrument. There is no requirement for autonomous switching to
support nominal operations.

The LDCM OLI shall not autonomously switch to a known failed redundant
component.

Rationale: to prevent switching to failed units

The LDCM OLI autonomous functions, automatic safing or switchover shall
be over-ridden via ground command.

Rationale: To diagnose failures and anomalies within the instrument

The LDCM OLI shall report autonomous state changes and reconfigurations
in housekeeping telemetry.

The LDCM OLI shall report component and subsystem and instrument
housekeeping telemetry to observatory housekeeping data.

The LDCM OLI shall not require autonomous reconfiguration for normal
operations of the instrument.

Rationale: Autonomous fail over is limited to safing the OLI instrument.

The LDCM OLI shall in the event of an anomaly safely configure the
instrument and report the anomaly to the ground in telemetry.

## Availability

The LDCM OLI shall be available for acquiring OLI instrument data that
meets the imaging requirements at least 94% \[TBC\] of the time during a
WRS-2 Observation Period.

Rationale: Availability: Orbit Maneuvers of 12 hours / 28 days +
Off-Nadir Maneuvers of (5\*28\*.2) hours / 28 days = 1-40/672 approx.
94%; OLI must support Lunar Cal of 1.6 hour / 28 days + Solar Cal of 1
hour / 28 days

The LDCM OLI shall be capable of continuous operations in the normal
Earth pointing attitude for a minimum of 16 days during mission mode.

Rationale:

## Ground Support Equipment

The LDCM Ground Support Equipment (GSE) designed and built or purchased
under a LDCM contract shall be in compliance with NASA-STD-5005 Ground
Support Equipment.

The OLI GSE shall consist of the following:

a.  System Test Equipment (STE)

b.  Calibration Test Equipment (CTE)

c.  Handling fixtures

d.  Test fixtures

e.  Shipping / storage containers

The LDCM OLI GSE shall provide an interface to OLI System Test Equipment
for real-time data capture and recording of data as received from and
transmitted to the LDCM spacecraft.

#### Hardware Interface Simulator (HIS)

The LDCM OLI HIS shall simulate the OLI response to hardware or discrete
commands and commands received across the communications bus.

The LDCM OLI HIS shall generate realistic response characteristics for
analog telemetry, housekeeping telemetry and mission data.

The LDCM OLI HIS shall provide a flight like OLI instrument interface
connection for mating to the LDCM Spacecraft.

#### System Test Equipment (STE)

The LDCM OLI STE shall provide all possible interfaces, e.g., power,
clock, command, and telemetry.

The LDCM OLI STE shall be capable of recording, displaying,
distributing, and analyzing the data received from the OLI and ground
support equipment including all instrument test points.

The LDCM OLI STE shall be capable of real-time data capture and
recording all data as received from the OLI and GSE.

The LDCM OLI STE shall be capable of real-time OLI housekeeping and
diagnostic data display.

The LDCM OLI STE shall have the capability of generating hard copy print
out of all analysis results, screen dumps, and processed data.

The LDCM OLI STE shall have the capability of generating and receiving
hard media (e.g., Tape, DVD).

The LDCM OLI STE shall furnish all power, timing signals, and commands
needed by the OLI and normally supplied by the spacecraft.

The LDCM OLI STE shall physically isolated all power lines from signal
lines.

Rationale: To protect communication circuits from high voltage OLI
should use shielded and separate cables.

The LDCM OLI STE power supplies shall have short-circuit protection and
voltage-transient protection.

The LDCM OLI STE capabilities shall include:

a.  Performing a self-test

b.  Sending commands to the instrument

c.  Controlling the simulated S/C interfaces and external calibration
    GSE

d.  Receiving data from the OLI, GSE, and test chamber

e.  Performing health and safety checks to guarantee the safety of the
    instrument (in all states)

f.  Analyzing the data in real-time and in an off-line mode

The LDCM OLI STE shall be capable of data analysis / processing during
testing within 2 hours (exclusive of time required to collect the data).

The LDCM OLI STE shall include engineering and instrument data trending
capability and sensor data analysis tools to determine the performance
characteristics of the instrument.

The LDCM OLI STE shall simultaneously operate and monitor the instrument
and perform data analysis.

The LDCM OLI STE shall display instrument engineering data as well as
external GSE data.

The LDCM OLI STE shall have the capability of selecting information to
be displayed from a set of pre-stored display templates.

The LDCM OLI STE shall have the capability of displaying test data in SI
Units as well as raw digital numbers.

The LDCM OLI STE shall have an operator interface.

The LDCM OLI STE shall provide an interface with the OLI CTE so that
data will be entered into the automated data system and correlated
(TBD).

The LDCM OLI STE shall operate from a 115-volt, 60-Hertz (Hz) line.

The LDCM OLI STE shall have the capability of monitoring all command
states, selected voltages, currents, temperatures, and other telemetered
and derived parameters of the OLI and ancillary GSE telemetry in
real-time.

The LDCM OLI STE shall monitor OLI Critical Functions.

The LDCM OLI STE shall automatically protect the instrument if
appropriate operator action is not taken.

The LDCM OLI STE shall verify all operational modes of the OLI

The LDCM OLI STE shall record and alert the operator of any
out-of-tolerance items as they occur.

The LDCM OLI STE shall be capable of bypassing or terminating all
automatic sequences resident in the instrument or in the LDCM OLI STE.

The LDCM OLI STE shall operate, at the first application of power during
instrument integration and continuing through all periods of operation
and/or test, a limits check program.

The LDCM OLI STE shall maintain a command and operational time log.

#### Mechanical Ground Support Equipment (M-GSE)

The LDCM OLI M-GSE shall have the capability of moving and rotating the
OLI.

The LDCM OLI M-GSE shall lift the OLI from and return it to its
shipping/ storage container.

The LDCM OLI M-GSE shall provide for the integration of the OLI onto the
spacecraft.

The LDCM OLI M-GSE shall provide support for the performance
verification, environmental testing and calibration of OLI.

#### Shipping/ Storage Containers

The LDCM OLI Shipping & Storage Containers shall be reusable,
water-resistant, and airtight with filtered pressure control system.

The LDCM OLI Instrument Shipping & Storage Container shall incorporate
means of purging with dry nitrogen or dry air.

The LDCM OLI Instrument Shipping & Storage Container shall incorporate
means of measuring and recording shocks, temperature and humidity within
the container.

The LDCM OLI Instrument Shipping & Storage Container shall have external
indicators for temperature, humidity, and pressure monitoring.

The LDCM OLI Instrument Shipping & Storage Container shall maintain
airtight conditions for over 30 days with an internal pressure greater
than 1.05 atmospheres.

The LDCM OLI Instrument Shipping & Storage Container shall be capable of
being airlifted without loss of internal pressure.

The LDCM OLI Shipping & Storage Containers shall be provided for all
other GSE.

The LDCM OLI Shipping & Storage Containers shall be suitable for use in
the clean room, after a minimal amount of cleaning.

## Software Simulator

The LDCM OLI Software Simulator shall be capable of operating
independently from the Mission Operations Element.

The LDCM OLI Simulator shall integrate into the LDCM Spacecraft
Simulator.

The LDCM OLI Simulator shall simulate the operations of the OLI command
and data handling system.

The LDCM OLI Simulator shall realistically simulate the OLI response
characteristics do to LDCM Spacecraft attitude changes.

The LDCM OLI Simulator shall accurately simulate the inputs of the
observatory attitude sensors and the dynamics of the observatory for
simulations, such that telemetry responses accurately represent what
would be received from the LDCM OLI in flight.

The LDCM OLI Simulator shall simulate the operations of the mass storage
system.

The LDCM OLI Simulator shall simulate the operations of the power
system.

The LDCM OLI Simulator shall simulate the operations of the telemetry
and command response characteristics of the OLI instrument.

Rationale: For FOT training and for OLI instrument software updates, as
applicable, the observatory simulator should simulate the appropriate
telemetry responses to commands. The mission data is not seen at the MOC
so there is no need to include this data in the simulator.

The LDCM OLI Simulator shall interface with the LDCM Spacecraft
Simulator.

Rationale: So that the observatory software simulator can talk to the
MOE there needs to be a ground station interface. This requirement
addresses the fact that the ground RF is not present for the simulator.

The LDCM OLI Simulator shall be capable of simulating all instrument
operational modes and mode transitions.

The LDCM OLI Simulator shall verify valid commands, table updates and
flight software modifications.

The LDCM OLI Simulator shall receive commands in any flight valid format
and data rate.

The LDCM OLI Simulator shall receive, process, and execute flight
software updates (including complete version updates, patches, and table
updates) that are identical to updates for the flight instrument.

The LDCM OLI Simulator shall accurately simulate the timing of command
responses.

The LDCM OLI Simulator shall generate real-time housekeeping telemetry
streams with representative instrument data in all valid formats and
data rates.

The LDCM OLI Simulator shall simulate the response characteristics of
failed instrument subsystems.

The LDCM OLI Simulator shall simulate user defined faults in the
instrument.

The LDCM OLI Simulator shall respond to real-time operator changes in
the configuration of the simulated instrument.

The LDCM OLI Simulator shall accept inputs from the user to set and
change simulation variables.

Rationale: allows users to inject faults, vary initial conditions, etc.

The LDCM OLI Simulator shall accept inputs from the user to set and
synchronize simulation time with observatory clock time and ground
system time.

Rationale: To synchronize the events on-orbit with the events in the
simulation

The LDCM OLI Simulator shall be capable of saving an executed simulation
and simulation data.

Rationale: To allow trainers to establish a baseline set of training
simulations and be able reproduce a simulation

The LDCM OLI Simulator shall be capable of running a previous executed
simulation.

Rationale: To allow trainers to establish a baseline set of training
simulations and be able reproduce a simulation

## Software Development and Verification Facility

The LDCM Software Development and Verification Facility (SDVF) shall
include Engineering Test Unit versions of the LDCM OLI command and data
handling processor, and the power control/ distribution system and other
hardware necessary to replicate the flight hardware needed for software
development, verification, and anomaly resolution purposes.

