EUROPA-PROP-SOW-0019,_Draft_3,_4_Apr_2017.docx

EUROPA-PROP-SOW-0019, Draft 2 EUROPA Propulsion, Code 597

National Aeronautics and Space Administration

DST-13 Risk Reduction Program No. 2

(RR2)

Statement of Work Draft 3 April 4, 2017

National Aeronautics and Space Administration Goddard Space Flight Center Greenbelt, Maryland

Effective Date: <Date> Expiration Date: <Date> [as required]

CHECK https://ipdtdms.gsfc.nasa.gov

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

DST-13 Risk Reduction Program No. 2 (RR2) Statement of Work Signature/Approval Page Prepared by:

Richard Driscoll

Reviewers/Approvers:

<CM will list the names of all reviewers and approvers at time of release>

Approved by:

<CM will enter PDL’s name here>

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

CM FOREWORD

This document is a Europa Project - Propulsion System Configuration Management (CM)-controlled document. Changes to this document require prior approval of the applicable Configuration Control Board (CCB) Chairperson or designee. Proposed changes shall be submitted to the Europa GSFC CM Office (CMO), along with supportive material justifying the proposed change.

Questions or comments concerning this document should be addressed to:

Europa GSFC Configuration Management Office Mail Stop 597 Goddard Space Flight Center EUROPA-PROP-SOW-0019, Draft 1 Effective Date: <Date>

Greenbelt, Maryland 20771 ii CHECK https://ipdtdms.gsfc.nasa.gov

TO VERIFY THAT THIS IS THE GSFC CORRECT VERSION PRIOR TO USE.

Change History Log

(Reference the SCoRe Approval Date)

CHECK https://ipdtdms.gsfc.nasa.gov

TO VERIFY THAT THIS IS THE GSFC CORRECT VERSION PRIOR TO USE.

Table of Contents

Appendix A: RR2 Hot Fire Test Matrix ……………………………………………………..43

Introduction

0. General Information

The Europa mission is being formulated and implemented as a joint partnership between the Jet Propulsion Laboratory and the Applied Physics Laboratory, with NASA GSFC building the propulsion system for the Applied Physics Laboratory.

This document defines the work to be performed by the Supplier to conduct a risk reduction program to develop a modified version of the DST-13 engine for the Europa spacecraft. The work to be performed under this contract is as follows:

· Develop a single seat solenoid valve using Teflon PFA as the valve seat material

· Develop a thrust chamber with a partially coated nozzle

· Conduct tests using the new valve and nozzle

This work shall be conducted at the supplier’s and supplier’s subcontractor’s facilities. The work under this contract will not require the use of government facilities.

The expected period of performance from the start of the contract to the completion of the Task 3 testing is seven (7) months. The expected period of performance from the start of the contract to the completion of all work is ten (10) months.

Program Objectives

The objective of this program is to develop and demonstrate a new valve and thrust chamber for the DST-13 engine for use on the Europa spacecraft. The DST-13 engine uses a dual seat solenoid valve and a thrust chamber and nozzle which is completely coated with hafnium oxide (HfO) on the exterior surface. A new version of DST-13, which for the purpose of this Statement of Work (SOW) is designated as DST-13E, is needed for Europa. DST-13E will use a single seat solenoid valve and a nozzle which is partially coated with HfO.

The objectives of the tasks in this program are to

· Develop and fabricate the single seat valve with the Perfluoroalkoxy (PFA) seat

· Develop and fabricate the chamber with the partially coated nozzle

· Assemble the engine with the single seat valve and the partially coated nozzle

· Verify the DST-13E engine meets critical EUROPA mission performance requirements and can be used as the baseline engine for the EUROPA mission

· Conduct tests on the DST-13E engine to:

· obtain steady-state and pulse mode performance data

· evaluate the performance of the new valve under hot fire conditions

· evaluate the partially coated chamber under hot fire conditions The testing during this program is limited in scope and does not constitute a complete engine qualification test program. The objective of the tests is to verify the DST-13E prototype design will meet critical mission requirements before committing to production and qualification for the flight units for EUROPA.

This program consists of three tasks described below.

Task 1: Development of the Single Seat Solenoid Valve

The Supplier Model 51-178 dual seat solenoid valve is currently used on the DST-13 engine. This valve shall be modified to a single seat configuration and shall incorporate Teflon PFA as the seat material. Three (3) valves shall be fabricated. One (1) valve shall be subjected to a limited set of qualification tests and two (2) valves shall be used during the Task 3 hot fire tests.

All the drawings, processes and other non-recurring expenses (NRE) associated with the development of the single seat valve shall be done under this task. The purpose of this program is to demonstrate that the single seat valve developed during this program is qualified for use in the DST-13E EUROPA engine production program.

