SOLAR ORBITER Solar Orbiter Science Objectives and Status Update

Daniel Mueller ESA [email protected] SOLAR ORBITER Solar Orbiter – The mission to understand how the Sun creates and controls the Heliosphere

• Science Goals • Mission design and payload • Status

LL Ori SOLAR ORBITER Solar corona, wind and magnetic activity → dynamic heliosphere SOLAR ORBITER How does the Sun create and control the Heliosphere – and why does solar activity change with time ? SOLAR ORBITER How does the Sun create and control the Heliosphere – and why does solar activity change with time ?

? SOLAR ORBITER The Mission

• Solar Orbiter is a logical and timely next step after Ulysses and SOHO, combining remote sensing and in-situ experiments.

• Solar Orbiter carries a dedicated payload of 10 selected remote-sensing and in-situ instruments measuring from the photosphere into the solar wind.

SOLAR ORBITER How does the Sun create and control the Heliosphere ?

Q1) How and where do the solar wind plasma and magnetic ﬁeld originate in the corona?

Q2) How do solar transients drive heliospheric variability?

Q3) How do solar eruptions produce energetic particle radiation that ﬁlls the heliosphere?

Q4) How does the solar dynamo work and drive connections between the Sun and the heliosphere? SOLAR ORBITER How does the Sun create and control the Heliosphere ?

Q1) How and where do the solar wind plasma and magnetic ﬁeld originate in the corona?

Q2) How do solar transients drive heliospheric variability?

Q3) How do solar eruptions produce energetic particle radiation that ﬁlls the heliosphere?

Q4) How does the solar dynamo work and drive connections between the Sun and the heliosphere? SOLAR ORBITER Linking in-situ and remote-sensing observations

•Correlation between remote-sensing and in-situ composition measurements is fundamental

SPICE

SWA/HIS SOLAR ORBITER What are the source regions of the solar wind and heliospheric magnetic ﬁeld?

polar coronal hole coronal funnel Tu, Zhou, et al., Marsch Science 2005 SOLAR ORBITER

The Slow Solar Wind

There are multiple sources of slow solar wind – active regions are one source. Identifying the source directly in the wind by the time it gets to 1 AU is extremely challenging and can only be carried out on a statistical basis. Understanding the detailed physical processes can only be achieved by getting closer. SOLAR ORBITER Disentangling Space/Time Structures

…requires viewing a given region for more than an active region growth time (~ 10 days) → implies going closer to the Sun.

www.jhelioviewer.org SOLAR ORBITER How does the Sun create and control the Heliosphere ?

Q1) How and where do the solar wind plasma and magnetic ﬁeld originate in the corona?

Q2) How do solar transients drive heliospheric variability?

Q3) How do solar eruptions produce energetic particle radiation that ﬁlls the heliosphere?

Q4) How does the solar dynamo work and drive connections between the Sun and the heliosphere? SOLAR ORBITER How do CMEs evolve through the corona and inner heliosphere?

Coronal shock SOLAR ORBITER How does the Sun create and control the Heliosphere ?

Q1) How and where do the solar wind plasma and magnetic ﬁeld originate in the corona?

Q2) How do solar transients drive heliospheric variability?

Q3) How do solar eruptions produce energetic particle radiation that ﬁlls the heliosphere?

Q4) How does the solar dynamo work and drive connections between the Sun and the heliosphere? SOLAR ORBITER How and where are energetic particles accelerated at the Sun? SOLAR ORBITER Understanding release and transport mechanisms requires going close to the Sun

Helios 1 / IMP 8: interplanetary scattering → smoothing at 1 AU

Helios 1 / IMP 8. Scattering -> ! smoothing at 1 AU!

Wibberenz & Cane, ApJ 2006 SOLAR ORBITER How does the Sun create and control the Heliosphere ?

Q1) How and where do the solar wind plasma and magnetic ﬁeld originate in the corona?

Q2) How do solar transients drive heliospheric variability?

Q3) How do solar eruptions produce energetic particle radiation that ﬁlls the heliosphere?

Q4) How does the solar dynamo work and drive connections between the Sun and the heliosphere? SOLAR ORBITER How is magnetic ﬂux transported to and reprocessed at high solar latitude?

