1、CHECK THE MASTER LIST VERIFY THAT THIS IS THE CORRECT VERSION BEFORE USE MSFC - Form 454 (Rev. October 1992) MSFC-PROC-3257 National Aeronautics and BASELINE Space Administration EFFECTIVE DATE: June 13, 2002 George C. Marshall Space Flight Center Marshall Space Flight Center, Alabama 35812 ED31 MUL
2、TIPROGRAM/PROJECT COMMON-USE DOCUMENT OUTGASSING TEST PROCEDURE FOR NON-METALLIC MATERIALS ASSOCIATED WITH CONTAMINATION SENSITIVE SURFACES IN A THERMAL VACUUM ENVIRONMENT STANDARD OPERATING PROCEDURE NOTICE: This document is not intended to be a substitute for adequate training on this system. APPR
3、OVED FOR PUBLIC RELEASE; DISTRIBUTION IS UNLIMITED Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Standard Operating Procedure OUTGASSING TEST PROCEDURE FOR NON-METALLIC MATERIALS ASSOCIATED WITH CONTAMINATION SENSITIVE SURFACES IN A THERMAL VACUUM
4、ENVIRONMENT Document No.: MSFC-PROC-3257 Revision: BASELINE Effective Date: June 13, 2002 Page 2 of 13 CHECK THE MASTER LIST VERIFY THAT THIS IS THE CORRECT VERSION BEFORE USE DOCUMENT HISTORY LOG Status (Baseline/ Revision/ Canceled) Document Revision Effective Date Description Baseline 06/13/2002
5、Baseline release Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Standard Operating Procedure OUTGASSING TEST PROCEDURE FOR NON-METALLIC MATERIALS ASSOCIATED WITH CONTAMINATION SENSITIVE SURFACES IN A THERMAL VACUUM ENVIRONMENT Document No.: MSFC-PRO
6、C-3257 Revision: BASELINE Effective Date: June 13, 2002 Page 3 of 13 CHECK THE MASTER LIST VERIFY THAT THIS IS THE CORRECT VERSION BEFORE USE TABLE OF CONTENTS Page GENERAL OPERATIONAL CONCERNS 4 1. SCOPE/PURPOSE. 5 2. APPLICABLE DOCUMENTS 5 3. DEFINITIONS/ACRONYMS. 6 4. CHAMBER OPERATION 7 4.1 CHAM
7、BER BAKEOUT FOR SEVERE CONTAMINATION 7 4.2 CHAMBER BAKEOUT FOR ROUTINE TESTING 9 4.3 CHAMBER CERTIFICATION 10 4.4 CHAMBER OPERATION FOR ROUTINE TESTING 12 5. RECORDS 13 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Standard Operating Procedure OUTG
8、ASSING TEST PROCEDURE FOR NON-METALLIC MATERIALS ASSOCIATED WITH CONTAMINATION SENSITIVE SURFACES IN A THERMAL VACUUM ENVIRONMENT Document No.: MSFC-PROC-3257 Revision: BASELINE Effective Date: June 13, 2002 Page 4 of 13 CHECK THE MASTER LIST VERIFY THAT THIS IS THE CORRECT VERSION BEFORE USE GENERA
9、L OPERATIONAL CONCERNS Before engaging in any task, operators should first be familiar with all associated documents, guidelines and procedures referenced in this document. Likewise, they should be trained and qualified by approved procedures in ED31-OWI-001 “Personnel Training and Certification.” A
10、lways use appropriate protective equipment (gloves, eye wear, etc.) during cleaning and servicing of test components. All appropriate measures should be employed to minimize introduction of contaminants into chamber. Always wear clean, approved gloves when working inside chamber or handling any obje
11、ct that is to be placed in chamber. Prior to any test or operation of the vacuum system, inspect all components for proper configuration, loose fittings or fasteners, coolant leaks, fluid level in bath, electrical and instrumentation connections, proper pressure settings on pneumatic systems, and an
12、y potential unsafe conditions. Verify that all necessary equipment is operational. Compare current equipment ECNs to prior test data sheet to determine if any changes have been made to the equipment configuration. Note all equipment changes on new data sheet and file in VCMO Lab notebook. Verify cal
13、ibration is current for all critical measurement devices. Should a component fail during any operational phase, the risk to personnel and the test should be determined and appropriate action taken. Any potential safety hazard should lead to an immediate termination of testing, repressurization of ch
14、amber, and correction of the hazard. WARNING: Care should always be given to back-fill of the chamber. When using a pressurized gas source (GN2, Missile Grade Air, etc.) always use the minimum pressure possible on regulator and monitor pressure gauges. Although the primary test chamber has an overpr
15、essure relief valve, failure to employ these measures could lead to an over-pressurization of the chamber causing damage to test samples, instrumentation, chamber hardware or an explosion. WARNING: The primary test chamber in Building 4711 room E179B has electrical power fed from two independent sou
16、rces. The main power feed comes from the UPS system located in E114. This powers all equipment that is necessary for routine testing chamber requirements. The secondary power supply is exclusively for the bell jar shroud bakeout heaters. Any time access panels are to be removed or any electrical wor
17、k is to be done, verify that BOTH power sources are disconnected and follow proper lockout/tagout procedures. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Standard Operating Procedure OUTGASSING TEST PROCEDURE FOR NON-METALLIC MATERIALS ASSOCIATED
