The Moon as a Platform for High Resolution Solar Imaging

Transcription

1 The Moon as a Platform for High Resolution Solar Imaging F. Berrilli, Dept of Physics, Univ. Of Rome Tor Vergata A. Bigazzi, CE Consulting-Altran and INAF A.Ruzmaikin, N. Murphy, NASA JPL F.Manni, SRS Group

2 The Moon Solar Monitor

3 The 1-m Solar Telescope - Layout Primary Mirror Diameter: 1000 [mm] System Focal Ratio: 25 System Focal Length: Obstruction Ratio: 8.4% Angular Field: 0.12 Deg

4 A Lightweight Telescope Carbon Fiber 0.7 x [kg] Steel, Al, Cu,.. Al [kg]

5 Space grade Optics: SiC Foam Technology (OAB Brera Galileo Avionica) 31cm mirror 15 Kg/m 2 1m:12kg 19 nm rms error Foamed primary mirror substrate in SiC ( 310 mm dia.) Two SiC face sheets deposited on a foam core of the same material Very light and stiff mirrors for space applications Ion beam figuring polishing (final few microns) New process: foam generation, skin deposition, cladding. Courtesy O.Citterio, OAB, Brera Observatory

6 Why monitoring the Sun

7 The Sun is a magnetically active star Sun s MF is continuously shaping the Heliosphere Interacting with the Earth s and the other planet s environments

8 Space weather refers to violent transfers of matter and energy from the Sun to the Earth. CME blast and subsequent impact at Earth This illustration shows a CME blasting off the Sun's surface in the direction of Earth. Two to four days later, the CME cloud is shown striking and beginning to be mostly deflected around the Earth's magnetosphere. The blue paths emanating from the Earth's poles represent some of its magnetic field lines. The magnetic cloud of plasma can extend to 30 million miles wide by the time it reaches earth. These storms, which occur frequently, can disrupt communications and navigational equipment, damage satellites, and even cause blackouts. University of Colorado at Boulder Courtesy of SOHO/LASCO consortium. SOHO is a project of international cooperation between ESA and NASA

9 Risk for human exploration A massive flare took place on August 7 th 1972, in between Apollo 16 (April) and Apollo 17 (December) human missions to the Moon.

10 Science goals: Understanding and monitoring the Dynamic Sun

11 ESA Cosmic Vision [ ] The solar magnetic field is continuously generated and destroyed on timescales ranging from fractions of a second to decades. The varying magnetic field of the Sun is directly responsible for changes in the solar ultraviolet and X-ray emission, and is also closely related to the [ ] possible forcing role in climatic variations These topics will remain major scientific challenges in the Cosmic Vision timeframe. Cosmic Vision: Space Science for Europe Executive Summary May 2006

12 NASA Sun-Earth Connection (SEC) Roadmap Living With a Star (LWS) Solar Terrestrial Probes (STP) Primary science objectives of the SEC Division and relation to LWS and STP

13 NASA SEC Questions and Themes

14 Science Instruments - 1 Multi-band (NIR-VIS / UV), high-res spectral polarimeter NIR: 50% of radiative output Mostly unobserved Probing Km under visible surface: MF rooted there Strong interaction w Earth Atm UV: Solar Corona Climate drive 3D magn. Fields. Tomography LOS velocities. Stringent Requirements: Resolution 0.1 arcsec FoV 2-4 arcmin 2 Cadence 1 image (full Stokes/full line) 30 s. Time baseline several days Spectral Resolution 500pm Polarimetric accuracy 10-4 / (1.4Mm) solar granulation SST

15 Science Instruments 2: Compact Imaging Vector Magnetograph (Cacciani) Resolution 2 /pix (5cm ap) Mass 14 kg Power <30W Operations K nm Ruzmaikin,Moynihan, Vaughan, Cacciani, 1998SPIE R Accuracy Linearity Cells lifetime Operating Detector EFocal Length Na nm 3m/s; 3Gauss-30img +/- 4Km/s > 5 Years 0-40 C 1024x1024 CCD or APS (CMOS, JPL) 126 cm Missions with severe mass and power constraints Easy optical system alignment. No moving parts Extended Cells lifetime Simultaneous Dopplergram (V) and Magnetogram (B) Wavelength stability, narrow passband, high throughput. JPL

16 Imaging Vector Magnetograph applications Local and Global Helioseismology. Subsurface flows and MF dynamics

17 Why The Moon

18 Observations protected from Earth s disturbances Extended spectral coverage, from NIR to UV ( nm) UV chromospheric network IR COmosphere (Current models do not explain the observed chromospheric structures) Solar UV and IR Variability (Climate Drive) Enabling multi-layer imaging and analysis, from deep Photosphere (NIR) to the Chromosphere (UV) Achieving the highest resolution on the photosphere with a small telescope working at the diffraction limit 1m telescope achieves (VIS) the limit resolution of a photon s mean free path (the physical limit): about 75 km on the photosphere VIS: 0.1 UV: 0.05 NIR: 1 micron)

19 No satellite control center required (orbit maintenance. Compare e.g. to L2 S-E orbiting S/Cs such as SOHO) Continuous, high-rate downlink to Earth stations. Little on-board processing and storage needed Daylight operations (...by definition!) Power availability! greater flexibility in Mission design, as far as mass and power budget, landing site determination, telescope s housekeeping and communications framework are concerned. Extended (14 days), continuous observation capability. monitoring evolution of long-living magnetic field complexes global helioseismology

20 A Lunar Precursor Mission A Technology laboratory for Lunar Missions

21 Characterizing a real operational environment on the Moon Technology challenges and returns: Testing of Unassisted Operation in a hostile environment Mechanic (dust!;iinterface with the lunar surface) Thermal (night-day excursion up to 250 K ) Radiation (unshielded Solar Wind and Cosmic Rayselectronic hazards).. Control systems for post-landing telescope alignment Stabilisation and precision pointing operations Precision Landing (either equatorial or polar i.e.aitken Basin) Characterization optics performance in a dusty atmosphere

22 Summary First-class scientific output. Timely, well blending with current Space Programs Technology Demonstrator Lunar environment characterization Lightweight, relatively simple instrument affordable budget High media exposure (imaging). Prototype for larger telescopes and instrumentation.

23 Thank you for your attention