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Solar Power Sail - Hybrid Propulsion and its Applications

- A Jovian Orbiter and Trojan Asteroid Flybys

Jun’ichiro Kawaguchi, JSPEC, ISAS/JAXA 　

ISSS 2010

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A Solar Power Sail Mission proposed at JAXA

A Proposal from the Solar Power Sail Working Group (WG) at JSPEC, ISAS/JAXA.

A Conceptual Study is summarized here.

The Mission aims at Technology Demonstration of A Combined Solar Electric/Photon Powered Sail to Jupiter for Science Mission.

This briefly introduces the Ikaros demonstration flight.

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What’s new in ‘Solar Power Sail to Jupiter’ Proposal

1. World’s First Solar Powered Jovian Explorer, but Juno.

2. World’s First Combined Jovian Orbiter / Flyby Mission,

3. World’s Highest Performance Ion Engines,

4. World’s First Photon/Electric Hybrid Sail Propulsion,

5. World’s First Background Emission Mapping,

6. World’s First Access & Rendezvous to Trojan Asteroids,

7. World’s First Formation Flight in Jovian Magnetosphere. (TBD)

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1. Sooner or later, Nuclear Propulsion represented by Fission / Fusion Reactors will prevail for Large and Heavy Interplanetary Transportation in 21st century.

2. However, Nuclear Propulsion weighs heavy and not efficient for smaller spacecraft, and Solar powered electric propulsion continues to be sought for the time being.

3. Contemporary Ion Engines performance characterized in terms of specific impulse will shift for higher region dramatically. Ultra-High specific impulse era does come.

4. Pure Solar Photon propulsion is useless for rendezvous and orbiter missions and the applications will be confined to smaller flyby probes.

5. This Prospect infers : Solar powered high-specific-impulse Ion Engines combined with Solar photon propulsion will be utilized for medium-to-smaller missions in near future. (Hybrid Propulsion)

A Prospect for Solar Sail Technology Utilization

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Comparison : Proposed Solar Power Sail and Ulysses

Ulysses:

Mass: 370 kg, Powered by: RTG,

Launched by STS-41 with Double Upper Stage (1990),

Trajectory : ballistic.

Proposed Solar Power Sail:

Mass: 650 kg including a Jovian Orbiter, Powered by Thin Film Solar Cells, Launched by Expendable Smaller ELVs,

Trajectory : Hybrid Combined SEP (Solar Electric Propulsion) with Photon

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Solar Power Hybrid Sail Approaching to Jupiter

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Major Technology Demonstration Itmes

1. A Large Membrane Space Structure including Deployment strategy,

2. A Hybrid Propulsion using both Photon and High Performance Ion Engines,

3. Thin Film Solar Cells,4. Reaction Control System (Jet) functioning at

very Low Temperature, 5. An Integrated Propulsion/Power System

using Fuel Cells.6. Formation Flight in Jovian system, (TBD)7. Electric Delta-VEGA technique departing for

outer solar system,8. Ultra Stable Oscillator for 1-way range or

VLBI orbit determination,9. Ka-band for Interplanetary Missions,10. Radiation-Resistant Technology for Jovian

Orbiter,

* Ultra High Speed Entry Probe for Jovian Atmosphere. (optional)

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Thin Film Solar Cells and Large Membrane Space Structure

• Developing Thin Film Solar Cells leads NOT ONLY to solar powered planetary missions BUT to a new space era represented by Solar Power Satellites etc.

• The use of Thin Film Solar Cells should be used NOT for a mere demonstration, BUT for a real and essential space science.

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Future Solar System Voyage Deep Space Port, Infrastructures

(Outline) Deep Space Port built at L2, and Earth-to-Planetary Reusable Transportation System

(Strategy) 　 Large Spaceships are never launched from ground. Propulsion will be driven by nuclear power. Completely Reusable spaceships will be operated in future.

(Prospect) 　 Flight/Voyage will fly through Relay Port (Deep Space Port) Multi-objective On-orbit Stations are constructed. The traffic infrastructure will include commuter craft between gravity-well to the Port.

