1. CONTAMINATION CONTROL
SME-Course
D : Materials
Materials and Processes Division
Materials Physics and Chemistry Section
Jaco M. Guyt TOS-QMC
Topics
1 Types of contamination
2 Cleaning procedures
3 Prevention
Materials and Processes Division
ESA-ESTEC TOS/QM

2. Materials and Processes Division
Introduction
Why contamination control ?
Satellites are operational in orbit - no maintenance after launch
Sophisticated equipment with higher demands on performance
Increased mission duration
Increased reliability is needed
Materials and Processes Division
ESA-ESTEC TOS/QM

3. Part 1 Types of contamination
Introduction
Origin of Contaminants
Requirements
Verification of requirements
Handling of contamination problems
Materials and Processes Division
ESA-ESTEC TOS/QM

4. Materials and Processes Division
Introduction
Definition
Any foreign matter
Unwanted deposition on surfaces.
Contamination effects
On thermal control surfaces - changes  and  ratios
On solar arrays - decrease on power output
On optical instruments - decrease signal / scattering
In waveguides - Multipaction
Materials and Processes Division
ESA-ESTEC TOS/QM

5. Types of contamination
Organic and Inorganic contamination coming from
Humans - Skin, handling greases/salts, hair, cosmetics
Clothing - Fibres, dust collected in clothing
Materials - Outgassing, solvent extraction, creeping(oil
greases), direct contact, degradation
Vacuum test - Pump oils, chamber history, turbulence at
start, venting (lines and gas quality)
Machining - Drilling, abrasion, polishing, cleaning
Transport - Packaging, pressure drop in plane
Space - Pyro-valves, wire cutters, thrusters
Exposure C. R.- Working activities, soldering, air circulation
Materials and Processes Division
ESA-ESTEC TOS/QM

6. Materials and Processes Division
Requirements
Inorganic / Particulate contamination
Airborne
ISO (1999) – superseded FED-Std-209)
“ Cleanrooms and associated controlled environments”
PSS / ECSS Q
“Cleanliness and Contamination control”
Surface contamination
IEST-Std-CC1246D - “Product Cleanliness levels and Contamination control program” superseded Mil-Std-1246C
PSS / ECSS Q-70-01
Materials and Processes Division
ESA-ESTEC TOS/QM

7. Materials and Processes Division
Requirements
Materials and Processes Division
ESA-ESTEC TOS/QM

8. Requirements Fed-Std-209E
Materials and Processes Division
ESA-ESTEC TOS/QM

9. Materials and Processes Division
Requirements ISO-14644_1
Materials and Processes Division
ESA-ESTEC TOS/QM

10. Materials and Processes Division
Requirements ISO-14644_1
Materials and Processes Division
ESA-ESTEC TOS/QM

11. Requirements Mil-Std-1246C
Materials and Processes Division
ESA-ESTEC TOS/QM

12. Requirements Mil-Std-1246C
Materials and Processes Division
ESA-ESTEC TOS/QM

13. Requirements Mil-Std-1246C
Materials and Processes Division
ESA-ESTEC TOS/QM

14. Requirements IEST-STD-CC1246D
Materials and Processes Division
ESA-ESTEC TOS/QM

15. Requirements IEST-STD-CC1246D
Materials and Processes Division
ESA-ESTEC TOS/QM

16. Materials and Processes Division
Requirements
Organic Contamination
PSS / ECSS Q-70-01
exposure in clean room during a continuous period of one week, less than 2.0x10-7 g/cm2
Exposure in vacuum chamber after a blank test of 24 hours, less than 1.0x10-7 g/cm2
Project depending, more stringent levels.
ECSS Q-70-02A
Outgassing requirements of materials.
IEST-Std-CC1246D
Level AA5 up to level J, what is 10 ng till 25 mg per 0.1m2
Materials and Processes Division
ESA-ESTEC TOS/QM

17. Requirements Mil-Std-1246C
Materials and Processes Division
ESA-ESTEC TOS/QM

18. Requirements IEST-STD-CC1246D
Materials and Processes Division
ESA-ESTEC TOS/QM

19. Verification of requirements
Organic Contamination
Visual inspection - levels unto 10-6 g/cm2 range
ECSS-Q (old PSS ) “Thermal vacuum outgassing test for the screening of space materials”
PSS (ECSS-Q-70-05) “The detection of organic contamination of surfaces by infrared spectroscopy”
ASTM E1235 “Gravimetric Determination of Nonvolatile Residue (NVR) in Environmentally Controlled Areas for Spacecraft”
ESTEC work instructions : contact and immersion test
Materials and Processes Division
ESA-ESTEC TOS/QM