Task 2: Development of the Partially Coated Nozzle

It is desirable to reduce heat loss from the Europa spacecraft during the cruise portion of the mission. An effective way to do this is to reduce the heat being radiated to space from the engine nozzle. Analysis has shown that removing the HfO coating from the nozzle section will result in a significant reduction in the heat loss from the engine.

The current DST-13 chamber/nozzle assembly uses a hafnium oxide (HfO) to increase the radiative emissivity of the exterior surface and reduce the chamber temperature. The nozzle is welded to the chamber section at a location about 0.60 inches downstream of the nozzle throat. The uncoated section of the RR2 program nozzle is expected to start approximately 2.50 inches from the chamber inlet or 1.50 inches from the nozzle throat or 0.90 inches from the chamber/nozzle weld.

Under this task Supplier shall develop and demonstrate all the processes necessary to produce a chamber with a partially coated nozzle. The process shall be suitable for use on the production engines. One (1) partially coated chamber will be produced under this task, assembled to a DST-13E engine and hot fire tested under Task 3.

Under a separate procurement GSFC has acquired from Supplier an uncoated production chamber for thermal testing. GSFC shall provide this chamber to Supplier for coating using the processes developed under Task 2. This chamber will be used during the Task 3 hot fire testing. It will not be necessary to procure an additional chamber for Task 2.

All the drawings, processes and other non-recurring expenses (NRE) associated with developing the partially coated nozzle for production engines shall be done under this task. One purpose of this program is to demonstrate that at the completion of the RR2 program, the partially coated nozzle has demonstrated that it is ready for use in the DST-13E EUROPA engine production program.

Task 3: Testing of the DST-13E Prototype Engine

The DST-13 engine (SN-031) from the Solar Dynamics Observatory Program (SDO) was used during the Europa Engine Risk Reduction Program No. 1 (RR1). This engine shall be modified to the DST-13E configuration using the two valves fabricated under Task 1 and the chamber fabricated under Task 2. The DST-13E prototype engine shall be subjected to shock and vibration testing, and hot fire testing using the test matrix given in Appendix A. The purpose in using the RR1 engine is to obtain a one-to-one comparison of the thermal and performance characteristics of the DST-13E engine with the DST-13 engine tested during RR1. The objective is to understand the differences, if any, associated with the change to the single seat valve and a partially coated nozzle. The Task 3 test data shall be used to support the decision as to whether or not the DST-13E engine will meet the Europa mission requirements and is ready for production.

Test Engine

The engine to be used in these tests shall be DST-13, SN-031. This engine was used for the testing under Europa Risk Reduction Program No. 1 (RR1).

Engine Operational Range and Nominal Condition

For the Europa system the maximum propellant tank pressure is 300 psia. The operational ranges for the engine are as follow:

The nominal thrust and mixture ratio for the DST-13E engine are given below. The DST-13E engine shall be orificed to meet these conditions.

Scope

The supplier shall provide the facilities, personnel, services, tools, equipment, and materials necessary to conduct the program described herein. The equipment to be furnished to this program by GSFC is described in Section 2.9.

Management, Reporting, Reviews, and documentation

0. Program management

The supplier shall designate an individual who will be given full responsibility and authority to manage and administer all the work specified by the contract and ensure that all objectives are accomplished within schedule and cost. This individual shall be the sole point of contact with the NASA GSFC Contracting Officer’s Representative (COR) for the conduct of this program.

The supplier shall designate an individual as the point of contact with the GSFC COR for all technical aspects of the contract.

The supplier shall establish and apply a program control system for managing all resources, engineering, manufacturing, procurement activities, configuration management, quality assurance, documentation control, and distribution.

Reporting

Reporting during this program shall consist of a written monthly status report, a weekly telephone update, and three (3) reports documenting the work done under the three tasks described in Sections 1.3, 1.4 and 1.5.

Weekly Program Status Update

The supplier’s Program Manager (PM) and the GSFC COR shall have a weekly telephone call of approximately 30 minutes duration. The purpose of this call is for the supplier PM to update the GSFC COR on the status of the program activities and to inform the GSFC COR of any anomalies which may have occurred or issues or problems which need attention. The supplier PM shall inform the GSFC COR during this call of anything that may or is having an impact on the program schedule or technical progress and be prepared to discuss the steps required to rectify those things which are having an adverse effect on the program.

Monthly Status Report

The supplier shall deliver to the GSFC COR a monthly contract status report on the first day of each month. This report shall be a narrative report in the supplier’s format. This report shall:

· Summarize the contract activities for the preceding month, including the activities at the suppliers subcontractors

· Review the progress of contract activities against the Program Plan and schedule

· Identify any issues at both the supplier’s or subcontractor’s venues which could adversely affect work on the contract or the contact schedule

· Provide additional information which is relevant for understanding the contract status

Task 1, 2 and 3 Reports

Details about the task reports and their required content are given in Sections 3, 4 and 5. The supplier shall deliver a draft of the Task 1, 2 and 3 reports to the GSFC COR thirty (30) days after the completion of the each task. The GSFC COR shall review the draft report and return it to the supplier with comments fifteen (15) days after receipt. The supplier shall incorporate the comments from the GSFC COR into the final report and deliver the final report to the GSFC COR fifteen (15) days after receipt of the draft with the GSFC COR’s comments. These reports shall be delivered electronically.