Rationale: The SDVF needs to consist of the proper hardware to
accurately simulate OLI behavior for anomaly resolution, and to maintain
and update flight software over an extended operational period of the
mission.

The LDCM SDVF shall be self contained and not require additional
software or hardware to perform LDCM flight software development and
verification.

Rationale: SDVF may consist of a suite of tools, compilers, de-buggers,
performance assessment tools, etc. but should be all within one
facility. These tools should remain under configuration control
equivalent to the flight software.

# Imagery Requirements 

## General

This section establishes the requirements for image characteristics and
image quality to be provided by the Operational Land Imager. This
section also describes the requirements for image correction that are
necessary in order to verify Operational Land Imager performance.

The LDCM OLI shall have a minimum field of view that provides a 185 km
cross-track swath width at the equator for the LDCM operational orbit.

Rationale: This is a nominal value assessed at the equator. For the
poles the cross-track cover will be larger.

The LDCM OLI image requirements only apply to nadir imaging.

Rationale: Off-nadir images are important to the mission requirements of
LDCM but do not drive the instrument performance. It would be nice if
the processing algorithms could correct for the off-nadir pointing. The
requirements on OLI concerning off-nadir are to ensure that the
instrument design operates reliably and off-nadir does not impact the
nadir operational life of the instrument.

## Data Compression and Non-uniformity Correction

If the LDCM OLI implements an image data compression to keep from
exceeding the maximum data playback rate, then the requirements of
section 5.2.1 shall apply.

Rationale: If data compression is required to reduce the total volume of
image then it needs to be back out once the data is back on the ground.

If the LDCM OLI implements a non-uniformity correction on the image data
in support of data compression, then the requirements of section 5.2.2
shall apply.

Rationale: If NUC is required to improve the compressibility of the
image data then it needs to be back out once the data is back on the
ground.

### Image Data Compression 

The LDCM OLI data compression algorithm applied to OLI image data or
ancillary data shall be lossless.

The LDCM OLI data compression algorithm shall be commandable on and off.

The LDCM OLI data compression algorithm shall be performed in either the
Solid State Recorder or in the OLI instrument electronics.

Rationale: It is the data rate to the ground that must not be exceeded.
If there are advantages to compressing data before the SSR that is fine.

### Image Data Non-uniformity Correction (NUC)

The LDCM OLI NUC algorithm implemented shall be fully reversible.

The LDCM OLI NUC algorithm implemented shall be reconfigurable to allow
for updates.

The LDCM OLI shall record and transmit the NUC coefficients used with
each image data file.

The LDCM OLI shall receive and implement updated NUC coefficient data.

## Data Processing Algorithms

The following section describes the allowable set of data processing
algorithms required to make corrections to the LDCM mission data; to
detect, evaluate and correct systematic errors in the LDCM data; and to
use government-provided support data to correct residual errors in the
LDCM data so that the resulting corrected LDCM data meet the imagery
requirements of sections 5.6 and 5.7.

Rationale: This limitation is to prevent the use of an open-ended "fix
it on the ground" approach that would allow, for example, image-based
band registration correction methods. Such methods tend to be highly
data dependent making in difficult to verify that performance
requirements are met in general rather than only for selected test data
sets.

### Radiometric Correction Algorithms

Information: The radiometric correction algorithms correct the raw
detector sample data, mission data, so that the radiometrically
corrected LDCM data meet the radiometric performance requirements in
sections 5.6.1, 5.6.2.3 and 5.6.5.

#### Detector Bias Determination

The detector bias determination algorithm shall calculate the
appropriate bias level for subtraction from each detector for the
subsequent conversion to reflectance or radiance.

Note: Historical bias data and/or bias trends, focal plane temperatures,
temperature sensitivity coefficients, simultaneous dark detector data,
and/or pre and post interval dark image data may be used as necessary
for bias determination.

#### Conversion to Radiance

The conversion to radiance algorithm shall take the raw output of each
detector in digital numbers and convert it to spectral radiance
(W/m\^2-sr-**μ**m) using the detector-by-detector bias levels from
5.3.1.1, and previously derived gain coefficients.

Note: Radiometric corrections may include sensitivities to ancillary
data, e.g., Gain = C~1~e^c2T^ or Gain = C~1~ + C~2~X + C~3~Y where C~1~,
C2 and C~3~ are considered gain coefficients and T, X and Y are
ancillary data inputs.

##### Conversion to Radiance Algorithm Restrictions

The conversion to radiance algorithm shall not rely on the content of
the specific scene being corrected to determine the gain corrections.

#### Conversion to Reflectance 

The conversion to reflectance algorithm shall take the raw output of
each detector in digital number and convert it to TOA fractional
reflectance using the detector-by-detector bias levels from 5.3.1.1, and
previously derived absolute and relative gain coefficients.

##### Conversion to Reflectance Algorithm Restrictions

The conversion to reflectance algorithm shall not rely on the content of
the specific scene being corrected to determine the gain corrections.

#### Inoperable Detector Replacement

The inoperable detector replacement algorithm shall replace the
responses from detectors failing to meet the requirements for
operability with values estimated from the surrounding detectors.

##### Inoperable Detector Replacement Methods

The inoperable detector replacement algorithm shall provide selectable
replacement methods including, but not limited to: nearest-neighbor
replacement or linear interpolation replacement.

### Geometric Correction Algorithms

The algorithms which correct for georegistration, geolocation and other
geometric effects register radiometrically corrected LDCM data to an
absolute Earth coordinate reference system so that the resulting
geometrically corrected LDCM data meet the geometric and geolocation
performance requirements in section 5.7.

#### Ancillary Data Preprocessing

The ancillary data preprocessing algorithm shall operate on the LDCM
ancillary data to detect and correct erroneous ancillary data, perform
units rescaling and coordinate system conversions, and apply ancillary
data calibration corrections (e.g., clock correction, response/transfer
function compensation, temperature sensitivity compensation). Auxiliary
calibration parameters, quality thresholds, and other reference data
sets may be used in this process.

Information: The resulting corrected LDCM ancillary data are used by
subsequent geometric correction algorithms.

#### Line-of-Sight (LOS) Model Creation

The LOS model creation algorithm shall use preprocessed ancillary data
in conjunction with auxiliary calibration parameters to construct a
model that relates each LDCM pixel line-of-sight to an absolute
Earth-referenced coordinate system, such as Earth Centered Inertial of
Epoch J2000.

##### LOS Model Creation Algorithm Restrictions

The LOS model creation algorithm shall not use image-derived
measurements to improve accuracy.

#### Line-of-Sight Projection

The LOS projection algorithm shall use the LDCM LOS model in conjunction
with the WGS84 G1150 or current version, Earth model to intersect each
pixel line-of-sight with the Earth's surface, as defined in the
following sections.

##### LOS Projection to the Earth Ellipsoid Surface

The LOS intersection algorithm shall intersect each pixel line-of-sight
with the WGS84 Earth ellipsoid surface.

##### LOS Projection to the Terrain Surface

The LOS intersection algorithm shall intersect each pixel line-of-sight
with the Earth's topographic surface as defined by government-furnished
digital elevation data accurate to 12 meters (90% linear error).

##### LOS Projection Algorithm Restrictions

The LOS intersection algorithm shall not use image-derived measurements
to improve accuracy.

#### Line-of-Sight Model Correction

The LOS model correction algorithm shall use measurements of
government-provided ground control points in the radiometrically
corrected LDCM imagery to correct residual systematic errors in the LOS
model constructed using the LDCM ancillary and calibration data, as
described in section 5.3.2.2.

The government-provided ground control points will be accurate to 3
meters (90% circular error) horizontally and 12 meters (90% linear
error) vertically, with 5 or more points distributed in the along- and
cross-track directions across the WRS-2 scene area.

##### LOS Model Correction Algorithm Restrictions

The LOS model correction algorithm shall not use ground reference data
beyond that provided by the government.

### Image Resampling

The image resampling algorithm shall interpolate at-sensor radiance
values for Earth-referenced sample points from the radiometrically
corrected LDCM image data.

#### Input Image to Resampled Output Image Mapping

The image resampling algorithm shall use the line-of-sight projection
algorithms of 5.3.2.3 to geometrically remap the input radiometrically
corrected detector samples from 5.3.1 to an output Earth-referenced map
projection coordinate system.

#### Resampling Interpolation Method

The image resampling algorithm shall use the cubic convolution algorithm
\[reference 1\] for image interpolation.

### Data Processing Algorithm Performance

The radiometric correction algorithms of section 5.3.1 and the geometric
correction algorithms of section 5.3.2 shall create a radiometrically
and geometrically corrected LDCM image (all spectral bands) for a WRS-2
scene-sized area, at the nominal ground sample distance for each
spectral band, using one commercially available off-the-shelf
workstation, in 2 hours or less.

## Spectral Bands

### Spectral Band passes

#### Spectral Band Edges

The band edges for each spectral band shall fall within the range of the
minimum lower band edge and the maximum upper band edge as listed in
Table 5.4-1.

Note: The Full-Width-Half-Maximum (FWHM) points of the relative spectral
radiance response curve define the bands edges for each spectral band.
The shortest wavelength with 0.5 of peak relative response is the lower
band edge; the longest wavelength with 0.5 of peak relative response is
the upper band edge.

#### Center Wavelength

The center wavelength of the spectral response, i.e. the mid-point
between the band's upper and lower band edges, shall be the values
listed in Table 5.4-1 within the specified tolerances also listed in
Table 5.4-1.

