Attachment C GIRD.pdf

Effective Date: February 03, 2021 418-XO-GXIGIRD-0025 Expiration Date: Five years from date of last signature Version 1.1 Responsible Organization: GeoXO Flight Project/Code 418

Check the GeoXO portal at https://goesportal.ndc.nasa.gov to verify correct version prior to use.

Geostationary and eXtended Observations (GeoXO) General Interface Requirements Document (GIRD)

Signature page

Prepared by:

Electronically approved 02/03/2021

Michael A. Shallcross Date GeoXO Flight Project, System Eng.

NASA GSFC, Code 418

Reviewed by:

Alexander Krimchansky Date GeoXO Flight Project, Sys. Eng. Mgr.

NASA GSFC, Code 599

Phillip Driggers Date GeoXO Flight Project, Sys. Eng. Mgr.

NASA GSFC, Code 599

Approved by:

Jason H. Hair Date GeoXO Flight Project, Project Manager NASA GSFC, Code 418

/GeoXO Flight Project System Engineering

GIRD

418-XO-GXIGIRD-0025, RM Version, GeoXO General Interface Requirements Document (GIRD)

Version: 1.1 Printed by: rkhoover Printed on: Tuesday, February 2, 2021

No filter applied.

No sort applied.

Generated from DOORS 9.6.1.11

Contents

1 1Interface Requirements

1.1 1Requirements Terminology

2 2Documents

2.1 2Applicable Documents

3 3Requirements

3.1 3General Requirements

3.1.1 3On-Orbit Concept

3.1.2 3Coordinates

3.1.3 4Yaw Flip

3.2 4Interface Requirements

3.2.1 4Mechanical

3.2.1.1 4Nadir Pointed Instrument Alignment

3.2.1.1.1 4Placement

3.2.1.1.2 4Initial Alignment Knowledge

3.2.1.1.3 4Alignment Rate of Change

3.2.1.2 4Attitude and Disturbances for Nadir Pointed Instruments

3.2.1.2.1 4Attitude Error

3.2.1.2.2 5Attitude Rate Error

3.2.1.2.3 5Spacecraft Translation Acceleration Limits

3.2.2 7Thermal

3.2.2.1 7Thermal Control Concept

3.2.2.1.1 7Coupled Unit - Heat Transfer Flux Density

3.2.2.1.2 7Independent Unit - Net Heat Transfer

3.2.2.2 7Interface Temperatures

3.2.3 8Instrument Electrical Power

3.2.3.1 8Electrical Power Interfaces

3.2.3.1.1 8Power Definitions

3.2.3.2 8Instrument Operational Power Grounding

3.2.3.3 9Data Transfer Between the Instrument and Spacecraft

3.2.3.4 9Guaranteed Delivery

3.2.3.5 9Source Packet Format

3.2.3.6 9Pulse Per Second (PPS)

3.2.3.7 9Control and Monitoring

Project: GeoXO Flight Project System Engineering Module: GIRD Baseline Version: 1.1

Contents ii

3.2.4 9Environmental Conditions

3.2.4.1 9On-Orbit Radiation Environment

3.2.4.2 9Launch Environment

3.2.4.3 9Eclipse

3.3 10Attitude and Orbit Data

3.3.1 10Attitude Knowledge

3.3.1.1 10Accuracy

3.3.1.2 10Update Rate

3.3.1.3 10Latency

3.3.2 10Spacecraft Angular Rate

3.3.2.1 10Accuracy

3.3.2.2 11Bandwidth

3.3.2.3 11Update Rate

3.3.3 11Spacecraft Orbit

3.3.3.1 11Accuracy

3.3.3.2 11Update Rate

3.4 11Instrument-to-Spacecraft Disturbances

4 12Acronyms

Contents iii

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Object Number

1.1

1.1.0-1

1.1.0-2

1.1.0-3

1.1.0-4

418-XO-GXIGIRD-0025, RM Version, GeoXO General Interface Requirements Document (GIRD)

1 Interface Requirements

1.1 Requirements Terminology

The term “shall” designates a requirement that must be achieved and is synonymous with the term “threshold.”

The term “should” designates a desired level of performance the government would like the contractor to strive towards achieving and is synonymous with the term “goal.”

All other terms, including “will”, only designate statements of fact or intentions of the government and are not to be interpreted as contractor requirements.

