Attachment_B_EUROPA-PROP-SPEC-0006_12-06-2017.docx.pdf

Effective Date: 12/06/2017

Expiration Date: 12/06/2022

Check https://ipdtdms.gsfc.nasa.gov to verify that this is the correct version prior to use

400-FORM-0002 (4/16/2014)

National Aeronautics and

Space Administration

EUROPA-PROP-SPEC-0006, Revision -

EUROPA Clipper Propulsion, Code 597

Low Pressure Latch Valve

Specification

GSFC Europa Clipper Propulsion

CMO K. Mrowczynski

12/06/2017

RELEASED

Goddard Space Flight Center

Greenbelt, Maryland https://ipdtdms.gsfc.nasa.gov/

LPLV SPEC EUROPA-PROP-SPEC-0006, Revision -ii

Low Pressure Latch Valve Specification

Signature/Approval Page Prepared by:

Eric Golliher

Reviewers/Approvers:

Caitlin Bacha

Dan Ramspacher

Erin Lalime

Timothy Johnson

Eric Haggquist

Oscar Cheatom

Megan Casey

Thomas Correll

Mark Fiebig

Luis Gallo

Approved by:

Caitlin Bacha

*** Electronic signatures are available on-line at https://ipdtdms.gsfc.nasa.gov*** https://ipdtdms.gsfc.nasa.gov/ iii

Preface

This document is a Europa Clipper Propulsion project signature-controlled document. Changes to this document require prior approval of the applicable Product Design Lead (PDL) or designee. Proposed changes shall be submitted in the EUROPA Propulsion Technical Data

Management System (TDMS) via a Signature Control Request (SCoRe) along with supportive material justifying the proposed change. Changes to this document will be made by complete revision.

All of the requirements in this document assume the use of the word "shall" unless otherwise stated.

Questions or comments concerning this document should be addressed to:

Europa Clipper Propulsion Configuration Management Office

Mail Stop: 597

Goddard Space Flight Center

Greenbelt, Maryland 20771 iv

Change History Log

Revision Effective Date Description of Changes

(Reference the SCoRe Approval Date)