Reviews and Meetings

The meetings listed below are part of this contract. These meetings shall be held at the supplier’s site in Niagara Falls, NY. Four (4) meetings will be held: a Kickoff Meeting, two (2) Technical Interchange Meetings (TIM’s) and one (1) Test Readiness Review (TRR). All meetings are expected to be one (1) day in duration. For these meetings the supplier shall provide WebEx and conference telephone services so people who are offsite can participate in these meetings.

As well as GSFC representatives, attendance at the Kickoff Meeting, TIM’s and TRR may include representatives from Johns Hopkins Applied Physics Laboratory (JH/APL) and the Jet Propulsion Laboratory (JPL) in Pasadena, CA.

It may become necessary to hold meetings at the supplier’s facility to resolve issues which arise in the course of this contract. The supplier shall support such meetings as they become necessary. These unscheduled meetings do not constitute a TIM.

Kickoff Meeting

The supplier shall organize and hold a Kickoff Meeting at the supplier’s facility prior to any activity identified in this SOW. This meeting shall occur within three (3) weeks after award of the contract.

The objectives of the Kickoff Meeting are for GSFC to:

· Review the Supplier’s Program Plan

· Approve a mutually agreeable Program Plan

· Provide authorization for the Supplier to start work

The supplier shall provide GSFC with a Kickoff Meeting Presentation Package seven (7) calendar days prior to the meeting. The Kickoff Meeting shall address program management and organization, subcontractors, and the detailed plan and schedule. Information to be included as part of the Kickoff Meeting agenda is described below.

The supplier shall present a detailed program plan and schedule describing how the work under Tasks 1, 2 and 3 will be conducted. At this meeting the GSFC COR and other members of the EUROPA team shall review and comment on these plans. Approval from the GSFC COR is required before the supplier can implement the plan.

The supplier shall develop a Program Plan that includes the elements give below.

· How the working program is to be managed (key personnel)

· Who are the key management, technical and quality assurance people

· How are NASA GSFC Quality Assurance requirements to be implemented

· Who are the subcontractors and their role in the program

· How the supplier plans to manage their subcontractors

· What are the programmatic and technical risks

The Program Plan shall also include the elements given below.

· A breakdown of the work elements needed to complete the three tasks

· A breakdown of the work to be completed by the subcontractors

· The approach to the design of the single seat valve

· The testing required to complete these tasks

· A qualification-by-similarity matrix for the single seat valve based on the qualification status of the 51-178 and 51-331valves

· Other information needed to understand how the work is to be accomplished

The technical elements to be presented at the Kickoff Meeting are discussed in the introductory sections of Sections 3, 4 and 5. The supplier is expected to provide sufficient technical details at this meeting such that GSFC can understand how the work is to be performed and the technical risks associated with each task.

Technical Interchange Meetings

The supplier shall plan for two (2) Technical Interchange Meetings (TIMs). One (1) TIM shall support review and coordination of technical issues as needed. The second TIM is expected to be held after the Task 3 tests have been completed and will constitute a review of the Task 3 test data.

Test Readiness Review

The supplier should plan for a Test Readiness Review (TRR) which shall occur at least three (3) weeks prior to the start of the Task 3 testing.

The TRR presentation package shall be submitted to the GSFC COR for review at least 14 days before the TRR. Test procedures for the Task 3 tests shall be submitted to the GSFC COR for review and approval at least 21 days before the TRR.

The TRR presentation shall demonstrate the readiness of all facilities and personnel required for testing, and note any activities that are not yet ready. In particular, the supplier shall review the test matrix, test procedures and test equipment.

The TRR package shall address:

· The responsibilities of the supplier’s team members for each element of the test program, i.e., who is responsible for what

· The list of tests to be conducted

· The status of all procedures and paperwork required for the Task 3 tests

· Availability of facilities and personnel

· Tests to be conducted at subcontractor facilities and how such tests are to be monitored and conducted

· Special test equipment for both hot-fire and non-hot-fire tests and in particular, the equipment for the cold propellant and cold injector tests

· An instrument list for each test including a sketch showing the location of the instrumentation on the test article

· Accuracy and calibration status of instruments used to record test data

· How the tests are monitored and signed off, i.e. who is responsible

· Accept / reject criteria for each test

· How the data is recorded and transmitted to GSFC

· The load cell zero shift during steady-state test, the level of zero shift which is expected, the reason the zero shift occurs and the rationale for using a linear zero model to reduce the thrust data

· The effect of the load cell zero shift on the accuracy of the thrust, Ibit and specific impulse (Isp) data for short and long burns

· The accuracy of the pulse mode Ibit and Isp data including a description of how Ibit is measured and a discussion of the pulse tank accuracy for measuring the propellant mass per pulse

· How anomalies during the test program are identified, reported to the GSFC COR, resolved and documented

· Any risks associated with any test, including safety risks, risks in not obtaining accurate data, or any other risk which it is appropriate to discuss.

