Jet Propulsion Laboratory      California Institute of Technology                                           NASA Project M...
Jet Propulsion Laboratory      California Institute of Technology                                             Outline     ...
Jet Propulsion Laboratory      California Institute of Technology                                            Project Overv...
Jet Propulsion Laboratory      California Institute of Technology                                           Juno Science O...
Jet Propulsion Laboratory      California Institute of Technology                                                        J...
Jet Propulsion Laboratory      California Institute of Technology                                                    Space...
Jet Propulsion Laboratory      California Institute of Technology                                           Instrument Sui...
Jet Propulsion Laboratory      California Institute of Technology                                                       Th...
Jet Propulsion Laboratory      California Institute of Technology                               Juno Trajectory Through Ra...
Jet Propulsion Laboratory      California Institute of Technology                                           Juno Radiation...
Jet Propulsion Laboratory      California Institute of Technology                                                       Ju...
Jet Propulsion Laboratory      California Institute of Technology                                           End of Mission...
Jet Propulsion Laboratory      California Institute of Technology                                           Titanium Vault...
Jet Propulsion Laboratory                 California Institute of Technology                                           Jun...
Jet Propulsion Laboratory      California Institute of Technology                                           IESD Mitigatio...
Jet Propulsion Laboratory      California Institute of Technology                                           Juno Micromete...
Jet Propulsion Laboratory      California Institute of Technology                                           Micrometeoroid...
Jet Propulsion Laboratory      California Institute of Technology                                             Juno Magneti...
Jet Propulsion Laboratory      California Institute of Technology                                           AC Magnetic Su...
Jet Propulsion Laboratory      California Institute of Technology                                           Effects on Spi...
Jet Propulsion Laboratory      California Institute of Technology                                             DC Magnetic ...
Jet Propulsion Laboratory      California Institute of Technology                                            Summary      ...
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Sammy.kayali

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Sammy.kayali

  1. 1. Jet Propulsion Laboratory California Institute of Technology NASA Project Management Challenge February 9-10, 2010 Juno Project Overview and Challenges for a Jupiter Mission Sammy Kayali Mission Assurance ManagerFebruary 9-10, 2010 Slide - 1
  2. 2. Jet Propulsion Laboratory California Institute of Technology Outline • Juno Mission Overview • Spacecraft Design • Instrument Suite • The Juno Challenge • Jupiter Environment – Radiation Environment – Charging Environment – Solid Particle Environment – Magnetic Environment • SummaryFebruary 9-10, 2010 Slide - 2
  3. 3. Jet Propulsion Laboratory California Institute of Technology Project Overview Salient Features • First solar-powered mission to Jupiter EFB 10/9/2013 Launch • Eight instrument payload to conduct gravity, magnetic and atmospheric investigations 8/05/2011 • Single polar orbiter (simple spinner) launches in August 2011 – 5 year cruise to Jupiter, JOI in July 2016 – 1 year operations, EOM via de-orbit into Jupiter in 2017 • Elliptical 11 day orbit swings below radiation belts to minimize radiation exposure • Key Juno partners: SwRI, JPL, ASI, LM-Denver and GSFC DSM Sep 2012 Science To improve our understanding of the solar system by Understanding the origin and evolution of Jupiter, Juno will: • Determine the global O/H ratio (water abundance) in Jupiter’s atmosphere • Measure latitudinal variations in Jupiter’s deep atmosphere (composition, temperature, cloud opacity, and dynamics) JOI • Map Jupiter’s magnetic and gravitational fields 7/5/2016 • Characterize Jupiter’s polar magnetosphere and aurorae Tilted Ecliptic Pole View (Vernal Equinox Direction Up) 30-day Tick MarksFebruary 9-10, 2010 Slide - 3
  4. 4. Jet Propulsion Laboratory California Institute of Technology Juno Science Objectives • Origin – Determine O/H ratio (water abundance) and constrain core mass to decide among alternative theories of origin. • Interior – Understand Jupiters interior structure and dynamical properties by mapping its gravitational and magnetic fields. • Atmosphere – Map variations in atmospheric composition, temperature, cloud opacity and dynamics to depths greater than 100 bars. • Polar Magnetosphere – Explore the three-dimensional structure of Jupiters polar magnetosphere and aurorae.February 9-10, 2010 Slide - 4