18、 WITH CONTAMINATION SENSITIVE SURFACES IN A THERMAL VACUUM ENVIRONMENT Document No.: MSFC-PROC-3257 Revision: BASELINE Effective Date: June 13, 2002 Page 5 of 13 CHECK THE MASTER LIST VERIFY THAT THIS IS THE CORRECT VERSION BEFORE USE 1. SCOPE/PURPOSE The purpose of this procedure is to define the o
19、perational test method to support MSFC-SPEC-1443 “Outgassing Test for Non-Metallic Materials Associated with Contamination Sensitive Surfaces in a Thermal Vacuum Environment.” This specification was written to supplement JSC-SP-R-0022 “Specification for Vacuum Stability Requirements of Polymeric Mat
20、erial for Spacecraft Application” since it was found that materials could meet the requirements of JSC-SP-R-0022 but still contaminate sensitive surfaces to a point that they become non-functional. The scope of this procedure is limited to the VCMO test chamber (ECN 1440934) and associated support h
21、ardware and instrumentation located in Building 4711 room E179B. Operators are expected to be familiar with ASTM E 595, MSFC-SPEC-1443 and all current governing ISO documents before proceeding with testing. 2. APPLICABLE DOCUMENTS Documents listed below provide requirements, specifications, standard
22、s, and procedures applicable to this procedure. For each of these documents, the latest revision in effect at time of document approval will apply. ASTM E 595 Standard Test Method for Total Mass Loss and Collected Volatile Condensable Materials from Outgassing in a Vacuum Environment ED31-OWI-001 Pe
23、rsonnel Training and Certification ED31-OWI-002 Documentation and Data Control ED31-OWI-003 Control of Quality Records JSC-SP-R-0022 Specification for Vacuum Stability Requirements of Polymeric Material for Spacecraft Application MPG 8730.5 Control of Inspection, Measuring, and Test Equipment MSFC-S
24、PEC-1443 Outgassing Test for Non-Metallic Materials Associated with Sensitive Optical Surfaces in a Space Environment Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Standard Operating Procedure OUTGASSING TEST PROCEDURE FOR NON-METALLIC MATERIALS AS
25、SOCIATED WITH CONTAMINATION SENSITIVE SURFACES IN A THERMAL VACUUM ENVIRONMENT Document No.: MSFC-PROC-3257 Revision: BASELINE Effective Date: June 13, 2002 Page 6 of 13 CHECK THE MASTER LIST VERIFY THAT THIS IS THE CORRECT VERSION BEFORE USE 3. DEFINITIONS/ACRONYMS The following definitions relate
26、to terms applicable to this procedure: Collected Volatile Condensable Material (CVCM): quantity of outgassed matter from a test specimen that condenses on a collector maintained at a specific, constant temperature for a specified time. CVCM is expressed as a percentage of initial specimen mass and i
27、s calculated from condensate mass determined from the difference in mass of collector plates before and after test. Collector Plate: a cooled sample plate on which outgassing vapors condense. The weight of condensed material is used for calculating CVCM. Plates for the standard test are chromium-pla
28、ted aluminum, but other materials which better simulate surfaces of interest are optional. Contamination Sensitive Surfaces: any surface of flight hardware that could be adversely affected by contamination, e.g. mirrored optics, windows, detectors, thermal control surfaces, etc. Contamination Witnes
29、s Sample (CWS): a test specimen, e.g. OWS, which represents contamination sensitive elements critical to performance of flight instrumentation. The CWS must be defined to accurately represent contamination critical elements or components. Optical Witness Sample (OWS): a CWS that represents the conta
30、mination sensitive optical elements critical to instrument performance. In the standard test the OWS is a one-inch diameter, 1/8 inch thick fused silica substrate polished to at least 0.1 wave at 546.1 nm. Substrates are coated with aluminum then a protective magnesium fluoride (MgF2) overcoat to op
31、timize reflectance at 121.6 nm. Minimum reflectance is required to be 70% from 120.0 nm to 200.0 nm. Total Mass Loss (TML): total mass of material outgassed from a specimen that is maintained at a specified constant temperature and operating pressure for a specified time. TML is calculated from the
32、specimen mass as measured before and after test and is expressed as a percentage of the initial specimen mass. Water Vapor Regained (WVR): mass of water vapor regained by a specimen after the optional reconditioning step. WVR is calculated from the differences in specimen mass determined after test
33、for TML and again after exposure to a 505% relative humidity environment at 232C for 24 hours. WVR is expressed as a percentage of initial specimen mass. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Standard Operating Procedure OUTGASSING TEST PRO