Revision - 12/06/2017 Released following approval of EUROPA-SCoRe-0083 v

Table of Contents

1.0 Introduction

1.1 General Information

1.2 Scope

1.3 low pressure Latch Valve Definition and Description

2.0 Applicable Documents

3.0 Functional & Performance Requirements

3.1 Valve function

3.2 Latch Valve Flight Unit Functional/Performance Requirements

3.2.1 Pressure

3.2.2 Leakage

3.2.3 Response Time

3.2.4 Coil Design ................................................ Error! Bookmark not defined.

3.2.5 Position Indication

3.2.6 Cycles

3.2.7 Filtration

3.2.8 Venting

3.3 Power

3.3.1 Primary Power Input Requirements

3.4 Electrical Grounding

3.4.1 Primary Power Isolation from Component Chassis

3.4.2 Latch Valve Status Signals and Ground to Primary DC Isolation

3.4.3 Mechanical Contact Impedance

3.4.4 Conductor Bleed Path

3.4.5 Shield Continuity

3.5 EEE Parts

3.5.1 EEE Part Standard Qualification

3.5.2 ESD Survival

3.6 Radiation

3.6.1 Soft Seat Material

4.0 Physical Requirements

4.1 Mass Properties

4.1.1 Component Mass

4.2 Physical Envelope

4.3 Mounting

4.3.1 Mounting Type

4.3.2 Fastener Accessibility

4.4 Interface tube

4.4.1 Dimension

4.4.2 Material

5.0 Environmental Requirements

5.1 Handling Environments

5.2 Mechanical Factors of Safety

5.3 Quasi-Static Acceleration

vi

5.4 Vibration

5.4.1 Random Vibration

5.5 Shock

5.6 External Pressure

5.7 Humidity

5.8 Thermal Requirements

5.8.1 Flight Interface Design Temperature Limits

6.0 Cleanliness

6.1 Surface Contamination & Planetary Protection

6.1.1 Surface Contamination Levels at Delivery

6.1.2 Biological Contamination

6.1.3 External Cleanliness

6.1.4 Internal Cleanliness

6.1.5 Material Selection

6.1.6 Low Volatile Materials

6.1.7 Assembly Outgassing

6.2 Magnetic Cleanliness

6.2.1 External Magnetic Fields

6.2.2 Magnetic Field Strength

7.0 Design & Construction requirements

7.1 Identification and Marking

7.2 electrical connection

7.2.1 Flying Leads

7.3 Interchangeability

7.4 Lifetime

Appendix A Abbreviations and Acronyms vii

List of Tables

Table Page

Table 1 Applicable Documents Table 2 Handling Environments

Table 3 Factors of Safety Table 4 Random Vibration Levels Table 5 Shock Levels Table 6 Operational Temperature Levels at Mounting Interface Table 7 Non-Operational Temperature Levels at Mounting Interface

List of Figures

Figure Page

Figure 1: Inlet & Outlet Dimensions (inches)

1.0 INTRODUCTION

1.1 GENERAL INFORMATION

The Europa Clipper mission is being formulated and implemented by a joint partnership between the Jet Propulsion Laboratory and the Applied Physics Laboratory, with NASA Goddard Space Flight Center (GSFC) building the propulsion subsystem for the Applied Physics Laboratory.

1.2 SCOPE

This specification describes the electrical, mechanical, environmental, and verification testing requirements for a space-qualified Propulsion Subsystem Low Pressure Latch valve (LPLV) for the Europa mission.

1.3 LOW PRESSURE LATCH VALVE DEFINITION AND DESCRIPTION

The Propulsion Subsystem Low Pressure Latch Valve is a latching type device that regulates the supply of propellant by electromagnetically opening and closing the valve.

Power is only required for valve opening, valve closing and position indication.

2.0 APPLICABLE DOCUMENTS

The following documents and drawings shall apply to the fabrication and to the electrical, mechanical, and environmental requirements of the Latch valve to the extent specified herein. In the event of conflict between this specification and any referenced document, this specification will govern, with the exception of the Europa Latch Valve Statement of Work (EUROPA-PROP-SOW-0006), in which case the Statement of Work (SOW) takes precedence.

The following is a list of the applicable specifications and publications.

Table 1 Applicable Documents

AIAA-S-080 Space Systems - Metallic Pressure Vessels, Pressurized Structures, and Pressure Components

Rev -, 1/1/1998

ASTM E-595 Standard test method for total mass loss and collected volatile condensable materials from outgassing in a vacuum environment

1993 (R03)E1

EEE-INST-002 Instructions for EEE Parts Selection, Screening, Qualification, and Derating

4/1/2008

EUROPA-PROP-

SOW-0006

Europa Project Low Pressure Latch Valve Statement of Work

Rev -

EUROPA-PROP-

SPEC-0001

Europa Project Propulsion Subsystem Specification Rev C

EUROPA-PROP-

ANYS-TBD

Propulsion Subsystem Pressure Drop Analysis Rev-

EUROPA-PROP-

ANYS-0002

Propulsion Subsystem Filtration Analysis Rev-

AMS 2244 Tolerances, Titanium and Titanium Alloy Tubing Rev C

ASTM D2116 Standard Specification for FEP Resin Molding and Extrusion Materials

ASTM D3307 Standard Specification for Perfluoroalkoxy (PFA) Resin Molding and Extrusion Materials

04/2016

EEE-INST-002 Instructions for EEE Parts Selection, Screening, Qualification, and Derating

04/2008

IEST-STD-CC1246 Product Cleanliness Levels - Applications, Requirements, and Determination

Rev E

JPL D-56068 Europa Project Electrical Interfacing and Grounding Requirements Document

