Solar Orbiter – Mission Update Reference launch: Oct 2013 (back-up: May 2015). Baseline mission design retained by both contractors after Mid Term Meeting (direct injection, SEP, 1.5 yr cruise, 3.2 yr nominal science phase, 2.4 yr extended science phase). Back-up mission designs are available but all impact either on cruise phase duration (up to 5 yr) or on total cost and risk. Strong commonality and programmatic link with Bepi Colombo mission is confirmed (e.g. HGA usable down to 0.3 AU from Sun). No technical show-stoppers identified to date. ‘Behind shield’ design is confirmed as most appropriate. Solutions available. Tight management of onboard resources is required (mass, thermal loads, TM link). Overall mission complexity lower than Bepi Colombo. Industrial Assessment Studies – key results

Solar Orbiter – Mission Update Remote Sensing Instruments: Ground rules from Integrated Payload Study -‘1m class’ instruments principle (as instrument size impacts on P/L and spacecraft dimensions  larger mass) -‘0.5 arcsec/pixel imaging/1 arcsec/pixel spectroscopy’ principle (as enhanced resolution implies larger apertures  unacceptable heat loads and again larger mass) -Commensurate focal plane detector size (Max 2k x 2k, as large array size implies large data volume  excessive TM needs) -Co-alignment of all RS units and design harmonisation (e.g. single technology for focal plane detectors) -Resources demands compatible with final PDD values and based on a realistic and thorough estimate. -Keep it simple approach…

Solar Orbiter – Mission Update Payload Definition Document (PDD) Consolidation Meeting – ESTEC Nov 1, 2004 Achieved milestones: -Industrial science payload study - Jan-June Internal ESA CDF study - Mar Parallel competitive industrial studies (Astrium, Alcatel) – KO end of April, Mid Term Review - Sep PDD revision and release of v3 - Sep Draft Technology Development Plan - Oct 2004 Ongoing: -Consolidation of Payload Definition Document -Consolidation of the Technology Development Plan

Solar Orbiter – Mission Update Payload Definition Document (PDD) Consolidation Meeting – ESTEC Nov 1, 2004 General Notes: -PDD Version 4 is the last one before the AO, i.e. it is the one we must get right. Version 3 is not ‘final’. -Final presentation from Industrial Study – Dec at ESTEC. PWG chairs to attend. -AO nominally at end of Early 2006 more likely (especially in light of national funding and NASA situation.

Solar Orbiter – Mission Update Payload Definition Document (PDD) Consolidation Meeting – ESTEC Nov 1, 2004 Technology Development: -PWG requested development/test activities, in particular support for detector development and optical surface/coating environmental (particle and thermal) tests. ESTEC now responding. -Activities identified by ESTEC for remote sensing payload: VIM – Fabry-Perot filter VIM – Polarisation modulation package VIM – Large narrow bandpass entrance filter EUS – Radiator grid entrance filter VIM/EUI/EUS/COR/STIX – Detectors ALL – Data compression ALL – Solar environment test facility.

Solar Orbiter – Mission Update Payload Definition Document (PDD) Consolidation Meeting – ESTEC Nov 1, 2004 Common Detector Needs: Given need from ESA for 1 m instruments, and 1 arcsec spectroscopy (pixel size) & 0.5 arcsec imaging, i.e. 150 km at perihelion for EUS and 75 km for VIM, EUI, is there a common need for detectors of 2 k x 2 k at 10 or 8 micron rather than different values (e.g. the 4 k x 4 k 5 micron detector for EUS is not driven by spatial resolution/instrument length). Does this cater for EUI, EUS, VIM, COR? Consider wavelength requirements, coatings (if any), compatible with MCP if COR needs it? Would it still be possible for EUS to have 5 micron array (for smaller instrument) – risks, optical performance (1 m instrument).

Solar Orbiter – Mission Update Payload Definition Document (PDD) Consolidation Meeting – ESTEC Nov 1, 2004 Data Compression: Seen as critical BUT action is delayed until instruments better defined – beyond initial studies already done through PDD activity.

Solar Orbiter – Mission Update Payload Definition Document (PDD) Consolidation Meeting – ESTEC Nov 1, 2004 Solar Environment Test Facility: Test facility of up to 23 solar constants envisaged by ESTEC team. Definition meeting this Friday at ESTEC. Sized for single instruments. Would not include particle environment, so additional tests would be required. Can this cover the requirements of the PWG? Who organises the test programme?

