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Thermal Vac 101 Implementing Thermal Tests in the ETL

Thermal Vac 101 Implementing Thermal Tests in the ETL. Patrick Martin Environmental Test Engineer. Training Objectives.

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Thermal Vac 101 Implementing Thermal Tests in the ETL

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  1. Thermal Vac 101Implementing Thermal Tests in the ETL Patrick Martin Environmental Test Engineer

  2. Training Objectives At the completion of this course you should have an understanding of what the Cog E needs to do to successfully conduct a bakeout, a thermal vacuum test, or a temperature test in the ETL. This includes: • Knowing what information will be needed by the ETL to schedule a test, prepare a cost estimate, open a work order, prepare a test procedure, and conduct a test • Knowing what equipment will need to be prepared • Knowing what activities will need to be coordinated • Knowing who will need to be involved at each step of the process

  3. Welcome to the ETL As the Cog E, you are ultimately responsible for all phases of the test program, but the ETL personnel are here to help yousucceed. Meet with us early and often in order to avoid surprisesbeforethey impact cost and schedule. Thermal Vacuum/Temperature Testing: Pat Martin Ext 4-1528 Patrick.J.Martin@jpl.nasa.gov MSI Instrumentation: Sandro Torres Ext. 3-3956 Sandro.L.Torres@jpl.nasa.gov

  4. About the Environmental Test Lab (ETL) • The ETL has a variety of certified thermal vacuum and temperature chambers located in buildings 144, 150, 248 and 306. • The ETL is staffed with experienced/certified environmental test engineers and technicians for testing flight hardware, JCI, and developmental hardware.

  5. What types of tests are performed in the ETL Thermal Vacuum Labs? • Thermal Vacuum Bakeout • Contamination Control Bakeouts (for molecular decontamination) • Planetary Protection Bakeouts (for biological decontamination) • Thermal Vacuum (T/V) and Solar Thermal Vacuum • Developmental (Non-Flight Hardware) • Qualification (Non-Flight Hardware) • Protoflight (Flight Hardware) • Flight Acceptance (Flight Hardware) • Life Test (Non-Flight Hardware) • Temperature (aka: Thermal Ambient or Atmospheric) Same types of tests as T/V but conducted at room ambient pressure under a nitrogen purge.

  6. What must you do to prepare for a test in the Thermal Vacuum Lab ? • Meet with Environmental Requirements Engineering, Sect. 5134, Kin Fung Man, Ext. 3-0255. to define the test requirements and fill out an Environmental Test Authorization Summary (ETAS). • What temperatures and vacuum will be required and what are the limits/tolerances? • What is the temperature profile (how many cycles, what are the soak durations, ramp rates, functional test requirements, CTE constraints, is solar simulation required, etc.)

  7. What must you do to prepare for a test in the Thermal Vacuum Lab ? • Meet with the Materials & Contamination Control (CC), Sect. 3566, Paul B. Willis, Ext. 4-6998, to define the CC requirements: • Will a QCM sample be required to measure the rate of outgassing? • Will a bare chamber bakeout be required? • Will cables and fixtures need to be baked out? Note: Biotechnology & Planetary Protection (PP), Sect. 352N, James Spry, Ext. 4-3073, may also have bakeout requirements if this is a mission to another planet.

  8. What must you do to prepare for a test in the Thermal Vacuum Lab ? C. Meet with Pat Martin to discuss the test requirements, determine which chamber and mounting hardware will be required, and schedule your test. Pat will prepare a cost estimate, open a work order, and prepare a Detailed Test Procedure. To do this, the following will be required: • Account and task number • Test profile with temperatures, soak durations, ramp rates, temperature limits, CTE ΔT limits, and vacuum requirements. • Number of thermocouples, PRTs, electric strip heaters, and heat exchangers • Contamination Control requirements (QCM, chamber cleanliness, bakeouts for cables and fixtures) • Size of test article(s) • Number of bulkhead feedthroughs required for GSE to Test Article cables • Viewing requirements such as video cameras or window • GSE power requirements • Will high voltage in the chamber require a vacuum failure relay? • Special requirements (solar simulation, liquid helium, CO2, etc.)