Notification of Testing

Supplier shall notify the GSFC COR of the plan to start any test activity at least two (2) weeks before the testing is to occur. This notification is to include the Acceptance Test Procedure (ATP) and qualification tests to be conducted on the valve under Task 1 and all the tests to be conducted during Task 3. This notification shall include tests to be conducted at Supplier’s subcontractors.

Attendance at Tests

The GSFC COR and its designated representative, and representative from JHU/APL and JPL shall have the right to observe all testing at supplier’s facilities. Visits to observe testing shall not constitute a TIM.

Subcontractor Visits

The GSFC COR and its designated representative, and representatives from JHU/APL and JPL shall have the right to observe all work, including all testing, at supplier’s subcontractors. Visits to observe testing shall not constitute a TIM.

Documentation

The supplier shall generate documentation, procedures, etc. as necessary to conduct the activities described for this program. All procedures shall be reviewed and approved by the GSFC COR; review and approval may be waived at the discretion of the GSFC COR.

The procedures governing any testing to be conducted during this program shall be submitted electronically to the GSFC COR 14 days before the activity is to be conducted for review and approval. These procedures shall list all test equipment, equipment measurement accuracies, thermocouple locations, and other such information as necessary to document the testing. Further, the test procedures shall document all special equipment to be used during the tests.

The test procedures shall include data sheets to record all test data generated during the execution of the procedures. These data sheets shall be made available to the GSFC COR as the tests are being conducted and shall be included in the test reports.

Deliverables

This section outlines the deliverables under this contract. Details are found in the specific sections associated with each task.

Encapsulated Valve Poppets

As noted in Section 3.0, as part of Task 1, when Supplier is fabricating the parts for the single seat valve with the PFA seat material, Supplier shall fabricate five (5) additional encapsulated poppets for delivery to GSFC. These poppets shall be delivered to GSFC as soon as practical after they have been fabricated.

DST-13 SN-031 Dual Seat Valves

During Task 3 the dual seat valves which were on the DST-13 SN-031 engine when delivered to Supplier will be removed and replaced with the single seat valve fabricated during Task 1. These dual seat valves shall be vacuum oven dried after their removal from the engine, placed in sealed bags and delivered to GSFC at the completion of the Task 3 tests.

DST-13 SN-031 Chamber

During Task 3 the coated chamber will be removed from the SN-031 engine and replaced with the partially-coated chamber fabricated during Task 3. The coated chamber shall be placed in protective cover to prevent damage and placed in a sealed bag to prevent contamination. This chamber shall be delivered to GSFC at the completion of the Task 3 tests.

GOES Program Coated Chambers

The three (3) coated chambers delivered by GSFC for use during the Task 2 shall be delivered to GSFC at the completion of the Task 3 tests.

SN-031 Engine

Upon completion of the Task 3 tests and the decontamination and other steps which follow, the SN-031 engine with the single seat valves shall be placed in a sealed bag and delivered to GSFC.

Test Reports and Meeting Presentations

The deliverables associate with the test reports, program management and meeting activities are described in Sections 2.2 and 2.3.

Test Data Deliverables

The data from all Tasks shall be recorded and documented in the standard files used by the supplier. The files for every test shall be made available to the GSFC COR or the on-site representative for review at the supplier’s facility as the tests are being conducted. The data files for the Task 3 hot-fire and non-hot-fire tests shall be delivered to the GSFC COR electronically within one (1) week after completion of the Task 3 testing.

The hot fire data to be recorded and delivered to GSFC shall be the same as delivered during the RR1 program.

The supplier shall prepare a data summary sheet in EXCEL format in which the most important engine test parameters are recorded on a single line for each test. This summary data sheet shall be the same as used during the RR1 program. This data sheet shall be updated at the end of every test day and presented to the GSFC COR or its representative for review at the start of the next test day.

Other test data not specifically described above shall be made available to the GSFC COR upon request.

All test data files shall be marked in accordance with FAR 52.227-14. In accordance with the terms of this clause, since all test data is being generated under a GSFC contract and not at the expense of the supplier, the Government has unlimited rights to this test data. The test data or data files shall contain no markings or any other feature which would indicate the supplier has any ownership rights to the test data.

NASA/GSFC Furnished Equipment

GSFC shall furnish the hardware described below.

