1. Solar Orbiter – Mission Update ESA’s Solar Encounter and High Latitude Mission

2. Solar Orbiter – Mission Update What’s happening?  July 2000 – Formal proposal to ESA  Sept 2000 – Presentation to ESA committees, by Marsch & Harrison  Selected! October 2000  ESA reassessed science programme Autumn 2003 – survived!  Last meeting - reported AO late 05/early 06, Launch 2013? Since then launch seemed to move quietly to 2015…  BUT… ESA Science Programme in difficulties. Orbiter is vulnerable as the last mission in the schedule  SPC met Feb 2006. SSAC suggestion - move Orbiter to 2017 - part of a package to complete approved missions. Support from nations for Orbiter, in particular for 2015 launch. Formal SPC report?

3. Solar Orbiter – Mission Update What’s happening?  May 2006? – Next SPC meeting – Not in the clear yet!  Internal meeting at ESTEC this week to discuss 2015 launch  Anticipate request for letters of intent later this year  AO next year?  October 16-20 2006 – Athens, Greece – 2 nd Solar Orbiter Workshop – See handout  Adv. Space Research 36, 2005, 1415 – EUS concept paper from Paris COSPAR Orbiter session

4. Solar Orbiter – Mission Update Industrial Studies Orbit : Basic idea of solar orbits achieving high heliographic latitudes (up to 38°) with perihelion ~0.2 AU, and co-rotation phases, has not changed Launch: Was 2013 or 2015? ; windows every ~ 19 months; Soyuz-Fregat from Baikonur baselined. Pressure for 2017, but 2015 not dead yet! Later than 2017 hits solar max in high latitude phase Spacecraft: 3-axis stabilised, Sun-pointed. Original plan: SEP benefits from BepiColombo; Now ballistic options baselined. 1296 kg lift-off mass Mission duration: Original plan: Cruise phase ~1.9 years (3 orbits); nominal mission ~2.9 years (7 orbits); extended mission ~2.3 years (6 orbits). Ballistic options not much longer – details depend on date Payload resources: Was 130 kg, 127 W, 74.5 kbit/s. Ballistic option allows more payload mass (removes SEP overhead)

5. Solar Orbiter – Mission Update Industrial Studies Astrium and Alcatel led studies on spacecraft and flight options. Periodic reports to ESTEC – attended by PWG chairs as community reps. Strawman instrument studies well developed and providing input to industrial studies. Done through PDD. Next version of PDD due now – in theory is final input before AO (forms part of AO documentation)

6. Solar Orbiter – Mission Update Strawman Payload InstrumentMass kg Power W Rate kbps Plasma Package (SWA)15.51114 Fields Package (MAG +RPW + CRS)11135.8 Particles Package (incl. Neutrons,gammas & dust) 15 4.5 Visible Light Imager & Magnetograph (VIM)302520 EU Imager (3 telescopes incl. FSI)302520 EU Spectrometer25 17 Spectrometer/Telescope Imaging X-rays (STIX) 4 40.2 Coronagraph (COR)10 7 Total140.512888.5

7. Solar Orbiter – Mission Update The need for an EUV Spectrometer  Solar EUV spectrometer – to identify & analyse emission lines from trace elements in the solar atmosphere, providing plasma diagnostic information for many applications – it is a general purpose solar plasma diagnostic tool!  Builds on the highly successful solar UV/EUV experience of the team (CDS, SUMER, EIS, CHASE, SERTS, EUNIS, etc…) CDS observation of twisted flows in a loop

8. Solar Orbiter – Mission Update  This is the best we can do now: EUV imaging with 0.5” (350 km) pixels and EUV spectroscopy with 2” pixels.  We know that the solar atmosphere is composed of fine- scale structures/phenomena and must aim to develop appropriate tools.  Our target is spectroscopy at ~150 km (1” at 0.2 AU, 0.2” at 1 AU). The need for an EUV Spectrometer

9. Solar Orbiter – Mission Update Instrument Requirements  Wavelengths – lines from chromosphere, transition region & corona is a major driver.  Pointing – payload bolted together, common pointing JOP approach.  Spacecraft limitations - <1 m class instruments, <30 kg  Extreme thermal and particle environments  Autonomy – during solar passes

10. Solar Orbiter – Mission Update EUS Consortium  Consortium has met five times – in 2001-2004, and dedicated wavelength meeting in 2003  Consortium Web site - http://www.orbiter.rl.ac.uk  But - the goal posts keep moving – we have been in limbo due to continually moving AO/launch dates and uncertainty that we even have a mission!  The result: Many good ideas but little need to force decisions. In effect, maintained instrument concepts with occasional bursts of activity.  In parallel, played full part in PWG/ESTEC activities and the Payload Definition Document

11. Solar Orbiter – Mission Update EUS Consortium  Baseline - Off-axis NI spectrometer with VLS grating and APS detector system. GI option still open.

