CII Environmental Guidelines

John CareyNASA CII Team

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General Background

CII Environmental Guideline Formulation Collection of existing interface and environmental requirements

documentation such as GEVS-SE, General Environmental Verification Specification

for STS & ELV GIRD, General Interface Requirements Document for EOS

Spacecraft/Instruments NASA & MILITARY Standards Documents NASA Design Rules Instrument ICDs such as APS, TIM, Cloud Cameras and

AIRS Instrument ERDs for SMAP, OCE, NuSTAR, and TES

Reviewed collected materials Selected guidelines appropriate for incorporation into the CII

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Environmental Interface Goals

Apply appropriate bounding to environments definition based upon review of existing environmental requirements Reduce instrument development cost through prevention of

under/over design and/or testing

Construct environmental guidelines for application as appropriate to operational environments Ground Launch Transient Low Earth Orbit (LEO) Geosynchronous Earth Orbit (GEO) Others as required…TBD

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Environmental Interface Assumptions

The majority of the environmental guidelines are NOT specific to either the instrument/spacecraft bus interface or the instrument configuration The environments that are NOT interface/configuration specific

have already been well defined The environments that are interface/configuration specific may or

may not be possible to define depending upon: Design Heritage Design Application

Initial environmental guidelines are for Ground, Launch Transient and Low Earth Orbit (LEO) operations

Currently working to define environmental guidelines for Geostationary Earth Orbit (GEO) operations

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Environmental Interface Drivers

The majority of environmental guidelines have little variability in application Binary nature Cost is defined by need

Instrument development cost data indicates a linear relationship to instrument mass

Since mass drives cost, conservation of instrument mass has been accommodated by the following: Quasi Static Acceleration defined by instrument mass though

application of a Mass Acceleration Curve Random vibration levels defined by instrument mass/weight

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Summary of Guidelines

Table of Contents from the Environmental Guidelines

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Key LEO Guidelines

The following environmental guidelines are defined to be “KEY” based upon

Impact to mass, volume or power or otherwise drive instrument cost or interface complexities

Variation from traditional requirements standards and require community vetting

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Key LEO Guidelines

ID Function Guidelines Rationale/Comment

9.2.1 Quasi‐Static Acceleration

The instrument should be designed to survive and fulfill its mission after the application of a launch vehicle‐induced quasi‐static acceleration environment represented by the Mass Acceleration Curve (MAC) defined in Figure 9‐1

Bounded for EarthScience Mission Launch Vehicles

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Key LEO Guidelines

ID Function Guidelines Rationale/Comment

9.2.3 Random Vibration

The instrument should be designed to survive and fulfill its mission after application of launch vehicle‐induced transient environments represented by the random vibration environment defined in Table 9‐2.  All flight article test durations are to be 1 minute per axis.  Non‐flight article qualification test durations are to be 2 minutes per axis.

Table 3.2‐2 represents the random vibration environment for instruments weighing ≤ 25 Kg.  Instruments weighing > 25 Kg may apply the following random vibration environment reductions:

The acceleration spectral density (ASD) level may be reduced for components weighing more than 25 Kg according to:

Bounded for EarthScience Mission Launch Vehicles

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Key LEO Guidelines

ID Function Guidelines Rationale/Comment

9.2.3 Random Vibration (continued)

ASDnew = ASDoriginal*(25/W)

Where W = instrument weight in Kg

The slope is to be maintained at ±6 dB/octave for instruments weighing ≤ 65 Kg.  For instruments > 65 Kg, the slope shall be adjusted to maintain an ASD of 0.01 g2/Hz @ 20 Hz and 2000 Hz for qualification testing and an ASD of 0.005 g2/Hz @ 20 Hz and 2000 Hz for acceptance testing.

Instruments weighing > 200 Kg are to maintain the ASD levels and slopes for a 200 Kg instrument.

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Key LEO Guidelines

ID Function Guidelines Rationale/Comment

9.2.3 Random Vibration (continued)

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Zone/Assembly Frequency (Hz) Acceptance Qualification

Instrument 20 0.013 g2/Hz 0.026 g2/Hz

20 - 50 +6 dB/octave +6 dB/octave

50 - 800 0.08 g2/Hz 0.16 g2/Hz

800 - 2000 -6 dB/octave -6 dB/octave

2000 0.013 g2/Hz 0.026 g2/Hz

Overall 10.0 grms 14.1 grms

Key LEO Guidelines

ID Function Guidelines Rationale/Comment

9.4.3 and9.4.4

Conducted and RadiatedEmissions

Adoption of  requirements CE102 and RE102 of MIL‐STD‐461F versus prior art (based upon MIL‐STD‐461C)

Latest MIL‐STD

9.4.5 thru9.4.9

Conducted and RadiatedSusceptibility

Adoption of  requirements CS101, CS114, CS 115,CS116 and RS103 of MIL‐STD‐461F versus prior art (based upon MIL‐STD‐461C)

Latest MIL‐STD

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GEO Considerations

The CII Team has reached out to the GEO ComSat vendors and operators to obtain hosted payload interface requirement documents Personal contacts have made and invitations to this CII

Workshop have been delivered to all steering committee members of the Hosted Payloads Alliance organization

Space Systems/Loral has provided an GEO Hosted Payload Interface Requirements Document

Intelsat has provided responses to the CII Team GEO ComSat hosted payload interface questionnaire

The CII Team patiently awaits additional industry inputs We would prefer to define Environmental Guidelines for GEO

based upon input from all of our potential hosts… We will continue our outreach efforts to industry

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Key Deltas to Guidelines for GEO

The following are initial observations regarding GEO environmental guidelines: Commercial environments appear to be more severe than is

typical for LEO Is this true in general and if so, we would like to understand

why?

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Responses to CII Workshop 1 Input

The following changes were made to the Environmental Guidelines based upon the feedback received from the CII Workshop 1: EMI/EMC has been addressed Common formats for both the CII Guidelines and the CII Workshop

Presentations were defined and deployed Background slides explaining the development of the Environmental

Guidelines were added Rationale/Comments have been added for all CII Guidelines

considered to be “Key” Inconsistencies in mission lifetime have been addressed

We hear you and appreciate your input Please continue augmenting the CII team through provision of

input and feedback to our effort and attendance of our workshops

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