An instrument may comprise more than one physical assembly, or unit. “Sensor unit” refers to the unit that contains the optics. “Instrument unit” means the sensor unit, electronics box (if applicable), or other units of the instrument.

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GIRD7

GIRD8

GIRD9

GIRD10

GIRD11

GIRD12

GIRD13

GIRD14

GIRD16

GIRD17

GIRD18

GIRD19

GIRD20

Object Number

2.1

2.1.0-1

2.1.0-2

2.1.0-3

2.1.0-4

2.1.0-5

2.1.0-6

2.1.0-7

2.1.0-8

2.1.0-9

2.1.0-10

2.1.0-11

418-XO-GXIGIRD-0025, RM Version, GeoXO General Interface Requirements Document (GIRD)

2 Documents

2.1 Applicable Documents

MIL-STD-461E Aug 99 - Requirements for the Control of Electromagnetic Interference Characteristics of Subsystems and Equipment

ECSS-E-50-12A - Space Wire - Links, Nodes, Routers and Networks, 24 January 2003 European Cooperation for Space Standardization (ECSS)

ISO/DIS 14644-1 - Cleanrooms and Associated Controlled Environments, May 1, CCSDS 133.0-B-1 Space Packet Protocol, Blue Book, Issue 1, September 2003

IEEE/ASTM SI-10 - American National Standard for Use of the International System of Units (SI): The Modern Metric System, December 2002

417-R-RPT-0027 - The Radiation Environment for Electronic Devices on GOES-R Series Satellites, August 14,2006

CCSDS 301.0-B-3 - Time Code Formats. Blue Book. Issue 3, January 2002

NASA/TM-2001-211221 - Guideline for the Selection of Near-Earth Thermal Environment Parameters for Spacecraft Design, October 2001

417-R-RPT-0050 - GOES-R Reliable Data Delivery Protocol Version 2.1 January 16, ISO/DIS 14644-3 Cleanrooms and associated controlled environments - Part 3:

Metrology and test methods, 9/26/02

SN-C-0005 Revision D, Contamination Control Requirements, July 20,1998

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ID

GIRD21

GIRD22

GIRD23

GIRD24

GIRD25

GIRD26

GIRD27

GIRD28

GIRD29

GIRD30

GIRD31

Object Number

3.1

3.1.1

3.1.1.0-1

3.1.1.0-2

3.1.1.0-3

3.1.1.0-4

3.1.1.0-5

3.1.2

3.1.2.0-1

3.1.2.0-2

418-XO-GXIGIRD-0025, RM Version, GeoXO General Interface Requirements Document (GIRD)

3 Requirements

3.1 General Requirements

3.1.1 On-Orbit Concept

The satellite will operate in a geosynchronous orbit (Semi-major axis of approximately 42,164 Km) located at either 75° or 137° west longitude. Normal on-orbit operations entail periodic station keeping maneuvers that keep the satellite within a 0.2° inclination about the equator and within ±0.2° of the onstation longitude.

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

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

The instrument will be in Survival Mode during launch.

Instruments shall survive a spacecraft attitude anomaly resulting in the sun sweeping through the fieldof-view (FOV) of the instrument radiator from “horizon to horizon” at a rate of 6O/minute, passing through radiator normal.

3.1.2 Coordinates

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

The ORF is orthogonal and right-handed.

The ORF origin is at the spacecraft center of mass.

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

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

The ORF +x axis completes the triad.

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

The BRF is orthogonal and right-handed.

The BRF is fixed to the body of the spacecraft.

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

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

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

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ID

GIRD32

GIRD33

GIRD34

GIRD35

GIRD36

GIRD37

GIRD38

GIRD39

GIRD40

GIRD41

GIRD42

GIRD43

GIRD44

GIRD45

GIRD46

GIRD47

GIRD48

GIRD49

GIRD50

Object Number

3.1.2.0-3

3.1.2.0-4

3.1.2.0-5

3.1.3

3.1.3.0-1

3.1.3.0-2

3.2

3.2.0-1

3.2.1

3.2.1.0-1

3.2.1.1

3.2.1.1.1

3.2.1.1.1.0-1

3.2.1.1.2

3.2.1.1.2.0-1

3.2.1.1.3

3.2.1.1.3.0-1

3.2.1.2

3.2.1.2.1

418-XO-GXIGIRD-0025, RM Version, GeoXO General Interface Requirements Document (GIRD)

If there is a yaw-flip, the spacecraft will be flown upright (+Y BRF pointed in the +Y ORF direction) during northern hemisphere winter and inverted (+Y BRF pointed in the -Y ORF direction) during northern hemisphere summer. i.e., the +Y BRF axis is generally in the same hemisphere as the Sun.