· DST-13 engine, SN – 031, for use during the Task 3 tests.

· Flight chamber A0872136, SN-1578 (uncoated) for use during Task 2 and 3.

· Three (3) surplus HfO coated chambers, PN A0872135, SN-1144, 1150 and 1151, from the GOES Program are available for use during Task 2.

Quality Assurance Provisions

Quality Assurance Plan/Manual

The supplier shall implement a Quality Management System that meets with the intent of the requirements of American Standards Institute (ANSI)/ISO, American Society for Quality (ASQ) Q9001 (1994 or 2000 version) or equivalent, as documented in a Quality Assurance Plan. This plan shall be described at the Kickoff Meeting and made available upon request.

Surveillance of the Supplier

The work activities and operations of the supplier and subcontractors are subject to evaluation, review, survey, and inspection by a GSFC representative.

The supplier shall provide the GSFC representative with documents, records, equipment, and workings areas within their facilities that are required by the representative to perform their surveillance activities.

Government Source Inspection

The Government may elect to perform inspections at a supplier's facilities. The following statement shall be included on all procurement documents: “All work on this order is subject to inspection and test by the Government in accordance with the inspection clauses in the contract.”

The Government Quality Representative who has been delegated NASA quality assurance functions on this procurement shall be notified immediately upon supplier receipt of any supplier/subcontractor orders. The Government representative shall also be notified 48 hours in advance of the time that articles or materials are ready for inspection or test.

Supplier Source Inspection

The supplier shall ensure that its procurement documents impose the applicable requirements on subcontractors and other suppliers. The subcontractor and other suppliers shall in turn impose the requirements on their procurement sources.

The supplier shall perform source inspection at the subcontractor's or supplier's facilities in accordance with the procurement documentation or when one or more of the following conditions exist:

· In process, end item controls, or tests that are destructive in nature prevent the developer from verifying quality after delivery to the developer's facility.

· It is not feasible or economical for the supplier to determine the quality of procured articles solely by inspections or tests performed at the supplier’s facility.

· Qualification tests are to be performed by the subcontractor or supplier.

· Products are shipped directly from the source to NASA, by-passing the supplier's inspection facilities.

Government Mandatory Inspection Points (MIPs)

The government or its representative will inform the supplier of the MIPs at the Kick-off Meeting. The government may request additional MIPs as required. In the event that proper notification has been made and 48 hours have elapsed without the MIP being accomplished, the supplier can waive the MIP after receiving NASA/GSFC COR approval.

The MIPs shall include, but are not limited to, the potting of the coils, and all planetary protection measures, i.e. any final closeout, mating, and encapsulation unless approved by the NASA GSFC COR.

Anomaly Reporting

Any anomaly which occurs shall be reported verbally to the GSFC COR within 24 hours of the occurrence of the anomaly and in writing within 48 hours. Any anomaly during fabrication that delays the planned start of acceptance testing shall also be reported.

The supplier’s processes for review, disposition and approval of anomaly reports shall be described in their quality plan/manual or provided as a supplemental document. In addition, the supplier’s anomaly reporting document shall describe the members of the Material Review Board (MRB) and Failure Review Board (FRB). The MRB and FRB shall include EUROPA GSFC participation. These processes shall ensure that positive corrective action has been taken to preclude recurrence and that appropriate audits and tests are performed to verify the implementation of the corrective action.

The supplier shall routinely inform the EUROPA Project of MRB and FRB meeting schedules and agendas with sufficient notice to permit EUROPA Project participation if desired by EUROPA.

At the supplier’s facility, NASA/Government representatives may participate in MRB/FRB activities as deemed appropriate by Government management or contract.

The NASA/GSFC COR reserves disapproval rights on MRB and FRB decisions. To assure process consistency, the supplier shall provide the EUROPA Project on-line access to their EUROPA anomaly-reporting database.

The supplier shall provide, as part of the monthly report, a list of all open anomaly reports and a separate list of the anomaly reports closed during the month. For each reported anomaly, deviation, or nonconformance, there shall be a report that documents the investigation and engineering analysis needed to determine the cause and corrective actions to disposition the nonconformance, and identify any closed problem reports that do not have a definitive cause or corrective action. Reports shall be submitted to the NASA/GSFC COR for review and approval of the disposition.

The supplier shall establish and maintain documented procedures to ensure product that does not conform to specific requirements is prevented from unintended use or installation. This control shall provide for identification, documentation, evaluation, segregation (when practical), disposition of nonconforming product, and for notification to the functions concerned.

Valve Qualification

The Task 1 valve shall be flight-like and manufactured using the same assembly techniques and fabrication processes as the flight hardware including structure, thermal design, shielding, cabling, circuit layout, power consumption, functional modes, and electrical parts with the same signal characteristics. The testing under Task 1 is considered to be a valve-level qualification program and therefore, the quality assurance provisions applicable to a qualification program apply to the Task 1 valve fabrication and test activities.