12/5/2016

JPL D-80301 Europa Project Electro-static Discharge (ESD) Control Plan

10/21/2016

JPL D-55605 Europa Temperature Requirements Table (TRT)

J-STD-001ES Requirements for Soldered Electrical and Electronic Assemblies

12/1/2010

Mil-PRF-26539 PROPELLANTS, DINITROGEN TETROXIDE 4/7/2017

Mil-PRF-27404 PROPELLANT, MONOMETHYLHYDRAZINE 4/20/2012

MIL-STD-1629A Procedures for Performing a Failure Mode, Effects and Criticality Analysis

11/28/1984

MIL-STD-883 Test Method Standard for Microcircuits G

NASA-Std. 8719.24 Rev. A

NASA Expendable Launch Vehicle Payload Safety Requirements

Rev A

3.0 FUNCTIONAL & PERFORMANCE REQUIREMENTS

The component shall be designed to withstand the operational and non-operational environments specified in the following section without degradation to mission goals and performance requirements.

3.1 VALVE FUNCTION

The valve shall maintain its position without further supplied power.

Rationale: Derived from the Europa Propulsion Subsystem Spec, EUROPA-PROP-

SPEC-0001.

3.2 LATCH VALVE FLIGHT UNIT FUNCTIONAL/PERFORMANCE

REQUIREMENTS

3.2.1 Pressure

MEOP

The Maximum Expected Operating Pressure (MEOP) shall be 300 psia at the inlet and outlet and across the valve seat in the flow direction.

Rationale: Derived from the Europa Propulsion Subsystem Spec, EUROPA-PROP-

SPEC-0001.

Proof Pressure

The valve shall withstand an internal proof pressure of 900 psig in the open position with ambient external pressure without permanent deformation. The valve shall withstand a proof pressure of 900 psig both upstream and downstream of the seal in the closed position. The valve will not be required to cycle open or closed at this pressure.

Rationale: (MEOP + 150 (Back Pressure Relief, Upstream Valve) + 150 (Back Pressure Relief Downstream Valve)) x 1.5; refer to NASA STANDARD 8719.24, REV. A.

Burst Pressure

The valve shall withstand an internal burst pressure of 1500 psig in the open position without rupture. Permanent deformation is acceptable.

Rationale: (MEOP + 150 (Back Pressure Relief, Upstream Valve)) + 150 (Back Pressure Relief, Downstream Valve) x 2.5; refer to NASA STANDARD 8719.24, REV. A.

Interface Tube Design Proof Pressure

The interface tube design proof pressure capability of the latch valve shall be at least 900 psia.

Rationale: (MEOP + 150 (Back Pressure Relief, Upstream Valve) + 150 (Back Pressure Relief, Downstream Valve)) x 1.5 for lines and fittings with diameter less than 1.5 in; NASA

STANDARD 8719.24, REV. A.

Interface Tube Design Burst Pressure

The interface tube of the latch valve shall withstand a burst pressure of at least 2400 psia.

Permanent deformation is acceptable.

Rationale: (MEOP + 150 (Back Pressure Relief, Upstream Valve) + 150 (Back Pressure Relief, Downstream Valve)) x 4 for lines and fittings with diameter less than 1.5 in; NASA

STANDARD 8719.24, REV. A.

Flow Rate/Pressure Drop

The latch valve shall have a maximum pressure drop of less than 0.7 psid at 0.0623 lbm/sec for monomethylhydrazine (MMH) and a maximum pressure drop of less than 1.13 psid at 0.1018 lbm/sec for mixed oxides of nitrogen (MON-3) per MIL-PRF-26539 at T = 70 degrees Fahrenheit and with no filter contamination.

Rationale: Derived from the Propulsion Pressure Drop Analysis, EUROPA-PROP-ANYS- 0004.

Back Relief Pressure

The latch valve shall have a back relief pressure of 50-150 psig. Back relief pressure is the pressure differential between the downstream and the upstream fluids required to force the latch valve to relieve downstream pressure..