[]{#__RefHeading___Toc150245789 .anchor}**Table 5.4‑3 Spectral Bands**

+---+---------------+------------+------------+----------+----------+
| * | **Band**      | **Center   | **Center   | *        | *        |
| * |               | Wa         | Wavelength | *Minimum | *Maximum |
| \ |               | velength** | Tolerance  | Lower    | Upper    |
| # |               |            | (±nm)**    | Band     | Band     |
| * |               | **(nm)**   |            | Edge     | Edge     |
| * |               |            |            | (nm)**   | (nm)**   |
+===+===============+============+============+==========+==========+
| 1 | Coastal       | 443        | 2          | 433      | 453      |
|   | Aerosol       |            |            |          |          |
+---+---------------+------------+------------+----------+----------+
| 2 | Blue          | 482        | 5          | 450      | 515      |
+---+---------------+------------+------------+----------+----------+
| 3 | Green         | 562        | 5          | 525      | 600      |
+---+---------------+------------+------------+----------+----------+
| 4 | Red           | 655        | 5          | 630      | 680      |
+---+---------------+------------+------------+----------+----------+
| 5 | NIR           | 865        | 5          | 845      | 885      |
+---+---------------+------------+------------+----------+----------+
| 6 | SWIR 1        | 1610       | 10         | 1560     | 1660     |
+---+---------------+------------+------------+----------+----------+
| 7 | SWIR 2\*      | 2200       | 10         | 2100     | 2300     |
+---+---------------+------------+------------+----------+----------+
| 8 | Panchromatic  | 590        | 10         | 500      | 680      |
|   | \*\*          |            |            |          |          |
+---+---------------+------------+------------+----------+----------+
| 9 | Cirrus        | 1375       | 5          | 1360     | 1390     |
+---+---------------+------------+------------+----------+----------+

\* Minimum bandwidth is 180 nm for band 7

\*\* Minimum bandwidth is 160 nm for the panchromatic band

### Spectral Band Shape

#### Spectral Flatness 

##### Flatness Between Band Edges 

The relative spectral radiance response between the lower band edge
(lowest wavelength with 0.5 of peak relative response) and the upper
band edge (highest wavelength with 0.5 of peak relative response) is
required to have the following properties:

###### Average Response 

The average relative spectral radiance response shall be greater than
0.8.

###### Minimum Response 

No relative spectral radiance response shall be below 0.4.

##### Flatness Between 0.8 Relative Response Points

The relative spectral radiance response between the minimum wavelength
within the band with a 0.8 relative response point and the maximum
wavelength within the band with a 0.8 relative response point shall
always exceed 0.7.

#### Out of Band Response 

##### Beyond 0.01 Relative Response Points

The ratio of the integrated relative spectral radiance response outside
the 0.01 response points of each defined spectral band to the integrated
relative spectral radiance response between the 0.01 response points of
each defined band shall be less than 2%.

Note: The 0.01 relative response points are the points closest to the
center wavelength where the relative response first drops to 0.01 of the
peak relative response on each side of the center wavelength. The
integrated responses will be weighted by the solar TOA irradiance. The
MODTRAN 4 "Chkur" solar spectrum will be used for this calculation
\[reference 2, Section 2.3\]. Electrical crosstalk is not included
within this requirement.

##### Response at Outer Wavelengths

###### VNIR and Cirrus

For bands 1, 2, 3, 4, 5 8 and 9, the value of the out of band relative
spectral response at wavelengths lower than the lower band edge of the
FWHM point minus 50 nm and the wavelengths higher than the higher band
edge of the FWHM point plus 50 nm shall not exceed 0.001. Electrical
crosstalk is not included within this requirement.

###### SWIR

For bands 6,7, and 8 the value of the out of band relative spectral
response at wavelengths lower than the lower band edge of the FWHM point
minus 100 nm and the wavelengths higher than the higher band edge of the
FWHM point plus 100 nm shall not exceed 0.001. Electrical crosstalk is
not included within this requirement.

### Relative Spectral Response Edge Slope 

#### Wavelength Intervals -- Case 1 

The wavelength interval between the first 0.05 and the first 0.5
relative spectral response points and the last 0.5 and the last 0.05
relative response points shall not exceed the values in Table 5.4-2.

#### Wavelength Intervals -- Case 2 

The wavelength interval between the first 0.01 and the first 0.5
relative spectral response points and the last 0.5 and the last 0.01
relative response points shall not exceed the values in Table 5.4-2.

[]{#__RefHeading___Toc150245790 .anchor}Table 5.4‑4 Spectral Edge Slope
Intervals for Reflective Bands

  -------- -------------- ------------ ------------ ------------ ------------
  **\#**   **Band**       **Lower Edge **Lower Edge **Upper Edge **Upper Edge
                          Slope        Slope        Slope        Slope
                          Interval\    Interval\    Interval\    Interval\
                          0.01 to      0.05 to      0.50 to      0.50 to
                          0.50\*       0.50\*       0.05\*       0.01\*
                          (nm)**       (nm)**       (nm)**       (nm)**

  1        Coastal        15           10           10           15
           Aerosol                                               

  2        Blue           25           20           20           25

  3        Green          25           20           20           25

  4        Red            25           20           15           20

  5        NIR            25           20           15           20

  6        SWIR 1         40           30           30           40

  7        SWIR 2         50           40           40           50

  8        Panchromatic   50           40           40           50

  9        Cirrus         15           10           10           15
  -------- -------------- ------------ ------------ ------------ ------------

\* Normalized to peak spectral response for the band

### Spectral Uniformity 

Within a band the measured FWHM bandwidths for each detector shall be
within ±3% of the measured mean FWHM bandwidth.

Note: Section 5.6.2.3 imposes additional spectral uniformity
requirements.

### Spectral Stability

Band center wavelengths and band edges shall not change by more ± 2 nm
over the life of the mission.

### Spectral Band Simultaneity

For any point within a single WRS-2 scene, the imaging sensor shall
acquire data for bands 1 through 9 within a 1.5 second period.

## Spatial Performance

### Reflective Band Ground Sample Distance 

#### Multispectral Bands 

##### Pixel-to-Pixel Increment

OLI instrument data shall provide a pixel-to-pixel increment, in the
in-track and cross-track directions, equivalent to a Ground Sampling
Distance (GSD) less than or equal to 30 m across the WRS-2 scene for
bands 1, 2, 3, 4, 5, 6, 7 and 9.

#### Panchromatic Band 

OLI instrument data shall provide a single panchromatic band with a
pixel-to-pixel increment, in the in-track and cross-track directions,
equivalent to a GSD less than or equal to 15 m across the WRS-2 scene.

### Edge Response 

The relative edge response in the in-track and cross-track directions
for radiometrically corrected sensor data, per paragraph 5.3.1.2, shall
conform to the criteria described in the following subsections.

Note: Table 5.5-1 lists the bands, their maximum allowable GSD, and the
minimum edge slope and maximum half edge extent of the edge response.
The edge response, in the context below, is the normalized response of
the imaging system to an edge. That is, the edge response is normalized
so that the mean low-side steady state edge response is set to zero and
the mean high-side steady state edge response is set to 100%.

[]{#__RefHeading___Toc150245791 .anchor}Table 5.5‑5 GSD, Minimum Edge
Slope and Maximum Half Edge Extent Specifications

  ----------------------------------------------------------------------------
  **\#**   **Band**          **Maximum     **Minimum Slope** **Maximum Half
                             GSD**                           Edge Extent**
  -------- ----------------- ------------- ----------------- -----------------
  1        Coastal Aerosol   30 m          .027 / m          23.0 m

  2        Blue              30 m          .027 / m          23.0 m

  3        Green             30 m          .027 / m          23.0 m

  4        Red               30 m          .027 / m          23.5 m

  5        NIR               30 m          .027 / m          24.0 m

  6        SWIR 1            30 m          .027 / m          28.0 m

  7        SWIR 2            30 m          .027 / m          29.0 m

  8        Panchromatic      15m           .054 / m          14.0 m

  9        Cirrus            30m           .027 / m          27.0 m
  ----------------------------------------------------------------------------

[]{#__RefHeading___Toc150245783 .anchor}Figure 5.5‑2 Relative Edge
Response

![](media/image4.wmf){width="6.172916666666667in"
height="4.226388888888889in"}

#### Response Slope 

The relative edge response slope for the OLI bands shall exceed the
values shown in Table 5.5-1 for radiometrically corrected OLI instrument
data, per paragraph 5.3.1.2, across the entire field-of-view.

Note: The relative edge response slope is defined as the slope between
the 40% and 60% response points as depicted in Figure 5.5-1.

Rationale: Edge slope captures the primary optical and electrical
effects that constrain image spatial performance. Edge slope is chosen
as the key specification here over MTF so that the specifications can be
expressed in absolute ground units (meters) independent of the ground
sample distance, so that over sampling is not discouraged as it can be
with specifications that scale with the sample distance. Edge response
is also more amenable to direct measurement/characterization than is MTF
which is usually computed analytically based on edge or impulse
measurements.

#### Half Edge Extent 

The upper half edge extents and the lower half edge extents for the OLI
spectral bands shall be less than the maximum half edge extent values
shown in Table 5.5-1 for radiometrically corrected image sensor data,
per paragraph 5.3.1.2, across the entire field-of-view.

Note: The lower half edge extent is defined as the horizontal distance,
in meters, between the 5% and 50% relative response points as depicted
in Figure 5.5-1. The upper half edge extent is defined as the horizontal
distance, in meters, between the 50% and 95% relative response points as
depicted in Figure 5.5-1.

Rationale: Imaging system simulations have shown that certain types of
image degradations (e.g., ghost images with small displacements) can
significantly degrade the overall edge response performance even when
their effect on the central 40%-60% portion of the edge is minimal.
Including a specification that covers more of the edge better protects
against this type of localized degradation. The upper and lower half
edge extents are both used to protect against artifacts that only effect
one side of the edge.

#### Edge Response Overshoot 

The overshoot of any edge response for all bands shall not exceed 5% for
OLI instrument data.

Note: Overshoot applies to both the high (100% response) and low (0%
response) sides of the edge so that the maximum response is less than
105% and the minimum response is greater than -5%.

