> **LANDSAT DATA CONTINUITY**
>
> **MISSION**

**Operational Land Imager (OLI)**

**-to-**

> **National Polar Operational Environmental Satellite System (NPOESS)
> 2130 Spacecraft Interface Requirements**
>
> **Effective Date: June 15, 2005**
>
> **Expiration Date: June 15, 2010**

![](media/image1.jpeg){width="1.125in" height="1.125in"}

**[Signature Page]{.underline}**

+----------------------------------+-----------------------------------+
| ***Prepared by:***               |                                   |
+----------------------------------+-----------------------------------+
| *[Original Signed]{.underline}*  |                                   |
| [06/07/05]{.underline}           |                                   |
|                                  |                                   |
| Nick Speciale Date               |                                   |
|                                  |                                   |
| LDCM Mission Systems Engineer    |                                   |
|                                  |                                   |
| GSFC Code 599                    |                                   |
+----------------------------------+-----------------------------------+
| ***Reviewed by:***               |                                   |
+----------------------------------+-----------------------------------+
| *[Original Signed]{.underline}*  | *[Original Signed]{.underline}*   |
| [06/07/05]{.underline}           | [06/07/05]{.underline}            |
|                                  |                                   |
| Del Jenstrom Date                | Jeanine Murphy Morris Date        |
|                                  |                                   |
| LDCM Observatory/Pallet Manager  | LDCM OLI Instrument Manager       |
|                                  |                                   |
| GSFC Code 427                    | GSFC Code 427                     |
+----------------------------------+-----------------------------------+
| ***Approved by:***               |                                   |
+----------------------------------+-----------------------------------+
| *[Original Signed]{.underline}*  | *[Original Signed]{.underline}*   |
| [06/08/05]{.underline}           | [06/15/05]{.underline}            |
|                                  |                                   |
| William Ochs Date                | James M. Schaeffer Date           |
|                                  |                                   |
| LDCM Project Manager             | IPO Chief Systems Engineer        |
|                                  |                                   |
| GSFC Code 427                    | NPOESS Integrated Program Office  |
+----------------------------------+-----------------------------------+

**LDCM PROJECT**

**DOCUMENT CHANGE RECORD**

Sheet: 1 of 1

+------------+----------------------------------------------+---------+
| REV        | DESCRIPTION OF CHANGE                        | DATE    |
|            |                                              |         |
| LEVEL      |                                              | A       |
|            |                                              | PPROVED |
+------------+----------------------------------------------+---------+
| \-         | Initial Release. CCR 000001.                 | 0       |
|            |                                              | 6/15/05 |
+------------+----------------------------------------------+---------+

**TABLE OF CONTENTS**

> [Page]{.underline}

[1 INTRODUCTION 1-1](#introduction)

[1.1 Scope 1-1](#scope)

[1.2 Conventions 1-1](#conventions)

[1.3 OLI / NPOESS GIID Compliance 1-2](#oli-npoess-giid-compliance)

[1.4 IRD Precedence Over NGIID and NPOESS System Specification
1-2](#ird-precedence-over-ngiid-and-npoess-system-specification)

[2 OLI / NPOESS Mass, Volume, and Power Accommodation
2-1](#oli-npoess-mass-volume-and-power-accommodation)

[2.1 OLI Volume and Location on Spacecraft
2-1](#oli-volume-and-location-on-spacecraft)

[2.2 OLI Mass 2-1](#oli-mass)

[2.3 OLI Power 2-1](#oli-power)

[3 OLI / NPOESS Field of View Accommodation
3-1](#oli-npoess-field-of-view-accommodation)

[3.1 Nadir Field of View 3-1](#nadir-field-of-view)

[3.2 Solar Calibration Field of View
3-1](#solar-calibration-field-of-view)

[4 NPOESS 2130 Orbit Requirements for OLI
4-1](#npoess-2130-orbit-requirements-for-oli)

[4.1 Orbit Parameters 4-1](#orbit-parameters)

[4.2 Cross-Track Repeat Cycle Variability
4-1](#cross-track-repeat-cycle-variability)

[5 NPOESS OLI Stored Mission Data Interface
5-1](#npoess-oli-stored-mission-data-interface)

[5.1 Operational Concept 5-1](#operational-concept)

[5.2 OLI Stored Mission Data Interface Circuit
5-1](#oli-stored-mission-data-interface-circuit)

[5.3 Mission Data Transfer Timing 5-2](#mission-data-transfer-timing)

[5.4 OLI Mission Data Transfer Interface Data Format
5-3](#oli-mission-data-transfer-interface-data-format)

[6 OLI Command, Telemetry, Time, and Ancillary Data Interfaces
6-1](#oli-command-telemetry-time-and-ancillary-data-interfaces)