  5. 5. Jet Propulsion Laboratory California Institute of Technology Juno Flight System SA Wing #3 Spacecraft: 1600 Kg dry mass 3625 kg wet mass Power at 1 Au (theoretical): 15 kW Power at JOI: 486 W Power at EOM: 428 W 8.86 m SA Wing #12.647 m 2.02 m 2.36 m 2.64 m SA Wing #2February 9-10, 2010 Slide - 5
  6. 6. Jet Propulsion Laboratory California Institute of Technology Spacecraft Solar Wing #3 HGA JADE Electron (3) MWR A5 JEDI (3) MWR A6 Solar Wing #1 Solar Wing #2 A4 A3 Nutation Damper Fuel Tank Oxidizer Tank 55 Ah Li Ion Battery (2) Main Engine MWR A2 Toroidal Antenna Waves MSC CoverFebruary 9-10, 2010 Slide - 6
  7. 7. Jet Propulsion Laboratory California Institute of Technology Instrument SuiteFebruary 9-10, 2010 Slide - 7
  8. 8. Jet Propulsion Laboratory California Institute of Technology The Juno Challenge Solar Thermal Environments Radiation Particles Plasma Requirement EM Fields Input Magnetics Instruments need to measure But environmental Jupiter’s exposure is a environment threat to the spacecraft Measurement System Design Capability Science Signal Noise Spacecraft Design The spacecraft cannot create excess noise which would disguise instrument signalsFebruary 9-10, 2010 Slide - 8
  9. 9. Jet Propulsion Laboratory California Institute of Technology Juno Trajectory Through Radiation Belts • Juno trajectory exposes spacecraft to the Jovian radiation belts for less than one day per orbit – Electrons – Protons • Early orbits are relatively benign – ~25% of the mission TID received by the end of Orbit 17 • Late orbits are severe – ~25% of the mission TID received over the last 4 orbits Perijove Passage through Jupiter’s Radiation EnvironmentFebruary 9-10, 2010 Slide - 9
  10. 10. Jet Propulsion Laboratory California Institute of Technology Juno Radiation Environment Jupiter Trapped Peak Average Proton & Electron Flux • Juno radiation environment has several 1.E+08 challenging features 1.E+07 Proton & Electron Flux – Large population of electrons > 10 MeV that Electrons (particles/cm2-s) 1.E+06 Protons cause high mission TID and DDD 1.E+05 – High electron flux near Perijove that causes 1.E+04 noise in sensors and charging of surfaces and 1.E+03 shielded dielectric materials 1.E+02 1.E+01 1 10 100 1000 Energy (MeV)February 9-10, 2010 Slide - 10
  11. 11. Jet Propulsion Laboratory California Institute of Technology Juno TID Environment Comparison 1.0E+09 1.0E+08 1.0E+07 Mission TID rad(Si) GLL dose through J35 (GIRE) 1.0E+06 Cassini 1.0E+05 MRO Juno 1.0E+04 1.0E+03 1.0E+02 1 10 100 1000 10000 Aluminum Spherical Shell Thickness, mil • Galileo TID > Juno TID > Cassini > MRO TID • Juno TID behavior parallels Galileo for shield thickness > 100 mils aluminum Juno TID is ~ 1/4 of Galileo TIDFebruary 9-10, 2010 Slide - 11
  12. 12. Jet Propulsion Laboratory California Institute of Technology End of Mission Radiation TID Levels Solar Wing #3 Solar Cell Coverglass (> 100 Mrad) Deck Component Surface Dose Z (under blanket) (11 Mrad) Vault Electronics (25 Krad) Solar Wing #1 MAG Boom Solar Wing #2 Solar Cell Junctions Instruments Outside Vault (3 Mrad) (<0.6 Mrad in 60 mil housing)February 9-10, 2010 Slide - 12
  13. 13. Jet Propulsion Laboratory California Institute of Technology Titanium Vault Protects Electronics • Juno spacecraft electronics are shielded by a vault – The thickness and composition of the vault walls are optimized to attenuate Juno’s mix of electrons and protons using the minimum mass – Vault equipment packing factor maximizes shielding from neighboring electronics boxes – Vault shielding designed to limit the TID of all internal electronics to 25 Krad or less – Divided into zones for equipment with different lifetimes and radiation hardness • Electronics outside the vault have local shielding designed for their location and part hardnessFebruary 9-10, 2010 Slide - 13
  14. 14. Jet Propulsion Laboratory California Institute of Technology Juno Charging Environment – Comparison • The Jovian electron environment 1.E+10 Juno WC IESD Flux (10x) deposits charge in materials Galileo Orbiter Peak Flux 1.E+09 Juno Spatially Worst 10-hour flux (1x) – Dielectric materials GEO WC Flux – Ungrounded metals 1.E+08 -1 • Juno electron charging Flux, (cm s) environment threat is severe 2 1.E+07 – ~2X higher than Galileo 1.E+06 – >10X higher than GEO spacecraft threat 1.E+05 • Juno charging mitigation 1.E+04 – Grounding non-conducting 0.1 1 10 100 surface materials Energy, MeV – Prohibit ungrounded metals – Analyze charge deposition in internal dielectric materials – Test hardware that is expected to discharge • HarnessFebruary 9-10, 2010 14 Slide - 14
  15. 15. Jet Propulsion Laboratory California Institute of Technology IESD Mitigation – Analysis and Test Coax cable in test chamber MWR G10 washer in antenna element Electric field: 1.02 x 104 V/cm No discharges expected Spacecraft Space Steel Connector Housing View G10 Washer (20mil thick, .33” dia.) • Electric field analysis of dielectrics Hollow Brass Annulus (15mil thick walls, .26” dia.) – Circuit boards – Gaskets and washers BeCu Probe • Testing to characterize IESD pulses – Harness Aluminum Wall Aluminum Walls with Slots (40mil thick each) (40mil thick)February 9-10, 2010 Slide - 15
