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San Diego, SPIE August, 26 th 2007

ASPIICS on PROBA-3 Association de Satellites Pour l’Imagerie et l’Interférométrie de la Couronne Solaire. Sébastien Vives, Philippe Lamy Laboratoire d’Astrophysique de Marseille.

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San Diego, SPIE August, 26 th 2007

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  1. ASPIICS on PROBA-3Association de Satellites Pour l’Imagerie et l’Interférométrie de la Couronne Solaire Sébastien Vives, Philippe Lamy Laboratoire d’Astrophysique de Marseille France: P. Levacher (LAM), M. Marcellin (LAM), S. Koutchmy (IAP), J. Arnaud (LUAN), E. Quemerais (SA), L. Damé (SA), R. Lallement (SA), J. C. Vial (IAS) UK: R. Harrisson (RAL), N.R. Waltham (RAL) Belgium: P. Rochus (CSL), J. M. Defise (CSL), D. Berghmans (ORB), J. F. Hochedez (ORB) Spain: J. Pacheco (ASRG/UAH), J. Blanco (ASRG/UAH) Portugal: J. M. Rebordao (INETI/LAER), D. Maia(INETI/LAER) Switzerland: W. Schmutz (PMOD/WRC), A. Benz (PMOD/WRC) Italy: G. Naletto San Diego, SPIE August, 26th 2007

  2. Proposed scientific Payload for PROBA-3 • The proposed scientific payload for the PROBA-3 mission is composed of: • ASPIICS: Association de Satellite Pour l’Imagerie et l’Interferometrie de la Couronne Solaire • a giant solar coronagraph to observe the middle corona with high spatial resolution and diagnostic (spectral) capability. • ARaSS: New generation Absolute Radiometer and Sun Sensor • ARaSS will contribute to the long-term measurement of the solar constant, and could possibly be operated beyond the nominal lifetime of the FF mission at very little cost. San Diego - SPIE

  3. Ground-based coronagraph: Low spatial resolution and atmospheric noise SOHO/LASCO-C2 R > 2.5 Rsol SOHO/LASCO-C1 High level of straylight and operated at solar minimum only Total solar Eclipses: Ideal but very rare and only a snapshot! Current observational status of the inner corona • After 40 years of space coronagraphy the lower corona (<2.5Rsol) remains practically unobserved • STEREO/COR-1 is also affected by large amounts of stray light and it needs an elaborated image reduction process to reveal bright structures from 1.4 Rsol. San Diego - SPIE

  4. ASPIICS objectives ASPIICS aims at achieving conditions close to total eclipses ASPIICS Field Of View Ground-based coronagraph SOHO/LASCO-C1 coronagraph SOHO/LASCO-C2 coronagraph Ground-based image obtained during a total solar eclipse San Diego - SPIE

  5. Scientific objectives • ASPIICS will offer a unique perspective to study processes occuring above 1.02 Rsun in both W-L and monochromatic ionic emissions. • ASPIICS will allow characterizing the main magnetic, dynamical and thermo-dynamical processes in the inner corona • ASPIICS will adress the following questions: • How is the corona heated? What is the role of waves? • How are the different components of the solar wind, slow and fast, accelerated? • To what degree do coronal inhomogeneities affect the heating and acceleration processes? • How are CMEs accelerated? • What is the nature of the interaction between the CME plasma and the magnetic field that drives the eruption? • What is the configuration of the magnetic field in the corona? San Diego - SPIE

  6. Performances are driven by the distance between the external occulter and the entrance pupil www.esa.int/proba What is ASPIICS ? • 2 S/C separated by 150 m realize a giant coronagraph and will achieve conditions close to a total solar eclipse San Diego - SPIE

  7. Unique Aspects of ASPIICS • Ambitious science objectives • Imaging the inner corona (1.075 - 3 Rsol) at high spatial resolution (<3arcsec/px) • Diagnostics of emission lines (velocity, turbulence, waves) • Topology of the coronal magnetic field • Operating in the visible • 3D spectroscopy of coronal emission lines • Simplicity • Optimum conditions • Drastic reduction of instrumental stray light • NO competitor in the coming 10-15 years San Diego - SPIE

  8. High resolution imaging… San Diego - SPIE

  9. … With unprecedented spatial resolution • White light imaging (540-630nm) • from 1.075 to 3 Rsun • at spatial resolution of 2.8 arcsec/px. Pixel limited Diffraction limited San Diego - SPIE

