N93-26898 SPACE ENVIRONMENTAL INTERACTIONS FOR THE SPACE EXPLORATION INITIATIVE Dale C. Ferguson National Aeronautics and Space Administration Lewis Research Center Cleveland, Ohio 44135 SPACECRAFT ENVIRONMENTAL EFFECTS f u Effluents _,I ,.,o,o,.o,.o,o,_.:.==-='-',e ® '_¢ _(_ (_) PLASMA Sputtering (_) Space Environmental Interactions Atomic Oxygen Attack • LOW PLANETARY ORBITS ONLY - Material Specific - Preferentially in Ram - Low MarsO, rblt Also Contains AO - For Some=Ma.teria!s,'Synergy W/ UV - Ionized AO Also Reactive. • CHANGES MATERIAL SURFACE PROPERTIES - Optical and Th,ermal Properties Surface Conductivities Strength of Exposed Fibers 69 1000 -- I(APTON HASS LOSS RATES VS, OXYGEN ENERGY a - LeRC HIGI{ ENERGY ION BEAH I/J b - RF PLASHA ASII_R " " _/ c - A_ROSPACK CORP. ATOMIC BEAH 100 d - LeRC STS-B'FLIGI|T RESULTS J'Jl_/ . - L.RC.1^sEo_r PLAs.A j//'e - E I0 E f_ 1.0 .1 .01 .! 1..0. 10 I00 1000 E, eV Copyright o AIAA 1986 - Used with permission. Visentine, J.T. and Leger, L.J., A Consideration of Atomic Oxygen Interaction with the Space Station, J. Spacecraft and Rockets, 23, 5,505-511, 1986. ORIGINAL PAQE iS 7O OF POOR QUALITY Load Biased to 100V Neg. w.r.t. Body Z1.88 19.8e 17.elB 15._ Y 13.88 i !1.88 9.88 7.88 S.SqB 3.l_ 1.88 -1._ -3._ 3 S 7 9 11 13 IS 17 19 ZI Z3 ZS Z7 Z_; 31 Z-AXIS Minimum Potential = -1.01E+eZ Haxi_JmPotential =-Z.72_-e8 3.88 (Z( 31.88, --3._ 1 (Y< Zlo_,' CUTPL_FF_E'TX = Space Environmental Interactions Arcing and Discharges • GEOSYNCHRONOUS ENVIRONMENT - Differential Charging in Geo Substorms - Solar Flares in Interplanetary Space • LOW PLANETARY ORBITAL ENVIRONMENTS - Arcing TO or Thru Ionized Plasma - Dielectric Breakdown of Anodized Surfaces - Arcing at Conductor-Insulator Junctions • PASCHEN BREAKDOWN- PLANETARY SURFACE - Martian Atm Pressure Ideal for Discharges - Lunar Camps Create Local Atmospheres 71 i0o I0-I 10-2 I i0-3 vm e_ J_ 0 PIX IIflight I0-4 " • PIX II ground I • Leung • Miller I0-5 I Threshold I0-6 I 100 2O0 600 I000 20O0 -V,V Figure 7. - Arc rate versus voltagefor $1andardinterconnect cells. Normal- izedtoLEOramconditions (see'lextl. r Copyright • AIAA 1986 - Used with permission. Ferguson, D.C., The voltage threshold for arcing for solar cells in LEO-flight and ground test results, AIAA paper 86-03621 1986. 72 Space Environmental Interactions Micrometeoroids and Debris • SURFACE DAMAGE - Pinholes in Insulators - Change of Thermal Properties - Sites for Arcing, Sputtering - Possible Site of Kapton Pyrolysis • NEED FOR REDUNDANCY OR HEALING - Fluid Lines and Heat Pipes • LOCAL PLASMA CREATED AT SITE - May Produce Prompt Arcing - Arcs Enlarge Damaged Area • DEBRIS PROBLEM IN PLANETARY ORBITS C3 INSIDECRATER 10000"1 I4 STS7WINDOW CRATER t. .4 COUNTS '1'' J | L 0.0 ENERGY(KEV) 10.0 73 Space Environmental Interactions State-of-the-Art ,Computer Tools • S-CUBED DIV. OF MAXWELL LABORATORIES • NASCAP (3-D, Particle Tracking) - Calculates Charging in GEO - Obtainable thru COSMIC - Mature Code, Industry Standard • NASCAP/LEO (3-D, Particle Tracking) - Calculates Charging, Currents in LEO - Release thru COSMIC This Year - Under Final Testing • EPSAT, EWB (l-D, Systems Tools) - Evaluate Multipl e Interactions - QUick, APproximate - Under Beta Testing - May Be Ideal Starting Point for SEI NASCAP model of NASA's Advanced Communications Technology Satellite. 74 Figure 6 SP-IO0 Floating Potential ...,..._.._.__:,_E_PSAT s Architecture Combines _::_,:_.,... . /i .iA POwerfu!Dispiay_With • / Chan_beable & Expandable Modeling Capabilities i!ii_ili_ii_!_ _ _i i¸ iiiiiiiiiii_i_!_i_iiiiiiiiiiiiiii ii!iiiiii!_i_i;ii iiiii iiii!i!iii!!iiiiiiiii!!iii __iiiiiiiiiiiiiiiiiiiili iii iiii!iiiiiii_iiii!!_ iiiiil//i/iiiiii • ............................ _':]__i0 _._:,_ _I leuncllon=ll _iiiiiiiiiiiiiiiiiii!iiiiii!iiiirii_iiiiiiiii!i!i!iii!iiiii!iii _1 I modulIe .... , iliiii!iii!i!!iN_N _ ', i_!ill i!i! ii{iiiiiiiiiiii i i!iiiiil!ii iiiiiii! _i_i_i_i_i_i_i_i_i_i_i_i_i_!_i_i_!_i_!_z!_i_iz__i_i_!_i_i_i_i_i_;' .........-..-................. !iiili!_i__ ii !!!i;ii 75 PO _'_: wer System Models I SCenosluomrnDeDgernadsiattieiosn Outgasslng J Ambient Environments SPhliuemldes I Plume - Ram - Outgassing Scattering Plumes Legend 105 o_ o _e I04 tO3 102 "10 o 10 _ LLJ I0° i0-I I0-2 i0-3 02 103 Orbit AIt;tude Total atomic oxygen erosion during a 10-year mission life for three conductive coatings as a function of altitude for 60° inclination circular orbits. 76 KAPTO4N1HOURSEXPOSURTOEATOMICOXYGEONNSTS-8 15TS-8 FLXGHT SAMPLES LeR¢ PRELIHIIt_RY riASS LOSS I_AS_I_IIT$ ?67 77 ORIGINAL PAQ,E IS OF POOR QUALITY Space Environmental Interactions Current Collection and Snapover • ELECTRON COLLECTION AND SNAPOVER - SnapOver at Potentials _ +100 V - Insulators Act as Electron Conductors - Large Power Drains • ION,COLLECTION AND SPUTTERING - Ions Focused Onto Insulation Defects - Sputtering at Potentials _ -100 V • FLOATING POTENTIALS - ion and Electron Currents Must Balance - Ease ofElectron Collection Makes Systems Float Negative • POWER SYSTEM GROUND IMPORTANT - Grounds on Moon, Mars Difficult? 78