Rationale: Derived from the Europa Propulsion Subsystem Spec, EUROPA-PROP-

SPEC-0001.

3.2.2 Leakage

Internal Leakage

The internal leakage rate of the latch valve shall not exceed 10 scch of GHe from 50 psia to MEOP in the flow direction and over the operational temperatures.

Rationale: Required level maintains system performance throughout the mission per Leakage Analysis.

External Leakage

The external leakage rate of the latch valve shall not exceed 10-6 sccs of GHe at MEOP and over the operational temperatures. Pressure shall be applied at the valve inlet and outlet simultaneously.

Rationale: Required level maintains system performance throughout the mission per Leakage Analysis.

3.2.3 Response Time

The valve opening response time shall be ≤ 120 ms over the range of pressure differentials from 0 psid to MEOP supplied to the valve inlet with the voltage range specified in “Operating Voltage Range” over the operational temperature range.

The valve closing response time shall be ≤ 120 ms over the range of flow rates from no flow to full flow as defined herein with the voltage range specified in “Operating Voltage Range” over the operational temperature range.

Rationale: Fault correction during a maneuver. In these cases, it is critical to identify erroneous engine firings and shut down the system quickly.

3.2.4 Position Indication

Configuration

The latch valve shall have one or more position indicator(s) which give positive confirmation of the closed position. It is acceptable to have both closed and open switch contacts and a common lead shared between closed and open switch contacts.

Position Indicator Type

The position indicator type shall be either a reed switch or mechanical microswitch that meets all other specifications.

Position Indicator Resistance

The resistance of the position indicator when the contacts are OPEN shall be greater than 1 Megohm. The resistance of the indicator when the contacts are CLOSED shall be less than 1 ohm.

Rationale: Derived from the Europa Propulsion Subsystem Spec, EUROPA-PROP-

SPEC-0001.

3.2.5 Cycles

The latch valve shall be qualified for at least 2000 functional cycles while maintaining all performance requirements. One cycle is defined as the valve position moving from closed to open to closed.

Rationale: Compliance with NASA STANDARD 8719.24, REV. A, which requires a minimum capability of 2000 cycles for safety critical components.

3.2.6 Filtration

The latch valve shall have an inlet filter with a filtration rating greater than or equal to 25 microns absolute. The inlet filter shall be sized properly to provide adequate protection for the latch valve seat. The filter shall have a capacity of at least 1 mg while maintaining flow and pressure drop requirements.

Rationale: Filtration Analysis, EUROPA-PROP-ANYS-0002.

3.2.7 Venting

The latch valve shall be designed with margin to survive without degradation an external depressurization rate of -4.4kPa/s (-0.638 psi/s) during launch (Atlas V). A 1.5x margin for analysis shall be applied to this depressurization rate.

3.3 POWER

3.3.1 Primary Power Input Requirements

The latch valves shall draw no more than 2.0 A at 36 VDC input voltage at 0°C.

Nominal Current Through Position Indicator

The position indicator shall be designed to operate properly while carrying a 0.4 to 0.6 mA measurement current.

Operating Voltage Range

The latch valve shall be designed to operate over the bus voltage range of +19 to +36 VDC at its primary power inputs.

Rationale: Derived from the Europa Propulsion Subsystem Spec, EUROPA-PROP-

SPEC-0001.

Voltage Survival Range

The latch valve shall survive without electrical overstress after exposure to an anomalous voltage that varies between -40 and +40 VDC without internal fluid for a continuous 30 seconds duration.

Rationale: Derived from the Europa Propulsion Subsystem Spec, EUROPA-PROP-

SPEC-0001.

Pull-in Voltage

The low pressure latch valve pull-in voltage shall demonstrate a minimum force margin of 25% to the worst case force produced over the operating conditions specified herein.

Sudden Removal of Power

The low pressure latch valve shall be tolerant to the sudden (and unannounced) removal of power, without suffering permanent hardware degradation or damage.