12. Solar Orbiter – Mission Update EUS Consortium - Progress  APS detectors – 4k x 3k 5 micron back-thinned array developed and tested - Nick  Trade-off optical study – Kevin, Luca, Roger – including possible NI option with all three bands  EUS VLS grating ready to fly on EUNIS – Roger/Joe  Progress in thermal, mechanical, throughput analysis  Consortium responsibilities/contributions – all groups have stated possibilities

13. Solar Orbiter – Mission Update EUS Consortium – Burning Issues?  Wavelength Selection  Can we have all three in one instrument? Are the solar people asking too much?  There are excellent arguments for all bands and groups who are only interested in the instrument if certain bands are included – we have kept all options open to date!  Decision time! – Can we find a design that can do this for us with the required optical performance? If ‘no’ – we have to choose.  If this is the NI approach, are we happy that the multilayer coatings will work in the extreme conditions?  If we are looking to detect all three bands we are almost certainly looking at both filter/backthinned APS detectors and another option (e.g. MCP/APS) for the long wavelength band. What does this do for mass/power?

14. Solar Orbiter – Mission Update EUS Consortium – Burning Issues?  NI vs GI Selection  Can we show that the NI (or even the GI) design can cope with the thermal load?  If ‘yes’ – and if the shorter wavelength can be catered for - do we forge ahead with the NI baseline as top priority?

15. Solar Orbiter – Mission Update EUS Consortium – Burning Issues?  Detectors  Can we decide on a baseline wavelength band selection and assess the impact on detector requirements – i.e. long wavelength option (MCP/APS?), short/mid wavelength options (APS backthinned/filter)  Given all of the above – can we see a viable thermal/mechanical/optical approach?  Given all of the above – can we define the consortium responsibilities?

16. Solar Orbiter – Mission Update EUS Consortium – Responsibilities?  Detectors  Can we decide on a baseline wavelength band selection and assess the impact on detector requirements – i.e. long wavelength option (MCP/APS?), short/mid wavelength options (APS backthinned/filter)  Given all of the above – can we see a viable thermal/mechanical/optical approach? Or at least a path to get there!  Given all of the above – can we define the consortium responsibilities?

17. Solar Orbiter – EUV Spectrometer (EUS) Consortium Responsibilities – ‘Wish list’: PI institute/Project Management/Systems EngineeringRAL Electronics (CDHS)MSSL/RAL/MPI/SWRI Power supply (EPS)MSSL/MPI/SWRI Mechanism drive electronicsNRL/SWRI DetectorsRAL/MPI Primary mirror procurementPadua/MPI/IAS/NRL Grating procurementGSFC/Padua/IAS/NRL/SWRI Mirror scanning systemNRL/Padua/RAL/SWRI Slit change mechanismNRL/RAL/Padua SlitsGSFC/NRL Optical designRAL/Padua/GSFC Stray light analysis/designRAL Structure design and procurementRAL

18. Solar Orbiter – EUV Spectrometer (EUS) Consortium Responsibilities – ‘Wish list’: Thermal design and hardwareRAL Cleanliness control and monitoringRAL Grating focus mechanismNRL ShutterNRL AIVRAL EGSE/ground softwareOSLO/GSFC EGSE hardwareMSSL CalibrationRAL/GSFC/PTB Onboard softwareRAL/MSSL FiltersMSSL Door mechanismNRL (Likely to be s/c supplied) Slit Jaw cameraSWRI (Not in baseline design) Other UK CoI teams: Aberystwyth, Armagh, Cambridge, Imperial College, UCLAN etc…

19. Solar Orbiter – EUV Spectrometer (EUS) Consortium Next steps:  This meeting: – decisions/pointers on key issues…  From this: - better definition of consortium responsibilities  Set up regular telecons and visits, and schedule  Expand Web site – documents, drafts, papers