  9. What must you do to prepare for a test in the Thermal Vacuum Lab ? D. Meet with MSI Instrumentation Engineer, Sandro Torres. • Discuss instrumentation requirements including thermocouples (TCs), PRTs, electric strip heaters, accelerometers, strain gauges, string pots, recording GSE voltages or currents. • Instrumentation engineering will mount the instrumentation, and set up a data logger (TDAS) to monitor and record the data during the test. • Instrumentation will order the TCs.

  10. What must you do to prepare for a test in the Thermal Vacuum Lab ? E. Schedule the test on the TFM server. Glenn Putnam, Ext. 3-5030, can help with this task. • Schedule cable and GSE bakeouts with Pat Martin and Glenn Putnam. The bakeout requirements come from the Contamination Control (CC) and Planetary Protection (PP) engineers. Performing the bakeout will require an AIDS.

  11. What must you do to prepare for a test in the Thermal Vacuum Lab ? G. Prepare a test plan. As a minimum the test plan should include: • A description of the test article • A description of the test objectives and methods • A description of how the instrument will be mounted • Temperature profile(s) • Temperature limits and tolerances • Instrumentation requirements (TCs, PRTs, Strip heaters) • A description of job responsibilities • Functional test requirements • Cautions about test article vulnerabilities (CC, ESD, CTE limits, etc.)

  12. What must you do to prepare for a test in the Thermal Vacuum Lab ? H. If the test article is going to be mounted on a heat exchanger (Hx), the ETL has a selection of Hx adapter plates they can provide. I. The JPL machine shop can install inserts in the Hx adapter plate for mounting the test article. J. Apreliminary bakeout may be required to clean the adapter plate after machining, check with CC.

  13. What must you do to prepare for a test in the Thermal Vacuum Lab ? K. Procure cable bulkhead feedthroughs if the ETL doesn’t have what you need. L. Feedthroughs can be purchased at general stores. Feedthrough mounting plates can be made by the machine shop. Pat Martin can supply a drawing for the mounting plate. The ETL will need to perform a helium leak check on the feedthroughs. Don’t buy cheap feedthrough bulkhead connectors! Angel Garnica, 4-9100, can help make the right selections.

  14. What must you do to prepare for a test in the Thermal Vacuum Lab ? M. Schedule an Operational Safety Survey (OSS) with Systems Safety, Cami Vongsouthy, Ext. 4-6317. The survey should be attended by representatives from Systems Safety, QA, the ETL, and the Cog E. Conduct the survey a couple of weeks before the test. Some “Gotcha” questions are: • Do you have automated data recording for functionals? • Do you have a way to protect your instrument from burning up if it draws too much current or gets too hot? • Do you have an UPS to prevent data loss if power fails? • Do you have enough people to support 24-hour testing? • Do you consider donuts to be a basic food group?

  15. What must you do to prepare for a test in the Thermal Vacuum Lab ? N. Coordinate floor space allocations with Pat Martin. Multiple jobs may be competing for floor space. O. A Test Readiness Review (TRR) may be required by the project. An ETL representative should be invited. Provide the ETL representative with a copy of your test plan in advance. P. Prepare an AIDS for the test. A bakeout does not require a test plan, so the AIDS is used to define the requirements such as temperature, temperature limits, pressure, duration, and QCM sampling requirements.

  16. What must you do to prepare for a test in the Thermal Vacuum Lab ? Q. Arrange for Flight Technicians to support handling your hardware, call Jim Pearson, Ext. 4-6447. R. Arrange with Transportation to deliver your Test Article and GSE to the ETL. Coordinate the delivery with ETL to insure the facility doors can be opened at the time of delivery.

  17. What must you do to prepare for a test in the Thermal Vacuum Lab ? • Arrange QA support for test activities in the ETL. The ETL does not have a QA person assigned to it. • Bring clean room clothes, and clean bags for packaging the test articles after the bakeout or test has been completed.

  18. What must you do to prepare for a test in the Thermal Vacuum Lab ? U. If the test article or instrumentation is ESD sensitive, the Cog E must arrange for an ESD survey of the test setup. Talk to the your QA representative about conducting this survey and handling your ESD sensitive hardware. The Cog E is responsible for supplying ESD straps, ESD mats, air ionizers, and calibrated ESD testers.