Example: Round-Trip to Jupiter

0

2

4

6

8

-6 -4 -2 0 2 4 108 (km)

Earth

Sail

Jupiter

108 (km)

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Evolution of Solar Power Sail・ Solar Power Sail combines photon propulsion with electric propulsion by taking the advantage of thin film solar cells technology, which optimizes highly efficient delta-V-fuel characterized by the solar photon sail through higher thrust nature to accomplish the missions within admissible period.

Thin Film Solar Cells

Thin Film Solar Sail

Ikaros Jupiter and Trojan Asteroids Explorer

Film Cells

Solar Sail

Jovian Probe Trojan Asteroids Explorer

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Preparing for the Real Mission• Detail the Science Requirements for both Cruise, Jupiter and Trojan

Sciences.• System Design

– Satisfying the science requirements,– Enhancing payload capability.

• Elemental Studies at the Working Group

• Schedule– WG Studies until 2011,– Pre-Project Activity from 2011 to 2013– PM(EM) Design & Fabrication, TTM/MTM: 2013~2015– FM Design and Fabrication: 2016~2017– FM IVV: 2018~2019

– Launch: 2019~2020– Cruise Science: 2020~ （ beyond main belt asteroids in 2025

～）– Arrival at Jupiter & Orbiter Measurements : 2026~28– Rendezvous with Trojan Asteroids : 2030.

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Typical Transfer

Sequence

-4 108

-2 108

0

2 108

4 108

6 108

8 108

-1 109 -8 108 -6 108 -4 108 -2 108 0 2 108

Earth-Jupiter 14-17 Outbound (Inertia)

10/27, '14 DepartureV_inf=9.14 km/s

Earth

E Sail Craft

Jupiter

3/27, '17 ArrivalV_inf=5.9 km/s

Launch

1st SW 5.4km/s

Double EDVEGA

Single EDVEGA

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Trajectory Examples

-6 108

-4 108

-2 108

0

2 108

4 108

6 108

-4 108 -2 108 0 2 108 4 108 6 108 8 108

Earth to Jupiter

Departure Earth 5/13/2021

Jupiter

Jupiter Swingby & JOI10/22/2023

Sun

Launch→Single EDVEGA→Jupiter Swingby

Cruise Observation

Beyond Main Belt Asteroids

　　　　

　　

-1 109

-5 108

0

5 108

1 109

-1 109 -5 108 0 5 108 1 109

Jupiter to Achilles

Sun

Jupiter Swingby 10/22/2023

Achilles Rendezvous 10/8/2028

Jupiter

Achilles at L4

Jupiter →Trojan asteroid rendezvous

Trojan Asteroids

　　

　　

Cruise Observation

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Jupiter and Trojan Asteroids Explorer

Mother Spacecraft Wet@Launch Flight Time Payload Xe for EP Fuel for BP Membrane Area ThinFilm Cell Net Bus(kg) (year) (kg) (kg) (kg) (kg) [m2] (kg) [m2] (kg)

Double EDVEGA H- IIA 204 4S*1 3600 11 116.4 756.0 499.0 166.2 590.8 211.8Single EDVEGA H- IIA 204 4S*1 2150 9.5 202.7 344.0 227.0 99.2 352.8 163.7Direct H- IIA 204 4S*1 1040 7.5 112.4 124.8 82.4 48.0 170.7 113.8

Mother spacecraft (Trojan Rendezvous and Cruising Observation)

J ovian Orbiter Payload BP Fuel*3 Film Cell*4 Net Bus Science Payload(kg) (kg) (kg) (kg) (kg)

Double EDVEGA H- IIA 204 4S*1 116.4 48.9 10 8.6 17.4Single EDVEGA H- IIA 204 4S*1 202.7 85.1 10 11.3 45.9Direct H- IIA 204 4S*1 112.4 47.2 10 8.4 16.1

Jovian Orbiter (Magnetosphere Measurement)

• Mission Scenario– Single EDVEGA Strategy ： to assure ample science payload– By 4.5 years flight, the mother spacecraft jettisons the Jovian orbiter,

which independently decelerates the orbital speed to stay around the Jupiter for scientific observation.

– The mother spacecraft leaves the Jupiter for the Trojan Asteroids by 5 years flight.