If there is no yaw-flip, the spacecraft will be flown upright all year.

The reference coordinate system of each instrument unit shall be nominally parallel to the spacecraft BRF coordinate system, with the exception of solar-pointing instruments.

3.1.3 Yaw Flip

For an instrument with passive cryogenic detector cooling, the GeoXO spacecraft will be rotated 180O about the Z-axis (yaw) twice per year to keep the -Y axis side of the spacecraft shaded, within ±4 days of the Sun crossing the orbit plane.

Instruments shall meet all performance requirements whether or not the spacecraft performs a yaw flip, except for instruments with cryogenic detectors cooled by a passive radiator.

3.2 Interface Requirements

All instrument-to-spacecraft interfaces shall be single fault tolerant.

3.2.1 Mechanical

The instrument contractor will provide all kinematic mounts, plus vibration isolation and thermal isolation mounting hardware.

3.2.1.1 Nadir Pointed Instrument Alignment

3.2.1.1.1 Placement

The placement of the instrument alignment reference frame with respect to the spacecraft IRU reference frame shall be to within 0.25 degrees per axis, including variation over all launch and on-orbit environments.

3.2.1.1.2 Initial Alignment Knowledge

The prelaunch alignment knowledge of the instrument alignment reference frame with respect to the spacecraft IRU input axes shall be 300 microradians or better per axis.

3.2.1.1.3 Alignment Rate of Change

The rate of change of the alignment of the instrument mounting frame with respect to the spacecraft IRU input axes shall not exceed 100 microradians per hour per axis. This requirement includes on-orbit environments and spacecraft structural and thermal stability.

3.2.1.2 Attitude and Disturbances for Nadir Pointed Instruments

3.2.1.2.1 Attitude Error

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ID

GIRD51

GIRD52

GIRD53

GIRD54

GIRD56

GIRD57

GIRD58

GIRD59

Object Number

3.2.1.2.1.0-1

3.2.1.2.1.0-2

3.2.1.2.2

3.2.1.2.2.0-1

3.2.1.2.2.0-2

3.2.1.2.3

3.2.1.2.3.0-1

3.2.1.2.3.0-2

418-XO-GXIGIRD-0025, RM Version, GeoXO General Interface Requirements Document (GIRD)

The attitude error of the instrument mounting frame relative to the desired ORF-referenced attitude shall not exceed 360 microradians, 3-sigma, per axis. Attitude error is defined as the difference between the desired attitude and the actual, or true, attitude of the instrument mounting frame.

The instrument mounting frame attitude shall be stable to within 500 microradians, peak-to-peak, per axis, over any 60 sec window.

3.2.1.2.2 Attitude Rate Error

For a given total spacecraft gyro signal phase delay, the instrument mounting frame attitude rate error relative to the desired ORF-referenced attitude shall not exceed ± the corresponding limit from the Total Spacecraft Gyro Signal Phase Delay and Rate Error Trade Space Figure provided below, per axis, when the rate is filtered by a fourth order Butterworth low pass filter with a -3dB frequency of 15 Hz.

Total Spacecraft Gyro Signal Phase Delay and Rate Error Trade Space Figure

3.2.1.2.3 Spacecraft Translation Acceleration Limits

The translational accelerations at the spacecraft side of each instrument sensor unit mount shall not exceed the limits specified in the Translational Acceleration Limits for Spacecraft to Instrument Table below. The limits apply to each orthogonal axis after the acceleration is bandpass-filtered using at least a fourth-order band-pass Butterworth filter with -3dB frequencies of f1 and f2. Note that the filter has fourth-order rolloff on both sides of the response. The accelerations can be present at any combination of the instrument sensor unit mounts and along any combination of the three orthogonal axes at each mount.