20. Verification of requirements Micro VCM
Materials and Processes Division
ESA-ESTEC TOS/QM

21. Verification of requirements Micro VCM
Materials and Processes Division
ESA-ESTEC TOS/QM

22. Verification of requirements Micro VCM
Materials and Processes Division
ESA-ESTEC TOS/QM

23. Verification of requirements
Acceptance limits PSS : TML < 1.0%, CVCM < 0.1%
Acceptance limits ECSS-Q-70-02A : RML < 1.0%, CVCM < 0.1%
Micro VCM results
TML RML CVCM WVR Remarks
A % 0.05% 0.01% 1.07% Too high water
B % 0.45% 0.23% 0.11% Too high CVCM
C % 1.01% 0.09% 1.14% Too high TML/RML
D % 9.50% 6.17% 0.02% Too high RML/CVCM
Materials and Processes Division
ESA-ESTEC TOS/QM

24. Verification of requirements
PSS (ECSS-Q-70-05) “The detection of organic contamination of surfaces by infrared spectroscopy”
Identification due to specific absorption of the molecule due to vibrations and rotations of atoms
Quantification by Lambert/Beers Law relation
Abs. = E * b * C
E = Molar Absorption Coefficient
b = Pathlength
C = Concentration
Calibration curves for four standards
Paraffin, Di-octylPhthalate ester, Methylsilicone and MethylPhenylsilicone
Abs.
Absorption of sample
Concentration
of sample
Concentration
Materials and Processes Division
ESA-ESTEC TOS/QM

25. Verification of requirements
Materials and Processes Division
ESA-ESTEC TOS/QM

26. Verification of requirements
Materials and Processes Division
ESA-ESTEC TOS/QM

27. Verification of requirements
Materials and Processes Division
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28. Verification of requirements
Sampling for infrared analysis
Indirect by rinsing surface with solvent and analyse of NVR
Indirect by wiping surface with tissue and analyse of NVR
Direct by using infrared transparent windows ZnSe, CaF2
Materials and Processes Division
ESA-ESTEC TOS/QM

29. Verification of requirements
Particulate Contamination
Airborne Counters - Fed Std 209E
Surface contamination
Visual inspection, less than 300 ppm
ECSS-Q-70-50, Particle Fall Out measurement
ASTM E1216, Tape lift method
ASTM F312, Counting and sizing particles
ASTM F311, Liquid samples
Materials and Processes Division
ESA-ESTEC TOS/QM

30. Verification of requirements PFO - meter
Materials and Processes Division
ESA-ESTEC TOS/QM

31. Verification of requirements
Particulate Contamination
PFO meter and correlation with cleanliness specifications table
Materials and Processes Division
ESA-ESTEC TOS/QM

32. Verification of requirements
Tape lift method as performed at ESTEC
Define area which needs to be checked
Take Polyethylene transparent tape from 3M Scotch 480
Stick it on a surface of at least 5 x 5 cm
Take with tweezers the 0.45 micron filter paper with grid
Apply the filter paper against the just released tape
Cut excessive tape away
Count particles by Microscope in different size ranges
Materials and Processes Division
ESA-ESTEC TOS/QM

33. Handling of contamination problems
Define problem and location
Define starting point of problem
Write Non Conformance Report (NCR)
Identification of contamination by analysis
Search for possible sources
on location
Detailed Material Lists
Excluding by analysis / search / calculation
Materials and Processes Division
ESA-ESTEC TOS/QM

34. Handling of contamination problems
Can the problem be solved?
Can we live with it?
Will it happen again?
Can we avoid the risk by preventive actions or adjusting procedures?
Materials and Processes Division
ESA-ESTEC TOS/QM

35. Part 2 Cleaning Procedures
Introduction
Selection of Cleaning method
Verification of cleaning efficiency
Cleaning procedure
Materials and Processes Division
ESA-ESTEC TOS/QM

36. Materials and Processes Division
Introduction
Definition of clean
A contamination level below the acceptance limits or not detectable with the used method.
Procedure for cleaning is needed for
Customer - that you are cleaning and how
Personnel - that they know how to clean and what
Sub-contractor - that they know how and what are the requirements
Materials and Processes Division
ESA-ESTEC TOS/QM

