DESTINY+: Deep Space Exploration Technology Demonstratorand Explorer to Asteroid 3200 PhaethonHiroyuki Toyota1, Kazutaka Nishiyama1, Yasuhiro Kawakatsu1, Shunsuke Sato1, Takayuki Yamamoto1, Shun Okazaki1,Tetsuya Nakamura1, Ryu Funase2, Takaya Inamori3, Tomoko Arai4, Ko Ishibashi4, Masanori Kobayashi4, DESTINY+ Team1 JAXA, 2 The University of Tokyo, 3 Nagoya University, 4 Chiba Institute of Technology

惑星探査研究センターPlanetary Exploration Research Center

Japan’s Space Science Programs

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Small-class Space Science Programs

Middle-class Space Science Programs

- Every 3 years- \15B = $150M- Epsilon rocket

- Every 5 years- \30B = $300M- H2A rocket

SPRINT-A/HISAKI ERG/ARASE SLIM DESTINY+

MMX(Mars Moon eXploration) Solar Sail

2013 2016 2019 2022

2024 2020s

Japan’s Space Science Programs

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Small-class Space Science Programs

- Every 3 years- \15B = $150M- Epsilon rocket

SPRINT-A/HISAKI335 kg

950 x 1150 kg, 30 deg.

ERG/ARASE355 kg

460 x 32000 km, 31 deg.

SLIM DESTINY+

2013 2016 2019 2022

Epsilon rocket is not capable of launching 500-kg class spacecraft into interplanetary space.

DESTINY+ realizes low-cost planetary missions utilizing Epsilon rocket.

What is DESTINY+?

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Demonstration andExperiment of

SpaceTechnology for

INterplanetaryvoYage

PhaethonfLyby with

reUSableprobe

1. Launch intohighly elliptical orbit.

2. Orbit raisingby electric propulsion.

3. Departure withLunar swing-by.

4. 3200 Phaethon flyby.

Daughter spacecraft6U, 10 kg

DESTINY mothership

Daughter spacecraft was cancelled in exchange for more redundant system

Schedule2015: Proposal2016: MDR2017: SRR2018: RFP, SDR2019: PDR2020: CDR2022: Launch

Currently conducting Phase-A study.

dUSt science

What is DESTINY+?

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Demonstration andExperiment of

SpaceTechnology for

INterplanetaryvoYage

PfLease

reUS

1. Launch intohighly elliptical orbit.

2. Orbit raisingby electric propulsion.

3. Departure withLunar swing-by.

4. 3200 Phaethon flyby.

Daughter spacecraft6U, 10 kg

DESTINY mothership

Schedule2015: Proposal2016: MDR2017: SRR2018: RFP, SDR2019: PDR2020: CDR2022: Launch

help !

Daughter spacecraft was cancelled in exchange for more redundant system

Currently conducting Phase-A study.

DESTINY+ System Design

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12.6 m 1.6

m

Mission Period > 4 years

Mass 480 kg (including 60 kg Xenon and 15.4 kg Hydrazine)

Launcher Epsilon rocket + kick motor

Trajectory 230 km x 49913 km, 30 deg. Lunar swing-by Phaethon transfer

Attitude control 3-axis (Error < 1 arc-min.)

Communication X band (GaN SSPA, HGA 4 kbps, MGA 1 kbps, LGA 8 bps at 1.9 AU)

Solar Array High-specific power light-weight paddle (138 W/kg, 4.7 kW (BOL), 2.6 kW (EOL))

Battery Li-ion (42 Ah, 11s1p)

Propulsion RCS (Hydrazine) + Ion thrusters (µ10 x 4)

Thermal control Loop heat pipes, Reversible Thermal Panels

Radiation dose Approx. 30 krad (with aluminum shield of 3-mm thick)

System Block Diagram

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System Block Diagram

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Power System

Attitude and OrbitControl System

Science InstrumentsCommunicationSystem

Satellite Management SystemIon EngineSystem

Reaction ControlSystem

Mission Profile

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Period Operation

1 1 monthLaunched into a highly elliptic orbit (230 x 49913 km) by Epsilon rocket