#### Edge Response Ripple

Edge response ripple for all bands shall not exceed 5% for image sensor
data.

Note: Ripple applies to both the high (100% response) and low (0%
response) sides of the edge so that the response is greater than 95%
beyond the 95% response point and the response is below 5% beyond the 5%
response point.

#### Edge Response Uniformity 

The relative edge response slope shall not vary by more than 10%
(maximum deviation from the band average) in any band across the
field-of-view and by not more than 20% (maximum deviation from the
multi-band average) between spectral bands 1, 2, 3, 4, 5, 6, 7, and 9
for OLI instrument data.

Rationale: This specification ensures consistent spatial performance
across the field of view and across the spectral bands to reduce
application performance sensitivity to target location within the FOV
and control spectral mixing due to spatial effects.

### Aliasing 

The product of the relative edge response slope and the GSD provided by
OLI instrument data shall be less than 1.0 for both the in-track and
cross-track directions.

Rationale: This specification protects against data undersampling by
ensuring that the sample spacing (GSD) is commensurate with the actual
edge slope performance.

### Light Rejection and Internal Scattering 

Definition: A light rejection scene or a scene to assess internal light
scattering is defined as follows:

-   The OLI instrument data are collected from a circular region having
    a radius = 0.25 degrees and having a uniform target radiance = LT.

-   That target region is surrounded by an annular region having an
    inner radius = 0.25 degrees and an outer radius = 25 degrees and
    having a uniform background radiance = LB.

-   When LB = LT, the OLI instrument data radiance measured at the
    center of the target region has a nominal value = LT.

> All angles are measured relative to the sensor nadir view.

The magnitude of the change in the OLI instrument measured radiance for
all spectral bands at the center of the light rejection scene shall be
less than 0.004 times the magnitude of the difference between LB and LT,
where target and background radiance levels range from a minimum of zero
to a maximum of LMax, such that LT - LB ranges from a minimum of -LMax
to a maximum of + LMax.

Note: This requirement applies to all spectral bands for the duration of
the nominal observatory design life for target and background radiance
levels ranging from a minimum of zero to a maximum of LMax, such that
LT - LB ranges from a minimum of -LMax to a maximum of + LMax.

### Ghosting 

An extended object at a radiance level just below the detectors
saturation level, anywhere in the OLI instrument telescope full FOV,
shall not produce a significant (as described below) ghost image
anywhere in the active detectors area of the focal-plane. This
requirement applies to all spectral bands across the entire focal plane.

Note: A ghost image is either a secondary image of an object within the
FPA FOV or an image of an object that is outside the FPA FOV. In either
case the ghost appears as either an attenuated rendition of the original
object or a blurred and attenuated version of the original object. A
ghost also has a constant displacement vector from the original image. A
significant ghost is defined as an image artifact when its peak signal
after background level subtraction and radiometric calibration is above
2% of the typical radiance (L~typ~) for that band. This restriction is
intended to prevent ghosting from significantly affecting the
radiometric errors during normal operations.

## Radiometry

### Absolute Radiometric Uncertainty 

The OLI instrument absolute radiometric uncertainty requirements are
given in Table 5.6-1 for the range of L~typical~ to 0.9 L~max~ (Table
5.6-2). At any other radiance across the range of 0.3 L~typical~ to
L~typical~ the absolute uncertainty shall not exceed the values in Table
5.6-1 by more than 0.5%. This requirement applies to extended, spatially
uniform, unpolarized targets with a known spectral shape.

Pre-launch radiance uncertainties shall be established relative to
National Institute for Standards and Technology (NIST) standards.

Uncertainty estimates shall include the NIST standard uncertainties.

[]{#__RefHeading___Toc150245792 .anchor}Table 5.6‑6 Absolute Radiometric
Uncertainty Requirements

  ----------------------------------- -----------------------------------
  **Parameter**                       **Requirement (1-sigma)**

  Radiance                            5%

  Top of Atmosphere (TOA) Reflectance 3% of actual TOA
  ----------------------------------- -----------------------------------

[]{#__RefHeading___Toc150245793 .anchor}Table 5.6‑7 Radiance Levels for
Signal-to-Noise Ratio (SNR) Requirements and Saturation Radiances

  -------- --------------- -------------- ------------- ------------------------
  **\#**   **Band**        **Radiance                   **Saturation Radiances,
                           Level for SNR,               L~Max\
                           L\                           ~(W/m^2^ sr µm)**
                           (W/m^2^ sr                   
                           µm)**                        

                           **Typical,     **High,       **Requirement**
                           L~Typical~**   L~high~**     

  1        Coastal Aerosol 40             190           555

  2        Blue            40             190           581

  3        Green           30             194           544

  4        Red             22             150           462

  5        NIR             14             150           281

  6        SWIR 1          4.0            32            71.3

  7        SWIR 2          1.7            11            24.3

  8        Panchromatic    23             156           515

  9        Cirrus          6.0            N/A           88.5
  -------- --------------- -------------- ------------- ------------------------

### Radiometric Signal-to-Noise and Uniformity 

#### Detector Signal-to-Noise Ratios (SNRs) 

The median SNRs required for all OLI data for each spectral band shall
be as listed in Table 5.6-3**.**

a.  50% of all detectors for each band shall meet or exceed these SNR
    values.

b.  Any detector below 80% of these values shall be considered
    out-of-specification per paragraph 5.6.7.4.

[]{#__RefHeading___Toc150245794 .anchor}Table 5.6‑8 SNR Requirements

  --------------- ------------------------ ---------------- ---------------
  **\#**          **Band**                 **SNR            
                                           Requirements**   

                                           **At             **At
                                           L~Typical~\***   L~High~\***

  1               Coastal Aerosol          130              290

  2               Blue                     130              360

  3               Green                    100              390

  4               Red                      90               340

  5               NIR                      90               460

  6               SWIR 1                   100              540

  7               SWIR 2                   100              510

  8               Panchromatic             80               230

  9               Cirrus                   50               N/A
  --------------- ------------------------ ---------------- ---------------

\* - see Table 5.6-2 for definition of L~Typical~ and L~High~

#### OLI Data Quantization 

OLI data shall be quantized to 12 bits.

OLI data SNR performance shall not be quantization noise limited at
L~typical~ and above, i.e., system noise is greater than or equal to 0.5
Digital Number, unless meeting this requirement would force greater than
12 bit quantization.

#### Pixel-to-Pixel Uniformity 

The following environmental conditions and measurement approach shall
apply to requirements 5.6.2.3.1, 5.6.2.3.2, and 5.6.2.3.3.

-   The requirements shall apply for uniform sources with the radiance
    level above 2\*L~typical~

-   The radiometric values shall be corrected per paragraph 5.3.1.2.

-   Temporal noise shall be averaged to verify compliance with this
    specification.

-   Target radiances with spectral characteristics as follows:

    -   Spectral radiance from bare desert soil as observed through a
        dry atmosphere (excluding band 9)

    -   Spectral radiance proportional to the TOA solar irradiance

    -   Spectral radiance from a dense vegetation target as observed
        through a moist atmosphere (excluding band 9)

    -   These spectral radiances are shown in Figure 5.6-1 and given in
        "Top of Atmosphere Radiance Values, MODTRAN 4 Model" table
        values, see LDCM 427-XX-XX Top of Atmosphere Radiance Values.

-   Target radiances are all determined using the same gain calibration
    coefficients.

##### Full Field of View

The standard deviation of the radiometrically corrected values across
all pixels within a line of OLI data within a band shall not exceed
0.25% of the average radiance.

This requirement is met when:

$$\begin{array}{r}
\sqrt{\frac{\sum_{}^{}{({\overline{L}}_{i}} - \overline{L}')^{2}}{N - 1}} \leq 0\text{.}\text{0025} \cdot \overline{L}' \\
\text{Where:} \\
{\overline{L}}_{i}\text{ is the temporal average response of pixel i;} \\
\overline{L}\text{' is the 2 dimensional }(\text{temporal first and then spatial})\text{ average response for a spectral band;} \\
\text{N Total number of pixels in a spectral band line}\text{.}
\end{array}$$

##### Banding 

a.  The root mean square of the deviation from the average radiance
    across the full line for any 100 contiguous pixels within a line of
    radiometrically corrected OLI instrument data within a band shall
    not exceed 0.5% of that average radiance.

> This banding requirement is met when, for all n:

$$\sqrt{\sum_{}^{}{({\overline{L}}_{i}} - \overline{L}'\frac{)^{2}}{\text{100}}} \leq 0\text{.}\text{005} \cdot \overline{L}'$$

Where:

n is the pixel number in a line of data;

$${\overline{L}}_{i}\text{ is the temporal average response of pixel i;}$$

$$\overline{L}\text{© is the 2 dimensional }(\text{temporal first and then spatial})\text{ average response for a spectral band}\text{.}$$

b.  The standard deviation of the radiometrically corrected values
    across any 100 contiguous pixels within a line of OLI instrument
    data within a band shall not exceed 0.25% of the average radiance
    across the full line. The average radiance across the line (FOV) is
    used here merely as a reference for deriving the magnitude of the
    0.25%. The mean in the standard deviation calculation is, by
    definition, the mean of the 100 pixel sample set and not the entire
    FOV mean.

> This banding requirement is met when for all n:

$$\sqrt{\sum_{}^{}{(\overline{L_{i}}} - \overline{L}\frac{)^{2}}{\text{99}}}\text{   } \leq 0\text{.}\text{0025} \cdot \overline{L^{'}}$$

Where:

n is the pixel number in a line of data;

${\overline{L}}_{i}\text{ is the temporal average response of pixel i}$;

![](media/image5.wmf){width="0.1388888888888889in"
height="0.18055555555555555in"} is the average calibrated detector
response across the 100 pixel sample set in radiance units

$\overline{L} = \frac{\sum_{}^{}L_{i}}{\text{100}}$

$$\overline{L}\text{© is the 2 dimensional }(\text{temporal first and then spatial})\text{ average response for a spectral band}\text{.}$$

##### Streaking 

The maximum value of the streaking parameter within a line of
radiometrically corrected OLI instrument data shall not exceed 0.005 for
bands 1-7 and 9, and 0.01 for the panchromatic band.

