Presentation on theme: "ASPIICS on PROBA-3 Association de Satellites Pour l’Imagerie et l’Interférométrie de la Couronne Solaire San Diego, SPIE August, 26 th 2007 Sébastien Vives,"— Presentation transcript:
ASPIICS on PROBA-3 Association de Satellites Pour l’Imagerie et l’Interférométrie de la Couronne Solaire San Diego, SPIE August, 26 th 2007 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
26 August 2007 San Diego - SPIE 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.
26 August 2007 San Diego - SPIE 3 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 R sol. SOHO/LASCO-C2 R > 2.5 Rsol SOHO/LASCO-C1 High level of straylight and operated at solar minimum only Ground-based coronagraph: Low spatial resolution and atmospheric noise Total solar Eclipses: Ideal but very rare and only a snapshot!
26 August 2007 San Diego - SPIE 4 Ground-based coronagraphSOHO/LASCO-C1 coronagraph ASPIICS objectives SOHO/LASCO-C2 coronagraph Ground-based image obtained during a total solar eclipse ASPIICS aims at achieving conditions close to total eclipses ASPIICS Field Of View
26 August 2007 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?
26 August 2007 San Diego - SPIE 6 What is ASPIICS ? 2 S/C separated by 150 m realize a giant coronagraph and will achieve conditions close to a total solar eclipse Performances are driven by the distance between the external occulter and the entrance pupil
26 August 2007 San Diego - SPIE 7 Unique Aspects of ASPIICS Ambitious science objectives Imaging the inner corona ( 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 years
26 August 2007 San Diego - SPIE 8 High resolution imaging…
26 August 2007 San Diego - SPIE 9 … With unprecedented spatial resolution White light imaging ( nm) from to 3 R sun at spatial resolution of 2.8 arcsec/px. Pixel limited Diffraction limited
26 August 2007 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, 1.8x10 6 K) Fe X: nm (coronal holes, 1.0x10 6 K) He I: nm (cold matter, 1.0x10 5 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)
26 August 2007 San Diego - SPIE 11 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. 16 th 1980) which has allowed to derive: –Intensity, Doppler shift, line broadening and splitting Desai, Chandrasekhar & Angreji, 1981
26 August 2007 San Diego - SPIE 12 Conceptual Layout L1L2 L3 F-P Filter Wheel Detector Internal occulter Polarizer Cover (door) Shutter 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)
26 August 2007 San Diego - SPIE 13 Optical Layout Entrance Pupil M1 M3 M2 Internal Occulter O2 O3 Focal Plane Fabry-Perot Blocking Filters Polarizer
26 August 2007 San Diego - SPIE 14 Thermo-Mechanical Concept 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 CCB CCD radiator M1 M3 FPA M2 CEB CCB
26 August 2007 San Diego - SPIE 15 FF Specifications Inter-Satellite Distance (ISD) ~ 150 m (±2 m variation over the year) Absolute Displacement Error (ADE) Lateral positioning: ± 3.4mm (3 ) with 20 arcsec APE Can be relaxed to ± 6.0mm (3 ) at the expense of the APE (8 arcsec) Longitudinal positioning: ±740mm (3 ) Inter-Satellite Distance (ISD) Absolute Displacement Error (ADE)
26 August 2007 San Diego - SPIE 16 Orbit and Launch Baseline: 24h HEO 800/70000 km Inclination 63° Visibility: 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) Create/Delete FF Launch Configuration Coronagraph S/C Occulter S/C Lisa Path Finder Module
26 August 2007 San Diego - SPIE 17 PROBA-3/ASPIICS: programmatic Phase A Phase B Phases C/D Operations Launch ITT Final Decision
26 August 2007 San Diego - SPIE 18 ASPIICS and Formation Flying missions ASPIICS/PROBA-3 is a needed step toward most demanding future FF missions. T h e cm arcmin mm arcsec nanometer sub-arcsec Step 1 Prisma Step 3 Xeus Darwin Step 2 Aspiics
26 August 2007 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 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
26 August 2007 San Diego - SPIE 20 MERCI ! Thank You …