JAXA's research strategy to orbital debris mitigation

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1 JAXA's research strategy to orbital debris mitigation March 4, 2016 International Symposium on Ensuring Stable Use of Outer Space Ryoichi IMAI, JAXA 1

2 CONTENTS 1. Background 2. R&D activities for Space Debris Observation and Mapping Protection Removal 3. Conclusion 2

3 R&D organization was reformed to strengthen the cross-cutting research activities for creating the innovative technologies Research and Development Directorate(RDD) 300 researchers and engineers More than 13 groups according to subdivided technology fields Research Unit 1 R&D theme Research Unit 2 Research Unit 3 Research Unit 4 System Technology Unit Guidance & Navigation, Trajectory, Communication, Power System, Space Environment, Electrical Parts, Materials, etc. Thermal Control, Structure, Mechanical System, Robotics, Propulsion System, ECLS, etc. Simulation, Software Engineering, IT Space Transportation technologies Systems Engineering, System Design Innovative Satellite Technology Demonstration Group Space Demonstration by Small or Nano Satellites Sensor System Research Group Target Oriented Research Team Earth Observation Sensor SSPS, KITE(Konotori Integrated Tether Experiment) 3

4 1. Background Basic Plan on Space Policy : Promoting the international activities to draw up the ICOC( International Code of Conduct for Outer Space Activities ) Improving the capability of SSA Addressing the R&D on debris removing technologies JAXA s R&D activities : Proposing the technical guidelines for debris mitigation through the activities on IADC( Inter-Agency Space Debris Coordination Committee ). Taking advantage of Japan's strengths and promoting the research and development on the space debris mitigation technologies such as observation, protection and safety removal. 4

5 Status quo: Total Mass in Earth Orbit > 7kt Observable: Objects Mass >1t: 1000 Objects in LEO Hole on a Solar array >120 C/A Operations in a year ISS JAXA/NASA 5

6 ) NASA Observable : > 10cm (LEO) Possible protection size < a few millimeters Challenge themes of R&D 6

7 2. R&D activities for Space Debris : Observation Ground Observation and In-Orbit Observation Estimation (Conjunction Assessment and Collision Avoidance) Maneuver Planning Protection Test and Modeling Guidelines for the Protection Designs Removal Cost-effective removal scenario Vision based navigation Capture and Deorbit 7

8 Observation From Ground Optical (Discovery of un-cataloged object) Radar Superposition of a faint bright spot Observation In Orbit Onboard Camera (GEO, >1cm) Impact sensor (LEO, >0.1mm) HTV-5 (space debris monitor) Goal: Seamless Mapping 8

9 Estimation Effective Number of Objects ( 10 cm) in LEO Projection of the LEO Populations (Reg Launches + 90% PMD) ASI ESA ISRO JAXA 5000 NASA UK Transition Prediction of Debris environment Year Based on the observation data, JAXA develops the debris environment model To predict the future changes in the number of debris : "debris transition model" To assess the damage caused by debris collision probability : "debris collision damage analysis tool" Reflected in the design rules for spacecraft as well as in the regulatory rules for debris prevention Collision probability and effects estimation 9

10 Maneuver Planning Because of the low determination accuracy of debris orbit, there is a high uncertainty to estimate the collision risk. Increasing number of space debris makes higher the operation load of collision avoidance. - Current Criteria : Radial distance of 200m and total miss distance of 1000m スペースデブリの軌道誤差が大きい場合スペースデブリの軌道誤差数 100メートル~ 数 10キロメートル(1σ) スペースデブリの軌道誤差が小さい場合最接近距離 Closest distance 運用衛星の軌道誤差数 10メートル~ 数 100メートル(1σ) No need to C/A maneuver 最接近距離スペースデブリ位置の不確定性 ( 誤差 )が大きいために衝突リスク( 衝突確率 )が高いと計算される場合がある最接近距離は上の図と同じであるが衝突リスクは低いと判断することができる Improving the orbit determination and prediction of space debris Effective use of Japanese own observation data (Opt.& Radar) Modeling the determination error with the operation history data 10

11 Protection X-ray CT 5mm 5mm Front Back 10mm Collision Test to the honeycomb sandwich panel Object of 1mm φ with the velocity of 10km/sec AL-Skin Honeycomb Panel : tskin=0.25mm, hcore=25.4mm At the 10mm away point from the outer skin, the energy of impact will be reduced by 15-20% Ref. Higashide, et al., Trans. JSASS Aerospace Tech. Japan, 2012 Reflected in the design guidelines and the damage evaluation 11

12 Active Debris Removal (ADR) Removal of large objects in congestion orbit is effective More than Half of them are upper stages of launch vehicles Upper stages are simple in shape and stable in motion Upper stages are most effective and urgent target for ADR Effective Number of Objects (>10 cm) PMD PMD + ADR02 PMD + ADR05 No ADR ADR 2/yr. ADR 5/yr. Active debris removal of 5 large objects every year will preserve the current status (NASA) FGAN image of H-2A second stage : Stabilized by gravity gradient Year NASA 12

13 Problems to be solved in ADR Implementation scenario ( Property, Liability, Business viability ) Technical subjects ( Capture of non-cooperative target ) Research subjects 1Scenario 2Propulsion 3Capture 4GN&C 5Deorbit & safety re-entry 6Simulation 13

14 Technical Heritage in JAXA HTV(2009- ) Hayabusa ( ) ETS-Ⅶ( ) 14

15 Basic Strategy of Upper Stage Removal Navigation: AON(simple Angle Only Navigation with Vis & IR Camera) Motion Estimation: Camera image Capture: Extended boom (simple mech.) Deorbit: EDT(No-fuel) Goal: Reliable and low cost system 15

16 Vision based Navigation Navigation Target : Circular structure image of PAF(Payload Attachment Fitting ) Testing the relative navigation and motion estimation using the Camera Image under the various lighting conditions. Visible Camera Image IR Camera Image Earth background (Chroma key) Lighting simulator Visual Navigation motion simulator 16

17 EDT experiment using HTV-6 (2016) Electrodynamic Tether Length: 700m Collecting the electron and Producing the Lorentz Force Tether End Mass Reflector Brake Spool End Mass Deployment Pod Deployment Velocity: >1m/s Visual Camera Monitoring the motion of End Mass Rendezvous sensor Charging Monitor Measurement of Plasma potential and Induced electromotive force X Y Z HTV-6 Electron Emission (FEC) Generate the 10mA Tether electrical current 17

18 3. Conclusion : JAXA is promoting the comprehensive approach to Space Debris Mitigation The primary goal of JAXA is to develop the practical technologies for removing the upper stages of launch vehicles in the congestion orbit R&D on the key technologies such as camera-based navigation and EDT are in progress steadily Feasible scenario for sustainable activities including the cooperation with international partners and private companies is important Thank you for your attention ご清聴ありがとうございました 18

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