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ID

GIRD59

GIRD60

GIRD61

Object Number

3.2.1.2.3.0-2

3.2.1.2.3.0-3

3.2.1.2.3.0-4

418-XO-GXIGIRD-0025, RM Version, GeoXO General Interface Requirements Document (GIRD)

Translational Acceleration Limits for Spacecraft to Instrument Table f1 (Hz) f2 (Hz)

Peak Limit (mg) f1 (Hz) f2 (Hz)

Peak Limit (mg) f1 (Hz) f2 (Hz)

Peak Limit (mg)

0.0 0.9 6.3

20.2 64.0 203.2

9.0 9.5

10.1 10.7 11.3 12.0 12.7 13.5 14.3 15.1 16.0 17.0 18.0 19.0 20.2 21.4 22.6 24.0 25.4

512.0 10.1 32.0 101.6 322.5 512.0 10.1 10.7 11.3 12.0 12.7 13.5 14.3 15.1 16.0 17.0 18.0 19.0 20.2 21.4 22.6 24.0 25.4 26.9 28.5

18.44 1.50 1.00 4.29 10.55 15.16 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40

26.9 28.5 30.2 32.0 33.9 35.9 38.1 40.3 42.7 45.3 47.9 50.8 53.8 57.0 60.4 64.0 67.8 71.8 76.1 80.6 85.4 90.5 95.9 101.6 107.6

30.2 32.0 33.9 35.9 38.1 40.3 42.7 45.3 47.9 50.8 53.8 57.0 60.4 64.0 67.8 71.8 76.1 80.6 85.4 90.5 95.9 101.6 107.6 114.0 120.8

0.40 0.40 1.40 1.40 1.40 1.40 1.40 1.40 1.40 1.40 1.40 3.18 3.18 3.18 3.18 3.18 3.18 1.40 1.40 1.40 1.40 1.40 1.40 1.40 2.40

114.0 120.8 128.0 135.6 143.7 152.2 161.3 170.9 181.0 191.8 203.2 215.3 228.1 241.6 256.0 271.2 287.4 304.4 322.5 341.7 362.0 383.6 406.4 430.5 456.1

128.0 135.6 143.7 152.2 161.3 170.9 181.0 191.8 203.2 215.3 228.1 241.6 256.0 271.2 287.4 304.4 322.5 341.7 362.0 383.6 406.4 430.5 456.1 483.3 512.0

2.40 2.40 2.40 1.40 1.40 1.40 3.02 3.02 3.02 3.02 2.56 2.56 2.56 2.56 2.56 2.56 2.56 2.56 2.56 2.56 2.56 2.56 2.56 2.56 2.56

The translational accelerations at the spacecraft side of each instrument sensor unit mount shall produce an absolute peak acceleration Shock Response Spectra (SRS) less than the limits set in the On Orbit Operational SRS Acceleration Limits Table below. The limits apply to each orthogonal axis for SRS natural frequencies when using a quality factor, Q, of 50. The SRS is computed after the acceleration is high pass filtered with a fourth order Butterworth filter with a -3dB cut off at 1.0 Hz. Use a logarithmic interpolation for both frequency and acceleration terms in the On Orbit Operational SRS Acceleration Limits Table.

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ID

GIRD61

GIRD62

GIRD63

GIRD64

GIRD65

GIRD68

GIRD69

GIRD66

GIRD67

GIRD70

GIRD71

Object Number

3.2.1.2.3.0-4

3.2.2

3.2.2.1

3.2.2.1.0-1

3.2.2.1.0-2

3.2.2.1.1

3.2.2.1.1.0-1

3.2.2.1.2

3.2.2.1.2.0-1

3.2.2.2

3.2.2.2.0-1

418-XO-GXIGIRD-0025, RM Version, GeoXO General Interface Requirements Document (GIRD)

3.2.2 Thermal

3.2.2.1 Thermal Control Concept

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

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

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

In general:

⦁ Instrument electronic units are thermally-coupled.

⦁ Instrument sensor units are thermally-independent.

3.2.2.1.1 Coupled Unit - Heat Transfer Flux Density

For conductively-coupled units, peak local heat transfer fluxes conducted to the spacecraft shall be less than 0.25 watts per square centimeter.

3.2.2.1.2 Independent Unit - Net Heat Transfer

For Independent Units, the net heat transfer averaged over the instrument independent unit interface plane area shall be less than 15.5 watts/m².