Coil Induction

Each coil shall have an inductance greater than 0.2 mH and less than 250 mH.

Rationale: Derived to insure margin on design decisions.

Non-actuation Voltage

The low pressure latch valve shall not change valve positions when 0.5 VDC is applied to the opening coil, closing coil or both coils simultaneously.

Rationale: Derived from the Europa Propulsion Subsystem Spec, EUROPA-PROP- SPEC-0001. Valve coils could see up to 0.5 VDC continuously due to radiation degradation of valve drivers.

3.4 ELECTRICAL GROUNDING

3.4.1 Primary Power Isolation from Component Chassis

Power input leads shall be isolated from chassis by a resistance greater than 20 MΩ.

Rationale: Derived from the EIG (D56068) RQ100.461, with allowance for resistance expected in the drive circuits.

3.4.2 Latch Valve Status Signals and Ground to Primary DC Isolation

The latch valve status signals and signal return shall be isolated from primary power and return by a DC resistance of greater than 1 MΩ and a capacitance less than 400 pF.

Rationale: Derived from the EIG (D56068) RQ100.241.

3.4.3 Mechanical Contact Impedance

The DC resistance of a mechanical contact from the top of the latch valve mounting feet to the bottom of the latch valve mounting feet shall be less than or equal to 1 mΩ DC resistance.

Rationale: 1.0 mΩ is an allocation to meet the component to chassis requirement of 25 mΩ in the chassis requirement of the EIG (D56068) RQ103.521.

3.4.4 Conductor Bleed Path

All conductors with areas in contact greater than 1 mm3 within the valve shall have a bleed path to the feet or case of the valve with a resistance less than or equal to 100 mega-ohm.

3.4.5 Shield Continuity

The DC resistance of a mechanical contact from the shield on any lead wire to the bottom of the latch valve mounting feet shall be less than or equal to 2.5 mΩ DC resistance.

Rationale: Implement the EIG (D56068) RQ100.596.

The shield on each lead wire shall be terminated to the housing in a 360 degree manner.

Rationale: Implement the EIG (D56068) RQ100.295.

3.5 EEE PARTS

3.5.1 EEE Part Selection Screening, and Qualification

All EEE Parts within the valve shall meet the level 1 requirement per EEE-INST-002, except as called out in the LPLV Statement of Work, EUROPA-PROP-SOW-0006

3.5.2 ESD Survival

All EEE Parts within the valve shall survive repeated exposure to ESD pulses up to 1000 V Human Body Model per MIL-STD-883G.

Rationale: The ESD Control Plan (D-80301) calls out MIL-STD-883G, Class 1A (human body model, 100 pF, 1000 V, 1500 ohm) when tested in accordance with MIL-STD- 883G, method 3015.7. Analysis should be acceptable verification for the EEE parts expected within the low pressure latch valve due to the large anticipated margins

3.6 RADIATION

3.6.1 Radiation Dosage

All polymers within the valve and EEE Parts shall be capable to withstand a Total Ionizing Dose (TID) of 250 krad.

Rationale: ERD Radiation Requirement including the required Radiation Design Factor of 2.

3.6.2 Soft Seat Material

Any soft good material used for at the valve seat shall consist of either Fluorinated Ethylene Propylene (FEP) per ASTM 2116 or Perfluoroalkoxy Alkane (PFA) per ASTM D3307. The seat material selection shall be approved by the Contracting Officer Representative (COR).

Rationale: FEP & PFA are the available soft good materials capable of handling the expected radiation levels.

4.0 PHYSICAL REQUIREMENTS

4.1 MASS PROPERTIES

4.1.1 Component Mass

The latch valve shall have a mass of less than or equal to 0.88 kg. This mass excludes the mass of the associated flying leads.

Rationale: Selected to fit in the baseline mechanical design. Derived from the Europa Propulsion Subsystem Spec, EUROPA-PROP-SPEC-0001.

