JAXA’s Exploration of the
Solar System Beyond the
Moon and Mars
2015
2025
地球の今を知る。
(a) 月が教える地球の進化
(b) 太陽が支配する地球環境
(c) 金星・水星・火星、姉妹惑星の素顔
(d) 近傍小惑星、地球の原材料を探す
PHASE 1
太陽系探査
—宇宙からの全太陽系史— 生命を育む環境の解明
太陽系の生い立ちを知る。
(a) 太陽と地球がたどる未来
(b) 火星、金星、地球になれなかった訳
(c) 木星、太陽系最大の惑星の素顔
(d) 原始小惑星・彗星、生命の原材料を
PHASE 3
PHASE 2
生命惑星の存在理由を知る。
(a) 恒星太陽と地球、その未来
(b) 生命を育む「惑星系」の条件
(c) 更なる未踏域、太陽系全域への到達
(d) 宇宙における太陽系、その普遍性
2025年の宇宙観測・太陽系探査
太陽系全域への到達
彗星、メインベルト小惑星サンプルリターン
木星に到達、極周回、詳細探査
金星気球、火星飛行機実現、惑星気候の解明
宇宙の果ての観測
最初の銀河と最初のブラックホールの発見
第２の地球発見
重力波望遠鏡立ち上げ
Planet-C mission to Venus
2010 Launch- Arrival
Science themes of the Venus mission
• Atmospheric dynamics
 Super-rotation
 Meridional circulation
 Meso-scale processes
• Lightning
• Cloud physics
• Detection of active volcanism
Venus wind system
Images from different altitude
UV
Lower
stratosphere
Near-Infrared
Mid-Infrared
Upper
troposphere
Cloud Top
VEX(ESA) & Planet-C(JAXA)
• Optimization: Spectroscopy ⇔ Imaging
• Orbit:
Polar ⇔ Equatorial
• Global images:High latitudes ⇔ Low latitudes
BepiColombo
Mercury Magnetospheric Orbiter
H. Yamakawa, H. Ogawa, H. Hayakawa, Y. Kasaba, T. Mukai
and Mercury Exploration Working Group
C. Noshi/RASC, Kyoto Univ.
MMO
MPO
Schedule
2012.mid
Launch
Mercury Magnetospheric Orbiter
BepiColombo: Two Orbiters
MPO (Mercury Planetary Orbiter)
３-
axial
MPO
～Low-altitude polar orbit: for Surface & Interior observations～
Study of the planetary formation near the Sun
Camera: Surface geology
IR/UV/X/Gamma/neutron spectrometer: Compositon
Magnetometer: Internal & Magnetospheric magnetic field
Precise orbit determination: Gravitational field, Relativity
etc.
MMO (Mercury Magnetospheric Orbiter)
Spin
～Elliptical polar orbit: for Magnetosphere & Exopsphere～
First comparative study of
the planetary magnetic field and Magnetosphere
Magnetometer: Internal & Magnetospheric magnetic
field
Plasma particle, Electric field, Plasma waves:
Magnetosphere - Structure, Dynamics, enegetic
processes
Energetic neutrals: Sputtered particles from Surface
Mercury Planetary Orbiter
MMO
Mercury Magnetospheric Orbiter
C. Noshi/RASC, Kyoto Univ.
MMO: Configuration & Target
Mercury will provide a unique chance of
the Creation of comparative study of
Magnetic Field & Magnetosphere
of the terrestrial planets with internal B-field.
MMO (Mercury Magnetospheric Orbiter)
Spin
～for Global coverage of Magnetosphere & Exosphere～
Full-comparative study of
the planetary magnetic field and magnetosphere
[Model Payload]
Magnetometer: Internal & Magnetospheric magnetic field
Plasma particle, Electric field, Plasma waves:
Magnetosphere - Structure, Dynamics, energetic
processes
Energetic neutrals: Sputtered particles from Surface
Na imager: Exosphere – Structure & Variation
MMO
Mercury Magnetospheric Orbiter
C. Noshi/RASC, Kyoto Univ.
Science: Magnetic field & Magnetosphere [MMO
Origin & Structure of Magnetic Field
Why do planets have magnetic field? Mercury provides
the first chance to compare the magnetic field with
Earth.
Magnetosphere: Similar or Different ?
Mercury’s special Magnetosphere without Ionosphere
will provide the another view of the planetary
Magnetosphere.
○ Magnetic field: Why does Mercury have?
→ Precise measurement of magnetic field structure
enables the structure & origin of the internal fields.
○ Magnetosphere: No ionosphere & Different scales
→ Detailed structure/dynamics/energetic process show
what is general / special in Magnetosphere physics.
○ Exosphere: Highly variability
→ Observations of structure & variations of Na
Exosphere
enable its generation/loss & origins.
○ Inter planetary space in the most inner solar system
→ Highest Mach number shocks (~40) which are only
directly observed around the Mercury.
Discovery of magnetic field by
Mariner10
Internal magnetic field describes the
internal structure & its evolution
?
Model of Magnetosphere /
Exophere
Magnetosphere different from the Earth
pgenerates the comparative study of
the planetary Magnetosphere.
Science: Interior / Surface [MPO]
History of Inner Solar System
Magnetic field is connected to the peculier inner
structure of Mercury, its large core.
Mercury’s high density and composition tell us the
initial stage of the planetary formation at the
innermost region of Solar system.
Red: Commitment from Japanese
scientists are planned.
○ Origin of peculier Composition
→ IR-Visible-UV spectroscopy、X/γ/neutron detection,
and Neutrals/Plasmas from Surface provides
keys for the origin of Mercury.
Surface taken by Mariner10
Opposite side is unknown.
○ Origin of peculier Large core
→ Combination of Gravitational field & magnetic field
mapping provides the detailed inner structure.
○ Detection of Polar Ice
→ γ/neutron observation will provide its proof.
○ Geology of old Surfaces
→ High-resolution imaging covering all area provides
the
Radius-Density relation
Mercury is not on the trend.

水冷サーマルセンサ（高出力・平均パワー測定）