1.0 TASK 1: DEVELOPMENT OF THE SINGLE SEAT SOLENOID VALVE

The objective is to develop a single seat solenoid valve for the DST-13E engine. This valve shall be developed as a modified version of the Supplier Model 51-178 dual seat solenoid valve. The modifications are from a dual seat to a single seat configuration and a change in the valve seat material from Polytetrafluoroethylene (PTFE) to PFA.

Under this task, a design for the single seat valve shall be developed, three (3) single seat valves shall be fabricated and then subjected to acceptance testing. One valve will be used for qualification testing and two (2) valves will be installed on the DST-13E engine for testing under Task 3.

The intent of Task 1 is to develop and demonstrate a valve which is qualified for use on the DST-13 Europa engine. Valve fabrication and test shall be done in accordance with the NASA quality assurance provisions described in Section 2.10. The valve tests to be conducted under this task together with any Qualification-By-Similarity (QBS) elements shall constitute a the valve-level qualification for the new valve. The testing to be done under Task 3 with the valve attached to the engine will provide the data for shock and vibration testing to complete the valve-level qualification.

1. PLAN AND SCHEDULE

The Supplier shall develop a plan and schedule which shall be presented at the Kickoff Meeting for review and approval.

The plan to be followed is given below.

· Design the single seat valve

· Fabricate and procure parts for three (3) single seat valves

· Fabricate five (5) additional encapsulated valve poppets for delivery to GSFC

· Assemble one valve

· Conduct acceptance tests

· Conduct qualifications tests

· If the qualification tests are determined to be successful

· Assemble two valves from the parts

· Conduct ATP’s on the two valves

· Use these two valves in the Task 3 tests

· If the qualification tests are determined to be not successful

· Complete the work under Task 2

· Do not initiate or stop ongoing work under Task 3

· Determine why the valves failed to meet requirements

· Convene a TIM to review the failure investigation results and to determine the actions needed to fix the valve deficiencies

· Develop a plan to fix the valve and then proceed to Task 3 Single Seat VAlve Design

The first element of Task 1 is to develop a design for the single seat valve which uses PFA as the valve seat material and meets all the requirements given in Section 3.11. It is expected that the single seat valve design shall be derived from the design of the 51-178 valve and shall use the same coil, spring and casing, etc., as the 51-178 valve so as to minimize the scope of the design activity. Supplier’s approach for the single seat valve shall be presented at the Kickoff meeting. At this meeting Supplier shall describe any risks associated with their design approach. Supplier shall not proceed with the fabrication of the single seat without the approval of the GSFC COR.

VAlve Poppets For Delivery To GSFC

When fabricating the single seat valve, Supplier shall fabricate five (5) additional poppets consisting of the PFA material encapsulated in the holder for this material. The poppets shall be identical to those used in the three valves fabricated during Task 1. These poppets shall be delivered to GSFC as soon as practical following their fabrication.

VAlve Fabrication: Processes and Procedures

Under Task 1 Supplier shall develop the processes and procedures necessary to fabricate and test the single seat valve. These processes and procedures should be, as near as possible, the same as those which would be used to fabricate the valves for the flight units. These processes and procedures should be configuration controlled.

Quality Assurance Provisions

The quality assurance steps which would be used for the flight valves should be used during the fabrication and test activities for the Task 1 valves. The GSFC Quality Assurance Provisions are described in Section 2.10 apply for the valve fabrication, acceptance and qualification tests.

Qualification By Similarity

While the single seat valve is a derivative of the production 51-178 dual seat valve and the 51-331 single seat valve, because of the change in the valve seat material, the new valve cannot be qualified by similarity. If the supplier has any recommendations regarding qualification by similarity, the supplier should present them for review at the kickoff meeting.

1.1 VALVE ACCEPTANCE TESTS

The Acceptance Test Procedure (ATP) for the single seat valve shall be identical to the supplier’s procedure for the 51-178 valve except as modified for this project. Any modifications to the ATP recommended by the supplier shall be by the GSFC COR. The ATP shall verify that the valve meets the requirements given in Section 3.11. The supplier shall submit the Acceptance Test Procedure to the GSFC COR at least one (1) month before acceptance tests are to be conducted for review and approval. ATP testing shall not be started until the GSFC COR has approved the ATP.

VAlve Qualification Tests

Qualification tests shall be conducted on one valve selected by GSFC after acceptance testing. A complete engine qualification test will be conducted as part of the fight engine procurement so some tests will be deferred until that time. Also, some tests (shock, vibration) can only be conducted at the engine level so they will be deferred to Task 3. The purpose of the qualification tests at the valve level is to demonstrate that the PFA seat material will meet cycle life requirements and leakage requirements over the qualification temperature range.