  19. What is the sequence of events in a Thermal Test? Note: The Cog E is responsible for directing all test activities, and documenting what happens to the Test Article on an AIDS, Test Procedure, and PFR. QA should witness and sign off steps where the Test Article is handled and where functional tests are conducted.

  20. What is the sequence of events in a Thermal test? • A Detailed Test Procedure (DTP) will be prepared by the ETL Test Engineer based on the requirements provided in the test plan and/or AIDS. • The DTP will be reviewed and signed by the ETL Test Engineer, ETL Manager, Cog E, and QA. • A pre-test meeting will be conducted by the ETL Test Engineer or Lead Technician to acquaint everyone who will be working on the test with the facility alarms, safety constraints, and emergency procedures. The test objectives, methods, fail-safe settings, and limits will be discussed to insure an understanding of how to protect the test article.

  21. What is the sequence of events in a Thermal Test? • If a crane will be used to lift the Test Article, a pre-lift meeting will be conducted by the Cog E or Test Director. QA and Safety need to witness the lift. • Flight Techs will remove the test article from the shipping box, mount it to the support fixture, and connect the GSE cables to the test article. The Flight Techs should bring their own tools (e.g. calibrated torque wrench).

  22. What is the sequence of events in a Thermal Test? • The DTP’s pre-test checklist will be filled out. The questions that must be answered by the Cog E are: • Is the test specification available? What is the number of the AIDS or Test Plan? • Has an ETAS (Environmental Test Authorization and Summary) been issued by Reliability Engineering? • Has the Contamination Control engineer inspected the test article and setup for vacuum compatibility? • Is QA coverage available, and is a PFR/Test Report Summary Form system operational? • Are there any special test requirements such as contamination control protocols or ESD sensitivity?

  23. What is the sequence of events in a Thermal Test? • The MSI Instrumentation Engineer will mount thermocouples (TCs) on the test article. The Instrumentation Engineer will also mount PRT’s, strain gauges, or electric strip heaters if they are required. • An ETL thermal vacuum technician (T-Vac Tech) will plumb the heat exchanger(s). • The T-Vac Tech will leak check the heat exchanger(s) and bulkhead feedthroughs.

  24. What is the sequence of events in a Thermal Test? • With approval of the Test Director, the T-Vac Tech will close the chamber door. • The Instrumentation Engineer will perform a TDAS health check, and the T-Vac Tech will verify the continuity of the control and fail-safe TCs.

  25. What is the sequence of events in a Thermal Test? L. After test article’s baseline functional test has been completed, the chamber will be pumped to high vacuum. A pump and purge may be conducted to eliminate water vapor if the test will be conducted at Mars pressure (8 Torr).

  26. What is the sequence of events in a Thermal Test? M. The temperature profile will be conducted as per direction of the Cog E or Test Director. For complex tests, a Thermal Engineer should be responsible for wrangling multiple TCs by providing real time direction for controlling the chamber shrouds, heat exchangers, electric strip heaters, and IR lamps. The Cog E will conduct the required functional tests.

  27. What is the sequence of events in a Thermal Test? N. At the end of the test, the chamber will be backfilled with nitrogen gas when the chamber content is above the dew point, and cool enough that it is not a burn hazard. O. The Flight Technicians will remove and package the Test Article. The Cog E is responsible for providing clean room bags, garments, and ESD support equipment. QA needs to witness handling the test article.

  28. What is the sequence of events in a Thermal Test? • The Cog E will make arrangements with Transportation to move the Test Article and GSE. The Cog E should coordinate the pickup so that the facility door can be opened without creating a contamination risk to other test articles. • The ETL will scan the data package and forward the master copy of the data package to the Cog E. The data package will include the ETL test procedure, data sheets, temperature plots and QCM plots. The ETL data package will be part of the end item data package submitted by the Cog E.

  29. Frequently Asked Questions Q. What is the difference between atmospheric vs. vacuum testing? A. The following are differences: • Thermal atmospheric (Temp.) test is conducted in a Temp. chamber; T-Vac test is conducted in a vac. chamber. • Temp. uses convective heat transfer; T-Vac uses radiative and conductive heat transfer. • Temp. tests cost less/hour and may take less time. • Temp. tests do not require bulkhead feedthroughs or bakeouts to mitigate chamber contamination. • Temp. testing may not achieve same results as vacuum testing because of convective heat transfer and outgassing.