2 0.5-2 yearsSpiraled orbit raising by electric propulsion

3 0.5 years Lunar swing-by

4 2 years Phaethon transfer orbit

5 Several days Phaethon flyby

6 2 years Earth swing-by transfer orbit

7 Several days Earth swing–by (T.B.D.)

8 T.B.D. Transfer orbit to next target

EarthLunar swing-by

Transfer to3200 Phaethon

Orbit raising byelectric propulsion

EarthDESTINY+

3200 Phaethon

DESTINY+ as Technology Demonstrator

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µ10 Ion Thruster

Orbit raising usingElectric Propulsion

High-specific EnergyLight-weight Solar Array PaddleAdvanced Thermal Control

µ10 Ion Thruster

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HAYABUSA (2003-2010) HAYABUSA 2 (2014-) DESTINY+ (2022-)

Spacecraft mass (wet) 510 kg 610 kg 480 kg

Thruster µ10 µ10 µ10

# of thrusters (total) 3 (4) 3 (4) 4 (4)

Total thrust 30 mN 30 mN 40 mN

Specific impulse 3000 s 3000 s 3000 s

Acceleration 47 µm/s2 49 µm/s2 83 µm/s2

Power 1140 W 1250 W 1670 W

Heat dissipation 509 W 494 W 620 W

Xenon mass 66 kg 66 kg 60 kg

Total delta-V 2.2 km/s 2.0 km/s 4.0 km/s

Ion engine system dry mass 61 kg 66 kg 59 kg

µ10 Ion Thruster

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HAYABUSA (2003-2010) HAYABUSA 2 (2014-) DESTINY+ (2022-)

Spacecraft mass (wet) 510 kg 610 kg 480 kg

Thruster µ10 µ10 µ10

# of thrusters (total) 3 (4) 3 (4) 4 (4)

Total thrust 30 mN 30 mN 40 mN

Specific impulse 3000 s 3000 s 3000 s

Acceleration 47 µm/s2 49 µm/s2 83 µm/s2

Power 1140 W 1250 W 1670 W

Heat dissipation 509 W 494 W 620 W

Xenon mass 66 kg 66 kg 60 kg

Total delta-V 2.2 km/s 2.0 km/s 4.0 km/s

Ion engine system dry mass 61 kg 66 kg 59 kg

Ion thrusters are very efficient, but…

Require large amount of electric power

Light-weight solar paddles

Generate large amount of heat during operation, requiring large amount of heater power during non-

operation

Advanced thermal control

1670 W

620 W

Light-weight Solar Array Paddle

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IMM 3J Solar Cellt = 20 µm, Eff = 30.8 %

Glass-type Space Solar Sheet Light-weight Solar Array Paddle

Cross sectionBOL: 4.7 kWEOL: 2.6 kW (2.77E+15 e/cm2

of equivalent 1 MeV electrons)(AM0, 80 deg.C)

Light-weight Solar Array Paddle

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IMM 3J Solar Cellt = 20 µm, Eff = 30.8 %

Glass-type Space Solar Sheet Light-weight Solar Array Paddle

0

50

100

150

0 5 10

Spe

cifi

c p

ow

er

[W/k

g]SAP output power [kW]

QZSS

DRTS

GOSAT

GCOM WINDS

ALOS

ETS-VIII

DESTINY+

138 W/kg

SPRINT-A

Cross section

Conventional rigid panels

Advanced Thermal Control

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E

Sun

light

HAYABUSA 2operates ion thrusters

only in interplanetary space

DESTINY+

operates ion thrustersin Earth orbit

S

Sunlight incident only on +Z panel.No sunlight incidence in ion thrusters.

Sunlight incident on all panels on which solar array paddles are not mounted.Ion thrusters are illuminated by sunlight even during operation

Advanced Thermal Control

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Ion thrusters

X

YZ

IES Power Processing Units

Heat pipes

Loop Heat Pipes (LHPs)

• Flexible LHPs are applicable for heat transfer from ion thrusters on a moving gimbal.

• LHPs can also work as a heat switch that stops heat transfer.

Reversible Thermal Panels (RTPs)

• Flexible multilayer graphite sheet enables reversible operation.

• Automatically changes angle using shape memory alloy actuators.

• While ion thrusters operate, RTPs are deployed for efficient heat dissipation.

• While ion thrusters stop, RTPs are stowed for saving heater power.

Stowed Deployed

Scientific Objective of DESTINY+

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Earth

To the Sun (1) IDPs provided to the Earth, moving inward to the Sun

Miscellaneous dusts from comets & asteroids provided to zodiacal dusts

Dusts accretion in solar nebulae

Formation of primitive bodies

Orbital evolution inward Gas/dusts ejection

by solar heating

Mass loss & breakup

Last stage of primitive bodies evolutionThermal and orbital evolution of primitive bodies

(3) Meteor shower parent bodies crossing Earth’s orbit

Understand origin and nature of dusts, which are key sources of organic matter to Earth.