The streaking parameter is defined by the following equation:

$Si = \frac{\left| \overline{L}i - \frac{1}{2}\left( \overline{L}i - 1 + \overline{L}i + 1 \right) \right|}{\overline{L}}i$

Where:

> $\overline{L}i$ is the temporal average calibrated radiance value
> measured for pixel I;
>
> $\overline{L}i - 1$ and $\overline{L}i + 1$ are similarly defined for
> the (i--1)th and (i+1)th pixels.

##### Temporal Stability 

The requirements of section 5.6.2.3.1- 5.6.2.3.3 shall be met for the
7-day period extending forward in time from the calibration update using
the same gain calibration coefficients.

Note: Bias determination can be performed during the 7-days per
paragraphs 5.3.1.1. Gain calibration coefficients may include a
dependency on parameters including instrument temperatures and voltages.

![](media/image6.wmf){width="5.843055555555556in" height="3.275in"}

[]{#__RefHeading___Toc150245784 .anchor}Figure 5.6‑3 Top of Atmosphere
Spectra for Uniformity Analyses

#### Coherent Noise 

Each pixel column in a uniform scene or dark background image in any
band acquired by the OLI instrument, after radiometric calibration per
5.3.1.2, shall only contain coherent noise (CN) components with relative
percentage amplitude (DN%), that are lower than the DN%~max~ level
denoted by the following formula (see Figure 5.6-2):

DN%~max~(f) = 9.0 f + 1.9.

Where:

f is frequency in cycles/pixel;

DN%~max~ is in %.

The DN% is given by the ratio of the individual CN component
zero-to-peak amplitude to 3 times the standard deviation of a full WRS-2
scene-sized area, i.e.,

DN% = (Amplitude of Coherent component) / (3 times the standard
deviation of the image)\*100%

Note: the individual CN component amplitude is the amplitude of the wave
pattern generated, for example, in the model of a sine wave it will be
the amplitude of a sine wave defined as Asin(b+phase). Pixels failing
this specification will be considered out-of-spec per paragraph 5.6.7.4.

![](media/image7.png){width="5.479861111111111in"
height="3.671527777777778in"}

[]{#__RefHeading___Toc150245785 .anchor}Figure 5.6‑4 Coherent Noise
Threshold Curve

### Saturation Radiances 

The OLI instrument shall detect, without saturating, signals up to the
L~max~ as shown in Table 5.6-2, starting 180 TBR days after
commissioning.

Note: For bands 1-8, this corresponds to the radiance reflected off of a
Lambertian target of 100% reflectance illuminated by the sun at a solar
zenith angle of 22.5°.

### Polarization Sensitivity

The OLI instrument polarization sensitivity, as defined by the linear
Polarization Factor (PF), shall be less than 0.05, where PF =
(Imax-Imin) / (Imax+Imin).

### Radiometric Stability 

Over any time period up to 16 days, after radiometric correction per
5.3.1.2, with one set of gain coefficients that were determined prior to
the 16 day period, the scene averaged OLI instrument data for
radiometrically constant targets with radiances greater than or equal to
L~-typical~ shall not vary by more than plus or minus 1% (95% or 2 sigma
confidence interval) of measured radiance.

Over any time period between 16 days and 5 years, after radiometric
correction per 5.3.1.2, the scene-averaged OLI instrument data for
radiometrically constant targets with radiances greater than or equal to
L~-typical~ shall not vary by more than plus or minus 2% (95% or 2 sigma
confidence interval) of target radiance.

Between 2 adjacent WRS-2 scenes, the scene-averaged OLI instrument data
for radiometrically constant targets with radiances greater than or
equal to L~-typical~ shall not differ by more than 0.5% of target
radiance.

### Image Artifacts 

#### Bright Target Recovery 

Bright target recovery requirements apply when an image pixel is exposed
to a radiance level of up to 1.5 times that of the saturation radiance
(Table 5.6-2).  Any pixel outside the 7 x 7 pixel region around that
pixel shall not have its signal change by more than 1% of its radiance
for bands 1-7 and 9 and by more than 2% for the panchromatic band.  This
requirement only applies when the pixels outside the 7 x 7 region are
observing radiances at or above L~typical~.

#### Detector-to-Detector Crosstalk 

When any region of detectors is illuminated by radiance levels less than
the saturation level, the signal on any other detector that is more than
ten detectors away from the illuminated region shall not change by more
than 1% of the affected detector's radiance. This requirement only
applies when the receiving detectors' radiance is at or above L~typical~
and after radiometric correction per 5.3.1.2.

Note: Detector-to-detector crosstalk addresses artifacts caused by
electrical and optical crosstalk between two detectors.

### Dead, Inoperable, and Out-of-Spec Detectors 

#### Dead or Inoperable Detectors 

Less than 0.1% of all detectors shall be dead or inoperable.

Note: dead or inoperable detectors may be removed from any performance
averages and standard deviations for determining compliance to
performance specifications.

#### Dead or Inoperable Detectors per Band 

Less than 0.2% of the detectors in any spectral band shall be dead or
inoperable.

#### Adjacent Dead or Inoperable Detectors

There shall be no across track adjacent dead or inoperable pixels.

#### Out-of-Spec Detectors 

Less than 0.25% of the operable detectors in any spectral band shall
fail to meet one or more performance requirements.

Note: Out-of-spec detectors may be removed from any performance averages
and standard deviations for determining compliance to performance
specifications.

## LDCM Geometric Precision, Geolocation, and Cartographic Registration 

The following sections detail the LDCM image geometric accuracy
requirements that must be achieved when the correction algorithms
provided in accordance with section 5.3 of this specification are
applied to LDCM mission data to produce a scene product. The specific
correction algorithms that apply to each geometric imagery requirement
are shown in table 5.7-1.

[]{.mark}

[]{#__RefHeading___Toc150245795 .anchor}Table 5.7‑9 Image Requirement to
Processing Algorithm Verification Mapping

  --------------- -------------- -------------- --------------- ------------- -------------- ------------- --------------
                  **5.3.1        **5.3.2.1      **5.3.2.2       **5.3.2.3.1   **5.3.2.4 LOS  **5.3.2.3.2   **5.3.3 Image
                  Radiometric    Ancillary Data Line-of-Sight   LOS           Model          LOS           Resampling**
                  Correction**   Processing**   (LOS) Model     Projection to Precision      Projection to 
                                                Creation**      WGS84         Correction**   Terrain       
                                                                Ellipsoid                    Surface**     
                                                                Surface**                                  

  5.7.1 Band      X              X              X               X             X              X             X
  Registration                                                                                             
  Accuracy                                                                                                 

  5.7.2 Image     X              X              X               X             X              X             X
  Registration                                                                                             
  Accuracy                                                                                                 

  5.7.3Geodetic   X              X              X               X                                          X
  Accuracy                                                                                                 

  5.7.4 Geometric X              X              X               X             X              X             X
  Accuracy                                                                                                 
  --------------- -------------- -------------- --------------- ------------- -------------- ------------- --------------

### Band-to-Band Registration Accuracy 

Corresponding pixels from the spectral bands in LDCM data that have been
geometrically corrected including compensation for the effects of
terrain relief shall be co-registered with an uncertainty of 4.5 meters
or less in the line and sample directions at the 90% confidence level.

### Image-to-Image Registration Accuracy

Two LDCM data sets of the same area, acquired on different dates, that
have been geometrically corrected, including compensation for the
effects of terrain relief, shall be capable of being co-registered by
with an uncertainty less than or equal to 12 meters**,** in the line and
sample directions at the 90% confidence level when image-to-image
correlation is applied to data from the same spectral band. This
requirement applies to data from all spectral bands except band 9.

### Geodetic Accuracy

#### Absolute Geodetic Accuracy

The pixels for targets at the Earth\'s topographic surface in
geometrically corrected LDCM data shall be located relative to the WGS84
geodetic reference system, G1150 or current version, with an uncertainty
less than or equal to 65 meters (90% circular error*)*, excluding
terrain effects. This specification applies to the horizontal error of
ground control points measured in the processed image, after
compensation for control point height.

#### Relative Geodetic Accuracy

The pixels for targets at the Earth\'s topographic surface in
geometrically corrected LDCM data shall be located relative to the WGS84
geodetic reference system, G1150 or current version, with an uncertainty
less than or equal to 25 meters (90% circular error), excluding terrain
effects, over a WRS-2 scene, after the removal of constant offsets. This
specification applies to the standard deviation of ground control points
measured in the processed image, after compensation for control point
height.

### Geometric Accuracy 

The pixels for targets at the Earth\'s topographic surface in LDCM data
that have been geometrically corrected, including pointing refinement
using ground control and terrain compensation using digital elevation
data, shall be located relative to the WGS84 geodetic reference system,
G1150 or current version, with an uncertainty less than or equal to 12
meters (90% circular error), including compensation for terrain effects.

## In-Flight Calibration 

The OLI instrument shall have on-board calibration systems that provide
sufficient data with precision and accuracy to meet the calibration and
stability requirements of the OLI instrument or as described in this
document.

### Reflective Band Calibration Sources

Sources for the in-flight calibration shall include celestial objects
including both the sun and the moon, and on-board sources such as lamps.

### Reflective Band On-board Calibration Systems

The calibration systems shall at a minimum include:

a.  A full aperture full system pressed and sintered PTFE (space-grade
    Spectralon™ or equivalent with existing space flight response
    characteristics) solar diffuser with the capability to assess the
    diffuser deployment orientation stability with time.

b.  The solar diffuser shall be designed to perform calibrations at a
    solar zenith angle, (**θ**~S~), of no greater than 60° and a view
    zenith angle, (**θ**~V~), of no greater than 45°, see Figure 5.8-1.

c.  The diffuser shall be protected from solar illumination when not in
    use.