Solar Orbiter – Mission Update Payload Definition Document (PDD) Consolidation Meeting – ESTEC Nov 1, 2004 EUS Radiator Grid Entrance: EUS studies suggest that the radiator grid entrance filter may add complexity and risk and that it is more elegant to focus on the primary mirror plus the reflector/heat stop as a ‘simple’ approach. Action: Having the filter is not a requirement. We need to show that the latter is OK for ESA to remove the filter option from their Technology Development Activity list. If the primary mirror is the main thermal ‘item’, are we comfortable with SiC – i.e. not worry about the potential degradation of coatings (gold, multilayers). Comment on impact of this on wavelength selection.

Solar Orbiter – Mission Update Payload Definition Document (PDD) Consolidation Meeting – ESTEC Nov 1, 2004 Pointing & Stability: Requirements (note x is in the solar direction): ParameterLine of sight (x)Around line of sight Absolute pointing error< 2 arcmin< 20 arcmin Pointing drift error< 1 arcmin/10 days< 10 arcmin/10 days Relative pointing error< 1 arcsec/10 sec< 2 arcsec/10 sec RPE ‘achieved’0.5 arcsec/10 sec Note: 2 arcmin at 0.2 AU is equivalent to 24 arcsec at 1 AU. Do we need stabilisation systems for a 1 arcsec/pixel spectrometer or a 0.5 arcsec/pixel imager? (EUI PDD was listed as 0.1 arcsec/10 sec when pixel was 0.25 arcsec).

Solar Orbiter – Mission Update Payload Definition Document (PDD) Consolidation Meeting – ESTEC Nov 1, 2004 EUI Issues: Assume 9-10 micron pixels. Aperture: Astrium ‘scale down’ had resulted in 1 cm! Key is instrument size, mass, thermal situation. PDD back at 2 cm but is not a requirement. Mass (kg) Data rate (kb/s) Pixel size (arcsec) Pixel size 0.2AU) ArrayInstrument Size (cm 3 ) PDD# k x 2k180x44x25 PDD# k x 2k95x50x30

Solar Orbiter – Mission Update Payload Definition Document (PDD) Consolidation Meeting – ESTEC Nov 1, 2004 EUS Issues: PDD#1 and 3 assume 5 micron pixels. PDD#3’ assumes 8-10 micron pixels. Mass (kg) Data rate (kb/s) Pixel size (arcsec) Pixel size 0.2AU) ArrayInstrument Size (cm 3 ) PDD# k x 4k160x30x40 PDD# k x 2k80x15x15 PDD#3’ k x 2k96x24x18

Solar Orbiter – EUV Spectrometer (EUS) 4 th Consortium Meeting – November 4, Agenda: 09:30-12:30 Solar Orbiter and EUS Status Richard Harrison/Peter Cargill Report on Imager Plans Louise Harra Scientific IssuesPeter Young Mechanical & Thermal OverviewEric Sawyer, with Doug Griffin, Bryan Shaughnessy. Optical Design Kevin Middleton, Roger Thomas, Luca Poletto, & Clarence Korendyke (EIS/gratings)

Solar Orbiter – EUV Spectrometer (EUS) 4 th Consortium Meeting – November 4, Agenda: 13:30-17:30 Detector Status Nick Waltham (APS), Udo Schuehle (BOLD) Wavelength Selection (Discussion)Chair: Peter Young Consortium Responsibilities (Discussion)Chair: Richard Harrison Schedule to AO (Discussion)Chair: Richard Harrison

Solar Orbiter – EUV Spectrometer (EUS) 4 th Consortium Meeting – November 4, 2004 Schedule to AO: AO End 2005/Early 2006 Proposal draft productionFrom November 2005 Pre-Proposal Consortium Meeting~ September 2005 Detailed design phaseFrom January 2005 ‘Post Feasibility Study’ Consortium MeetingSpring 2005 ‘Feasibility phase’ Two basic design concepts established Optical, Thermal, feasibility/tradeoffs Consolidate (in parallel) wavelengths Define institute responsibilities Hardware Telecons/Meetings??? ESA Industrial Study Input/PDD4December Weekly Local Meetings at RALStarted…