Solar OrbiterExploring the Sun-heliosphere connection

Science questionsMission overview

Status update

The Sun creates the heliosphere

Why study the Sun-space connection?

• Addresses ESA’s Cosmic Vision question “How does the solar system work?”

• Study plasma phenomena which occur throughout the Universe– Shocks, particle acceleration, magnetic reconnection,

turbulence, etc.– Also addresses Cosmic Vision question “What are the

fundamental physical laws of the Universe?”• Solar wind and energetic particles directly affect life on Earth– Impact on space and ground-based assets

• Builds on European heritage: Ulysses and SoHO

The need for near-Sun observations

Solar Orbiter

In-situ density

Solar Orbiter

Days

1 2 3 4 5 6

Distance

How and where do the solar wind plasma and magnetic field originate in the corona?• Solar wind is

variable and structured

• Originates in complex magnetic “carpet”

• Small scale transient jets are common

polar coronal hole coronal funnel

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• Solar Orbiter will measure the spatial and temporal variability of the solar source and solar wind in unprecedented detail

Linking Sun and the solar wind

• We need to measure the same parameter on the Sun and in space to make the link– Heavy ion charge states and

composition– Magnetic polarity– Energetic particles

• Solar Orbiter will make all of these measurements with both remote sensing and in situ instruments

He+

H+

How do solar transients drive heliospheric variability?• How are substructures

of coronal mass ejections related to interplanetary transients?

• How are CMEs processed as they travel from the Sun?

• Solar Orbiter will image CMEs and measure their evolution in the inner heliosphere

Coronal mass ejections in space

How do solar eruptions produce energetic particle radiation?• Around 10% of coronal

mass ejection energy is in accelerated particles

• Understanding release and transport mechanisms requires going close to the Sun

• Solar Orbiter will measure energetic particles within a mean free path of their acceleration site

0.3 AU

1.0 AU

How does the solar dynamo work?

• The unexplored poles are central to the operation of the Sun’s dynamo

• Solar Orbiter will provide the first accurate measurements of polar flows and magnetic fields

The Sun has changed

What is required

• Close to the Sun• Out of the ecliptic• Long duration observations of the same region• Remote measurements of the Sun and corona• In situ measurements of fields and particles

• It is this unique combination provided by Solar Orbiter that makes it possible to address the question of how the Sun creates and controls the heliosphere

SummaryCarefully optimised payload of ten remote sensing and in situ instrumentsLaunch: January 2017Cruise Phase: 3 yearsNominal Mission: 3.5 yearsExtended Mission: 2.5 yearsPerihelion: 0.28 – 0.3 AUFast perihelion motion: solar features visible for almost complete rotationOut of ecliptic: first good view of solar poles

Mission profile

Solar Orbiter spacecraft

• Three-axis stabilised, Sun pointing• Heatshield at front• Re-use of BepiColombo

unit designs as practical• Mass: 1750kg• Power: 1100W• Launch: ELV

In situ instrumentsSWA Solar wind analyser Chris Owen, UK Sampling protons, electrons and heavy ions in

the solar wind

EPD Energetic particle detector Javier Rodriguez-Pacheco, Spain

Measuring timing and distribution functions of accelerated energetic particles

MAG Magnetometer Tim Horbury, UK High-precision measurements of the heliospheric magnetic field

RPW Radio and plasma wave analyser

Milan Maksimovic, France

Studying local electromagnetic and electrostatic waves and solar radio bursts

Remote sensing instrumentsPHI Polarimetric and

heliospheric imagerSami Solanki, Germany

Full-disc and high-resolution visible light imaging of the Sun

EUI Extreme ultraviolet imager Pierre Rochus, Belgium

Studying fine-scale processes and large-scale eruptions

STIX Spectrometer/telescope for imaging X-rays

Arnold Benz, Switzerland

Studying hot plasmas and accelerated electrons

METIS Multi-element telescope for imaging and spectroscopy

Ester Antonucci, Italy High-resolution UV and extreme UV coronagraphy

SoloHI Solar Orbiter heliospheric imager

Russ Howard, US Observing light scattered by the solar wind over a wide field of view

SPICE Spectral imaging of the coronal environment

Facility instrument, ESA provided

Spectroscopy on the solar disc and corona

SPICE and SIS

• ESA tasked external review committee to study scientific impact of NASA decision not to support SPICE and SIS

• Committee urged ESA to investigate ways to recover measurement capabilities of SIS and SPICE

SPICE – UV imaging spectrograph

• Returns 2D high resolution spectral images– Intensity, Doppler shift, line width– Complete temperature coverage from

chromosphere to flaring corona• Provides remote characterisation of

plasma properties near the Sun

• Map outflow velocities and composition of surface features to solar wind structures

SPICE - status

• Proposal exists for provision of SPICE instrument

• Retains Red Book capabilities– Full on disk capabilities– Off-limb up to 1.3 solar radii– METIS augments this with off-limb spectroscopy beyond

1.3 solar radii

• All mission science goals achieved

SIS – Supra-thermal ion spectrograph

• Measures supra-thermal heavy ions

• Part of EPD suite• Covers energy range

between solar wind and energetic particles

• Explores near-Sun ion pool, plus flares and shocks

SIS - status

• Proposal exists for provision of SIS instrument

• Retains Red Book capability

• All mission science goals achieved

Perihelion remote sensing

High-latitude remote sensing

High-latitude remote sensing

Science windows• Orbit: 150-168 days• In situ instruments on at all times• Three science “windows” of 10 days

each• All remote sensing instruments

operational• Observing strategies based on science

targets– Active regions, coronal hole

boundaries, flares, high speed wind, polar structures

• Autonomous burst mode triggers for unpredictable events

• Telemetry and mass memory tailored to return planned instrument data volumes

Links to Solar Probe Plus

• Many conjunctions will occur between Solar Orbiter and Solar Probe Plus– Extends science

return from both msisions

• Solar Probe Plus is not required for any Solar Orbiter science goal

Solar Orbiter

• Answers the Cosmic Vision question “How does the solar system work?”

• Unique combination of orbit and instruments• Selected payload is optimised answer the most fundamental

questions of solar and heliospheric physics• Timely, mature and well studied mission with compelling

scientific objectives