[6.1 Command and Telemetry Interfaces
6-1](#command-and-telemetry-interfaces)

[6.2 OLI Auxiliary Data Input from NPOESS Spacecraft
6-2](#oli-auxiliary-data-input-from-npoess-spacecraft)

[6.3 OLI Time of Day Input from NPOESS Spacecraft
6-2](#oli-time-of-day-input-from-npoess-spacecraft)

[7 Telemetry and Command Requirements
7-1](#telemetry-and-command-requirements)

[7.1 Command Uploads 7-1](#command-uploads)

[7.2 OLI Non-operational Point to Point Telemetry Interfaces
7-1](#oli-non-operational-point-to-point-telemetry-interfaces)

[7.3 Realtime Monitoring and Autonomous Fault Detection and Correction
7-1](#realtime-monitoring-and-autonomous-fault-detection-and-correction)

[7.4 Flight Software Loads 7-1](#flight-software-loads)

[8 NPOESS Disturbance environment at oli interface
8-1](#npoess-disturbance-environment-at-oli-interface)

[8.1 Alignment Knowledge Uncertainty between S/C Attitude Determination
Frame and the RBS Interface Reference (over a 17-day Orbital Cycle)
8-1](#alignment-knowledge-uncertainty-between-sc-attitude-determination-frame-and-the-rbs-interface-reference-over-a-17-day-orbital-cycle)

[8.2 Alignment Knowledge Uncertainty between S/C Attitude Determination
Frame and the RBS Instrument Interface Reference (over a 30 sec along
track interval)
8-1](#alignment-knowledge-uncertainty-between-sc-attitude-determination-frame-and-the-rbs-interface-reference-over-a-30-sec-along-track-interval)

[8.3 Disturbance Spectra at the Spacecraft-Instrument Interface
8-1](#disturbance-spectra-at-the-spacecraft-instrument-interface)

[9 OLI Point to Point CMD/TLM Interfaces
9-1](#oli-point-to-point-cmdtlm-interfaces)

[9.1 Pulse Commands 9-1](#pulse-commands)

[10 OLI --NPOESS Thermal Interface RequirementS
10-1](#oli-npoess-thermal-interface-requirements)

[10.1 Thermal Fields of View 10-1](#thermal-fields-of-view)

**LIST OF FIGURES**

[Figure]{.underline} [Page]{.underline}

[Figure 2-1 Illustration of OLI -- RBS Stowed / Deployed Volume Envelope
2-3](#__RefHeading___Toc105827076)

[Figure 2-2 Candidate Location for OLI on the NPOESS 2130 Spacecraft
2-4](#__RefHeading___Toc105827078)

[Figure 3-1 OLI Nadir and Glint-Free Nadir Fields of View
3-2](#__RefHeading___Toc105827079)

[Figure 3-2 OLI Unobstructed Glint-Free Solar Calibration Fields of View
3-3](#__RefHeading___Toc105827080)

[Figure 3-3 Adjacent Hardware Envelopes for OLI Calibration FOV
Accommodation 3-4](#__RefHeading___Toc105827081)

[Figure 5-1 OLI Mission Data Interface Circuits
5-2](#__RefHeading___Toc105827082)

[Figure 5-2 OLI Mission Data Transfer Timing
5-3](#__RefHeading___Toc105827083)

[Figure 5-3 OLI Mission Data Interface Data Format
5-3](#__RefHeading___Toc105827084)

[Figure 8-1 Spacecraft Linear Acceleration Disturbance Environment
8-2](#__RefHeading___Toc105827085)

[Figure 8-2 Spacecraft Rotational Disturbance Environment
8-4](#__RefHeading___Toc105827086)

**LIST OF TABLES**

[Table]{.underline} [Page]{.underline}

[Table 1-1 IRD Precedence Summary 1-3](#__RefHeading___Toc105827119)

[Table 2‑1 OLI Volume Envelope 2-1](#__RefHeading___Toc105827120)

[Table 6‑1 NPOESS Spacecraft Ancillary Data Update Rate and Accuracy for
OLI Interface 6-2](#__RefHeading___Toc105827121)

[Table 8-1 Spacecraft-Acceleration Environment
8-2](#__RefHeading___Toc105827122)

[Table 8-2 Spacecraft Rotational Disturbance Environment
8-4](#__RefHeading___Toc105827123)

[Table 10-1 DSAP Heat Rejection Capabilities for Locations A and B in
Figure 2-2 10-1](#__RefHeading___Toc105827124)

**OLI-to-NPOESS 2130 SPACECRAFT INTERFACE REQUIREMENTS**

# INTRODUCTION

This document defines interface requirements to integrate the Landsat
Data Continuity Mission (LDCM) Operational Land Imager (OLI) instrument
onto the National Polar-orbiting Operational Environmental Satellite
System (NPOESS) 2130 spacecraft such that the LDCM can be performed from
this observatory. The OLI is considered to consist of two major
components, the Reflective Band Sensor (RBS) and the Data Storage And
Playback (DSAP) system.