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Solar Power Sail (COSPAR04-A-01655, Paris, 2004 )

• Hybrid Propulsion combining Electric Propulsion with Photon Propulsion

• Deploying Large Membrane including Thin Film Solar Cell, spanned by Centrifugal Forece

• Rotor / Stator SpacecraftJupiter Entry Probe (option)

Jovian Orbiter

Spacecraft Hub

Cable to Petals

Ion Engines Tables Damper

Sail Drum

HGA

Aux. Solar Cell

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System Block Diagram

HGA

XTWT-ATRX-A

DHU

SA SA

SA SA

DRV

IPPU× 3

STT

CSAS× 5

ACM

ONC-AE

RCS × 12

ﾄ ﾗ゙ﾑ

Filter Wheeｌ

ｶ ﾝ゙ﾏﾃ ｨ゙ﾃｸﾀ

-赤外ﾃﾚｽｺ ﾌﾟ

ﾀ ｽ゙ ﾄｶｳﾝﾀ

MDP

PIM

DDE

HTR

EPT-SAPYRO

to COM COMPONENS

Obiter

SEP or CUT

from to PCD

PCU PCD SSR

BAT

COMPONENS PRIMARY POWER

to IPPU

Sail(SAP)

Sail(SAP)

2-2-2-1 図 探査機システムブロック図 ノミナル案（Ａ案）

PMU

MGA-A

MGA-A APM

MGA-B

MGA-B APM

LGA-A

LGA-B

TRX-B

XDIP-A

ONC-T

ONC-W2

ONC-W1

AOCU

ONC-E

to MGA-A APM

to MGA-B APM

to DATABUS

to ONC-E

DR

PIM

HCEPIM

TCIUPIM

to TCIU

PIM

KaTXKaTWTA

ITH× 4

IES GIMBALS

IES GIMBALS

MPA× 4

XTWT-BXDIP-B

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Jovian Small Orbiter Outline

Spin-Stabilized :

Size : 700mmf in diameter.Operational Temperature : -30degC (243degK) Heater power : 80W assumed.Power required : 150W (no- communication), 250W.(with communication XPA: 20W)Cells Film : 60m2. (~9mf) No Drum Structure required.Ka-band TLM via HGA fixedly mounted.

Routine operation assumes 0.5 hr/day. Heavy duty period is backed up by Fuel Cells aboard.

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-300 -200 -100 0 100 200 300-100

0

100

200

300

400

SUN

(ecliptic plane)

Phase Angle in Approach is 110 degrees.

Orbiter Trajectory (Jupiter-Sun FixedCoordinate)

(Ticks in 10 days)

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Scientific Objectives in Solar Power Sail Mission

1. A Mapping Observation of Background Emission,

2. In-situ Jovian Science : Magnetosphere, Jovian Satellites, Jovian Atmosphere (option)

3. Rendezvous with Trojan Asteroids and Main-belt Asteroids, (Extended Flight Segment)

4. Gamma-Ray Bursts Detectors, (was aboard Ikaros)

5. A Large Area Dust Counter. (was aboard Ikaros)

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m10(Hayabusa Heritage) to m10HIsp(15kV, Isp 10,000sec, 2.5kW)

Technology Development Example–1 Microwave-driven m10 engine to

m10HIsp

0

10

20

30

0 1000 2000 3000

推力

、ｍ

Ｎ

システム投入電力、Ｗ

10

20 10HIsp

MelcoIES

BoeingXIPS13

Astrium/RIT10

T/P:10mN/kWIsp:10,000sec

μ 　１０ μ２０

Astrium/UK10

T/P:30mN/kWIsp:3,000sec

m10HIsp Grid m10 Grid

15kV Acceleration

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Technology Development Example–2 Jupiter Entry Probe - Aerodynamic Heating

Flight Environment Comparison0

100

200

300

400

500

0

100

200

300

400

500

0 50 100 150 200

Gam=4deg

Hea

t Flu

x [M

W/m

2 ]

Altitude[km

]

Time[sec]

Altitude

q_total

q_radq_conv

qc =195 MW/m2

qr =320 MW/m2

Total = 490 MW/m2

HayabusaCapsule

JupiterCapsule

qc max

13 MW/m2 195 MW/m2

qr max 3 MW/m2 320 MW/m2

Qc 235 MJ/m2 9,850 MJ/m2

Qr 21 MJ/m2 12,000 MJ/m2

Ultra-High Heat Flux Environment

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Solar Electric Hybrid Sailor – Roadmap What was attempted at JAXA:

Aug. in 2003Sounding Rocket (S310-34)Dynamic Membrane Deployment (10m)Spinner

Aug. 2006Balloon Experiment on B200-7Quasi-Static Membrane Deployment (20m)Deployment resulted in Success.