![](media/image8.jpeg){width="3.5097222222222224in"
height="2.2645833333333334in"}

[]{#__RefHeading___Toc150245786 .anchor}Figure 5.8‑5 Diffuser Panel
Relative Geometry

d.  A calibration source with at least three selectable lamps, each of
    which illuminates all detectors and stimulates bands 1-9. The lamps
    shall be operable in constant irradiance and constant current modes.
    This calibration source shall have at a minimum an independent total
    optical power output monitor.

e.  A device by which the dark signal of all the detectors can be
    monitored without requiring non-nominal sensor operations.

f.  Permanently masked dark detectors for each sensor chip assembly to
    generate sufficient data to track bias stability during daylight
    acquisitions for each band

g.  A device by which the linearity of the OLI instrument with respect
    to radiance can be characterized on orbit

h.  A source designed to be stable between prelaunch and on orbit
    environments and throughout launch. This source shall be exercised
    prelaunch and postlaunch to test the transfer to orbit the stability
    of the OLI instrument.

> Note: Use of a single calibration device to meet more than one of
> these requirements is not excluded.

# Structural and Mechanical Systems

The LDCM OLI structure shall be of sufficient strength and stiffness to
maintain structural integrity and withstand all ground testing,
handling, transportation, launch, launch vehicle separation, and mission
orbit environments.

The LDCM OLI structure shall provide structural support and orientation.

The LDCM OLI structure shall provide a mounting interface for the OLI to
the LDCM Spacecraft.

The LDCM OLI structural and mechanical interface shall accommodate
manufacturing tolerance, structural, and thermal distortions.

The LDCM OLI structural system shall provide an external optical
alignment device.

Rationale: The OLI instrument needs to be co-aligned with the spacecraft
inertial reference system and with the Thermal InfraRed Sensor.

The LDCM OLI mechanical alignment device shall be aligned to the optical
axis of the OLI to less than 6.75 \[TBC\] micro-radians, 3-sigma for
each axis.

The LDCM OLI mechanical alignment shall be internally stable to less
than 6.75 \[TBC\] micro-radians, 3-sigma for each axis over the full
thermal operational design temperature range over a 16-day observation
cycle.

Rationale: The alignment stability of the OLI instrument is the single
most critical mechanical design challenge. Stability induced alignment
errors can not be back out of the on-orbit calibration data.

The LDCM OLI mechanical system shall provide a gaseous purge fitting.

Rationale: To allow a positive dry nitrogen gas purge within the OLI
during all stages of instrument and satellite integration, test,
shipment, launch site processing, and while on the launch pad up to T-0.

The LDCM OLI shall use a body reference coordinate system that is
defined as a right-hand, orthogonal, body fixed, XYZ coordinate system
with the +Z axis aligned with the OLI instrument optical axis. The
origin is located at the OLI to Spacecraft Bus interface plane.

Rationale: This orientation provides that when the observatory is in a
nominal earth pointing attitude, the +Z axis points towards the Earth
sub-satellite point.

The LDCM OLI shall provide easy access for the cleaning of all critical
telescope optical surfaces during all phases of Integration and Testing
(I&T) and the launch site.

Rationale: Easy access is defined as the ability to clean the telescope
optical surfaces in a single I&T shift without major sensor system
disassembly or de-integration from the OLI GSE or de-integration of the
OLI from the spacecraft bus.

# Thermal Control

The LDCM OLI shall be thermally safe for continuous operations in all
nominal operational modes.

Rationale: This does not include the OFF Mode.

The LDCM OLI shall maintain its subsystems within their survival
temperature range when the OLI is in Survival Mode.

Rationale: During Safe Hold the observatory subsystems including
instruments are allowed to thermally drift in order to minimize power
consumption.

The LDCM OLI shall maintain subsystems within their design operational
temperature range for nominal operational modes except for
Decontamination Mode.

Rationale: During de-contamination of the FPA or other elements it is
conceivable that components could exceed their design operational
temperatures.

The LDCM OLI shall provide heaters required for precision temperature
control.

The LDCM OLI precision temperature control heaters shall be located
within the OLI, controlled by the instrument electronics and using power
from the overall OLI power budget.

The LDCM OLI shall keep the imaging sensor thermally stable over a
16-day observation period within its design temperature range, while in
the operational modes.

Rationale: Keeping the imaging sensor thermally stable will have a
direct effect on quality of image data. It is anticipated that the OLI
instrument will have a long thermal constant and observing time could be
lost if its temperature is permitted to drift.

The LDCM OLI operational thermal range shall be reprogrammable on orbit.

The LDCM OLI survival heaters shall be on a power circuit independent of
the OLI instrument.

Rationale: OLI survival heaters must be powered when the rest of the
instrument is powered off. Survival heaters are assumed on while OLI is
in the OFF mode.

# Electrical System

The LDCM OLI shall provide short circuit protection or current limiting
for each power circuit coming into the instrument.

The LDCM OLI shall provide protection from over voltage and under
voltage conditions for power coming into the instrument.

The LDCM OLI shall be designed to operate from a 28 +/- 6 Volt direct
current power subsystem.

The LDCM OLI shall have an orbit average power consumption not to exceed
250 Watts \[TBC\].

The LDCM OLI shall have a peak power consumption not to exceed 450 Watts
\[TBC\] for a period of 10 minutes \[TBC\] per orbit.

The LDCM OLI shall have a survival power consumption not to exceed 100
Watts \[TBC\] orbit average.

# Flight Software 

## General

The LDCM OLI flight software shall be reprogrammable on orbit (excluding
FPGAs and ASICs).

Rationale: This requirement is not intended to have embedded flight
software in FPGA or permanently code state machines changed on-orbit.
However, programmable FSW contained in sensors, actuators and other
subsystem devices are included in this requirement.

The LDCM OLI shall possess sufficient non-volatile memory to contain two
entire copies of the OLI flight software image at launch.

The LDCM OLI shall monitor flight software tasks or functions to detect
for infinite loops or "hung" processes.

The LDCM OLI flight software shall protected against SEUs and other
memory and processor errors.

Rationale: This can be done through the use of design features such as
memory error detection and correction (EDAC), periodic software refresh
of critical hardware registers, processor and register majority voting,
watchdog timers, etc.

The LDCM OLI flight software shall verify the validity of all memory
areas.

Rationale: To ensure that valid data/ instructions, etc. are in use.
This task should run with a high enough frequency to fix environment
induced bit flips.

The LDCM OLI flight software shall detect and correct single bit memory
errors.

Rationale: Because bit flips happen.

The LDCM OLI flight software shall detect and report multiple bit errors
in memory.

Rationale: Because bit flips happen and not all errors can be corrected.

The LDCM OLI flight software shall provide the capability to monitor the
resource utilization by software subsystems or critical functions.

Rationale: To ensure that margins are maintain over the development life
of the software.

The LDCM OLI flight software shall make resource utilization monitors
available for downlink in telemetry.

Rationale: To verify functions are running smoothly and with expected
CPU utilization.

The LDCM OLI stored commands shall be unaffected by a flight software
upload.

Rationale: S/W patches should be independent of instrument command
queue.

The LDCM OLI flight software tasks shall have a defined execution
priority.

Rationale: Because critical tasks need to execute before non-critical
tasks.

The LDCM OLI flight software shall store the version identifier of
reprogrammable software onboard.

The LDCM OLI firmware shall store the version identifier of the embedded
software onboard.

The LDCM OLI flight software shall maintain a mapping of table name to
memory address location.

The LDCM OLI flight software shall be capable of updating memory table
locations through ground command table names.

The LDCM OLI flight software shall provide the capability to load any
location of on-board memory by referencing its physical memory address.

The LDCM OLI flight software shall be capable of dumping any location in
program memory.

Rationale: to support debugging efforts and provide additional telemetry
points which may have been unanticipated at development time

The LDCM OLI flight software shall be capable of dumping the entire
memory of on-board processors.

Rationale: To support debugging efforts and provide telemetry state of
the on-board flight software

The LDCM OLI flight software memory dump capability shall not disturb
nominal execution of the flight software.

Rationale: This requirement is not to effect the on-going observatory
operations or software processes. This requirement should only effect
(replace or supplement or use excess wideband data) capability to get
the memory dump telemetry on the ground.

The LDCM OLI shall implement independent time-based (watch-dog timer)
monitoring circuits.

Rationale: On-board processors should use hardware "watch dog" timers,
or some hardware implemented system independent of the CPU to interrupt
stuck software.

## Event Logging

The LDCM OLI flight software shall time tag events logged in telemetry
with an accuracy of 250 milliseconds or less.

Rationale: A reported event would contain information on the source
processor, flight software task or function, severity level, message
identifier and informational string that identifies the cause. The event
messages capture anomalous events, redundancy management switching of
components and important system performance events and warm and cold
restarts to the accuracy of command execution.

The LDCM OLI flight software shall report all event messages in the
observatory housekeeping telemetry.

## Initialization

The LDCM OLI shall preserve contents of the event log after rebooting or
power cycling a processor.

### Cold Restart

The LDCM OLI shall execute a cold restart of a processor's software from
Read Only Memory in response to a ground command.

Rationale: This is a reboot of the flight software instruction set
loaded from the non-volatile on-board memory (EEPROM, PROM, etc.) and
does not require a power-on reset.

The LDCM OLI flight software shall execute a Cold Restart initialization
process when starting execution from a hardware reset.

The LDCM OLI flight software shall execute a restart of a processor's
software from Read Only Memory following a power cycle or hardware
reset.

Rationale: This is a complete reboot of the flight software loaded from
the non-volatile on-board memory (EEPROM, PROM, etc.).

The LDCM OLI flight software shall default to a known telemetry
configuration following a Cold Restart.