## Scope

The purpose of this Interface Requirements Document (IRD) is to
establish a baseline for interface requirements between the NPOESS 2130
spacecraft and the OLI, and to serve as a core building block on which
the instrument-to-spacecraft interface can be designed. The technical
requirements contained herein primarily address those aspects of the OLI
to NPOESS 2130 spacecraft interface that are unique to this interface;
the remainder of the interface requirements are contained in the NPOESS
General Instrument Interface Document (GIID or NGIID) according to the
precedence stated in Section 1.4 below. The NPOESS spacecraft
integrating contractor and the OLI contractor shall each meet their
respective interface requirements as defined in this document.

This IRD includes interface requirements defined to the degree that they
can be defined at this time, prior to release of the OLI contract
solicitation. It is expected that this document will be further refined
by the Government after award of the OLI development contract and
establishment of the baseline OLI design.

## Conventions 

The requirements stated in this document are not of equal importance or
weight. The following three paragraphs define the weighting factors
incorporated in this document.

-   Shall: Designates the most important weighting level; that is,
    mandatory. Any deviations from these contractually imposed mandatory
    requirements require the approval of the contracting officer. *Note:
    Given the preliminary nature of this document, the Government will
    consider for adoption proposed deviations to "shall" requirements
    within this IRD that enhance the ability of the OLI design to meet
    its performance requirements (as specified in GSFC 427-50-01-001)
    and/or reduce its cost, schedule, or risk without unduly burdening
    the NPOESS spacecraft. Proposed deviations shall be negotiated and
    submitted in accordance with the OLI Request for Proposals.*

-   Should: Designates an intermediate weighting that indicates the
    requirements requested by the government are not mandatory. These
    are goal requirements that reduce the risk of accommodating the OLI
    onto the NPOESS 2130 spacecraft if they are met. Unless required by
    other contract provisions, noncompliance with the "should"
    requirements does not require approval of the contracting officer,
    but requires documented technical substantiation

```{=html}
<!-- -->
```
-   Will: Designates the intent of the government. Unless required by
    other contract provisions, noncompliance with the "will"
    requirements does not require approval of the contracting officer
    and does not require documented technical substantiation.

Some requirements contained herein are not yet fully specified.
Requirements needing further specification are indicated by the
following terms:

TBR: To Be Revised. Indicates that the requirement is particularly not
well defined at this time.

TBD: To Be Determined. Indicates values to be determined after OLI
contract award.

## OLI / NPOESS GIID Compliance

Unless otherwise stated in the sections below, the OLI shall comply with
all current requirements in the NPOESS General Instrument Interface
Document (GIID), Doc. No. D31418 Rev. B (in bidders' library).

## IRD Precedence Over NGIID and NPOESS System Specification

Interface requirements stated in this IRD shall either supplement the
corresponding NPOESS System Specification Document SY15-0007
requirements, or supplement or supersede the corresponding NPOESS GIID
document D31418 Rev B requirements as specified in each section of this
IRD and as summarized in Table 1-1.

In the event of conflicts between this IRD and the NPOESS System
Specification or NPOESS GIID, the content of this IRD shall be the
governing requirements.

  -------------------- ----------------- ----------------- -------------------
  **OLI-to-NPOESS      **Supplements     **Supersedes      **Supplements
  Spacecraft IRD       NPOESS System     NPOESS GIID       NPOESS GIID
  Section (incl.       Specification     Section**         Section**
  subsections as       Section**                           
  appropriate)**                                           

  **2.3.1**                              **3.2.4.3.1.4.4   
                                         paragraph         
                                         IF230930**        

  **4.0**              **3.2.1.4**                         

  **5.0**                                **3.2.4.8.3**     

  **6.1**                                                  **3.2.4.8**

  **6.2**                                                  **3.2.4.2.3.3.7**

  **6.3**                                                  **3.2.4.8.3.4**

  **7.0**                                                  **3.2.4.8.4**

  **7.1**                                **3.1.3.8**       

  **8.1**                                                  **3.2.4.2.3.3**

  **8.2**                                                  **3.2.4.2.3.3**

  **8.3**                                **3.2.6.3**       

  **9.0**                                                  **3.2.4.8.3.3**
  -------------------- ----------------- ----------------- -------------------

[]{.mark}

[]{#__RefHeading___Toc105827119 .anchor}Table 1-1 IRD Precedence Summary

# OLI / NPOESS Mass, Volume, and Power Accommodation 

The NPOESS 2130 Spacecraft shall accommodate an OLI that meets the
not-to-exceed (NTE) mass, volume, and power interface envelope values
specified below.