4.2 PHYSICAL ENVELOPE

The physical envelope of the latch valve shall be less than 6.7 in x 4.25 in x 2.50 in.

Rationale: Selected to fit in baseline mechanical design. Derived from the Europa Propulsion Subsystem Spec, EUROPA-PROP-SPEC-0001.

4.3 MOUNTING

4.3.1 Mounting Type

The latch valve shall accommodate being hard-mounted with mechanical fasteners on a single mechanical surface of the spacecraft structure.

Rationale: Fasteners are the primary method for mounting the latch valve.

4.3.2 Fastener Accessibility

The latch valve shall be designed such that there is line-of-sight of the fasteners holes in the mounting feet as viewed from above the valve, normal to the mounting feet.

Rationale: Lessons Learned. This enables the valve to be more easily installed and removed during I&T.

4.4 INTERFACE TUBE

4.4.1 Dimension

a. The total length from the inlet tube interface to the outlet tube interface shall be

6.630 +/- 0.030 inches.

b. The dimensions of the interface tubes shall meet the dimensions shown in Figure 1 and tolerances which conform to AMS2244C.

c. Inlet and Outlet Tubes shall be on the same axis.

Figure 1: Inlet & Outlet Dimensions (inches)

Rationale: Tolerances Given per SAE-AMS 2244C.

4.4.2 Material

The material at the tube interface shall be 6Al-4V Titanium.

5.0 ENVIRONMENTAL REQUIREMENTS

Environmental design requirements for the latch valve are specified in this section. The low pressure latch valve shall be capable of meeting the performance requirements after exposure to the environments specified in this section.

5.1 HANDLING ENVIRONMENTS

Flight hardware shall be designed to survive without degradation the thermal, pressure and relative humidity environments specified below in Table 2.

Table 2 Handling Environments

Control Parameter Low Limit High Limit

Air Temperature (Storage) +5°C +50°C

Air Temperature (Operational) +5°C +40°C

Temperature Change Rate -10°C/hr +10°C/hr

Pressure (10,000’ max altitude) 6.9x104 N/m2 1x105 N/m2

Relative Humidity 30% 70%

5.2 MECHANICAL FACTORS OF SAFETY

The latch valve shall demonstrate positive Margins of Safety (MS) under limit loads for all yield and ultimate failures using the Factors of Safety (FS) defined in

𝑀𝑆 =

𝐴𝑙𝑙𝑜𝑤𝑎𝑏𝑙𝑒 𝑆𝑡𝑟𝑒𝑠𝑠 (𝑜𝑟 𝐿𝑜𝑎𝑑)

𝐷𝑒𝑠𝑖𝑔𝑛 𝐿𝑖𝑚𝑖𝑡 𝑆𝑡𝑟𝑒𝑠𝑠 (𝑜𝑟 𝐿𝑜𝑎𝑑)𝑥 𝐹𝑆

− 1

Table 3 Factors of Safety

Yield Factor Ultimate Factor

1.25 1.4

1 – Factors of safety for pressurized systems to be compliant with NASA STANDARD 8719.24, REV. A, “NASA Expendable Launch Vehicle Payload Safety Requirements.”

2 – Factors shown should be applied to statistically derived peak response based on RMS level. As a minimum, the peak response shall be calculated as a 3-sigma value.

5.3 QUASI-STATIC ACCELERATION

Quasi-static acceleration represents the combination of steady-state accelerations and the low frequency mechanically transmitted dynamic accelerations that occur during launch.

The low pressure latch valve shall demonstrate its ability to meet its performance requirements after being subjected to a net limit load of 70 g’s at the center of mass of the valve. The low pressure latch valve shall be in the closed state during acceleration testing. The valve seats shall not change state while being subjected to the acceleration environment. This test shall be repeated in the positive and negative directions in all three orthogonal axes.

Rationale: Derived from the Europa Environmental Requirements Document (ERD).