  30. Frequently Asked Questions Q. What is a QCM? A. A TQCM is a Thermal Quartz Crystal Microbalance, capable of cooling itself to -40°C and heating itself to +110°C. It has a target crystal and a reference crystal. As molecules condense on the target crystal, a shift in the beat frequency occurs. The Hz/hour shift rate can be used by the Contamination Control Engineer for determining the rate out molecular outgassing. A CQCM is a Cryo Quartz Crystal Microbalance. The CQCM depends on external cooling, and is used when samples are required at less than 40°C. Note: The CC engineer will need to know the surface area of your hardware to determine outgassing requirements for tests with a TQCM or CQCM.

  31. Frequently Asked Questions • If the ETL Technicians have had Flight Hardware Safety training, why are Flight Technicians required to install my hardware? A. Since the Flight Technicians are more familiar with your hardware, they are less likely to mishandle it. The ETL does not want to assume the risk of handling delicate hardware that we may not be familiar with.

  32. Frequently Asked Questions • If the chamber has shrouds for temperature control, why would is a heat exchanger needed? A. Shrouds use radiative heat transfer; a heat exchanger uses conductive heat transfer. Conductive heat transfer is more effective and can save a great deal of time. Heat exchangers are needed for temperatures below -100°C because radiative cooling is not practical at cold temperatures.

  33. Frequently Asked Questions • How much does a test cost? • Costs vary greatly depending on the duration, chamber, instrumentation requirements, nitrogen usage, and labor. Here are a few oversimplified examples: • 24 hours in small bakeout chamber $ 2.3k • 24 hours in a temp. chamber $ 5.7k • 24 hours in small T-Vac chamber $13.4k • 24 hours in medium T-Vac chamber $18.3k • 24 hours in 25’ SS without sun $ 74k • 24 hours in 25’ SS with 1 Sun $107k Note: Instrumentation, setup, and post test labor charges are not included. Please call Pat Martin for a detailed cost estimate.

  34. Frequently Asked Questions • What are examples of lessons learned? • After a GSE cable bakeout, oil dripped off of chamber door due to dirty cable braid. Decontamination cost the project $24k. Make sure your cables are built by the JPL Cable Shop. • Silicone contamination resulted in chamber getting totally disassembled, shroud bead blasted, rebuilt, and baked out for two weeks. This cost the project $70k. Work with a Materials Engineer to assure your hardware is safe.

  35. Frequently Asked Questions Q. What are examples of lessons learned? • Flight hardware swung into chamber door when lifting fixture came apart due to improper fixture assembly after dye penetrant inspection. An AIDS needs to be generated and followed for all the steps regarding lifting fixture load testing, dye-pen inspection, and reassembly. • Poor quality bulkhead feedthroughs leaked costing the project 28 hours of test time in the chamber. This cost the project $20k for facility charges plus labor for several project personnel who were supporting the test. Use the subject matter expert to help select the right hardware.

  36. Frequently Asked Questions Q. What are examples of lessons learned? 5. A project manager proposed eliminating solar thermal vacuum testing of a spacecraft to save time and money because he had confidence in the thermal analysis that had been conducted. JPL insisted on conducting the test. The test revealed that the thermal blankets were inadequate and the spacecraft would have failed in flight with both hot and cold shut downs. Testing afforded the project the opportunity to correct the problem and have a successful mission. The majority of thermal vacuum tests conducted in the ETL reveal significant problems with test articles.

  37. Frequently Asked Questions • What is the Cog E supposed to do if the test article fails during a T-vac test? • Here is a list of things to do: • Request the ETL to lock down the test conditions if it is safe to do so. • Record the conditions, activities, and observations at the time of the failure. • Notify QA, the PDM, and line management. • Prepare a PFR.

  38. Tour of the T-Vac Facilities in B144 and B150 • Chambers and floor space • Test Article mounting options • Heat exchangers and adapter plates • Bulkhead feedthroughs • Facility power for GSE • Thermal Data Acquisition System (TDAS) • Meet the T-Vac Technicians Note: The ETL Users’ Guide is available on-line at https://jpl-web.jpl.nasa.gov/etl/documents/D-63875%20ETL%20Facilities%20Guide_030810.pdf

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