## OLI Volume and Location on Spacecraft

The OLI shall not exceed the volume envelopes specified in Table 2-1
(volume envelopes illustrated in Figure 2-1). The NPOESS 2130 Spacecraft
shall accommodate the OLI in the candidate locations indicated in Figure
2-2.

The spacecraft shall accommodate deployment into the calibration volume
for at least 10 (TBR) but not to exceed 20 (TBR) continuous minutes once
per week **(**TBR) during the operational phase of the mission. During
the initial orbital operations and check-out period the spacecraft shall
accommodate more frequent (TBR) deployments into the calibration volume.

Exceptions to the volumes specified herein due to protrusions shall be
negotiated between the OLI and NPOESS contractors on a case-by-case
basis.

  ----------- ------------------------ -----------------------------------
              **Stowed / Operational   **Calibration Volume**
              Volume**                 

  **RBS**     See figures 2-1 and 2-2  RBS Protrusions beyond the
              below                    Stowed/Operational Volume for
                                       calibration shall be negotiated on
                                       a case-by-case basis

  **DSAP**    0.5m (z) by 0.5m (x) by  N/A
              0.5m (y) (TBR) (located  
              per Figure 2-2)          
  ----------- ------------------------ -----------------------------------

[]{#__RefHeading___Toc105827120 .anchor}Table 2‑1 OLI Volume Envelope

## OLI Mass

The total mass of the OLI shall not exceed 400 kg. The total mass of the
OLI should not exceed 360 kg.

## OLI Power

###  {#section .unnumbered}

### Instrument External (Spacecraft) Power

This requirement supersedes paragraph IF230930 of NGIID Section
3.2.4.3.1.4.4, and as appropriate, other references made in the NPOESS
GIID to a nominal 28 Volt bus.

Instruments shall be designed to operate from a 22 to 38.6 Volt dc,
negative ground, unregulated power subsystem.

### Average Power

The total one-orbit average power of the OLI shall not exceed 425 W. The
total one-orbit average power of the OLI should not exceed 385 W.

### Peak Power

The total peak power of the OLI shall not exceed 510 W. The total peak
power of the OLI should not exceed 460 W.

![](media/image3.wmf){width="6.0in" height="7.729166666666667in"}

[]{#__RefHeading___Toc105827076 .anchor}Figure 2-1 Illustration of OLI
-- RBS Stowed / Deployed Volume Envelope

![](media/image4.wmf){width="6.0in" height="6.611805555555556in"}

[]{#__RefHeading___Toc105827078 .anchor}Figure 2-2 Candidate Location
for OLI on the NPOESS 2130 Spacecraft

# OLI / NPOESS Field of View Accommodation

## Nadir Field of View

### **Unobstructed Field of View**

####  {#section-1 .unnumbered}

The NPOESS 2130 Spacecraft shall provide an unobstructed minimum nadir
field of view for OLI that provides a 12.9 degree cross track width by
at least 1.7 degree along track length for any OLI optical aperture
location that falls within the X-Y dimension constraints of the
instrument. The boresight of the unobstructed field of view shall be
normal to the spacecraft nadir deck. (ref. Figure 3-1: Note, the
specific X-Y location of the nadir boresight shown in Figure 3-1 is
notional only)

### Glint-Free Field of View

The NPOESS 2130 Spacecraft shall provide the OLI an unobstructed FOV
within a conical 25° half angle of optical nadir for any OLI optical
aperture location that falls within the X-Y dimension constraints of the
instrument to minimize collection of scattered energy. The cone's
circular intersection on the +Z face shall envelope the oval-shaped
nadir port aperture. (ref. Figure 3-1: Note, the specific X-Y location
of the nadir boresight shown in Figure 3-1 is notional only)

## Solar Calibration Field of View

### Unobstructed Field of View

The NPOESS 2130 Spacecraft shall provide the OLI with a solar
calibration field of view unobstructed by spacecraft structures for any
time of the year across a range of solar elevation angles from -15° to
-25° relative to the local horizontal for the post eclipse exit portion
of the orbit.  To cover the seasonal variation in the solar azimuthal
position, the clear solar calibration field of view for the indicated
solar elevation range shall be 38°± 8° in azimuth towards the sun side
from the velocity vector for the post eclipse exit portion of the
orbit.  (Figure 3-2)

### Glint-Free Field of View

The NPOESS 2130 Spacecraft shall provide the OLI an unobstructed FOV
within a region bounded by --10 to --30° in elevation and 38°± 60° in
azimuth (towards the sun side) from the edges of the solar calibration
port. The bounding surface of this region's intersection with the
instrument shall envelope the rectangular shaped solar calibration
aperture (Figure 3-2). The spacecraft contractor shall accommodate this
FOV except for the obstructions shown in Figure 3-3.

