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JAXA's research strategy to orbital debris mitigation

March 4, 2016 International Symposium on Ensuring Stable Use

of Outer Space

Ryoichi IMAI, JAXA

CONTENTS

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

Space Transportation technologies

Thermal Control, Structure, Mechanical System, Robotics, Propulsion System, ECLS, etc.

Simulation, Software Engineering, IT

Research Unit 1

Research Unit 2

Research Unit 3

Research Unit 4

Research and Development Directorate（RDD）

System Technology Unit

Innovative Satellite Technology Demonstration Group

Sensor System Research Group

Systems Engineering, System Design

Space Demonstration by Small or Nano Satellites

Earth Observation Sensor

Target Oriented Research Team SSPS, KITE(Konotori Integrated Tether Experiment)

≒ 300 researchers and engineers

Guidance & Navigation, Trajectory, Communication, Power System, Space Environment, Electrical Parts, Materials, etc.

● R&D organization was reformed to strengthen the cross-cutting research activities for creating the innovative technologies

● ● ・・● More than 13 groups according to subdivided technology fields

R&D theme

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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

©JAXA/NASA ISS

● Total Mass in Earth Orbit > 7ｋｔ

● Mass >１ｔ： 1000 Objects in LEO ● Observable： 17000 Objects

● >120 C/A Operations in a year Hole on a Solar array

Status quo:

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Observable ： ＞ １０cm （LEO） ⇔ Possible protection size < a few millimeters

） NASA

Challenge themes of R&D

2. R＆D activities for Space Debris :

●Removal

●Observation

●Protection

⇒ Ground Observation and In-Orbit Observation ⇒ Estimation (Conjunction Assessment and Collision Avoidance) ⇒ Maneuver Planning

⇒ Test and Modeling ⇒ Guidelines for the Protection Designs

⇒ Cost-effective removal scenario ⇒ Vision based navigation ⇒ Capture and Deorbit

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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

● Observation From Ground ・ Optical (Discovery of un-cataloged object) ・ Radar

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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

Transition Prediction of Debris environment

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5000

10000

15000

20000

25000

30000

2000 2020 2040 2060 2080 2100 2120 2140 2160 2180 2200 2220

Effe

ctiv

e Nu

mbe

r of O

bjec

ts (≥

10 cm

) in

LEO

Year

Projection of the LEO Populations (Reg Launches + 90% PMD)

ASI

ESA

ISRO

JAXA

NASA

UK

● Estimation

Collision probability and effects estimation

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）

運用衛星の軌道誤差数10メートル～数100メートル（1σ）

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

スペースデブリの軌道誤差が小さい場合

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

最接近距離

Closest distance No need to C/A maneuver

⇒ 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

● 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

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5mm

5mm

X-ray CT

10mm

Front Back

At the 10mm away point from the outer skin, the energy of impact will be reduced by 15-20%

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

Ref. Higashide, et al., Trans. JSASS Aerospace Tech. Japan, 2012

● Protection

⇒ Reflected in the design guidelines and the damage evaluation

● Active Debris Removal (ADR)

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2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

1950 1970 1990 2010 2030 2050 2070 2090 2110 2130 2150 2170 2190 2210

Year

Effe

ctiv

e Nu

mbe

r of O

bjec

ts (>

10 c

m)

PMD

PMD + ADR02

PMD + ADR05

NASA

ADR 2/yr.

ADR 5/yr.

No ADR

Active debris removal of 5 large objects every year will preserve the current status (NASA)

・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

FGAN image of H-2A second stage : Stabilized by gravity gradient

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Implementation scenario（ Property, Liability, Business viability ）

②Propulsion ④GN&C ①Scenario ③Capture

⑤Deorbit & safety re-entry

Research subjects

⑥Simulation

Technical subjects （ Capture of non-cooperative target ）

● Problems to be solved in ADR

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14 ETS-Ⅶ（1997-1999）

● Technical Heritage in JAXA

HTV（2009- ）

Hayabusa （2003-2010）

● 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

Visible Camera Image IR Camera Image

Lighting simulator

Earth background (Chroma key)

Visual Navigation motion simulator

● 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.

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X Y

Charging Monitor

End Mass

Reflector

Brake

Spool

Tether

Rendezvous sensor

Generate the 10mA Tether

electrical current

Electrodynamic Tether

Length: 700m Collecting the electron and

Producing the Lorentz Force

Measurement of Plasma potential and Induced electromotive force

Deployment Velocity： >1m/s

End Mass Deployment Pod Visual Camera Monitoring the motion of End Mass

Electron Emission （FEC）

Z

● EDT experiment using HTV-6 (2016)

HTV-6

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● 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

18 ご清聴ありがとうございました

3. Conclusion :

Thank you for your attention