Last stage of primitive bodies evolution

Overview of Scientific Observations

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3200 Phaethon:Parent body of the Geminids meteor shower

0.14 AU x 2.4 AU22.2 deg.523.5 days

Earth

DESTINY+

During cruise phase …- observe interplanetary dusts- observe interstellar dustsusing a dust analyzer.

During a high-speed (> 30 km/s) flyby of 3200 Phaethon …- observe dusts from 3200 Phaethon using a dust analyzer- observe terrain using a telescopic camera- observe reflectance distribution using a multiband camerato understand the mechanisms of dust ejection.

Sun

DESTINY Dust Analyzer

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Cassini CDA

• DESTINY Dust Analyzer (DDA) is developed by Stuttgart University (PI: Prof. Ralph Srama) who also developed Cassini Cosmic Dust Analyzer (CDA).

• Carrying two DDAs (for cation and anion) is under consideration. It will be the world’s first attempt to observe dusts of opposite polarity at the same time.

Concept of double DDAs

Good luck with grand finale!

Property Value

Mass 2.7 kg/unit

Volume Cylinder diameter 263 mm, height 267 mm

Mass range 10-16 to 10-6 g

Speed range 5 to 100 km/s (< 10 %)

FOV 90 deg. cone

Arrival direction < 10 deg.

Mass resolution M/∆M > 150

Charge > 10-16 C

Flyby Observation of 3200 Phaethon

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FOV of Multiband Camera- 18.9 deg. x 14.2 deg.- Fixed at 40 deg. (T.B.D.) from +Z axis

FOV of Dust Analyzer- 90 deg. cone-shaped

FOV of Telescopic Camera- 1.1 deg. x 0.82 deg.- Track Phaethon with a rotating mirror

Time Distance Event

-7.3 h 860000 km Start observing light curve

-65 m 125000 km Detect Phaethon

-55 m 105000 km Attitude correction

-35 m 65400 km Start tracking Phaethon with mirror of telescopic camera

-8.7 m 17000 km Start observation with telescopic camera

-21.5 s 868 km Start observation with multiband camera

0 s 500 km Closest point to Phaethon

XY

Z

Telescopic Camera

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Telescopic CAmera for Phaethon (TCAP)

Property Value

Mass 15.8 kg

Volume 230 x 200 x 1000 mm

Effective aperture 110 mm

Focal length 950 mm

Viewing angle 1.1 deg. x 0.82 deg.

Sensor type CCD

Number of pixels 3296 x 2472

Pixel size 5.5 µm x 5.5 µm

Angular resolution 5.8 µrad/pix

Spatial resolution 11.6 µrad (MTF > 0.3)

Tracking function Yes (rotating mirror)

Field of view

Multiband Camera

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Multiband CAmera for Phaethon (MCAP)

Property Value

Mass 3.5 kg

Volume 150 x 150 x 200 mm

Effective aperture 21.15 mm

Focal length 55 mm

Viewing angle 18.9 deg. x 14.2 deg.

Sensor type CCD

Number of pixels 3296 x 2472

Pixel size 5.5 µm x 5.5 µm

Angular resolution 0.1 mrad/pix

Spatial resolution 0.2 mrad (MTF > 0.1)

Wavelength bands 390, 550, 700, 850 nm

Tracking function No (fixed at 40 deg. from +Z axis)

Summary• JAXA is developing DESTINY+, a technology demonstrator for future low-cost

deep space explorations, which will explore small body 3200 Phaethon, aiming at a launch in 2022.

• After launch into a highly elliptical orbit around the Earth by the Epsilon rocket, DESTINY+ raises its orbit using ion thrusters over one or two years, then transfers to an interplanetary orbit by lunar swing-by.

• Demonstration of light-weight solar array paddles and advanced thermal control devices, which are essential for operation of ion thrusters.

• Scientific objective of DESTINY+ is to understand origin and nature of dusts, key sources of organic matter to Earth.

• During the cruise phase, DESTINY+ will observe interplanetary and interstellar dusts with a dust analyzer developed by Stuttgart University.

• During the high-speed flyby of 3200 Phaethon, DESTINY+ will observe the surface with a telescopic and a multiband cameras.

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