Transcript High Resolution Solar Imaging from the Moon

High Resolution Solar
Imaging from the Moon
F. Berrilli - Tor Vergata University / INAF
&
A. Bigazzi - CE Consulting Altran Group / INAF
F.Manni - SRS Engineering Design Srl
A. Egidi - Tor Vergata University / INAF
Contribution:
V. Carbone (UNICAL) and S. Fineschi (INAF/TO)
Observation of the Universe from the
Moon - LNF INFN May 7, 2007
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The Sun as active star
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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.
Courtesy of SOHO/LASCO
consortium. SOHO is a project of
international cooperation between
ESA and NASA
University of Colorado at Boulder
Observation of the Universe from the
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A massive flare take place 1972
August 7th, between 1972 Apollo 16
(April) and Apollo 17 (December)
human missions on the Moon.
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Solar surface magnetism
consists of an amazing
hierarchy of discrete strongfield structures. The basic
element is the flux tube, a key
concept of MHD astrophysics.
Solar flux tubes have tiny
cross-sections (~0.1 arcsec)
corresponding to ~70km on the
solar surface.
Observation of the Universe from the
Moon - LNF INFN May 7, 2007
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Magnetic fields and flows interaction on
solar surface
Observation of the Universe from the
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Science: Local and Global
Helioseismology.
• Subsurface flows
and MF dynamics
Observation of the Universe from the
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The Moon as a platform for Solar
Observations
Observation of the Universe from the
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Attractive features
• Achieving the highest resolutions on the photosphere
and large FOVs with a small the telescope working at the
diffraction limit
• A 1m telescope may achieve limit resolution of a
photon’s mean free path (also, the physical limit)
About 50 km on the photosphere ,that is 0.05” - 0.1”
(UV - visible).
•On ground, high-res Adaptive Optics system have an
isoplanatic patch of a few arcsec.
• Extended spectral coverage, from NIR to UV (400-200nm)
•UV chromospheric network and Solar UV Variability
(Climate Drive)
• Multi-layer imaging from deep Photosphere to the
Chromosphere Observation of the Universe from the
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Attractive features (cont’d)
•
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Continuous visibility to few Ground Stations on Earth
No need for a Satellite Control Center (orbit maintenance.
Compare e.g. to L2 S-E orbiting S/Cs such as SOHO)
• Continuous, high-rate download link to few Earth stations.
• Little on-board processing and storage needed when a
relaying orbiting telecom infrastructure is present.
• Daylight operations - 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
Observation of the Universe from the
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ESA “Cosmic Vision” 2015-2025
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“The varying magnetic field of the Sun is directly
responsible for changes in the solar ultraviolet and Xray emission, and is also closely related to the […]
possible forcing role in climatic variations.
[…] The solar magnetic field is continuously
generated and destroyed on timescales ranging from
fractions of a second to decades.
These topics will remain major scientific challenges in
the Cosmic Vision 2015-2025 timeframe.”
Observation of the Universe from the
Moon - LNF INFN May 7, 2007
Cosmic Vision: Space Science for Europe 2015-2025 – Executive Summary – May 2006
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INAF/Piano Lungo Termine 2007-2017
The solar output, and associated
fluctuations due to the solar activity,
is the indispensable mechanism that
sustains life on the Earth and
generates the complex dynamics of
the Heliosphere. For these reasons
a task of primary interest for Science
and for astrophysics is to
understand our star: the Sun.
The paragraphs is derived from the scientific road map for the next 10
years of Italian solar physics presented by the National Institute for
Astrophysics-INAF.
Observation of the Universe from the
Moon - LNF INFN May 7, 2007
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Telescope Design
Telescope prototype for other
astronomical instruments
Primary Mirror Diameter: 1000
[mm]
System Focal Ratio: 25
System Focal Length: 25000
Obstruction Ratio: 8.4%
Angular Field: 0.12 Deg
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SiC Foam Technology (INAF/OAB – Off. Galileo)
•31cm mirror
•15 Kg/m2
•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
Observation of the Universe from the
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Environmental challenges: dust
1. The average dust grain size is about 70 µm, with a percentage of 1020% below 10 µm.  The dust is very pervasive, penetrates easily
everywhere (problems with spacesuits and with moving mechanisms).
2. The shape of the grains is variable from spherical to very angular (see
photo).
3. Low electrical conductivity  The dust keeps the charge acquired
through light exposure or charge deposition by the solar wind.
4. It thus adheres to surfaces both electrically and mechanically.
The lunar dayside charges positive, as photo electron
currents dominate; and the lunar nightside charges
negative, since plasma electron currents dominate.
Electric fields must thus exist near the terminator.
Optical measurements suggest that dust particles of 5-6
µm might electrically levitate within a few meters, and
that sporadically particles having much smaller size (0.1
µm) can levitate with a scale height of 10 km.
IMPACT OF LUNAR DUST ON THE EXPLORATION INITIATIVE. T. J. Stubbs, R. R. Vondrak and W. M. Farrell,
NASA Goddard Space Flight Center,
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Observation of the Universe from the
Greenbelt, MD 20771, USA, Lunar and Planetary
Science XXXVI (2005)
Moon - LNF INFN May 7, 2007
Weights
Carbon Fiber
0.7 x 6
2.1 [kg]
4.2
4.7
8.4
3.1
5.0
27.5
Al
25.5
Steel, Al, Cu,..
27.5
1.5
15.0
69.5 [kg]
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Technology Challenges
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Primary mirror building technology
Landing!
Control system for post-landing telescope
alignment and focus
Image stabilisation – Secondary mirror high
frequency adaptation
Unassisted Operation in hostile environment
• Mechanic (dust, rigid interface with lunar
surface)
• Thermal (night-day 250°K )
• Radiation (unshielded Solar Wind and Cosmic
Rays- electronic hazards).
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Summary
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High scientific output
Possible use as terrestrial or astronomical
telescope
Lunar environment characterization for
astronomical telescope
Technologically stimulating
Small, relatively simple instrument
“affordable” budget
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However (some argue):
The Apollo instrument complexes operated for years with little if
any problem from dust.
The laser retroreflectors left there are still reflective.
The instrument complexes included a dust-detector experiment
on Apollos 11, 12, 14, and 15 to measure possible accumulation
from the lunar module liftoff. The accumulation proved much
lower than expected.
The Surveyor 3 TV camera, returned after 31 months on the
Moon, showed some dust deposited by the module, but
investigators concluded that natural dust transport was "relatively
insignificant, if evident at all."
The long survival of natural lunar albedo features, such as the
100-million-year-old Tycho ray system, bears out the same
conclusion
Observation of the Universe from the
Paul Lowman Jr, (NASA GSFC),
Nov 2006
Moon Physics
- LNF INFN Today,
May 7, 2007
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Mass Evaluation
Physical evaluation parameters for various candidate mirror materials.
The best two values for each property are highlighted
Design and optimization of silicon carbide(SiC) mirrors for the Canadian Large Optical Telescope (LOT)
Joeleff Fitzsimmons, Scott Roberts
National Research Council Canada, Herzberg Institute of Astrophysics
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To solve the problem of Coronal heating:
• How the structure of the small-scale solar magnetic field
changes when we progress from the photosphere through the
chromosphere up to the corona
• How is energy that gives rise to coronal heating channelled?
• Is the field braided? Is energy transported via waves, and if
so what kind of waves? Or is magnetic energy stored in the
coronal field by continuous footpoint motions and released by
reconnection?
• Can we explain the vertical peristence of the magnetic
network?
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