The LDCM OLI flight software shall execute a Cold Restart when the
number of failed Warm Restart attempts equals or exceeds a predetermined
value.

### Warm Restart

The LDCM OLI flight software shall execute a Warm Restart initialization
processing when restarting the OLI flight software from software
command.

The LDCM OLI flight software Warm Restart initialization shall preserve
command processing statistics and memory tables and command sequences
that were previously uploaded.

## Failure Detection, Protection and Correction

The LDCM OLI shall automatically detect and report in telemetry hardware
and software out of limit and fault conditions.

The LDCM OLI subsystems that perform self diagnostics shall report the
results in telemetry.

The LDCM OLI subsystems that support self diagnostics shall accept
ground commands to run diagnostics and report the results in telemetry.

Rationale: Flexibility is necessary to support debugging conditions that
may not be known until after launch.

The LDCM OLI shall reject invalid commands.

The LDCM OLI shall report rejected commands in housekeeping telemetry.

## Hardware Commands

The LDCM OLI watchdog timer shall be enabled or disabled by a hardware
pulse command.

Rationale: Flexibility is necessary to support debugging conditions that
may not be known until after launch.

The LDCM OLI onboard processors shall be capable of being reset via
hardware pulse command.

Rationale: Flexibility is necessary to support debugging conditions that
may not be known until after launch.

# Solid State Recorder (SSR)

## Data Flow

The LDCM I-SSR shall assign unique CCSDS Packet Application
Identification by Spectral Band of OLI and TIRS data output.

Rationale: Band specific organization is more conducive to compression
and is how data is handled on the ground.

The LDCM I-SSR shall assign unique CCSDS Packet Application
Identification to the ancillary data.

Rationale: Packet by source is more conducive to how data is handled on
the ground.

The LDCM I-SSR shall assign unique CCSDS Packet Application
Identification by each instrument housekeeping source and uniquely for
the spacecraft bus housekeeping source.

Rationale: Packet by source is more conducive to how data is handled on
the ground.

## Operational Modes

The LDCM I-SSR shall at a minimum have the following operational modes.

Rationale: The SSR modes are identified here to provide consistent use
through the requirements documents. The contract must map their existing
modes to these modes to ensure compliance but does need to invoke these
modes by name.

### Power Off Mode 

The LDCM I-SSR shall have a power off mode where all LDCM I-SSR
functions and elements are powered down, except for survival heaters (as
required).

Rationale: There is no requirement to retain stored image and ancillary
data while the LDCM I-SSR is powered off. Survival heater power is
provided directly by the spacecraft bus.

### Power On Mode

The LDCM I-SSR power on mode shall provide an orderly start up and
configuration of the LDCM I-SSR processing, control, and memory
electronics, including execution of internal diagnostics and activation
of the SSR housekeeping telemetry (TLM) interface to the spacecraft bus.

Rationale: The SSR will start flowing its HK data directly to the bus
over the spacecraft bus to SSR HK telemetry interface.

The LDCM I-SSR shall be powered independently from any other LDCM
Observatory subsystem or instrument.

Rationale: The SSR will need to be checked out, tested, diagnosed
independently from the instruments and other equipment.

### Standby Mode

The LDCM I-SSR shall autonomously enter standby mode from the power on
mode after successful completion of all diagnostic checks.

The LDCM I-SSR shall retain indefinitely, unless power is cycled off,
all data stored in the LDCM I-SSR storage memory.

The LDCM I-SSR shall enter Standby mode either from power on mode or
from one of the other operational modes based on commands received from
the spacecraft bus.

### Self Test Mode

The LDCM I-SSR shall implement a Self Test Mode.

The LDCM I-SSR Self Test Mode shall generate a predetermined Self Test
image data pattern that is applied to each instrument interface at their
respective full data rate.

The LDCM I-SSR Self Test data pattern shall be stored up to the full
available capacity of the LDCM SSR.

The LDCM I-SSR shall be capable of playing back stored image or test
data to the downlink output interface while simultaneously recording the
test data.

### Downlink Test Mode 

The LDCM I-SSR shall implement a Downlink Test Mode.

The LDCM I-SSR Downlink Test Mode shall generate a pseudorandom noise
(PN, PRN) pattern of 32,767 bits length (PN15, 2^15^-1) to the downlink
output interface for bit error rate (BER) testing of each downlink
channel.

### Operational Mode

The LDCM I-SSR shall implement an Operational Mode.

The LDCM I-SSR shall concurrently record real-time data and playback
stored data.

Rationale: this capability can be selected in any permutation

The LDCM I-SSR shall output up to two unique and concurrent playback
streams of Mission Data.

Rationale: Simultaneous playback from two locations within the SSR. This
would consist of band ordered image data plus the ancillary data that
goes with it.

The LDCM I-SSR shall output 1 real-time Mission Data stream concurrently
with the two concurrent playbacks of Mission Data.

Rationale: Simultaneous real-time pass through and playback from two
memory locations within the SSR.

The LDCM I-SSR shall playback CFDF files based on ground schedules.

Rationale: The ground will establish playback schedules including
scheduling some files for priority playback.

### Safe Mode

The LDCM I-SSR shall implement a Safe Mode.

The LDCM I-SSR shall autonomously enter Safe Mode when exiting from
Power On Mode or Self-Test Mode and an anomaly has been detected.

Rationale: Entered Safe Mode whenever non-survival (i.e. data storage,
configuration or memory management errors) hardware or software errors
occur.

The LDCM SRR shall remain powered on, with telemetry available and
provided to the Spacecraft Bus telemetry interface when in Safe Mode.

Rationale: SRR buffers/registers/memory should be accessible as required
(for diagnostic dumps).

## Data Storage 

The LDCM I-SSR total capacity shall consist of the summation of the
following four requirements during any 24 hour period.

Rationale: The total data that can be stored at any time includes all
image data + all calibration data taken in the last 24 hours + the
corresponding ancillary data + the observatory housekeeping data for the
last 72 hours.

The LDCM I-SSR shall ingest and store the equivalent of 9 reflective
bands of 400 individual WRS-2 scenes.

Rationale: The SSR will serve as the primary mass storage device on the
observatory. It should be sized to support all systems needing mass
storage. This is the reflective band sensor, OLI.

The LDCM I-SSR shall ingest and store the equivalent of 2 thermal bands
of 400 individual WRS-2 scenes.

Rationale: This is the TIRS data storage

The LDCM I-SSR shall ingest and store all ancillary data associated with
the OLI and TIRS image collection.

The LDCM I-SSR shall ingest and store all lunar and solar calibration
data.

The LDCM I-SSR shall use Error Detection and Correction (EDAC) to ensure
data stored on the SSR has no more than one error in 10^12^ bits per 24
hour period.

Rationale: The bit error rate is to limit the number of bad bits prior
to transfer to the downlink interface.

The LDCM I-SSR shall ingest and store 1,036.8 kbits of observatory
housekeeping data.

Rationale: The 72 hours of observatory HK data is based on 4kbps for 72
hours =

The LDCM I-SSR shall store data in the CCSDS File Delivery Format (CFDP)
in compliance with CCSDS 727.0-B-3.

The LDCM I-SSR shall demultiplex OLI image data into unique CCSDS
formatted packets which contain separate and unique band sequential OLI
image data on 5 second \[TBC\] intervals.

The LDCM I-SSR shall concatenate together into a single file all Mission
Data packets of the same time interval into a CFDP file for storage.

Rationale: This requirement does not preclude the OLI from performing
some or all of the band sequential organization and CCSDS formatting of
image and ancillary data or compression of the image data.

The LDCM I-SSR shall assign a unique file header that contains a unique
ground defined identifier for the file name, a unique timestamp accurate
to 1msec accuracy relative to the OLI time reference, along with file
length, sequencing and configuration information with respect to the
formatting and processing modes of the LDCM I-SSR and OLI.

The LDCM I-SSR shall provide a means to assign file attributes that
denotes protected data, test data, and/or data that can be overwritten.

The LDCM I-SSR shall include file attributes when a directory listing is
requested.

The LDCM I-SSR shall have the capability to ingest and store LDCM
Spacecraft generated data independently of image operations.

Rationale: Ancillary data, observatory HK data generated by the
spacecraft will be available when the OLI is doing something besides
imaging. Therefore this data should be stored whether imaging or not
imaging.

The LDCM I-SSR shall have the capability to ingest and store LDCM
Instrument generated Mission Data independently.

Rationale: The LDCM instruments will at time operate independently of
each other and their mission data still needs to be stored.

LDCM I-SSR

## Data Playback 

The LDCM I-SSR shall have the capability to playback LDCM Spacecraft
generated data independently of image operations.

Rationale: Playback data acquired during periods when there were no
imaging operations

The LDCM I-SSR shall ensure a data rate not to exceed 230 megabits /
second for each physical downlink telemetry stream.

Rationale: The current capability of X-band transmissions systems is
around 230 megabits / sec. All the data needs to come down on a single
X-band channel. Therefore OLI instrument data may need to be compressed.
Sum the data on all the virtual channels assigned to a physical channel.

The LDCM I-SSR shall playback requested data based upon commands
received via the LDCM Observatory command and control interface.

The LDCM I-SSR shall support multiple playbacks of stored data.

The LDCM I-SSR shall playback data corresponding to file names specified
in a command string at the time specified in the command string.

The LDCM I-SSR shall playback data corresponding to physical memory
address locations specified in a command string at the time specified in
the command string.

The LDCM I-SSR shall be able to multiplex image and ancillary CCSDS
packets into a physical CFDP data stream.

The LDCM I-SSR shall ensure that complete CFDP files are provided to the
downlink interface when a playback command is executed.

The LDCM I-SSR shall always provide incrementally increasing Virtual
Channel Data Units (VCDU) counts, even when a partial mission data file
is being read out.

Rationale: Repeatedly is when portions of a file must be sent a second
or third time to recover a partial playback on the first
playback/readout attempt.

