The effects of atomic oxygen (AO) on materials in aerospace environments are examined. Materials are categorized according to their susceptibility to AO. The degradation effects of AO are examined to determine which materials are most vulnerable. Classes of spacecraft materials are listed and correlated with a performance category. The spacecraft orbits sensitive to AO interactions are also listed. Correlations are presented of AO effects on materials and of spacecraft glow effects

Leger, Lubert J.

Visentine, James T.

English

NASA Technical Reports Server

ATOMIC OXYGEN
N89-23557
LUBERT LEGER AND JAMES VISENTINE
NASA- JOHNSON SPACE CENTER
CHAIRMEN
MATERIAL PERFORMANCE CATEGORIES
PROPERTY
CHANGE
(_)
/ CATEGORY I MATERIALS -
/ HIGH SUSCEPTIBILITY TO
/ ATOMIC OXYGEN
, CATEGORY III MATERIALS-
/ // INTERMEDIATE OR
_ INCIPIENT SUSCEPTIBILITY
_f TOAO
/ _ (11) CATEGORY II MATERIALS-
/ LOW SUSCEPTIBILITY TO AO
EXPOSURE
PRECEDING PAGE BLANK NOT FILMED
545
https://ntrs.nasa.gov/search.jsp?R=19890014186 2020-03-20T03:13:04+00:00Z
WHAT MATERIALS ARE MOST VULNERABLE TO
ATOMIC OXYGEN DEGRADATION?
• CATEGORY I AND III MATERIALS ARE MOST VULNERABLE; CATEGORY II MATERIALS ARE
LEAST VULNERABLE
- FOR SOME APPLICATIONS, EVEN SMALL DEGRADATION DUE TO AO INTERACTIONS
MAY BE UNACCEPTABLE
- MOST SENSITIVE ORBITS ARE THOSE LEO ORBITS WHERE AO NUMBER DENSITIES
VARY BETWEEN 105 - 10 9 ATOMS/CM 3
- DEGRADATION EFFECTS VARY IN RELATION TO EXPOSURE TIME (FLUENCE)
- MATERIAL APPLICATIONS AND SYSTEM PERFORMANCE REQUIREMENTS
DETERMINE EXPOSURE CONDITIONS
- PROLONGED EXPOSURE OF SENSITIVE MATERIALS WILL RESULT IN DEGRADED
SYSTEM PERFORMANCE OR REQUIREMENTS FOR ON.ORBIT MAINTENANCE; BOTH
CONDITIONS CONTRIBUTE TO INCREASED MISSION COST AND REDUCED MISSION
OBJECTIVES
MATERIAL CLASSES FOR SPACECRAFT APPLICATIONS
MAT_.P_L_J._ pERFQRMANCE CATEGORy
• ORGANIC FILMS I-II
• INORGANIC II
• SILICONE PAINTS II
• LUBRICANTS I-I1-111
• ORGANIC ADHESIVES I
• ORGANIC COMPOSITES I
• METAL MATRIX COMPOSITES II
• THERMAL CONTROL COATINGS I-II-III
• OPTICAL COATINGS I-I1-111
546
SPACECRAFT ORBITS SENSITIVE TO AO INTERACTIONS
• MINIMUM ALTITUDE IS 100 KM
• MAXIMUM ALTITUDE IS 700 KM, ALTHOUGH VERY SENSITIVE SYSTEMS MAY BE
AFFECTED AT HIGHER ALTITUDES
• WHY? -- OXYGEN ATOM CONCENTRATIONS ARE DOMINANT WITHIN THESE ALTITUDE
RANGES
CORRELATION OF AO EFFECTS ON MATERIAL_
LABORATORY AND FLIGHT EXPERIENCE REPRESENT RELATIVELY IMMATURE DATA BASE
- FLIGHT DATA LIMITED IN FLUENCE AND ACCURACY OF FLUENCE ESTIMATES
- LABORATORY SIMULATIONS ONLY RECENTLY AVAILABLE