34、CEDURE FOR NON-METALLIC MATERIALS ASSOCIATED WITH CONTAMINATION SENSITIVE SURFACES IN A THERMAL VACUUM ENVIRONMENT Document No.: MSFC-PROC-3257 Revision: BASELINE Effective Date: June 13, 2002 Page 7 of 13 CHECK THE MASTER LIST VERIFY THAT THIS IS THE CORRECT VERSION BEFORE USE The following are acr
35、onyms commonly used in this and associated documents: ASTM - American Society for Testing and Materials ECN - Equipment Control Number GN2- Gaseous Nitrogen ISO - International Standards Organization JSC - Johnson Space Center MSFC - Marshall Space Flight Center SP - Set point TC - Thermocouple UPS
36、- Uninterruptible Power Supply VCMO - Volatile Condensable Material for Optics 4. CHAMBER OPERATION Vacuum pumping system components are “dry” or oil free pumps, so there is no threat of backstreaming molecular contamination into chamber from pumps. Chamber rough pressure is monitored by two TC gaug
37、es mounted on the bell collar. Another TC gauge is on the foreline of the roughing pump to monitor the turbo pump backing pressure. High vacuum is measured with a nude ion gauge mounted on the bell collar. A liquid feedthrough is mounted on the collar for the circulating bath ethylene glycol mix tha
38、t maintains the temperature of the collector base. Cartridge heater power is delivered to the copper sample towers via an electrical feedthrough, and a separate instrumentation feedthrough provides thermocouple connections to the two test towers. The “hot” and “cold” sides of each test tower have tw
39、o thermocouples each that are averaged by the control software and displayed on the computer screen. 4.1 CHAMBER BAKEOUT FOR SEVERE CONTAMINATION If gross contamination of chamber and test towers is suspected, a system bakeout must be performed per the following: Provided by IHSNot for ResaleNo repr
40、oduction or networking permitted without license from IHS-,-,-Standard Operating Procedure OUTGASSING TEST PROCEDURE FOR NON-METALLIC MATERIALS ASSOCIATED WITH CONTAMINATION SENSITIVE SURFACES IN A THERMAL VACUUM ENVIRONMENT Document No.: MSFC-PROC-3257 Revision: BASELINE Effective Date: June 13, 20
41、02 Page 8 of 13 CHECK THE MASTER LIST VERIFY THAT THIS IS THE CORRECT VERSION BEFORE USE Verify that the power strip to the right of computer is switched OFF. Turn on system computer and monitor. When boot is complete, control software should automatically run. Activate controls by going to the Pane
42、l pull down menu and click on Start Task. 1. Open vent valve and using TC gauge #1 verify that chamber pressure is at ambient. 2. Using hoist, raise bell to provide access to test towers. 3. Follow prescribed cleaning guidelines in ASTM E 595 sections A1.1.4 through A1.1.8 and reinstall components.
43、4. Prepare towers for bakeout by verifying that specimen containers are empty, CWS are removed, thermocouples are secure, and heaters are correctly mounted. 5. Verify that o-ring seal is correctly in place and free from particulate contamination. 6. Slowly lower bell with hoist until bell is complet
44、ely seated on collar and tension is released from hoist cable. 7. Close vent valve and verify that backfill valve is closed. 8. Open gate valve and turn on roughing pump. 9. When TC gauge #1 reads 1 torr press turbo pump start button. 10. When turbo pump controller shows pump has reached normal oper
45、ation, select BA gauge #1 and turn on emission. 11. Turn on circulating bath unit and set temperature to 100C. Be sure to turn the refrigeration switch to OFF. 12. On the chamber front control panel, activate bell heaters by turning on the switch labeled “HEATER ON/OFF.” For each of the controllers,
46、 raise SP to 75C. As the heaters reach the setpoint, continue increasing SP by 20-30C until bell heater setpoints are 150C. 13. Meanwhile, as the bell is heating up, activate the tower heaters by entering the set point for each at 150C, click on the OFF/ON virtual switch for each tower to ON, and tu
47、rn on the power strip to the right of the computer. 14. Once all devices reach their ultimate SP, leave all heaters on for 24 hours. Vacuum level should slowly drop to the low to mid 10-7torr range. 15. After the 24-hour bakeout, lower all heater SP settings to 20C. On the circulating bath, keep SP
48、unchanged until heater temps. drop below 50C. Then lower bath SP to 20C and turn refrigeration switch to ON. 16. When all temperatures within chamber and on bell have reached ambient temperature, turn OFF all bell heaters, turn OFF power strip and virtual switches for tower heaters, and turn off circulating bath. 17. Turn OFF BA #1 gauge by pressing the EMIS button and select TC #1 gauge. 18. Turn OFF turbo and roughing pumps. 19. Open valve on Nitrogen K-bottle. Regulator should be set for minimal flow, and low-pressure needle should