  10. Methodology: 3D-spectroscopy • Superimpose a system of fringes on the coronal image • Get all the spectral information in one image • Fe XIV: 5303 nm (coronal matter, 1.8x106 K) • Fe X: 637.4 nm (coronal holes, 1.0x106 K) • He I: 587.6 nm (cold matter, 1.0x105 K) • Tilt the F-P to displace the fringe pattern and improve the spatial coverage • Scientific quantities: • Ion densities (from intensities) • Temperatures (line broadening and comparison with W-L) • Velocities (Doppler shifts) • Turbulence (non thermal velocities) San Diego - SPIE

  11. Desai, Chandrasekhar & Angreji, 1981 ASPIICS with a Fabry-Perot (F-P) This solution has already been validated by several eclipse experiments on ground • Coronal interferogram on FeXIV emission line obtained during a total eclipse (Feb. 16th 1980) which has allowed to derive: • Intensity, Doppler shift, line broadening and splitting San Diego - SPIE

  12. Cover (door) L3 L1 L2 Internal occulter Polarizer F-P Detector Shutter Filter Wheel Conceptual Layout • Coronagraphic function: • The L1-objective re-images the occulting disk into the internal occulter to minimize straylight. • Spectro-polarimetric function: • The Fabry-Perot is located at the “Lyot stop” (pupil image) in a collimated beam after L2. • The polarizer is located in a collimated beam after L2. • Imaging function: • The L3-objective re-images the FOV onto a 2048x2048 CCD (15µm) San Diego - SPIE

  13. Optical Layout Entrance Pupil M1 Focal Plane M2 O3 O2 Fabry-Perot Blocking Filters Polarizer M3 Internal Occulter San Diego - SPIE

  14. Thermo-Mechanical Concept CCD radiator • The Coronagraph Optical Box (COB) appears as a parallelepiped in composite panels • The structure is decoupled from the S/C, mechanically and thermally, thanks to titanium bipods. • The thermal concept is based on both passive (MLI blanket) and active control (thermal lines). • The structure supports the CCD detector radiator by insulating spacers. CEB FPA M2 CCB CEB M1 CCB M3 San Diego - SPIE

  15. Absolute Displacement Error (ADE) Inter-Satellite Distance (ISD) FF Specifications • Inter-Satellite Distance (ISD) • ~ 150 m (±2 m variation over the year) • Absolute Displacement Error (ADE) • Lateral positioning: • ± 3.4mm (3s) with 20 arcsec APE • Can be relaxed to ± 6.0mm (3s) at the expense of the APE (8 arcsec) • Longitudinal positioning: ±740mm (3s) San Diego - SPIE

  16. Launch Configuration Coronagraph S/C Occulter S/C Lisa Path Finder Module Create/Delete FF Orbit and Launch • Baseline: 24h HEO • 800/70000 km • Inclination 63° • Visibility: 15-20 hrs/day • Eclipses (typical): from 0 to 3.9 hrs (180 days without eclipses per year) • Launch • 515 kg on a dedicated launch on VEGA/Verta launch (415 kg current) San Diego - SPIE

  17. PROBA-3/ASPIICS: programmatic 2009 2010 2011 2012 2006 2007 2008 Phase A Phase B Phases C/D ITT Operations Final Decision Launch San Diego - SPIE

  18. Step 2 Step 3 Darwin Xeus Aspiics 2008 2012 2015 2018 ASPIICS and Formation Flying missions Step 1 . • The • ASPIICS/PROBA-3 is a needed step toward most demanding future FF missions nanometer sub-arcsec mm arcsec Prisma cm arcmin San Diego - SPIE

  19. Conclusion • ASPIICS will address still unanswered science questions that the failed SOHO/LASCO-C1 coronagraph was supposed to investigate. Thanks to the following major improvements: • Straylight level: Externally occultation vs internally occultation • Spectral selection: Etalon Fabry-Perot vs Tunable • Strategy: Spatial vs spectral sampling • ASPIICS has no competitor in the coming 10-15 years • ASPIICS will give tremendous visibility to ESA's formation flying program thanks to spectacular results (movies of "explosions" are perfect for outreach) • ASPIICS will operate in synergy with contemplated disk imagers and wide field coronagraphs (SDO, SMESE, INTER-HELIOS, PROBA-2) • ASPIICS will help to prepare future formation flying missions San Diego - SPIE

  20. MERCI ! Thank You … San Diego - SPIE

  21. San Diego - SPIE

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