> ![](media/image5.wmf){width="4.0in" height="7.824305555555555in"}

[]{#__RefHeading___Toc105827079 .anchor}Figure 3-1 OLI Nadir and
Glint-Free Nadir Fields of View

![](media/image6.wmf){width="6.0in" height="7.95625in"}

[]{#__RefHeading___Toc105827080 .anchor}Figure 3-2 OLI Unobstructed
Glint-Free Solar Calibration Fields of View

![](media/image7.wmf){width="5.25in" height="8.261805555555556in"}

[]{#__RefHeading___Toc105827081 .anchor}Figure 3-3 Adjacent Hardware
Envelopes for OLI Calibration FOV Accommodation

# NPOESS 2130 Orbit Requirements for OLI 

This section supplements NPOESS System Spec Doc \# SY15-0007, Section
3.2.1.4 Orbit.

## Orbit Parameters 

The NPOESS 2130 Spacecraft shall operate the OLI in a geodetically
pointed 828km ±12km near-circular sun synchronous frozen orbit with a 17
day, 241-path repeatable ground track orbit inclined by 98.7 degrees
with an equatorial ascending node crossing time of 2130hrs (± 10
minutes).

## Cross-Track Repeat Cycle Variability 

The NPOESS 2130 orbit cross-track repeat variability at the equator for
the orbit defined in Section 4.1 above shall be maintained within ±5 km
of the path center of the revised World Reference-2 (WRS-2) grid.

# NPOESS OLI Stored Mission Data Interface

This section supersedes NGIID MIL-STD-1553 and IEEE-1394 interface
requirements in NGIID section 3.2.4.8.3.

## Operational Concept

The NPOESS 2130 S/C transmits Stored Mission Data via a Ka-Band downlink
to globally distributed ground receptor sites during the course of an
orbit. The ground periodically uploads an SMD contact schedule
(providing start times and durations for NPOESS and OLI access to the
SMD downlink) good for 48 hours into the future.

When it is OLI's turn to transmit SMD, as directed by the onboard
contact schedule, a command will be sent by the S/C via the 1553B data
bus activating the OLI Stored Mission Data Interface. Once activated,
OLI monitors the state of a hardwired Ready signal (RCV_RDY, see below)
and transfers a block of data each time the Ready signal transitions to
a true state.

The OLI Stored Mission Data interface protocol is designed to allow
transmission at a continuous 150 Mbps. Should OLI not respond to the
Ready signal in a timely enough fashion, the S/C will insert a fill
block into the downlink so as to maintain link data continuity. OLI's
next transmission opportunity will occur following transmission of the
fill block. At the end of the scheduled OLI SMD contact period, the S/C
will no longer activate the Ready signal thus inhibiting further data
transfer. A command will be sent by the S/C to OLI via the 1553B data
bus deactivating the OLI Stored Mission Data interface.

## OLI Stored Mission Data Interface Circuit

The OLI Mission Data Interface circuits shall comply with Low Voltage
Differential Signal (LVDS).

The OLI Mission Data Interface configuration shall be as depicted in
Figure 5-1.

The OLI Mission Data Interface signals shall consist of prime and
redundant signals designated as RCV_RDY_X/, DATA(7:0)\_X, DATA_CLK_X and
ENABLE_X/ where the X in each signal name corresponds to either A or B
depending upon the primary or redundant signal designation.

The NPOESS System shall provide OLI with access to the SMD downlink such
that an average transmission rate (over a 24-hour period) of no less
than 23 Mbps is supported.

![](media/image8.wmf){width="5.051388888888889in"
height="4.301388888888889in"}

[]{#__RefHeading___Toc105827082 .anchor}Figure 5-1 OLI Mission Data
Interface Circuits

## Mission Data Transfer Timing

Activation and deactivation of OLI Mission Data transfer shall be
commanded via the 1553B data bus interface.

OLI Mission Data interface activation and deactivation commands shall be
processed in OLI such that data transfers start and stop on block
boundaries.

When OLI Mission Data Transfer is activated, data shall be transferred
as a 1024 byte block, 8-bits (DATA(7:0)) per DATA_CLK, enveloped by the
ENABLE signal for each inactive to active RCV_RDY transition. Note: The
RCV_RDY may transition true prior to completion of the current block
transfer.

The DATA_CLK signal shall be a 45% to 55% duty cycle square wave at 20
MHz.

OLI Mission Data Transfer Timing shall be as depicted in Figure 5-2.

The Delay from activation of RCV_RDY_X/ to start of data transmission
shall be 1microsecond or less. Delays greater than 1us may result in the
insertion of a fill block into the SMD downlink. Inserted fill blocks
are considered part of the 23 Mbps rate allocation.