3.2.2.2 Interface Temperatures

For planning and preliminary design purposes, the interface temperature (spacecraft side) for Earthviewing instruments shall be:

a) 0°C to 40°C during operation

b) -30°C to 50°C during non-operation

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GIRD72

GIRD73

GIRD74

GIRD75

GIRD76

GIRD77

GIRD78

GIRD79

GIRD80

GIRD81

GIRD82

GIRD83

GIRD84

Object Number

3.2.3

3.2.3.1

3.2.3.1.0-1

3.2.3.1.1

3.2.3.1.1.0-1

3.2.3.1.1.0-2

3.2.3.1.1.0-3

3.2.3.1.1.0-4

3.2.3.1.1.0-5

3.2.3.1.1.0-6

3.2.3.2

3.2.3.2.0-1

3.2.3.2.0-2

418-XO-GXIGIRD-0025, RM Version, GeoXO General Interface Requirements Document (GIRD)

3.2.3 Instrument Electrical Power

3.2.3.1 Electrical Power Interfaces

The spacecraft shall supply functionally independent, redundant operational power buses to each instrument for normal instrument operation.

3.2.3.1.1 Power Definitions

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

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

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

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

Peak Current (Operational) - The maximum (never to be exceeded) current drawn by the instrument. Peak current is typically calculated as 1.5 times the maximum power at worst case nominal voltage (TBS Vdc).

The instrument shall operate in accordance with the instrument performance specification within the range of TBS volts Vdc at the instrument operational power input connector.

3.2.3.2 Instrument Operational Power Grounding

The instrument electrical power grounding shall be in accordance with the Electrical Grounding Figure.

Electrical Grounding Figure

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ID

GIRD86

GIRD87

GIRD88

GIRD89

GIRD90

GIRD91

GIRD92

GIRD93

GIRD94

GIRD95

GIRD96

GIRD97

GIRD98

GIRD99

GIRD100

GIRD101

GIRD102

GIRD103

GIRD104

GIRD105

Object Number

3.2.3.3

3.2.3.3.0-1

3.2.3.4

3.2.3.4.0-1

3.2.3.5

3.2.3.5.0-1

3.2.3.6

3.2.3.6.0-1

3.2.3.7

3.2.3.7.0-1

3.2.3.7.0-2

3.2.3.7.0-3

3.2.3.7.0-4

3.2.3.7.0-5

3.2.4

3.2.4.1

3.2.4.1.0-1

3.2.4.2

3.2.4.2.0-1

3.2.4.3

418-XO-GXIGIRD-0025, RM Version, GeoXO General Interface Requirements Document (GIRD)

3.2.3.3 Data Transfer Between the Instrument and Spacecraft

All data transferred between the instrument and the spacecraft shall use the European Cooperation For Space Standardization (ECSS) ECSS-E50-12A (Space Wire) standard through the packet layer as a minimum.

3.2.3.4 Guaranteed Delivery

All data transferred between the instrument and the spacecraft shall provide guaranteed data delivery as defined in GOES R Reliable Data Delivery Protocol document.

3.2.3.5 Source Packet Format

All data transferred over the SpaceWire shall use the CCSDS 133.0-B-1 Section 4.1 Protocol Data Unit

3.2.3.6 Pulse Per Second (PPS)

The spacecraft shall provide the instrument a 1 PPS time code sequence accurate to ±10 microseconds relative to UTC.

3.2.3.7 Control and Monitoring

The spacecraft shall provide remote access to all critical telemetry and control.

Critical telemetry is defined as telemetry points that are required to monitor the instrument in powered off state.

Non-critical telemetry is defined as telemetry points that are required to monitor the instrument in powered on state.

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

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

3.2.4 Environmental Conditions

3.2.4.1 On-Orbit Radiation Environment

The instruments and spacecraft shall comply with the on-orbit radiation requirements that are described in the GSFC document 417-R-RPT-0027 titled "The Radiation Environment for Electronic Devices on the GOES-R Series Satellites."

3.2.4.2 Launch Environment

The instruments and spacecraft shall be designed to meet the launch environment described herein. The baseline launch vehicle is planned to be an expendable SpaceX Falcon 9 Heavy or Atlas V 551.

