LMX_UIID_DRAFTr13.pdf

LMX UIID DRAFT for Phase A Study r13

1 Scope The purpose of this Unique Instrument Interface Document (UIID) is two-fold. The first is to allocate GeoXO series spacecraft resources to the

Lightning Mapper Instrument (LMX). The second is to serve as a core building block on which the LMX-spacecraft interfaces can be designed.

The spacecraft integrating contractor and the LMX contractor will meet each of their respective interface requirements as defined in this document.

This UIID will govern the development of an Interface Control Document (ICD) which will be a joint activity of the LMX and spacecraft contractors.

The LMX ICD establishes the details of the electrical, communications, mechanical, thermal, integration and test, and command and data handling (C&DH) interfaces between the LMX instrument and the GeoXO spacecraft.

After the ICD is signed and approved by all parties, the spacecraft contractor will maintain the ICD.

The LMX is a single-wavelength, non-scanning imaging instrument designed to detect lightning. The instrument collects data on a three-axis body-stabilized satellite in geosynchronous orbit. SNR, coverage, resolution and geolocation accuracy are prime requirements of the LMX. The instrument requires primary power and command input data from the spacecraft. Instrument output data to the spacecraft contains instrument telemetry and ancillary data. The sensor unit contains the optical system, detectors, and electronics. The electronics unit contains the power supply module, command, control, and data processing circuitry.

1.1 Document Overview

Together, the General Interface Requirements Document (GIRD) and the LMX UIID establish the LMX-spacecraft interface requirements. The

GIRD applies to all GeoXO instruments while the LMX UIID is specific to the LMX. Section 1 explains the use of this document. Section 2 lists reference documents. Section 3 allocates spacecraft resources, such as mass, power, and data rate, to the LMX instrument. Section 4 contains government-accepted operation constraints. Section 5 contains government-accepted deviations from the GIRD. Section 6 contains Design

Verification Requirements. Section 7 contains a list of acronyms used within this document.

1.2 Requirements Terminology

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

The use of “should” designates good practice.

The use of “will” is a statement of fact.

The use of “may” designates permission by the Government.

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

The term “(TBR)”, which means “to be refined/reviewed”, means that the requirement is subject to review for appropriateness and subject to revision. The contractor is liable for compliance with the requirement as if the “TBR” notation did not exist. The “TBR” merely provides an indication that the value is more likely to change in a future modification than requirements not accompanied by a “TBR”.

The term “(TBS)”, which means “to be specified”, means that the contractor will supply the missing information in the course of the contract.

These serve as a placeholder for future requirements. The contractor is not liable for compliance with these “placeholder” requirements, as insufficient information is provided on which to base a design.

1.3 Order of Precedence

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

Instrument Description Document (IDD).

2 Applicable Documents

2.1 Applicable Documents

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

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

December 2015

2. 418-XO-GXIGIRD-0025 - General Interface Requirements Document (GIRD)

2.2 Reference Documents

The following documents provide reference material for part of this document.

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

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

3 Allocations The GeoXO spacecraft provides communications, power, and a mounting platform for the LMX instrument. The following paragraphs allocate these resources to LMX.

3.1 Command and Data Handling

3.1.1 Instrument-to-Spacecraft Science Rate

The instrument science and engineering data rate, including all overhead associated with Consultative Committee for Space Data Systems

(CCSDS) packetization by the instrument, at the spacecraft interface shall not exceed 75 Mbps when averaged over any 5 second period.

3.1.2 Telemetry Data Rate

Housekeeping telemetry data rate, including all overhead associated with CCSDS packetization by the instrument, at the spacecraft interface shall not exceed 1024 bits per second when averaged over any 5 second period.

3.1.3 Application Process Identifiers

The LMX shall use no more than 255 consecutive Application Process Identifiers (APIDs) for science, telemetry, and command packets.

