Solar Orbiter – Mission Update

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 – 2nd 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

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 The need for an EUV Spectrometer • 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).

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 Engineering RAL Electronics (CDHS) MSSL/RAL/MPI/SWRI Power supply (EPS) MSSL/MPI/SWRI Mechanism drive electronics NRL/SWRI Detectors RAL/MPI Primary mirror procurement Padua/MPI/IAS/NRL Grating procurement GSFC/Padua/IAS/NRL/SWRI Mirror scanning system NRL/Padua/RAL/SWRI Slit change mechanism NRL/RAL/Padua Slits GSFC/NRL Optical design RAL/Padua/GSFC Stray light analysis/design RAL Structure design and procurement RAL

18. Solar Orbiter – EUV Spectrometer (EUS) Consortium Responsibilities – ‘Wish list’: Thermal design and hardware RAL Cleanliness control and monitoring RAL Grating focus mechanism NRL Shutter NRL AIV RAL EGSE/ground software OSLO/GSFC EGSE hardware MSSL Calibration RAL/GSFC/PTB Onboard software RAL/MSSL Filters MSSL Door mechanism NRL (Likely to be s/c supplied) Slit Jaw camera SWRI (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