5.4 VIBRATION

5.4.1 Random Vibration

The latch valve shall demonstrate its ability to withstand the random vibration environment, including meeting internal leakage while being subjected to these levels and meeting all performance requirements after being subjected to these levels. The valve shall not change position while being subjected to the random vibration environment. The vibration levels shall be applied at the latch valve interface in all three orthogonal axes.

Table 4 Random Vibration Levels

Frequency (Hz)

FA Accels. (g) (1 min per Axis)

Qual/PF Accels. (g) (2 min/1 min per Axis)

20 - 30 +11.9 dB/oct +11.9 dB/oct 30 - 50 0.05 g2/Hz 0.1 g2/Hz 50 - 70 +6.2 dB/oct +6.2 dB/oct 70 - 300 0.1 g2/Hz 0.2 g2/Hz 300 - 400 -9.6 dB/oct -9.6 dB/oct 400 - 500 0.04 g2/Hz 0.08 g2/Hz 500 - 2000 -3 dB/oct -3 dB/oct Overall grms: 8g 11.3g

Rationale: Derived from the ERD, REV A 16 October 2017.

5.5 SHOCK

The latch valve shall be designed to meet its performance requirements after being subjected to the shock environment in Table 5 applied at the latch valve mounting interface. The valve shall not change position, even momentary, due to the shock levels listed in Table 5 in either the open or closed positions.

Table 5 Shock Levels

Frequency (Hz) SRS, FA (g)

Q = 10 SRS, Qual/PF (g)

Q = 10 100 12.2 17 600 504 706

1800 1479 2070

10000 1479 2070

Rationale: Derived from the ERD, REV A 16 October 2017.

5.6 EXTERNAL PRESSURE

The latch valve shall be designed to meet all performance requirements while operating over an external pressure range of 1.01 x 105 N/m2 (760 Torr) to 1.3 x 10-12 N/m2 (1 x 10-

14 Torr).

5.7 HUMIDITY

The latch valve shall be able to meet performance requirements after exposure to relative humidity levels of 0% to 70% for the defined mission life.

Rationale: Derived from the Europa Propulsion Subsystem Spec, EUROPA-PROP-

SPEC-0001.

5.8 THERMAL REQUIREMENTS

5.8.1 Flight Interface Design Temperature Limits

The latch valve shall be capable of performing indefinitely without damage or permanent performance degradation when its temperatures are within the operational limits shown in Table 6.

Table 6 Operational Temperature Levels at Mounting Interface

Minimum Temperature (ºC)

Maximum Temperature (ºC)

Allowable Flight Temperature 0 +35

Flight Acceptance -5 +40

Protoflight or Qualification -12 +55

The valve shall meet its performance requirements after exposure to the non-operational temperatures specified with the valve in both the open and closed position. The valve shall meet its performance requirements after exposure to the allowable flight temperatures, flight acceptance and qualifications levels while in the open position.

Table 7 Non-Operational Temperature Levels at Mounting Interface

Minimum Temperature (ºC)

Maximum Temperature (ºC)

Allowable Flight Temperature 0 +35

Flight Acceptance -5 +40

Protoflight or Qualification -15 +55

Heat Microbial Reduction +116 Defined by supplier, based on valve’s temperature limitations

Rationale: Derived from the Temperature Requirements Table D-55605.

6.0 CLEANLINESS

6.1 SURFACE CONTAMINATION & PLANETARY PROTECTION

6.1.1 Surface Contamination Levels at Delivery

6.1.2 Biological Contamination

All of the parts of the valve shall be treated per Planetary Protection protocols such that the bioburden is reduced by the required amount per Europa Planetary Protection Plan as outlined in the LPLV SOW, EUROPA-PROP-SOW-0006. These protocols shall not degrade the performance of the valve.

Rationale: Derived from JPL Europa Planetary Protection requirements.

6.1.3 External Cleanliness

The LPLV external cleanliness shall meet IEST- VC-0.5-1000 per IEST-STD-CC1246, prior to delivery to the customer.