3.1.4 GeoXO Reliable Data Delivery Protocol Packet Rate

The LMX shall transmit to the spacecraft no more than 300 GRDDP Packets per second

3.2 Power

3.2.1 Average Operational Power

The LMX shall draw operational average power, inclusive of heaters, of no more than 325 Watts from up to four total feeds including primary and redundant feeds. Operational average power is the total power into an instrument averaged over any 5 minute period.

3.2.2 Maximum Operational Power

The LMX shall draw operational maximum power of no more than 520 Watts. Operational maximum power is the total power into an instrument averaged over any 20ms period.

3.2.1 Average Survival Power

The LMX shall draw average survival power of no more than 215 Watts (TBR) from the spacecraft. Average survival power is the total power into an instrument averaged over any 72 minute period.

3.2.2 Maximum Survival Power

The LMX shall draw maximum survival power of no more than 320 Watts (TBR) from the spacecraft. Survival maximum power is the total power into an instrument averaged over any 20 ms period.

3.3 Mechanical

The requirements in this section apply to the structural and mechanical components of the instrument flight units (sensor unit, electronics unit).

3.3.1 Mass Properties

The LMX, including all units and cabling between units, shall have mass less than 140 (TBR) kilograms.

3.3.2 Cabling Between Units

If there are external units mounted directly to the spacecraft, the LMX cable length between the units shall be 4 m

Cables between LMX units are the responsibility of the LMX contractor.

Spacecraft interface cabling is the responsibility of the spacecraft.

3.3.3 Volume

The LMX Sensor and Electronics Units stowed and operational (deployed) configurations, including mounts, thermal blankets and connectors, shall not exceed the dimension limits provided below.

Instrument Unit Envelopes Table

Component Width (cm)

(X)

Height (cm)

(Y)

Depth (cm)

(Z)

Sensor unit 125 123 150

Electronics unit 50 37.5 50

For the sensor unit, width is in the X direction of the body reference frame (BRF) defined in the GIRD. Height is measured in the Y direction of the BRF, and depth is in the Z direction of the BRF. For the electronic units, height is the direction normal to the mechanical interface plane.

In going from the stowed to the operational configuration, sensor unit depth (z-axis dimension) shall always be less than or equal to 186 cm.

3.3.4 Optical Port Field-of-View

The spacecraft shall provide the sensor unit’s optical port a clear field-of-view within 30o of nadir as shown in the following figure.

The Instrument LOS shall nominally be aligned with the +Z axis in the BRF as defined in the GIRD.

3.3.5 Radiator Field-of-View

The spacecraft shall provide the sensor unit’s radiator face a 2π steradian field-of-view to space excepting a field-of-view blockage with less than

50 W back loading.

The instrument shall dedicate the +Y face of the instrument for a radiator surface with the axis in the Body Reference Frame (BRF) as defined in the GIRD.

3.3.6 Mounting

The spacecraft shall provide the instrument sensor unit a nadir-facing mounting surface.

The spacecraft mounting surface shall have as a minimum the same dimensions of the sensor unit envelope anti-nadir plane.

The sensor unit mechanical interface shall lie within the anti-nadir plane of the sensor unit envelope.

The instrument sensor unit shall use kinematic mounts for its mechanical interface to the spacecraft.

The placement of the LMX reference frame with respect to the spacecraft instrument mounting reference frame shall be to within 0.125 degrees per axis, including variation over all launch and on-orbit environments.

Nominal LMX mounting orientations shall have the instrument Z axis parallel to the spacecraft Z axis and the instrument Y axis either parallel to or anti-parallel to the spacecraft Y axis.

3.4 Spacecraft Disturbances

3.4.1 Externally Sourced Translation Acceleration Limits

The translational accelerations responses from sources external to the instrument sensor unit at the spacecraft side of each instrument sensor unit mount shall not exceed the limits specified in the Externally Sourced Linear Acceleration Limits Table below. The limits apply to each orthogonal axis after the acceleration is filtered using at least a fourth-order band pass Butterworth filter with -3dB frequencies at f1 and f2 and with a fourth order roll off. Note that the filter has a fourth-order roll-off on both sides of the response.