The qualification tests to be conducted are listed below. The requirements for these tests are given in Section 3.11. These tests shall be performed at the Prototype/Qual level.

· Dry Cycle Test

· Cycle Life Test

· Survival Temperature Test

· Thermal Cycle Test

· Planetary Protection Bakeout

· Burst Test

· Disassembly and Inspection

Dry Cycle Test

The valve shall be subjected to 200 dry cycles. The functional tests listed in Section 3.8.7 shall be conducted following this test.

Cycle Life Test

The cycle life test shall test the valve to 1,000,000 cycles. The specific duty cycle to be used during this tests will be chosen after discussions and review of the supplier’s recommendation to be presented at the kickoff meeting. The functional tests described in Section 3.8.7 shall be conducted after 250,000, 500,000, 750,000 and 1,000,000 cycles. The cycle life test shall be performed prior to the survival temperature and thermal cycle test. The cycle life test shall be performed with the valve pressurized to 320 psig using a water or a water/IPA mixture.

Survival Temperature Test

The valve shall be subjected to the non-operational survival limit temperature of -65F. The valve temperature will be lowered to this level, held for a minimum of 2 hours at this limit and then returned to room temperature. The functional tests listed in Section 3.8.7 shall be performed following the survival temperature test. The survival temperature test shall be performed prior to the thermal cycle test.

Thermal Cycle Test

The valve shall be subjected to thermal cycle tests. The limits for the thermal cycles are given in Section 3.7.6. The upper cycle limit is 250F and the lower limit is 0F. The valve shall be held at the limit temperatures for two (2) hours. The valve shall be subjected to eight (8) thermal cycles. Each cycle is defined as 2 hours at the lower limit, the transition from the lower to the upper limit, a two hour hold at the upper limit and a transition back to the lower limit. The functional tests listed in Section 3.8.7, except for the external leakage and water flow test, shall be performed at the hot and cold plateaus during the first and last thermal cycle. The functional tests listed in Section 3.8.7 shall be performed at the end of the thermal cycle test.

Planetary Protection Bakeout

Planetary protection is critical for the Europa mission. For production engines the planetary protection bakeout will occur on a complete engine assembly. For this program this bakeout will occur at the valve level. Since this valve will used a new seat material, it is not known how this material will respond to the time-at-temperature planetary protection bakeout and how this will affect the valve function. A critical element of Task 1 is to determine the valve response to this process.

The valve shall be subjected to a heat microbial reduction (HMR) test. Heat microbial reduction is the process of elevating the temperature of the component or parts to a temperature of 116°C or greater for a prescribed time to reduce both surface and bulk bioburden. The temperature and time relationship, and order of magnitude reduction bioburden is defined parametrically in Table 1.

The time column to be used for the valve test is the “encapsulated” column. For this test the supplier shall select the temperature and time to be used for the test based on the supplier’s assessment as to which temperature/time combination is most suitable for meeting the planetary protection requirement and the valve operational and functional requirements described in Section 3.11. The supplier’s recommendation for the bakeout test shall be presented at the Kickoff Meeting for approval by the GSFC COR.

Table 1: HMR Temperature vs. Time Relationship

4-Order Bioburden Reduction

Disassembly And Inspection

Following the burst test, the valve shall be disassembled so that the parts can be examined. Of particular interest is the state of the valves seat material. The supplier shall inspect and photograph the valve parts to determine their state and if any damage occurred during the testing. Measurements of component parts shall be taken where appropriate. Of particular interest is the coining of the valve seat material which may have occurred during the testing, particularly during the long planetary protection bakeout. The supplier shall measure and record the depth of the seat coining.

Functional Tests

The functional tests listed below shall be performed as part of the Cycle Life, Survival Temperature, Thermal Cycle and Planetary Protection Tests as indicated in the Sections 3.8.1 - 3.8.5.

· Insulation Resistance

· Coil Resistance

· Pull-in Voltage

· Drop-out Voltage

· Open Response Time

· Closing Response Time

· Internal Leakage

· External Leakage

· Water flow / pressure drop test

Valve Seat Material

The radiation environment to be encountered by the Europa spacecraft in orbit near Jupiter is severe. Analysis indicates that the valve seat material will see a maximum radiation dosage of 210 krads. It has been determined that the PTFE material used in the seat of the 51-178 valve is not compatible with the Jupiter radiation environment and must be replaced by a different type of material with better radiation resistance qualities. NASA has determined that the best material for this purpose is Teflon PFA.

At this time the grade of PFA to be used in the single seat Europa valve seat has not be identified. Work to identify the PFA grade which will meet the radiation compatibility requirements and valve functional requirements is ongoing. For the purpose of this SOW it is assumed that the PFA grade to be use in the valve shall have been identified prior to the start of the contract.