![](media/image9.wmf){width="5.997222222222222in"
height="1.4465277777777779in"}

[]{#__RefHeading___Toc105827083 .anchor}Figure 5-2 OLI Mission Data
Transfer Timing

## OLI Mission Data Transfer Interface Data Format

Each 1024 byte Data Block transferred via the OLI Mission Data interface
shall be formatted as depicted in Figure 5-3.

![](media/image10.wmf){width="5.995833333333334in" height="1.10625in"}

[]{#__RefHeading___Toc105827084 .anchor}Figure 5-3 OLI Mission Data
Interface Data Format

The fields within the format depicted in Figure 5-3 shall correspond to
an Interleave Depth 4, CCSDS Channel Access Data Unit as specified in
CCSDS 701.0-B-2, Advanced Orbiting Systems, Networks and Data Links,
except as noted below.

The S/C ID field shall be as specified in NPOESS Reference Document
D35853, NPOESS Data Mapping APID, VCID, Downlink and Uplink.

The Virtual Channel ID field shall be as specified in NPOESS Reference
Document D35853, NPOESS Data Mapping APID, VCID, Downlink and Uplink.

OLI shall be capable of modifying the assigned S/C ID and VCID values
without disassembly.

The 24-bit Virtual Channel Data Unit Counter field shall be lengthened
by eight bits using the VCDU Counter Extension field resident in the
Insert zone.

The VCDU Counter Extension field shall form the MSBs of the total 32-bit
Virtual Channel Data Unit Counter.

OLI shall increment VDCU counts for every successive data frame
transferred within a VCID, including replays of partial fractional scene
files (that are being resent to provide a complete fractional scene file
to the \[USGS\] ground segment).

The Replay Flag shall not be used and set to '0'.

Spare fields shall be set to '0's.

The First Header Pointer field shall be set per CCSDS 701.0-B-2,
Advanced Orbiting Systems, Networks and Data Links.

The MPDU Packet zone shall contain multiplexed OLI Mission Data Packets.

### OLI Mission Data Packet Format

The OLI Mission Data Packet shall be formatted per CCSDS 701.0-B-2 and
301.0-B-2 using the CCSDS path Protocol Data Unit (CP_PDU) format (also
known as Version 1 Source Packet.

OLI Mission Data Packet size shall be limited to no more than 65,507
bytes including all headers.

The Application Process ID field shall be as specified in NPOESS
Reference Document D35853, NPOESS Data Mapping APID, VCID, Downlink and
Uplink.

# OLI Command, Telemetry, Time, and Ancillary Data Interfaces

## Command and Telemetry Interfaces

This section supplements requirements in section 3.2.4.8 of the NGIID.

The NPOESS / OLI Command and Telemetry interface shall be MIL-STD-1553B
interface in compliance with the requirements in NPOESS reference
document D34470, NPOESS 1553 Interface Requirements Document except as
tailored in the subsections below.

### Telemetry Formatting

The 1553B interface shall be utilized for the transfer of Test, Memory
Dump, Dwell, Housekeeping, LEO&A and Telemetry Monitor packets types (if
utilized) specified in D34470, NPOESS 1553 Interface Requirements
Document.

Engineering, Calibration, Diagnostic and Science packet types shall not
be transferred via 1553B.

### Number of Functionally Distinct Instrument Remote Terminals

OLI shall have no more than two dual redundant RT interfaces coupled to
the data bus.

### RT Physical Address Assignment

OLI's RT physical addresses shall be assigned per D34470, NPOESS 1553
Interface Requirements Document.

### OLI Combined Data Bus Rates

Peak data rates for OLI to S/C data transfers on the 1553B data bus
shall not exceed 2.048 kbps.

Should there be higher rate data transfers required, those higher rate
data types will be transferred via the OLI Stored Mission Data
Interface.

Peak data rates on the 1553B bus for S/C to OLI data transfers
(Commands, Time of Day, Ancillary and Uploads) shall not exceed 128
kbps.

It is recommended that OLI be designed to accept an input rate up to 128
kbps for commands and uploads. This rate assumes that the entire uplink
rate in a given uplink contact period is dedicated to OLI. The actual
input rate will be a function of how much of an uplink contact is
allocated to OLI versus NPOESS.

## OLI Auxiliary Data Input from NPOESS Spacecraft

This section supplements NGIID section 3.2.4.2.3.3.7.

The NPOESS 2130 spacecraft Command and Data Handling System shall
provide the OLI with periodic auxiliary data at the specified update in
Table 6-1. Detailed auxiliary data contents and formatting shall be
defined in the OLI-NPOESS 2130 ICD. This higher rate auxiliary data is
in addition to that provided in the Spacecraft Ephemeris and Attitude
Telemetry Diary specified in the Common Data Format Control Book --
External, Volume VII (D34862).