Externally Sourced Linear Acceleration Limits Table f1 (Hz) f2 (Hz)

LMX UIID

(mg) f1 (Hz) f2 (Hz)

LMX UIID

(mg) f1 (Hz) f2 (Hz)

LMX UIID

(mg)

0.0 512.0 10.97 26.9 30.2 0.22 114.0 128.0 1.94

0.9 10.1 2.29 28.5 32.0 0.22 120.8 135.6 1.94

6.3 32.0 0.83 30.2 33.9 0.22 128.0 143.7 1.94

20.2 101.6 3.18 32.0 35.9 0.22 135.6 152.2 1.56

64.0 322.5 8.06 33.9 38.1 0.22 143.7 161.3 1.56

203.2 512.0 9.13 35.9 40.3 0.45 152.2 170.9 1.56

9.0 10.1 0.22 38.1 42.7 0.45 161.3 181.0 2.29

9.5 10.7 0.22 40.3 45.3 0.45 170.9 191.8 2.29

10.1 11.3 0.22 42.7 47.9 0.45 181.0 203.2 2.29

10.7 12.0 0.22 45.3 50.8 0.60 191.8 215.3 2.29

11.3 12.7 0.22 47.9 53.8 0.60 203.2 228.1 3.33

12.0 13.5 0.22 50.8 57.0 0.60 215.3 241.6 3.33

12.7 14.3 0.22 53.8 60.4 1.86 228.1 256.0 3.33

13.5 15.1 0.22 57.0 64.0 1.86 241.6 271.2 3.33

14.3 16.0 0.22 60.4 67.8 1.86 256.0 287.4 3.33

15.1 17.0 0.22 64.0 71.8 1.86 271.2 304.4 3.33

16.0 18.0 0.22 67.8 76.1 0.82 287.4 322.5 3.33

17.0 19.0 0.22 71.8 80.6 0.82 304.4 341.7 3.33

18.0 20.2 0.22 76.1 85.4 0.82 322.5 362.0 3.33

19.0 21.4 0.22 80.6 90.5 0.82 341.7 383.6 3.33

20.2 22.6 0.22 85.4 95.9 0.82 362.0 406.4 3.33

21.4 24.0 0.22 90.5 101.6 0.82 383.6 430.5 3.33

22.6 25.4 0.22 95.9 107.6 0.82 406.4 456.1 3.33

24.0 26.9 0.22 101.6 114.0 0.82 430.5 483.3 3.33

25.4 28.5 0.22 107.6 120.8 1.94 456.1 512.0 3.33

The translational acceleration responses from sources external to the instrument sensor unit 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 Externally Sourced SRS

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 -3dB cut off at 1.0 Hz. Use a logarithmic interpolation for both frequency and acceleration terms in the Externally Sourced SRS Limits Table.

Externally Sourced SRS Limits Table f

(Hz)

SRS

Limit/ Q

(mg) f

(Hz)

SRS

Limit/ Q

(mg)

10.0 0.19 177.0 1.54

36.0 0.19 198.0 1.54

36.0 0.31 209.8 1.16

55.7 0.31 222.8 1.16

59.0 1.54 236.0 1.77

66.0 1.54 264.0 1.77

69.9 0.72 279.1 1.25

111.4 0.72 295.0 1.77

118.0 1.54 330.0 1.77

132.0 1.54 349.6 1.77

139.8 0.76 483.3 1.77

167.1 0.76 512.0 1.77

3.5 Thermal

The total heat transfer to the spacecraft from the instrument electronics unit shall not exceed 220 Watts.

3.6 Instrument Purge Requirements

The spacecraft shall provide a continuous GN2 purge to the LMX sensor unit when not under vacuum.