  16. 16. Jet Propulsion Laboratory California Institute of Technology Juno Micrometeoroid Environment • Spacecraft velocity and Jupiter gravity well result in impact velocities > 100 km/sec • Jupiter environment has a significant high velocity meteoroid flux relative to cruise • Spacecraft and payloads analyzed to determine probability of failure due to meteoroid strikes – Shielding is used to reduce impact damageFebruary 9-10, 2010 Slide - 16
  17. 17. Jet Propulsion Laboratory California Institute of Technology Micrometeoroid Analysis - Example JIRAM Instrument View Instrument Component Assumptions Factor Failure Criteria Assuming penetration of the JIRAM Instrument Material: Al, Impact Angle: 0, 0.125 60 mil top of sensor will cause failure Particle penetrating 29.6 mils of Cu (includes 4 mil of Cu over wrap, 3.4mils of Cu Material: Cu, Thermal Blanket: Kapton, Impact shielding (twisted pair braid), Angle: 0, ASSUMES NO STAND OFF B/W and full conductor diameter Data Cables 0.125 THERMAL BLANKET AND CABLE. 40 of 155 16); Insulator and thermal conductors exposed. 0.8 m exposed length. blanket converted in to Cu thickness using areal density. Failure is severance of one of the exposed conductors. • Micrometeoroid analyses determine the probability of failure of critical spacecraft Instrument Component Survival Probability components. JIRAM Instrument 98.1% – View factors and shielding Data Cables 99.1% – Equipment redundancy – Materials of construction – Failure criteria – Minimum science requirementsFebruary 9-10, 2010 Slide - 17
  18. 18. Jet Propulsion Laboratory California Institute of Technology Juno Magnetic Field Challenge JOI Earth LEO • The Juno spacecraft is exposed to intense magnetic fields at each perijove pass – 5-6 Gauss typical, 12 Gauss maximum – ~10X LEO spacecraft magnetic field strength; ~1000X GEO magnetic field strength • The AC magnetic field represents an operational challenge – Developed an AC Magnetic Susceptibility requirement and extensive test program • The effects of a spinning spacecraft in a magnetic field (VxB) were addressed • DC Magnetic cleanliness requirement represented a challenge for material selection and usage.February 9-10, 2010 Slide - 18
  19. 19. Jet Propulsion Laboratory California Institute of Technology AC Magnetic Susceptibility Mitigation Approach Design Shield Model Shield Build & Test Shield • Implemented plan of early assessment and mitigation by identifying and testing hardware that is susceptible to rapidly changing magnetic fields – Components with soft magnetic materials, solenoids, isolators, ferrites, large current loop areas etc. • AC magnetic susceptibility test approach developed – 2X margin on expected magnetic field at JOI and 1.3 during science – Equipment tested to +/- 9 Gauss at 5 RPM at JOI – Equipment tested to +/-16 Gauss at 2 RPM during scienceFebruary 9-10, 2010 Slide - 19
  20. 20. Jet Propulsion Laboratory California Institute of Technology Effects on Spinning Spacecraft in a Magnetic Field (VxB) • Plasma sees a potential φ=0 difference across the B moving spacecraft • Most positive part of the θ ITO coated array floats φ ≈ -300 V near local plasma potential v • Maximum difference between spacecraft and plasma is vxB potential plus array voltage –full batttery charge φ ≈ -615 V • Vmax ≈ -615 V • Grounding design practices implemented throughout the spacecraft mitigate the issue •Solar Array coupon tests conducted to validate analysis Juno SpacecraftFebruary 9-10, 2010 Slide - 20
  21. 21. Jet Propulsion Laboratory California Institute of Technology DC Magnetic Cleanliness Mitigation Approach Typical Mag Mapping QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Tests of Small and Large Items Juno Telecom x4 Multiplier • Key magnetic cleanliness impact items identified early, tracked and resolved – Latch valves identified as significant magnetic field contributors • Self compensation design implemented – Telecom components identified as a potential magnetic cleanliness contributor • Key components were analyzed, tested and self-compensated • Complete review of all materials for magnetic contribution – Expert panel reviewed material lists and identified areas of concerns – Changed or modified magnetic materials to suitable non-magnetic materials – Analysed and approved use of magnetic materials if low risk was determinedFebruary 9-10, 2010 Slide - 21
  22. 22. Jet Propulsion Laboratory California Institute of Technology Summary • The environmental challenges on Juno are considerable but surmountable • Early planning and attention to details have been essential in avoiding environmentally related problems – Having the “right” experts – Team Education – Utilize appropriate analysis tools – Detailed and thorough test to prove the design • Minimize new designs and rely on proven architectureFebruary 9-10, 2010 Slide - 22
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