  ----------------- ----------------- ----------------- -----------------
  **Spacecraft      **Minimum Update  **Accuracy 3      **Accuracy of
  Parameter**       Rate**            sigma**           Time Correlation
                                                        to GPS Time, 3
                                                        sigma**

  Individual gyro   32hz              2.25 arc-sec      48 (TBR) microsec
  axis rate data                      integrated over   
                                      30 sec window     

  RT Ephemeris      0.1 Hz            36m               48 (TBR) microsec
  Calculation                                           
  ----------------- ----------------- ----------------- -----------------

[]{#__RefHeading___Toc105827121 .anchor}Table 6‑2 NPOESS Spacecraft
Ancillary Data Update Rate and Accuracy for OLI Interface

## OLI Time of Day Input from NPOESS Spacecraft

This section supplements NGIID section 3.2.4.8.3.4.

The NPOESS / OLI Time of Day interface shall be as specified in NPOESS
reference document D34470, NPOESS 1553 Interface Requirements Document,
except as tailored below.

The Time of Day sent in the TOD packet shall correspond to international
standard UTC time at the occurrence of the TOD pulse +/- 48 microseconds
when normal once-per-second GPS updates are available (normal
operations).

# Telemetry and Command Requirements

This section supplements NGIID section 3.2.4.8.4.

## Command Uploads

This section supersedes the 60-day autonomy requirements in section
3.1.3.8 of the NGIID.

The OLI-NPOESS System command interface shall support daily command
uploads from the of NPOESS MOC command sequences which provide
autonomous operations of the OLI for 48-hour periods.

The NPOESS ground segment will generate a checksum for command upload
verification by the OLI instrument.

## OLI Non-operational Point to Point Telemetry Interfaces

The OLI-NPOESS Spacecraft interface shall provide real-time monitoring
of critical OLI instrument health and safety parameters during periods
where the instrument is non-operational (powered off).

## Realtime Monitoring and Autonomous Fault Detection and Correction

The NPOESS 2130 spacecraft shall provide real-time monitoring and
autonomous fault detection and correction of critical OLI health and
safety telemetry when the OLI is operationally powered on.

OLI shall provide to the S/C all monitor points requiring real-time
monitoring in a standalone TMON Packet.

OLI shall provide to the S/C the autonomous fault response algorithm for
each TMON monitor point.

## Flight Software Loads

The NPOESS ground segment will partition OLI flight software loads to
fit into available uplink opportunities. The NPOESS 2130 bus C&DH will
store partitioned flight software loads (in the SSR) until the complete
flight software load image has been received and then transfer complete
flight software loads to the OLI instrument. A checksum for flight
software upload verification by the OLI instrument will be generated.

# NPOESS Disturbance environment at oli interface

The following alignment and stability requirements supplement the
alignment stability requirements of NGIID section 3.2.4.2.3.3 and
supercede the linear acceleration and rotational jitter disturbance
requirements of NGIID section 3.2.6.3.

## Alignment Knowledge Uncertainty between S/C Attitude Determination Frame and the RBS Interface Reference (over a 17-day Orbital Cycle)

The RSS of all sources of Boresight Alignment Control Error between the
Spacecraft Attitude Determination Frame and the Instrument Interface due
to alignment drifts shall be less than 40 arcsec (3 sigma) per axis
within any period of 17 days.

###  {#section-2 .unnumbered}

## Alignment Knowledge Uncertainty between S/C Attitude Determination Frame and the RBS Interface Reference (over a 30 sec along track interval) 

The RSS of all sources of Boresight Alignment Control Error between the
Spacecraft Attitude Determination Frame and the Instrument Interface due
to all dynamic sources shall be less than 40 arcsec (3 sigma) per axis
within any period of 30 seconds.

## Disturbance Spectra at the Spacecraft-Instrument Interface

The OLI shall meet all performance requirements while operating in the
linear acceleration and rotational jitter environments described in
sections 8.3.1 and 8.3.2.

### Spacecraft Linear Disturbance Environment

For instruments directly attached to the spacecraft structure, the
maximum zero-to-peak accelerations (per axis at the Instrument
Interface) shall be less than those listed in Table 8-1, and shown in
Figure 8-1, per axis (3-sigma) for any given frequency.