The spacecraft shall provide a continuous T-0 GN2 purge to the LMX.

4 Constraints In order to ensure proper instrument performance or to prevent possible instrument damage, the following Government-approved constraints are imposed by the instrument developer on spacecraft integration and test activities, including launch, activation and operations.

No constraints have been identified at this time.

5 GIRD Deviations This section identifies GIRD requirements that the Government has deviated from for this instrument. Where appropriate, corresponding GIRD paragraph titles and numbers are identified in parentheses.

No GIRD deviations have been identified at this time.

6 Design Verification Requirements The following requirements represents only a portion of the overall system verification (i.e., contractor derived requirements are not described) that must be integrated into the total system program which verifies that the system will meet the mission requirements. A system performance verification program documenting the overall verification plan, implementation, and results is required which will provide traceability from mission specification requirements to launch and initial on-orbit capability. This will also provide the baseline for tracking on-orbit performance versus pre-launch capability.

6.1 Radiated Emissions, Electric Field (RE 102)

The test procedure used for this test shall be in accordance with MIL-STD-461G, RE102.

Radiated narrow band electric field levels generated by the instrument shall not exceed the levels specified in Figure RE102-3 of MIL-STD-461G, applicable to fixed wing external.

Radiated narrow band electric field levels generated by the instrument shall not exceed the levels specified in the Radiated Emission Notch Table.

Radiated Emissions Notch Table:

Frequency Range (MHz) Rationale Limits

(dBuV/meter)

1560 - 1595 (TBR) GPS 10 (TBR)

2033.5 - 2038 (TBR) CDAS Cmd, ORTT&C Cmd 12 (TBR)

6.2 Radiated Emissions in DCS Receiver Bands

Radiated emission measurements in the DCS receiver bands shall be made in accordance with MIL-STD-461G, RE102 with the EMI meter replaced by a spectrum analyzer preceded by a low noise pre-amplifier such that the test system noise figure is equal to or less than 3 dB, e.g., an HP-8566 spectrum analyzer preceded by a MITEQ AU-2A-0550 pre-amplifier or equivalent

The spectrum analyzer levels and the difference in the levels shall be recorded for both white noise and spurious signals before and after power is applied to the instrument clock and control signals.

The test antenna shall be tuned to the center of the frequency band specified in DCS EMC Test Parameters Table.

Prior to making the actual measurements, the test antenna shall be de-mated and the cable terminated with 50 ohms for self-calibration.

The noise floor of the measuring equipment shall be verified to be lower than the specified maximum signal level in a 100 Hz resolution bandwidth.

Radiated emission levels generated by the instrument shall not exceed the maximum signal levels specified in the DCS EMC Test Parameters Table below.

DCS EMC Test Parameters Table

Unit Name DCS Band (MHz)

Measurement Bandwidth (Hz)

Dwell Time (Seconds)

Minimum Measurement Time

Analog Measurement

Receiver (sec/kHz)

Max. Field Intensity (dBuV/m)

Instrument Electronics

Box

401.700 – 402.400

100 .015 0.15 10 (each box) (TBR)

Instrument Sensor Unit

401.700 – 402.400

100 0.015 0.15 -24 (TBR)

7 Acronyms APID Application Process Identifier

C&DH Command and Data Handling

CCSDS Consultative Committee for Space Data Systems dBuV Decibel micro volt

GeoXO Geostationary Extended Observations

GIRD General Interface Requirements Document

GOES Geostationary Operational Environmental Satellite

GSFC Goddard Space Flight Center

Hz Hertz

ICD Interface Control Document

IDD Instrument Description Document kg kilogram

LMX GEO-XO Lightning Mapper m meter

Mbps million bits per second

NASA National Aeronautics and Space Administration

SRS Shock Response Spectra

TBD to be determined

TBR to be resolved

TBS to be specified

UIID Unique Instrument Interface Document