- QUALITATIVE CORRELATION OF LABORATORY AND FLIGHT DATA FOR VERY LIMITED
NUMBER OF MATERIALS (REACTION EFFICIENCIES AND MORPHOLOGY CHANGES,
ACTIVATION ENERGY)
FUTURE FLIGHT EXPERIMENTS TO PROVIDE ACCURATE REACTION RATE MEASUREMENTS
FOR COMPARISON TO GROUND-BASED RESULTS
547
CORRELATION OF SPACECRAFT GLOW EFFECTS
• CORRELATION BETWEEN GLOW FLIGHT EXPERIMENTS AND LABORATORY RESULTS
- VISIBLE EMISSIONS
= MEASURED SPECTRUM SIMILAR TO LABORATORY NO2
-- PREDICTED PHENOMENA VERY DIFFICULT TO SIMULATE
= EFFECTS OF SURFACE PROPERTIES ON RECOMBINATION EFFICIENCY (INCLUDING
STICKING EFFICIENCIES VS TS ) NEEDS STUDY
UV EMISSIONS
= MEASURED SPECTRUM (1400-1800) SIMILAR TO LABORATORY SURFACE
RECOMBINATION (N 2 -LBH)
= NO GOOD FLIGHT UV DATA BASE
= PREDICTED PHENOMENOLOGY (1-5 EV N 2 ON SURFACE) HAS NOT BEEN DONE
- IR EMISSIONS
= FLIGHT DATA SPARCE
= LABORATORY EXPERIMENTS OF MANY PREDICTED PHENOMENA CAN BE SIMULATED
DO WE KNOW ENOUGH TO LAUNCH FOR 10-30 YEARS OF
SERVICE WITH CONFIDENCE?
NO FLIGHT OR LABORATORY DATA BASE FORFULL LIFE EXPOSURE; LIMITED EXPOSURE ONLY
MATERIALS ARE AVAILABLE THAT APPEAR TO BE NON-REACTIVE TO AO
- LIMITED KNOWLEDGE PLACES SEVERE CONSTRAINTS ON SYSTEM DESIGN
- EACH APPLICATION REQUIRES SPECIAL CONSIDERATIONS AND UNDERSTANDING
OF SYNERGISTIC EFFECTS
- DESIGN SOLUTIONS FOR 5-YEAR LIFE HAVE BEEN DEVELOPED
- ACCELERATED, FULL-LIFE TESTING OF PROTECTIVE COATING CONCEPTS TO BE
CONDUCTED IN GROUND-BASED LABORATORIES
SYNERGISTIC EFFECTS NOT ADEQUATELY UNDERSTOOD
548
ARE TERRESTRIAL LABORATORY FACILITIES ADEQUATE?
• AT LEAST TWO AO-BEAM FACILITIES HAVE ADEQUATE SIMULATION CAPABILITY
PHYSICAL SCIENCES CORP, STRENGTHS WEAKNESSES
LOS ALAMOS
LARGE BEAM (30-1.(300 CM 2 ) • PULSED SOURCE
MULTIPLE SAMPLES • HIGH INSTANTANEOUS FLUX
HIGH ENERGY (5-12 EV)
LONG EXPOSURES POSSIBLE
HIGH FLUX (1018 - 1016 ATOMS/CM 2 }
FLUENCE UP TO 10 21 ATOMS/CM 2
HAVE BEEN ACHIEVED
• CONTINUOUS BEAM • SMALL BEAM
• HIGH ENERGY (1-5 EV) • CONTAINS 02 , INSERT GAS,
• HIGH INTENSITY (IO 17 ATOMS/CM 2 ) 0•ANDUV
• LONG EXPOSURES i76 HRS)
FLUENCES TO 2 X 10 22 ATOMS/CM 2
HAVE BEEN ACHEIVED
• OTHER FACILITIES BEING DEVELOPED
• NEED TO PROVIDE NIGH DUALITY SIMULATION FACILITY TO COMMUNITY FOR MATERIAL
EVALUATIONS
SYNERGISM WITH OTHER FACTORS
SYNERGISM WITH OTHER FACTORS IMPORTANT RELATIVE TO MATERIAL EFFECTS
MOST IMPORTANT APPEAR TO BE DAMAGE TO PROTECTIVE COATINGS FOLLOWED BY
REACTION WITH SUBSTRATE
- RADIATION INDUCED FAILURE OF COATING
- MICROMETEOROID/SPACE DEBRIS (SMALL PARTICLES)
- THERMAL CYCLING
- CHARGING DAMAGE
ACCELERATION OF REACTION RATES
GLOW SYNERGISM WITH OTHER FACTORS