*Linear acceleration at the instrument interface due to jitter
consistent with Figure 8-1 on a frequency-by-frequency basis will be
considered in the design and performance evaluation of the instrument.
The disturbances shall be applied independently in each axis using the
single frequency in each axis that has the worst-case impact on sensor
performance.*

  ----------------------------------- -----------------------------------
  Frequency (Hz)                      Linear Acceleration (mG)

  0.100                               20.000

  1.000                               20.000

  1.200                               20.000

  5.000                               3.000

  8.000                               0.400

  12.000                              0.400

  28.000                              50.000

  45.000                              50.000

  48.000                              6.000

  52.000                              6.000

  85.000                              50.000

  100.000                             50.000

  1000.000                            10.000
  ----------------------------------- -----------------------------------

[]{#__RefHeading___Toc105827122 .anchor}Table 8-1
Spacecraft-Acceleration Environment

![](media/image11.png){width="5.997222222222222in"
height="4.101388888888889in"}

[]{#__RefHeading___Toc105827085 .anchor}Figure 8-1 Spacecraft Linear
Acceleration Disturbance Environment

### 8.3.2 Spacecraft Rotational Disturbance Environment {#spacecraft-rotational-disturbance-environment .unnumbered}

For instruments directly attached to the spacecraft structure, the
maximum zero to peak rotations of the instrument interface due to jitter
shall be less than 20 arcsec (3-sigma) per axis over any orbit and be
less than the values specified in Table 8-2, and shown in Figure 8-2,
per axis (3-sigma) for any given frequency.

*Rotational rates at the instrument interface due to jitter consistent
with Figure 8-2 on a frequency-by-frequency basis will be considered in
the design and performance evaluation of the instrument. The rotational
disturbances shall be applied independently in each axis using the
single frequency in each axis that has the worst-case impact on sensor
performance.*

  ----------------------------------- -----------------------------------
  Frequency (Hz)                      Rotation (arcsec)

  0.1                                 20.000

  0.75                                17.000

  5                                   2.000

  8                                   0.500

  12                                  0.500

  14                                  1.000

  15                                  0.825

  16                                  0.725

  17                                  0.642

  18                                  0.573

  19                                  0.514

  20                                  0.464

  21                                  0.421

  22                                  0.384

  23                                  0.351

  24                                  0.322

  25                                  0.297

  26                                  0.275

  27                                  0.255

  28                                  0.237

  29                                  0.221

  30                                  0.206

  31                                  0.193

  32                                  0.181

  33                                  0.170

  34                                  0.161

  35                                  0.152

  36                                  0.143

  37                                  0.136

  38                                  0.129

  39                                  0.122

  40                                  0.116

  41                                  0.110

  42                                  0.105

  43                                  0.100

  1000                                0.100
  ----------------------------------- -----------------------------------

[]{#__RefHeading___Toc105827123 .anchor}Table 8-2 Spacecraft Rotational
Disturbance Environment

![](media/image12.png){width="5.997222222222222in"
height="4.101388888888889in"}

[]{#__RefHeading___Toc105827086 .anchor}Figure 8-2 Spacecraft Rotational
Disturbance Environment

# OLI Point to Point CMD/TLM Interfaces

This section supplements NGIID section 3.2.4.8.3.3.

The NPOESS / OLI Command and Telemetry point to point interfaces shall
comply with the requirements in NPOESS reference document D31418, NPOESS
General Instrument Interface Document except as tailored in the
subsections below.

## Pulse Commands

OLI shall require no more than 6 (six) pulse command interfaces.

The Logic one state pulse command voltage shall be 19V min \@350 mA load
sink current.

# OLI --NPOESS Thermal Interface RequirementS

## Thermal Fields of View

*Note: Thermal analysis will verify the heat transfer adequacy at the
final mounting locations.  Details of adjacent hardware within the OLI
thermal FOV shall be provided by the spacecraft to a mutually agreed
upon level of fidelity**.***

### RBS Thermal FOV

The spacecraft shall provide to the +Y (cold) face of the RBS a
minimally obstructed hemispherical FOV for heat dissipation. This area
shall be located 1) as close as possible to the +Y (cold) edge of the
spacecraft structure and 2) in the spacecraft X-Z plane. 

### DSAP Thermal FOV

The spacecraft shall provide to the DSAP thermal FOV's with the thermal
heat rejection capabilities given in Table 10-1 at the candidate
locations indicated in Figure 2-2.

### Auxiliary Thermal FOV

The NPOESS 2130 spacecraft shall provide an area for thermal radiators
not to exceed 0.6 (TBR) square meters on the +Y (cold) face of the
spacecraft structure. The location of the radiator shall be mutually
agreed to by the OLI and NPOESS 2130 Spacecraft Contractors.

![](media/image13.wmf){width="8.75in" height="3.189583333333333in"}

[Assumptions]{.underline}

-   2130 Orbit, Beta angles of 26 and 45 Degrees

-   Worst Hot Case (Hot orbit, EOL properties)

-   Silverized Teflon Radiator Optical Properties

```{=html}
<!-- -->
```
-   Solar Alpha = 0.16 (EOL)

-   Emissivity = 0.75

[]{#__RefHeading___Toc105827124 .anchor}Table 10-1 DSAP Heat Rejection
Capabilities for Locations A and B in Figure 2-2