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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