Solar Orbiter will use local helioseismology to determine the currently unknown properties of the solar interior below the poles. SOLAR ORBITER Need to go out of ecliptic plane to observe polar ﬁelds and ﬂows

Solar Orbiter will characterize the properties and dynamics of the polar regions for the ﬁrst time. SOLAR ORBITER Summary

Faster spacecraft rotation rate

Dynamical reprocessing

105 km <0.3 AU 1 AU SOLAR ORBITER Payload SOLAR ORBITER Status of NASA-funded Payload

On March 7, 2011, ESA received the following communication from NASA HQ (extract):

“Our costs for both the launch vehicle and instrument development for the Solar Orbiter mission have increased signiﬁcantly. The NASA Heliophysics Division's Living With a Star budget has not increased during the same period. Unfortunately, it is necessary to reduce the project content. All investigations will complete the Phase A extensions to their contracts in June 2011, but only two investigations will be funded beyond the June date provided that their proposed content is achievable within our available funding. Unfortunately, the Suprathermal Ion Spectrograph and Spectral Imaging of the Coronal Environment investigations will not be funded beyond the June date.” SOLAR ORBITER Suprathermal Ion Spectrograph (SIS)

• SIS = Detector to measure suprathermal heavy ions • Sensor within Energetic Particle Detector (EPD) Suite • Covers critical energy range between solar wind and multi-MeV energetic particles • SIS will characterize unexplored suprathermal ion pool inside 1 AU, as well as solar ﬂare and shock events with very high mass resolution (m/σm ~ 50)

Fluence measurements at 1 AU using ACE data (from Mewaldt et al. 2001) SOLAR ORBITER SPICE

• SPICE is an Imaging Spectrograph with a movable UV ﬁlter to observe both on the solar disk and out to >3.0 Rs (baseline).

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• Returns 2-D high resolution spectral images !"#"$%&'"(I;J"$(7K9( • Intensity, Doppler shift, line width, FIP, m/q maps 6#2.()$$"*+#,( -"."%.&/()$$"*+#,( 01."1$23"4()56( • Complete temperature coverage from ?";.(-@*'( -"."%.&/$(789( chromosphere to ﬂaring corona

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• SPICE has the unique capability to remotely characterize plasma properties of regions near the Sun to directly compare with in-situ measurements from Solar Orbiter & Solar Probe+ SOLAR ORBITER Next Steps

ESA tasked external review committee

• To analyze the impact of the NASA instrument de-scope on the science return of Solar Orbiter • To assess, if necessary and where possible, proposed mitigation measures to recover the major Solar Orbiter scientiﬁc objectives in the absence of the above payload elements • To recommend, where appropriate, potential ways forward to ensure that the major Solar Orbiter scientiﬁc objectives will be met • To produce a report (by 15 May) for the advisory structure and eventually SPC SOLAR ORBITER Mission Overview

High-latitude Observations Summary Launch Date: January 2017 Cruise Phase: 3 years Nominal Mission: 3.5 years Perihelion Extended Mission: 2.5 years Observations Orbit: 0.28 – 0.30 AU (perihelion) 0.75 - 1.2 AU (aphelion) Out-of-Ecliptic View: Multiple gravity assists with Venus to increase inclination out of the ecliptic to >25° (nominal mission), >33° (extended mission) Reduced relative rotation: Observations of evolving structures on the solar surface & heliosphere for almost a complete solar rotation High-latitude Observations SOLAR ORBITER Mission Proﬁle SOLAR ORBITER 2017 Launch: Solar Latitude and Distance SOLAR ORBITER Observation Modes SOLAR ORBITER Spacecraft Basic Facts

• Three-axis stabilized spacecraft, Sun pointing • Closest Sun encounter 0.28 AU (2017 launch) • Heatshield to protect spacecraft and payload • Overall mass: ~ 1750 kg, Maximum power demand: ~ 1100W • Launch: NASA-provided EELV

• Several swing-bys (Earth and Venus) to crank up solar latitude; launch opportunity every 19 months. • Re-use BepiColombo unit designs or technology SOLAR ORBITER Spacecraft Temperatures SOLAR ORBITER Remote-sensing Instruments SOLAR ORBITER In-situ Instruments SOLAR ORBITER In-situ Boom-mounted Instruments SOLAR ORBITER Technical Baseline

• 3-axis stabilized, sun-pointing spacecraft • X-band telemetry and commanding • Separated mass: up to 1800 kg including all margins • Solar Generator: new design but technology directly inherited from BepiColombo • Require late access, purging until lift-off, high cleanliness • Mission Operations Centre at ESOC (Darmstadt, Germany) • Science Operations Centre at ESAC (Villafranca, Spain) • Nominal ground station: Malargüe, Argentina SOLAR ORBITER Solar Orbiter Development Status

• Bridging phase (B1 Extension) completed. • Consolidation Phase started in February 2011 • The Consolidation Phase will cover the preparation of procurement activities at subsystem level and will be concluded by the selection of the ﬁrst layer of subsystem providers. • Subject to SPC selection in October 2011: Initiation of Implementation Phase currently planned in Q4 2011. • Work progress today compatible with schedule for January 2017 launch. • Technical baseline incorporates progress and evolution during phases B1 and B1x • Overall spacecraft height increased by 200mm • TT&C baseline now 70W X-band only (and signiﬁcant additional ground station usage) instead of 35W+35W X/Ka-band.