- SURFACE CONTAMINATION
- GAS RELEASES OF REACTIVE PRODUCTS
HAS SYNERGISM BEEN TESTED OR EVALUATED?
- INITIAL CONSIDERATION OF COUPLING, BUT VERY LIMITED EVALUATIONS
- LABORATORY FACILITIES WITH COMBINED ENVIRONMENTS NOT AVAILABLE
549
NEED FOR SPACE EXPERIMENTS
SPACE EXPERIMENTS ARE NEEDED FOR MATERIAL INTERACTION ASSESSMENT
- VALIDATION OF GROUND-BASED MATERIAL EVALUATION SYSTEMS
- ESTABLISH MATERIAL REACTION DATA BASE
- ENHANCED UNDERSTANDING OF INTERACTION MECHANISMS LEADING TO CONFIDENCE
IN DESIGN
GLOW SPACE EXPERIMENTS ARE NEEDED
- ESTABLISH DATA BASE ON GLOW CHARACTERISTICS ACROSS SPECTRAL REGIONS
OF INTEREST
- VALIDATED EXISTING MODELS
PROPOSED EXPERIMENTS
LDEF RETRIEVAL
- EXPANSION OF DATA BASE
- HIGH FLUENCE EXPOSURE (1 X 1021 ATOMS/CM 2 )
- FLUX EFFECTS (LOW FLUX OVER LONG EXPOSURE)
- HARDWARE ASSESSMENTS
EOIM-3
- BENCHMARK REACTION RATE DATA BASE USING ON-BOARD MASS SPECTROMETER
- DATA FOR CORRELATION WITH GROUND SIMULATION SYSTEMS
DELTA STAR
- ACTIVE SENSOR DEVELOPMENT AND PERFORMANCE ASSESSMENT
- CORRELATION WITH GROUND-BASED SIMULATION FACILITIES
SMALL SATELLITES (INCLUDING LDEF)
- ORIENTATION CONTROLLED
- REAL TIME DATA
- RECOVERY (IN SOME CASES)
- DEPLOY IN DIFFERENT ORBITS INCLUDING HIGH ALTITUDE, LONG EXPOSURES
55O
PROPOSED EXPERIMENTS (CONTINUED)
LDEF REFLIGHT
- REAL TIME TELEMETRY DATA
- EVALUATE ADVANCED MATERIAL CONCEPTS
SATELLITE RETRIEVAL
- RECOVERING EXISTING SATELLITES FOR POST-MISSION INSPECTION
- SATELLITE ORBITS MAY NOT BE COMPATIBLE WITH STS MISSIONS--MAY REQUIRE SPECIAL
PROVISION FOR SHU'I-I'LE RECOVERY
SPACECRAFT GLOW
- NASA OAST OUTREACH EXPERIMENT
- INFRARED GLOW MEASUREMENTS
- CIV GLOW EFFECTS
DEVELOPMENT OF LOW-COST SATELLITE BASE AND ACTIVE SENSORS
EXPERIMENT CHARACTERISTICS
MATERIAL EFFECTS EXPERIMENTS
- LONG DURATION EXPOSURES
- CONTROLLED SPACECRAFT ORIENTATION
- DISTURBANCE INDEPENDENT
- PROVISIONS FOR ELECTRICAL POWER
- TELEMETRY
- GOOD CONTROL OF CONTAMINATION
GLOW INVESTIGATIONS--SAME REQUIREMENTS AS MATERIAL EFFECTS, EXCEPT:
- ELLIPTICAL ORBITS
- LONG DURATION DURATION EXPOSURES NOT NECESSARY
55]
VOLUME, WEIGHT, AND COMPLEXITY OF EXPERIMENTS
MATERIAL EXPERIMENTS
EOIM-3
- LDEF
- DELTA STAR
SPACECRAFT GLOW
- WEIGHT--1,000 LBS, WITH STS CARRIER
- VOLUME--I/8 SHUTTLE PAYLOAD BAY
- COMPLEXITY--MODERATE
COMPLEXITY (RAM ORIENTATIONS REQUIRED)
- PREVIOUSLY DESCRIBED
- WEIGHT--50 LBS
- VOLUME--SEVERAL CUBIC FEET
COMPLEXITY--LOW (ACTIVE TRAY)
WEIGHT--1,000 LPS, WITH STS CARRIER
VOLUME - 10 CUBIC FEET
552


Atomic oxygen

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