The LDCM I-SSR shall always output the LDCM Instruments' data and their
corresponding ancillary data together.

The LDCM I-SSR shall insert fill CADUs and fill packets as required to
maintain a synchronous, constant data rate output to the LDCM
Observatory downlink interface.

LDCM I-SSR

The LDCM I-SSR shall accept commands to designate any single or set of
data files as protected.

Rationale: To protect priority files or other data this would disable
the automated file overwrite feature.

The LDCM I-SSR shall accept commands to designate any single or set of
data files as available for overwrite.

Rationale: This allows the ground to go back and remove the protection
on files or other data.

The LDCM I-SSR shall, on command, provide a listing or directory of its
file system including key file attributes.

The LDCM I-SSR shall transfer file directory listings as a separate
CCSDS packet type via the wideband interface based on ground command.

The LDCM I-SSR shall transfer file directory listings as a separate
CCSDS packet type through the SSR control interface via the S/C
telemetry path to the ground based on ground command.

Rationale: Ground selectable transfer of the File Directory. This allows
getting the file directory but not using the X-band system.

The LDCM I-SSR shall provide the capability to change the attributes of
stored data from "protect" to "overwrite" to allow the reuse of memory
space.

The LDCM I-SSR shall overwrite data from oldest to youngest.

Rationale: provide the capability to change the attributes of stored
data from "protect" to "overwrite" to allow the reuse of memory space.

## SSR Fault Detection and Correction

The LDCM I-SSR shall have autonomous internal fault detection and
correction capabilities to provide notification of anomalous operating
conditions through the command and control interface.

## SSR Simulator

There's an SSR simulator...

# Command & Data Handling

## General

The LDCM OLI shall be capable of maintaining the health and safe
operations of all elements of the instrument without ground support.

The LDCM OLI shall continuously monitor its health and safety.

The LDCM OLI shall report the health and safety of the instrument to the
spacecraft.

The LDCM OLI shall time tag OLI instrument data with an accuracy
relative to the LDCM Observatory time reference of 150 microseconds or
less, 3-sigma.

Rationale: To ensure that the image data can be synchronized with the
ancillary data the two time references should be accurate to each other
within 50msecs.

The LDCM OLI will receive a one pulse per second from the LDCM
spacecraft for time synchronization.

The LDCM OLI reference time shall be accurate to within 50 microseconds
or less, 3-sigma of each LDCM Observatory 1-second timing pulse.

## Telemetry

The LDCM OLI shall provide sufficient telemetry to ensure proper control
and monitoring of OLI health and safety, and to identify anomalous
conditions.

Rationale: For proper insight into the state of health and on going
instrument activities

The LDCM OLI shall provide onboard storage for at least 4 \[TBC\]
different operator defined telemetry stream formats.

Rationale: Unique telemetry streams are likely to be needed to support
the various phases of instrument operations, commissioning, operations,
diagnostics, etc.

The LDCM OLI shall provide the capability to select a telemetry stream
definition from onboard storage via a single command.

The LDCM OLI shall report the command identifier in housekeeping
telemetry when executed.

Rationale: When OLI executes a command this information should be
written off into the HK telemetry.

The LDCM OLI shall generate and transmit real-time instrument
housekeeping data to the LDCM spacecraft.

Rationale: Real-time HK data is needed to monitor and control the
instrument.

## Command Capability

The LDCM OLI shall accept and execute discrete / hardware pulse commands
in real time only.

The LDCM OLI shall be capable of processing real-time commands while
concurrently executing long-duration commands.

Rationale: commands such as on-board processor uploads, imaging may take
several minutes and once these processes have started the instrument
should be able to continue processing normal functions.

The LDCM OLI shall be capable of receiving flight software loads across
multiple contacts.

The LDCM OLI shall be capable of receiving flight software updates by
patches at the function, unit or module level.

The LDCM OLI shall validate, process, and execute commands and data
loads.

The LDCM OLI shall not execute a command that has failed validation.

The LDCM OLI shall report commands that fail validation in housekeeping
telemetry.

The LDCM OLI shall have no command lockout.

Rationale: There is no command to lock-out or permanently disable the
OLI instrument

The LDCM OLI shall be capable of accessing information from one or more
separate data tables stored in onboard RAM through a single command.

The LDCM OLI shall be capable loading a parameter of a table without
loading the entire table.

The LDCM OLI real-time command shall perform only one function, fully
identified in the command data field establishing a known state and
condition.

Rationale: Using toggle commands can leave the state of a switch, box,
etc. unknown. It is better to have enables and disables be unique
commands and not just toggle back and forth. A toggle commands would not
be permitted as they do not fully define the final state.

The LDCM OLI shall execute a command at a frequency of at least 1 Hz
\[TBC\].

The LDCM OLI shall have a command execution accuracy of 0.1 seconds
\[TBC\].

# Technical Resource Margins

The LDCM OLI shall use the following equation for margin calculations:

Margin (in percent) = 100% x (Available Resource-Estimated Resource) /
Estimated Resource.

Rationale: The use of margins is intended to improve performance on
mission level cost and schedule in addition to mission performance. This
margin equation should be used for each technical resource.

The LDCM OLI shall use a maturity level to define required margins.

Rationale: By using the maturity level then new development items will
be properly combined with heritage items when the total observatory is
accounted.

The LDCM OLI technical resources shall have the following minimum
resource design margins at the end of a component's development phase:

+-----------------+---------+-------+----------+------+-------------+
| **Resource**    | **C     | **Mi  | **Pre    | **   | **Pre-En    |
|                 | ontract | ssion | liminary | Crit | vironmental |
|                 | ATP**   | D     | Design   | ical | Design      |
|                 |         | esign | Review** | De   | Review**    |
|                 |         | Rev   |          | sign |             |
|                 |         | iew** | **(Phase | Revi | **(Phase    |
|                 |         |       | B)**     | ew** | D)**        |
|                 |         | **(   |          |      |             |
|                 |         | Phase |          | **(P |             |
|                 |         | A)**  |          | hase |             |
|                 |         |       |          | C)** |             |
+-----------------+---------+-------+----------+------+-------------+
| **Mass**        | \>30%   | \>25% | \>20%    | \    | 5%          |
|                 |         |       |          | >15% |             |
+-----------------+---------+-------+----------+------+-------------+
| **Power (wrt    | \>30%   | \>25% | \>15%    | \    | \>10%\*     |
| End of Design   |         |       |          | >15% |             |
| Life            |         |       |          |      |             |
| Capacity)\***   |         |       |          |      |             |
+-----------------+---------+-------+----------+------+-------------+
| **Telemetry and | \>25%   | \>20% | \>15%    | \    | 2%          |
| Command         |         |       |          | >10% |             |
| Hardware        |         |       |          |      |             |
| Channels\*\***  |         |       |          |      |             |
+-----------------+---------+-------+----------+------+-------------+

Rationale:

\*At launch there shall be 10% predicted power margin for mission
critical and safe hold modes as well as to accommodate in-flight
operational uncertainties.

\*\* Telemetry and command hardware channels read data from hardware
such as thermistors, heaters, switches, motors, etc.

The LDCM OLI flight software shall have the following minimum resource
margins at the end of each development phase per processor:

+-------------------+----------+------------+----------+-------------+
| **Resources**     | *        | **P        | **       | **Pre-En    |
|                   | *Mission | reliminary | Critical | vironmental |
|                   | Design   | Design     | Design   | Design      |
|                   | Review** | Review**   | Review** | Review**    |
|                   |          |            |          |             |
|                   | **(Phase | **(Phase   | **(Phase | **(Phase    |
|                   | A)**     | B)**       | C)**     | D)**        |
+-------------------+----------+------------+----------+-------------+
| Central           | 50%      | 50%        | 40%      | 30%         |
| Processing Unit   |          |            |          |             |
| Utilization       |          |            |          |             |
+-------------------+----------+------------+----------+-------------+
| Central           | 50%      | 50%        | 40%      | 30%         |
| Processing Unit   |          |            |          |             |
| Deadlines         |          |            |          |             |
+-------------------+----------+------------+----------+-------------+
| Programmable      | 50%      | 30%        | 20%      | 5%          |
| Read-Only Memory  |          |            |          |             |
+-------------------+----------+------------+----------+-------------+
| Electrically      | 50%      | 50%        | 40%      | 30%         |
| Erasable          |          |            |          |             |
| Programmable      |          |            |          |             |
| Read-Only Memory  |          |            |          |             |
+-------------------+----------+------------+----------+-------------+
| Random Access     | 50%      | 50%        | 40%      | 30%         |
| Memory            |          |            |          |             |
+-------------------+----------+------------+----------+-------------+
| Peripheral        | 75%      | 70%        | 60%      | 50%         |
| Component         |          |            |          |             |
| Interconnect      |          |            |          |             |
| (PCI) bus         |          |            |          |             |
+-------------------+----------+------------+----------+-------------+
| 1553 bus          | 30%      | 25%        | 20%      | 10%         |
+-------------------+----------+------------+----------+-------------+
| Universal         | 50%      | 50%        | 40%      | 30%         |
| Asynchronous      |          |            |          |             |
| Rec               |          |            |          |             |
| eiver-Transmitter |          |            |          |             |
| (UART)            |          |            |          |             |
+-------------------+----------+------------+----------+-------------+
| Observatory       | 50%      | 50%        | 40%      | 30%         |
| Command Bus       |          |            |          |             |
| Throughput        |          |            |          |             |
+-------------------+----------+------------+----------+-------------+
| LVDS              | 50%      | 50%        | 40%      | 30%         |
+-------------------+----------+------------+----------+-------------+

# Launch Services

## Payload Processing Facility Compatibility

## Launch Site Support

## Launch Vehicle

# Science and Mission Requirements Document (SMRD) Traceability

To be supplied

# Verification Cross Reference Matrix (VCRM)

To be supplied