JAXA SOLAR-C Mission
http://hinode.nao.ac.jp/SOLAR-C/index_e.html

H. Hara1, JAXA SOLAR-C Working Group
1National Astronomical Observatory of JAPANThe Japanese solar physics community is proposing the next orbiting solar
observatory, SOLAR-C, following Hinode ( SOLAR-B ). Two mission
candidates are under study: PLAN-A and PLAN-B (no priority between thetwo plans at present ). One is going to be proposed to JAXA for a launch in
FY2016 after fundamental studies.

Japanese Orbiting Solar Observatories

1981-1982

PLAN-A: Magnetic/X-ray and helioseismic observations of the polar andequatorial regions of the Sun to diagnose the surface magnetic
activity and the internal flow/magnetic structures from anout-of-ecliptic orbit.
PLAN-B: High-spatial/throughput/cadence observations of the solar
photosphere to corona with largely enhanced spectroscopic
and polarimetric capabilities.

1991-2001

2006-

Mission Description

PLANPLAN-A

Mission Description
Magnetic/X-ray and helioseismic observations to diagnose
the surface magnetic activity and internal flow/magnetic
structures of the Sun from an out-of-ecliptic orbit
Solar polar-region exploration by out-of-ecliptic observations
Launched by JAXA H-IIA rocket

PLANPLAN-B

Maintain 1AU distance for the final orbit

Science Objectives:

Hi-spatial/throughput/cadnece observations of thesolar photosphere to corona with largely enhanced
spectroscopic and polarimetric capabilities
Observations with higher-spatial resolution fortransition region and corona than those in Hinode
Launched by JAXA H-IIA rocket
Sun-synchronous polar orbit or geosynchronous orbit
Chromospheric activity

Science Objectives:

Understand the internal structure of the Sun and the solar dynamo mechanism
Understand the mechanism for high-speed solar wind fromobservations at vantage points for Doppler measurements
Understand the variability of environments (space weather) in inner heliospherewith distance from the plane of the ecliptic

Science payload

Understand the solar chromospheric and coronal heating mechanisms byenhanced spectroscopic diagnostic capability
Understand the plasma dynamics throughout the outer solar atmosphere byhigh-throughput spectroscopic instruments
Understand the acceleration mechanism for fast and slow solar winds

Science Payload

Optical telescope to obtain full-disk magnetogram and Dopplergram
EUV (or X-ray) telescope for detecting coronal dynamics
EUV imaging spectrometer for understanding the fast solar wind mechanism
Solar irradiance monitor to understand the latitudinal contribution for TSI
Auxiliary: heliospheric imaging and in-situ measurements
Payload total mass: 100-140 kg (TBD)

Key Technology

Photosphric magnetic field Coronal activity

Near-IR-Visible-UV telescope with enhanced spectroscopic capability forchromsphere
X-ray/EUV telescope with the highest-spatial resolution ever achieved
EUV imaging spectrometer with enhanced throughput and imaging quality

Key TechnologyDiffraction limited telescope; heritage from HinodeHigh-thrust and long-life ion engine[ JAXA has a heritage of ion engine in Hayabusa mission. ]Image stabilization technique for all telescopes and S/C; heritage from Hinode
Stringent contamination control

High power (~5kW) system for ion engines
High-data rates interplanetary telemetry

Solar wind

Polar |B| field

High-data rates telemetry for continuous high-cadence observations

Filling lack of knowledge in polar regions

Candidate lines for Spectro-polarimetry

Orbit control methodology& max. polar visibility

Internal rotation

Polar view of |B|

SEP: solar electric propulsion
SEP1: no swing-by used, SEP2: Earth gravity assist used.

Deep survey at tachocline

Working Group Activity- SOLAR-C Science Definition Meeting held at JAXA/ISAS in Nov 2008
Many contributions were given from European and US scientists.
The next meeting is going to be held in early 2010.

SEP1 orbit

Conditions not finalized

SEP2 orbit- Sub-Working Group Activity
Five sub-WGs were organized to accelerate the studies on science cases andtechnical feasibility for preparing the best mission proposal. In the sub-WG
activity there are contributions from European and US scientists/engineers.

F.Y.
2007:

Provisional Schedule

SOLAR-C WG proposal
WG established2008-2009: Feasibility study
2010:
Submit mission proposal
2011:
Phase A
2012-2014: PM and FM
2015:
S/C tests
2016:
Launch