37. Selection of Cleaning method
Selection should be based on :
Method compatibility with hardware
ultrasonic, temperature, mechanical scratching
Method efficiency with hardware
accessibility design
Solvent compatibility with hardware
corrosion, chemical attack, dissolving, removable
Solvent efficiency for contaminant
what are you removing, polar/non-polar
Materials and Processes Division
ESA-ESTEC TOS/QM

38. Materials and Processes Division
Cleaning methods
Mechanical cleaning - grinding, brushing, blasting
Detergent cleaning or soap cleaning
Solvent bath / ultrasonic
Chemical cleaning - acids, alkalines and salts
Vacuum bake out
Vacuum cleaner / ionised air
Plasma cleaning
Dry ice
Polymer film
Adhesive
Materials and Processes Division
ESA-ESTEC TOS/QM

39. Verification of cleaning efficiency
By representative test samples and checked visually or by analysis
Visual inspection after cleaning
Check of hardware by taking samples, followed by analysis
Check performance of hardware and verify against previous tests
Materials and Processes Division
ESA-ESTEC TOS/QM

40. Materials and Processes Division
Cleaning procedure
Should contain description or information about
Hardware
Method, with details about e.g. solvents/duration and flow chart
Restrictions or hazards for hardware or personnel
Requirements
Verification of requirements
Inspection after cleaning
Operators (trained)
Logbook entry
Materials and Processes Division
ESA-ESTEC TOS/QM

41. Materials and Processes Division
Part 3 Prevention
Introduction
Material selection
Garment
Potential risks
Preventive actions
Contamination control plan
Materials and Processes Division
ESA-ESTEC TOS/QM

42. Materials and Processes Division
Introduction
Prevention is better and cheaper then the cure!!
Think ahead.
If you are not sure it will contaminate the hardware? Stop the activity! Because the answer is yes.
If something can go wrong, it will go wrong.
Working towards a dead-line is where prevention looses its power.
Materials and Processes Division
ESA-ESTEC TOS/QM

43. Materials and Processes Division
Material selection
Outgassing characteristics
low TML and CVCM
Mass of used material
Location
Optical applications
Cryogenic
High Temperature
Long term predictions with VBQC
Materials and Processes Division
ESA-ESTEC TOS/QM

44. Materials and Processes Division
VBQC
Materials and Processes Division
ESA-ESTEC TOS/QM

45. Materials and Processes Division
VBQC
Materials and Processes Division
ESA-ESTEC TOS/QM

46. Materials and Processes Division
VBQC
Materials and Processes Division
ESA-ESTEC TOS/QM

47. Materials and Processes Division
VBQC
Results taken out of the Mathematical treatment consist of Accelaration factor, Activation energy, Residence time - Temperature dependency.
Long term predictions with VBQC data is used within the temperature range of test.
The TML or CVCM data are fitted period by period with a sum of 6 exponential equations.
With W0.i the variables, affected with the time constant 0,i, which are 50, 20, 5, 1, 0.5 and 0.1 hour.
Materials and Processes Division
ESA-ESTEC TOS/QM

48. Materials and Processes Division
Garment
As humans are the main source of contamination, garment should be taken into account from the beginning of the project.
Depending of the contamination budget allocated to a specific operation, selection of garment can be done
Storage of garment should be separate from street clothing
Procedure of dressing should be trained to the personnel
Regular cleaning of garment by specialised company / quality check
Materials and Processes Division
ESA-ESTEC TOS/QM

49. Materials and Processes Division
Potential risks
Potential risks Preventive actions
Thermal vacuum tests Check procedure
Pumping oils Blank test
Outgassing of materials Check DML
Solar radiation Adequate thermal protection
Clean room operations Training of personnel
Too many personnel in C.R. Entry form
Unauthorised entry in C.R. Access code for CR / locked
Maintenance in C.R. Check impact, protect items
Violation of dress code Clear signs on doors,training
Dirty activity during AIT Separate from sensitive item
Materials and Processes Division
ESA-ESTEC TOS/QM

50. CONTAMINATION CONTROL PLAN
Preventive
All requirements are mentioned
Procedures for delicate handling or testing
Materials and Processes Division
ESA-ESTEC TOS/QM