3.2.4.3 Eclipse

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GIRD106

GIRD107

GIRD108

GIRD109

GIRD110

GIRD111

GIRD112

GIRD113

GIRD114

GIRD115

GIRD116

GIRD117

GIRD118

GIRD119

GIRD120

GIRD121

GIRD122

GIRD123

GIRD124

GIRD125

GIRD126

Object Number

3.2.4.3.0-1

3.3

3.3.0-1

3.3.1

3.3.1.0-1

3.3.1.1

3.3.1.1.0-1

3.3.1.1.0-2

3.3.1.1.0-3

3.3.1.1.0-4

3.3.1.2

3.3.1.2.0-1

3.3.1.3

3.3.1.3.0-1

3.3.2

3.3.2.0-1

3.3.2.1

3.3.2.1.0-1

3.3.2.1.0-2

3.3.2.1.0-3

3.3.2.1.0-4

418-XO-GXIGIRD-0025, RM Version, GeoXO General Interface Requirements Document (GIRD)

Solar Eclipse shall be considered as part of the environmental variation. The Solar Eclipse season occurs twice yearly, with each eclipse season lasting approximately 45 days. The maximum eclipse duration is 72 minutes.

3.3 Attitude and Orbit Data

All attitude, rate and orbit data shall be included in the spacecraft ancillary data packet.

3.3.1 Attitude Knowledge

The spacecraft shall provide a periodic attitude estimate to the instrument.

3.3.1.1 Accuracy

The attitude knowledge static error shall not exceed 1200 microradians, 3-sigma, per axis, precalibration.

This requirement together with the next two define separate static, diurnal and dynamic attitude knowledge components. These requirements bound the knowledge error, which is the difference between the estimated attitude and the true attitude.

The attitude knowledge diurnal error shall not exceed 45 microradians, 3-sigma, per axis. Diurnal error refers to that portion of the error that repeats from day-to-day.

The attitude knowledge dynamic error shall not exceed 30 microradians, 3-sigma, per axis. Dynamic error includes all non-static and non-diurnal errors.

3.3.1.2 Update Rate

The spacecraft shall update the attitude estimate at a rate no less than 1 Hz.

3.3.1.3 Latency

The attitude estimate latency shall not exceed 100 milliseconds.

3.3.2 Spacecraft Angular Rate

The spacecraft shall provide a periodic angular rate estimate to the instrument.

3.3.2.1 Accuracy

The integrated rate error of the spacecraft angular rate estimate shall not exceed 1 microradian, 3sigma, in the x and y axes, and 1.5 microradians, 3-sigma, in the z-axis over any 1 second window.

The integrated rate error of the spacecraft angular rate estimate shall not exceed 2 microradians, 3sigma, in the x and y axes, and 2.5 microradians, 3 sigma in the z-axis, over any 30 second window.

The integrated rate error of the spacecraft angular rate estimate shall not exceed 7 microradians, 3sigma, per axis, over any 300 second window.

The integrated rate error of the spacecraft angular rate estimate shall not exceed 20 microradians, 3sigma, per axis, over any 900 second window.

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ID

GIRD127

GIRD128

GIRD129

GIRD130

GIRD131

GIRD132

GIRD133

GIRD134

GIRD135

GIRD136

GIRD137

GIRD138

GIRD139

GIRD140

Object Number

3.3.2.2

3.3.2.2.0-1

3.3.2.3

3.3.2.3.0-1

3.3.3

3.3.3.0-1

3.3.3.1

3.3.3.1.0-1

3.3.3.1.0-2

3.3.3.2

3.3.3.2.0-1

3.4

3.4.0-1

3.4.0-2

418-XO-GXIGIRD-0025, RM Version, GeoXO General Interface Requirements Document (GIRD)

3.3.2.2 Bandwidth

The spacecraft angular rate estimate shall have a minus 3dB bandwidth of greater than 25 Hz.

3.3.2.3 Update Rate

The spacecraft shall update the angular rate estimate at a rate no less than 100 Hz.

3.3.3 Spacecraft Orbit

The spacecraft shall provide a periodic spacecraft orbit estimate to the instrument via the ancillary data packet.

3.3.3.1 Accuracy

The spacecraft position estimate shall be accurate to 100 meters 3-sigma, in-track (ORF x-axis), crosstrack (ORF y-axis) and radial (ORF z-axis) directions.

The spacecraft velocity estimate shall be accurate to within 6 cm/sec, 3-sigma, per axis.

3.3.3.2 Update Rate

The spacecraft shall update the orbit estimate at a rate no less than 1 Hz.

3.4 Instrument-to-Spacecraft Disturbances

At any time during the operational mode of the spacecraft, the sum of the magnitude of the instrument sensor unit’s uncompensated torques and the magnitude of its uncompensated linear forces multiplied by a lever arm of 2 meters shall not exceed 1.0 N-m.

The magnitude of the instrument unit’s uncompensated angular momentum shall not exceed 1.0 N-msec.

