10. August 2017
Goethe University Frankfurt am Main
Tamara Koch, Robin Nowok, Yannik Schaper
Überflieger Wettbewerb 2017
10. August 2017
EXCISS Team
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Y. Schaper (Physics) O. Christ (Mineralogy) M. Lindner (Geoscience)
F. Schmuck (Geoscience) P.-T. Genzel (Mineralogy) S. Rempt (Mineralogy)
Y. Matschey (Geoscience) D. Mederos Leber (Physics) R. Nowok (Mineralogy)
A. Beck (Geochemistry) T. Koch (NanoGeoscience)
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Introduction
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Chondrules
• One of the oldest materials in our solar system
• Building blocks for the planetary system
How did the first solid particles of our solar system form?
• Is the answer in the chondrules?
Kerr, Science (2013)
“(…) meteoritics who know chondrules must
collaborate with astrophysicists who know what it
was like at the beginning of our solar system.”
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What are Chondrules?
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oldest material in
our solar system
Ø mm-sized
spherical objects
consist of
silicates and metal
crystallized from a melt
(> 2000 K)
building blocks for
the planetary system
Summarized in Zanda, Earth & Planetary Science Letters (2004)
Video: NASA's Goddard Space Flight Center Conceptual Image Lab
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“We all know how chondrules are formed
– by chondrule formation processes”
Alan Rubin
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Chondrule Formation Processes
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Impact Plumes
Impact Jetting
FU Orionis
Hot Inner Nebula Bipolar Flows
Nebular Lightning
Magnetic Flares
Accretion ShocksNebular Shocks
Brandon et al., Nature (2017); Marrocchi et al., Science (2016); Johnson et al., Nature (2014); Kerr, Science(2013); Alexander et al., Science (2008); Cuzzi et al., Nature (2006); Desch, Nature (2006); Summary in Boss, Chondrules and the Protoplanetary Disk 1996
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Nebular Lightning Theory
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Fundamentals
• Electrical charging by grain-grain collisions in the nebula
• Rapidly discharge through lightning bolts
Arguments against:
• Unclear if charge separation is possible
• Insufficient energy to melt mm-sized aggregates
• Cooling rate is too fast to form chondrule textures
Whipple, Science (1966); Desch & Cuzzi, Icarus (2000); Desch & Connolly, Icarus (2002)
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Nebular Lightning Theory
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Fundamentals
• Electrical charging by grain-grain collisions in the nebula
• Rapidly discharge through lightning bolts
Arguments for:
• Fast enough for rapid heating
• Different chondrule properties are possible
• Repeating heating events
Whipple, Science (1966); Desch & Cuzzi, Icarus (2000); Desch & Connolly, Icarus (2002)
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Chondrule Formation Experiments
• 1 mm dust aggregates as starting material
• Tmax = 6500 K, electrical charging = 7 – 14 kV
• Most of the aggregates were destroyed
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Güttler et al., Icarus (2008)
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Experiments in Micro-Gravity
• No chondrule formation experiments in micro-gravity
• Processes after chondrule formation
• Collision dynamics of dust coated chondrules
• ZARM Drop tower in Bremen (7 s micro-gravity)
Too short for chondrule formation!
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Beitz et. al, Icarus (2012)
5 mm
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Experiments in Micro-Gravity
• NanoRocks in Nanorack cube
• Low energy collisions of mm-sized particles
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Brisset et al., EPSC abstract (2015)
1 cm
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EXCISS – Idea
• Chondrule formation
experiment under long-term
micro-gravity conditions
• Heating events by electrical
discharges
(Nebular lightning)
Experimental concept
Modified from
Scott, Chondrules and the Protoplanetary Disk (2007)
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EXCISS – Idea
• Combination of heating
and collision experiment
• Collisions of molten and
unmolten particles
• Several heating events
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Advantages of long-term
micro gravity
Modified from
Scott, Chondrules and the Protoplanetary Disk (2007)
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Experimental Set-up
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EXCISS – Sample Chamber
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• Pt electrodes, d = 3 mm
• 0.005 g of Mg2SiO4
(olivine)
• Particle size = 100 µm
• p = 250 Pa, Ne atmosphere
• Ubreakdown = 500 V
Properties
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1:1 model
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EXCISS – Circuit Diagram
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sample chamber
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Event Timeline at ISS
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10 min 50 min
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Data Analysis
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Camera Data
• Particle velocities
(absolute/relative)
• Collisions of molten and
solid particles
• Formation and growth of
aggregates
Sample
• Size and shape
• Microstructure
• Mineralogical and
chemical properties
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Sample Analysis
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TEM Philips CM 200
SEM Jeol JSM-6490
Renishaw Raman spectrometry
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Implementation Schedule
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Sample Synthesis
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Possible Scenarios Solution Approach
vibrations destroy electrical contacts tests on vibrating table
data transfer save data on mass storage
unexpected power loss additional batteries for raspberry
particles precipitate at electrodes
and sample chamber walls
tiny vibrating motor at the
sample chamber, IR coating
Risk Mitigation
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Outreach Projects
Frankfurter Allgemeine Zeitung, 04.04.2017
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Outreach Projects
• Social Media, Newspaper
• Design cooperation with
August-Bebel-Schule for
media design
• Scientific paper
• Scientific conferences
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Conclusion
• Chondrule formation experiment in long-term micro-
gravity: combines melting and aggregation induced by
electrical discharges
• A straight forward experiment will present crucial new
results to the origin of our solar system
• EXCISS, the first chondrule formation experiment at the
ISS? – definitely not the last!
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This experiment is only possible in micro-gravity!
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Acknowledgement
Unconditional support from the institute of geoscience at the Goethe
University
Prof. Frank E. Brenker
Prof. B. Winkler
M. Röder
D. Merges
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Thank you for your attention!
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