Sept. 2006Piggy-back ultra-small satellite on M-V#7Thin Film Solar Power GenerationFilm Deployed. Functioned for 6 hrs using Battery.Resulted in Failure.

Feb. 2006Subpayload on M-V#8Quasi-Static Membrane Deployment (10m)Deployment resulted in Partial Success.

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Sail Deployment Experiment • ISA/JAXA conducted the sail deployment experiment in

space via a sounding rocket via a sounding rocket S-310#34 that carried two types of sails whose diameter is 10m.

S-310#34 Sounding Rocket

Deployed Clover-Type Sail

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Series of Preliminary Experiments

Clover Sail Flight Demonstration via S-310-34 Aug., 2004

Square Sail Deployment Demo. via Balloon Aug., 2006

1st Deoloy 2nd Deoloy

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Membrane Deployment Experiments

Clover Sail （ ISAS ）

Double Accordion Sail (TMIT)

Fundamental Experiments were Repeated.

Membrane deployment is one of the keys in Solar Sails.

Pseudo Logarithmic Sail （ ISAS ）

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How JAXA Sail is characterized?

• It is spanned by Spin, Centrifugal force without use of any spar. Exclusion of spar leads to significant mass reduction.

• There is a drawback in adopting spin for extension. Hard to control huge angular momentum. (But we found a solution for it.)

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Ikaros Background – How it is appropriated?• While we had made a proposal of putting a Solar Power Sail to the

Jupiter, the proposal hardly passed through due to its high technology risks. Agency is always sensitive to the risks.

• The study team (WG) then decided to propose a technology demonstrator to show if the deployment of large membrane is feasible. To this end, the WG proposed a small spacecraft carried by a smaller independent vehicle of JAXA. At that time, the demonstration was sought on Earth orbit. The proposal cost proposed was about $40M excluding the vehicle cost.

• However, the proposal still did not go through, just because the cost is high in view of the risks.

• When Akatsuki (PLANET-C) was decided launched via H-IIA, large payload surplus was identified, and JAXA almost decided to carry a dummy mass on the vehicle.

• I, at that instance, raised my hand to propose a further low-cost solar sail demonstration by taking the advantage of this opportunity. The cost was proposed reduced down to about $20M.

• The development period was just 2.5 years with this small amount of budget. The development was not easy.

• I left the development to the younger generation with my participation as an adviser.

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“Ikaros” : Mission DefinitionThis Mission aims at the following four key targets ．

•Deployment and Expansion of a Large Membrane in space using similar mechanical device and procedures to those in Solar Power Sail craft.

•Obtaining a number of data indicating the expansion status of the membrane.

(1) Deployment of Large Membrane Sail

(2) Collecting Power from Thin Film Solar Cells•Demonstrating Solar Power from Thin Film Solar Cells

•System Verification with the same current as that in Solar Power Sail craft.

(3) Demonstrating Photon Propulsion•Verification of Reflectance as well as Comparison of them with Diffuse & Specular Property.

•Measurement of overall Reflectance with the rigorous relation examination of the temperature and surface status

(4) Demonstrating Guidance, Navigation Control Skills for Solar Sail Propulsion•Navigation / Orbit Determination under continuous and small acceleration

•Acceleration Direction Control via Steering via appropriate attitude control means

Minimum Success Criteria

Full Success Criteria

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Ikaros – Its Mission

IKAROSのミッション

① H-IIA打ち上げ太陽指向・スピン分離

③ ソーラーセイルの展開実験薄膜太陽電池による太陽光発電

④ ソーラーセイルによる加速実証

⑤ ソーラーセイルによる軌道制御・航行技術

② 初期動作チェック

ミニマムサクセス達成（数週間）

フルサクセス達成（半年間）

ミニマムサクセス：大型膜面の展開・展張，薄膜太陽電池による発電

フルサクセス：ソーラーセイルによる加速実証・航行技術の獲得

地球

金星

Earth Minimum Success during several weeks

Full Success during half a year

Venus

1) Launch via HIIA, Sun-Pointing, Spin-Separation

2) Initial Inspection 3) Minimum Success:

Deploying Membrane with Thin Film Solar Cells `Power Generation.