6.1.4 Internal Cleanliness

The latch valve shall be cleaned, and verified internally clean, to level 100A per IEST- STD-CC1246 (as modified by the following: no metal particles allowed above 25 um) prior to delivery.

6.1.5 Material Selection

6.1.6 Low Volatile Materials

The latch valve materials shall have a total mass loss (TML) less than 1.00% and a collected volatile condensable mass (CVCM) less than 0.10%, as specified in ASTM E- 595 unless a materials usage agreement has been generated and approved by the COR.

Silicones should be avoided or minimized. It is highly recommended that silicones be baked out at a high temperature prior to integration into the system to prevent extended bake-outs of the entire assembly.

Rationale: Derived from the Europa Propulsion Subsystem Spec, EUROPA-PROP-

SPEC-0001.

6.1.7 Assembly Outgassing

When measured in a vacuum of 10-6 Torr at 50°C, the latch valve outgassing shall not exceed 2E-10 g/sec per kg of unit under test of mass that is condensable on a Quartz Crystal Monitor (QCM) that is operated at -20°C.

Rationale: Derived from Europa Propulsion Subsystem Spec, EUROPA-PROP-SPEC- 0001.

6.2 MAGNETIC CLEANLINESS

The spacecraft and its subsystems are required to be “magnetically clean.” The following paragraphs provide requirements and guidelines for minimizing the magnetic field generated by the spacecraft.

6.2.1 External Magnetic Fields

The latch valve shall be designed to tolerate an external 50 gauss field without damage or change of required performance.

Rationale: Derived from the Europa Propulsion Subsystem Spec, EUROPA-PROP-

SPEC-0001

6.2.2 Magnetic Field Strength

The magnetic cleanliness of the valve shall be less than 10 nT under all operating conditions measured at one meter from the centroid of the valve.

7.0 DESIGN & CONSTRUCTION REQUIREMENTS

7.1 IDENTIFICATION AND MARKING

The unit shall be permanently marked with the supplier’s name, part number, flow direction, and a unique sequential serial number in an area that is approved by the COR.

7.2 ELECTRICAL CONNECTION

7.2.1 Flying Leads

The latch valve shall have flying leads with minimum length of 48 inches.

7.3 INTERCHANGEABILITY

The latch valve shall be directly interchangeable in form, fit, and function with other latch valves of the same part number.

7.4 LIFETIME

The latch valve shall be designed to operate for a minimum of 14.3 years as specified below:

- Integration and Test: 2 years

- Ground Storage: 1 year

- Mission Life: 11.3 years

APPENDIX A ABBREVIATIONS AND ACRONYMS

Abbreviation/ Acronym Definition

A Ampere

CCB Configuration Control Board

CCR Configuration Change Request

CM Configuration Management

CMO Configuration Management Office

COR Contracting Officer Representative

CVCM Collected Volatile Condensable Mass

DA Double Amplitude

DC Direct Current

EEE Electrical, Electronic, and Electromechanical

ERD Electrical Requirements Document

FA Flight Acceptance

FEP Fluorinated Ethylene Propylene

FS Factor of Safety

GHe Gaseous Helium

GSFC Goddard Space Flight Center

LPLV Low Pressure Latch Valve

MEOP Maximum Expected Operating Pressure

Mohms Megaohms

MS Margin of Safety

N/A Not Applicable

NASA National Aeronautics and Space Administration

PF Protoflight

PFA Perfluoroalkoxy Alkane

PSIA Pounds per Square Inch – Absolute

PSID Pounds per Square Inch – Differential

QCM Quartz Crystal Monitor

R Resistance

RMS Root Mean Square

SC Spacecraft

SCCH Standard Cubic Centimeters per Hour

SCCS Standard Cubic Centimeters per Second

SOW Statement of Work

TBD To Be Determined

TBR To Be Reviewed

TID Total Ionizing Dose

TML Total Mass Loss

V Volume

VDC Volts – Direct Current