Page 12 of 14 Printed Tuesday, February 2, 2021

ID

GIRD141

GIRD142

Object Number

4.0-1

418-XO-GXIGIRD-0025, RM Version, GeoXO General Interface Requirements Document (GIRD)

4 Acronyms %AC percent area coverage

A Ampere(s)

ASD Acceleration Spectral Density

BOL beginning of life

BRF body reference frame bps bits per seconds

C Celsius (Degrees) cm centimeter db decibel dc Direct Current

ECSS European Cooperation for Space Standardization

EED Electro-Explosive Device

EEE Electrical, Electronic and Electromechanical

ESD electro static discharge

FOR field of regard

FOV field-of-view g Earth’s gravitational acceleration

GIRD General Interface Requirements Document

GOES Geosynchronous Operational Environmental Satellite

GSE Ground Support Equipment

GSFC Goddard Space Flight Center

Hz hertz

ICD Interface Control Document

IDD Instrument Description Document

IRU inertial reference unit

ISO International Office for Standardization

Page 13 of 14 Printed Tuesday, February 2, 2021

ID

GIRD142

Object Number

4.0-1

418-XO-GXIGIRD-0025, RM Version, GeoXO General Interface Requirements Document (GIRD)

K kelvin kg kilogram

Km kilometer kPa Kilo Pascals

LOS line-of-sight

LSB Least Significant Bit m meter ma milli-ampere(s)

Mbps Mega bits per seconds

MHz Mega hertz mm millimeter

MAT Mission Allowable Temperatures

MEFL Maximum Expected Flight Level m-g milli-g (Earth’s gravitational acceleration)

MLI Multi-layer insulation

Ms milli-seconds

NASA National Aeronautics and Space Administration

N-m Newton-meter

N-m-sec Newton-meter-second nPa Nano Pascals

NVR Non-Volatile Residue

ORF Orbit reference frame

OSR Optical solar reflectors

PPB Parts Per Billion

PPM Parts Per Million

PPS Pulse Per Second

PSD power spectral density

QCM Quartz Crystal Microbalance

RIU Remote Interface Unit

Page 14 of 14 Printed Tuesday, February 2, 2021

ID

GIRD142

Object Number

4.0-1

418-XO-GXIGIRD-0025, RM Version, GeoXO General Interface Requirements Document (GIRD)

SCF SPP Coordinate Frame

SI International System of Units

SINDA System Integrated Numerical Differential Analyzer

SIS Solar Imaging Suite

SPP Sun-Pointing Platform

SRS Shock Response Spectra

TBD to be determined

TBR to be refined/reviewed

THC Total Hydrocarbons

UIID Unique Instrument Interface Document

UTC Universal Time Code µsec mico-seconds

V Volts

Vdc Volts-Direct Current

W Watts

Effective Date: February 03, 2021 418-XO-GXIGIRD-0025 Expiration Date: Five years from date of last signature Version 1.1 Responsible Organization: GeoXO Flight Project/Code 418

Check the GEO-XO portal at https://goesportal.ndc.nasa.gov to verify correct version prior to use.

Document Change Record (DCR)

CCR GEO-XO#: X00005 Rev: Title: GEO-XO – GXIGIRD Document Baseline Contract # N/A GOES S/C: GEO-XO Effectivity: Instrument CCB Status: Approved Doc #: 418-XO-GXIGIRD-0025 CCB Date: 11/02/2020 Doc Version: 1.0 Contract Mod#: N/A DOORs Version: 1.0 Doc Change Date: Nov. 02, 2020 DOORs ID #: 1.1

CCR GeoXO#: X00008 Rev: Title: GXIGIRD: Update GXIGIRD as GIRD Contract # N/A GOES S/C: GeoXO Effectivity: Instrument CCB Status: Approved Doc #: 418-XO-GXIGIRD-0025 CCB Date: 02/03/2021 Doc Version: 1.1 Contract Mod#: N/A DOORs Version: 1.1 Doc Change Date: Feb. 03, 2021 DOORs ID #: 1.1

CM Note: Version 1.0 states “Geostationary and eXtended Orbits (GEO-XO) Flight Project”, updated the title page, signature page, and Document Change Record (DCR) to “Geostationary eXtended Observations (GeoXO). Made changes in the acronym from GXIGIRD to GIRD. Additionally, updated all references from GEO-XO to GeoXO for v1.1.