1.1.1 Propellant Compatibility

The valve seat material must be compatible with long term exposure to propellants. For Europa this requirement is eight (8) years. The seat material shall not degrade due to propellant exposure and the valve must be able to meet all the requirements given below for this period.

1.1.2 Oxidizer Compatibility

The oxidizer shall be nitrogen tetroxide (NTO or N2O4) or MON-3. It is known that the Teflon class of materials will absorb oxidizer, causing the material to increase in volume. Under some circumstances depending on the valve design this swelling can cause an increase in the pressure drop across the valve, causing a reduction in the oxidizer flowrate and a decrease in the engine mixture ratio.

Based on current information (White Sands Test Facility Report 15-46719, 2 Oct. 2015), test data show that the swelling due to oxidizer exposure for virgin PTFE and PFA-350 are identical, within the measurement error. Therefore, it is not expected that the change from PTFE to PFA will impact the valve design due to oxidizer exposure. Further, if the valve pressure drop is controlled by the orifice and not the curtain, then the oxidizer-induced swelling should have only a negligible effect on the valve pressure drop. At the Kickoff Meeting the supplier shall provide its assessment of the effect of oxidizer-induced swelling of the Teflon on the valve pressure drop and recommendations to mitigate this effect if it would have a significant effect on engine propellant flowrates and mixture ratio.

Valve Driver Circuit and Valve Wiring

The valve driver circuit shown in Figure 1 shall be used for all tests during this program. This circuit is identical to the SDO valve driver circuit. For engine hot fire operations the fuel and oxidizer valves shall be wired in series so that both valves open and close at the same time. The configuration is such that it should not be possible to open one valve without opening the other.

Oxidizer Valve Coil Fuel Valve Coil

Figure 1. Valve Driver Circuit

1.2 VALVE REQUIREMENTS

The single seat valve shall meet all the requirements given below.

1.2.1 Valve Inlet Tube

The valve inlet tube shall have a 0.250 (+0.004, -0.000) inch OD with a 0.028 ±0.002 inch wall thickness. The material shall be 3Al-2.5V Titanium. The inlet tube length shall be no less than 1.6 inches.

1.2.2 Valve Voltage

The voltage supplied to actuate each propellant valve will be 18 to 36 VDC. The nominal voltage for response and other tests is 28 VDC.

Pull-In Voltage

The pull-in voltage is defined as the minimum voltage needed to actuate the valve at 70F when pressurized to 300 psia. The minimum pull-in voltage shall be ≤ 10 VDC. At the pull-in voltage the force margin shall be greater than 10%.

Drop-Out Voltage

The drop-out voltage is defined as the voltage below which an open the valve will close for a valve at 70F and pressurized to 300 psia. The drop-out voltage shall be ≥ 0.375 VDC and ≤ 2 VDC.

1.2.3 Propellant Temperatures

The valve shall meet all requirements given in this SOW when operated with propellants in the following temperature range:

· -10C to 55C (14F – 130F)

1.2.4 Valve Temperature Range

The valve shall meet the requirements given in this SOW under the following temperature conditions:

1.2.5 Coil Resistance

The resistance of the valve coil at 70F shall be 12 Ω ± 1 Ω.

1.2.6 Valve Power

The maximum power draw for an individual propellant valve shall be no greater than 93 watts with an applied voltage of 32 VDC. For two valves wired in series the maximum power draw shall be no greater than 46.5 watts at 32 VDC.

1.2.7 Response Time

The open and closing time for the single seat valve shall meet the requirements given below when operated with the valve power at 28VDC, the driver circuit shown in Figure 1 and with the valve at 70F and pressurized to 300 psia.

· Open time < 5 msec

· Close time < 3 msec

During the first test to measure response time, the valve opening and closing times shall be measured with the valve powered at 18, 22, 28 and 36 VDC.

1.2.8 Leakage

The maximum allowable internal and external leakage rates are given below. These leakage requirements shall be satisfied over the temperature ranges given in Section 3.11.6 and the inlet pressure range given in Section 1.4.

· Internal Leakage The maximum allowable leakage across the valve seat is 3 scc/hr (8.3 x 10-4 scc/sec) of GHe.

· External Leakage External leakage shall be measured with the valve seats in the open position. The maximum allowable leakage rate is 1 x 10-6 scc/sec of GHe.

1.2.9 Pressure Drop

The pressure drop across the valve shall be no greater than 8.00 psia at a water flowrate of 0.009 lbm/s.

1.2.10 Shock and Vibration

The shock and vibration requirements for the engine are given in Tables 2 and 3. Shock and vibration requirements are applied at the engine level. The supplier shall design the valve such that the DST-13E engine with this valve will meet these shock and vibration requirements without the valve failing or failing to meet all requirements in this specification after the shock and vibration tests.

Shock and vibration testing shall be conducted during Task 3 and shall be conducted in all three axes.