4) Demonstrating Photon Propulsion

5) Trajectory Control Demonstration with Steering capability

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Ikaros flying toward Venus

Launched in May to June of 2010, as an Extra Payload with PLANET-C (Venuc Climate Orbiter) toward Venus on H-IIA.

-2 108

-1.5 108

-1 108

-5 107

0

5 107

1 108

1.5 108

-1.5 108 -1 108 -5 107 0 5 107 1 108 1.5 108 2 108

Venus in '10

xsc

Sun

Venus

Earth

E Departure 6/14/'10

Venus Arrival 12/12/'10

-1.5 108

-1 108

-5 107

0

5 107

0 5 107 1 108 1.5 108 2 108

Venus in '10

xsr

Sun

Venus

Earth

Earth to Venus6/14/'10 -> 12/12/'10

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5rpm 2rpm

25rpm

先端マス分離機構を駆動し，先端マスを4個同時に分離

25rpmまでスピンアップし，相対回転機構（モータ駆動）で膜を保持している回転ガイドを動かし一次展開を開始

先端マス

回転ガイド

スピンダウン

先端マス分離

相対回転機構を動かすと遠心力によって膜面がゆっくりと伸展

一次展開（準静的）展開していくと徐々にスピンレートが小さくなる

ロケット分離

1

5/26（水）

先端マス分離終了

5rpm

6/8（火）一次展開終了

約15m

2rpm

6/10（木）二次展開終了

回転ガイドを展開し，膜の拘束を開放し二次展開開始

膜の拘束が解かれるため動的に展開

二次展開（動的）

約20m

Tip Mass Released

1st Deployment

2nd Deployment

Separated from Vehicle Spin-down Tip Mass

Extraction Guide

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Full Deployment of Ikaros Sail

Sail　Membrane

Tether

Harness

Deployed　Extraction　Guide　Roller

Captured by Camera Aboard Where the Camera is?

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Photon Acceleration was Confirmed.

2nd Deployment

Switching Doppler Measurement

Photon acceleration was legibly confirmed immediately after the 2nd deployment of the sail membrane.

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Diffusion Radiation Effect drifted Attitude Motionas Expected.

Circular shaped attitude motion caused by the Diffusion Radiation Effect was observed as predicted.

Spin-down

Spin-up

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Ikaros Photographed in Space

Tip Mass weighs 0.5kg each.

Dust Particle Sensor (Piezo-electric device)

Tethers

Thin Film Solar Cells (25 micron)

Liquid Crystal Steering Experiment Device

Membrane made of 7.5 micron poly-imide.

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Subsequent Speakers will report on Ikaros Achievements.

1. J. Kawaguchi on General Solar Sail Activity at JAXA,

2. O. Mori on Missions Operation,3. H. Sawada on Sail Deployment Device,4. Y. Shirasawa on Deployment Dynamics,5. R. Funase on Liquid Crystal Reflection Control

Device demonstrated,6. Y. Mimasu on New Steering Law based only on

Spin Rate Control.

* Ikaros Demonstration Team is lead by O. Mori with our colleagues. The Ikaros was also success in nurturing the next generation.

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Summary and RemarksA Solar Power Sail consisting of : Thin-Film Solar Cells in Large Area Membrane

deployment technology taps for a new era.

Baseline : Aiming at demonstrating a new strategy for outer solar system exploration by means of Solar Power, Hybrid propulsion spacecraft, also aims at background emission and Trojan asteroids flybys.

World’s First & First Class Scientific output and Technology demonstration expected.

Ikaros Demonstrator Mission was successfully placed.

We are ready to host joint WSs with International Partners, such as the Planetary Society.