Mission building blocks for outer solar system exploration

ABSTRACT The Rosetta mission to comet 67P/Churyumov–Gerasimenko has provided new data to better understand what comets are made of. The weak tensile strength of the cometary surface materials suggests that the comet is a hierarchical dust aggregate formed through gravitational collapse of a bound clump of small dust aggregates so-called ‘pebbles’ in the gaseous solar nebula. Since pebbles are the building blocks of comets, which are the survivors of planetesimals in the solar nebula, estimating the size of pebbles using a combination of thermal observations and numerical calculations is of great importance to understand the planet formation in the outer Solar system. In this study, we calculated the thermal inertias and thermal skin depths of the hierarchical aggregates of pebbles, for both diurnal and orbital variations of the temperature. We found that the thermal inertias of the comet 67P/Churyumov–Gerasimenko are consistent with the hierarchical aggregate of cm- to dm-sized pebbles. Our findings indicate that the icy planetesimals may have formed via accretion of cm- to dm-sized pebbles in the solar nebula.

Human outer solar system exploration via Q-Thruster technology

2015 IEEE Aerospace Conference ◽

10.1109/aero.2015.7118893 ◽

2015 ◽

Author(s):

B. Kent Joosten ◽

Harold G. White

Keyword(s):

Solar System ◽

Outer Solar System ◽

Solar System Exploration

Bifurcation of planetary building blocks during Solar System formation

Science ◽

10.1126/science.abb3091 ◽

2021 ◽

Vol 371 (6527) ◽

pp. 365-370

Author(s):

Tim Lichtenberg ◽

Joanna Dra̧żkowska ◽

Maria Schönbächler ◽

Gregor J. Golabek ◽

Thomas O. Hands

Keyword(s):

Solar System ◽

Planet Formation ◽

Numerical Models ◽

Building Blocks ◽

Protoplanetary Disk ◽

Outer Solar System ◽

Solar System Formation ◽

Source Regions ◽

Mass Divergence ◽

Internal Evolution

Geochemical and astronomical evidence demonstrates that planet formation occurred in two spatially and temporally separated reservoirs. The origin of this dichotomy is unknown. We use numerical models to investigate how the evolution of the solar protoplanetary disk influenced the timing of protoplanet formation and their internal evolution. Migration of the water snow line can generate two distinct bursts of planetesimal formation that sample different source regions. These reservoirs evolve in divergent geophysical modes and develop distinct volatile contents, consistent with constraints from accretion chronology, thermochemistry, and the mass divergence of inner and outer Solar System. Our simulations suggest that the compositional fractionation and isotopic dichotomy of the Solar System was initiated by the interplay between disk dynamics, heterogeneous accretion, and internal evolution of forming protoplanets.

Origins and Early Evolution of the Atmosphere and the Oceans

Geochemical Perspectives ◽

10.7185/geochempersp.9.2 ◽

2020 ◽

Vol 9 (2) ◽

pp. 135-313

Author(s):

Bernard Marty

Keyword(s):

Solar System ◽

Solar Nebula ◽

Noble Gases ◽

Building Blocks ◽

Anthropogenic Activity ◽

Outer Solar System ◽

Volatile Elements ◽

Isotopic Signatures ◽

Early Atmosphere ◽

The Earth

My journey in science began with the study of volcanic gases, sparking an interest in the origin, and ultimate fate, of the volatile elements in the interior of our planet. How did these elements, so crucial to life and our surface environment, come to be sequestered within the deepest regions of the Earth, and what can they tell us about the processes occurring there? My approach has been to establish geochemical links between the noble gases, physical tracers par excellence, with major volatile elements of environmental importance, such as water, carbon and nitrogen, in mantle-derived rocks and gases. From these analyses we have learned that the Earth is relatively depleted in volatile elements when compared to its potential cosmochemical ancestors (e.g., ~2 ppm nitrogen compared to several hundreds of ppm in primitive meteorites) and that natural fluxes of carbon are two orders of magnitude lower than those emitted by current anthropogenic activity. Further insights into the origin of terrestrial volatiles have come from space missions that documented the composition of the proto-solar nebula and the outer solar system. The consensus behind the origin of the atmosphere and the oceans is evolving constantly, although recently a general picture has started to emerge. At the dawn of the solar system, the volatile-forming elements (H, C, N, noble gases) that form the majority of our atmosphere and oceans were trapped in solid dusty phases (mostly in ice beyond the snowline and organics everywhere). These phases condensed from the proto-solar nebula gas, and/or were inherited from the interstellar medium. These accreted together within the next few million years to form the first planetesimals, some of which underwent differentiation very early on. The isotopic signatures of volatiles were also fixed very early and may even have preceded the first episodes of condensation and accretion. Throughout the accretion of the Earth, volatile elements were delivered by material from both the inner (dry, volatile-poor) and outer (volatile-rich) solar system. This delivery was concomitant with the metals and silicates that form the bulk of the planet. The contribution of bodies that formed in the far outer solar system, a region now populated by comets, is likely to have been very limited. In that sense, volatile elements were contributed continuously throughout Earth’s accretion from inner solar system reservoirs, which also provided the silicates and metal building blocks of the inner planets. Following accretion, it likely took a few hundred million years for the Earth’s atmosphere and oceans to stabilise. Luckily, we have been able to access a compositional record of the early atmosphere and oceans through the analysis of palaeo-atmospheric fluids trapped in Archean hydrothermal quartz. From these analyses, it appears that the surface reservoirs of the Earth evolved due to interactions between the early Sun and the top of the atmosphere, as well as the development of an early biosphere that progressively altered its chemistry.

Search for water and life's building blocks in the Universe

Proceedings of the International Astronomical Union ◽

10.1017/s1743921316005573 ◽

2015 ◽

Vol 11 (A29B) ◽

pp. 375-375

Author(s):

Sun Kwok ◽

Edwin Bergin ◽

Pascale Ehrenfreund

Keyword(s):

Solar System ◽

Common Ground ◽

Kuiper Belt ◽

Building Blocks ◽

Planetary Science ◽

Dust Particles ◽

Outer Solar System ◽

Water Ice ◽

Solar System Bodies ◽

Solid Bodies

Water is the common ground between astronomy and planetary science as the presence of water on a planet is universally accepted as essential for its potential habitability. Water assists many biological chemical reactions leading to complexity by acting as an effective solvent. It shapes the geology and climate on rocky planets, and is a major or primary constituent of the solid bodies of the outer solar system. Water ice seems universal in space and is by far the most abundant condensed-phase species in our universe. Water-rich icy layers cover dust particles within the cold regions of the interstellar medium and molecular ices are widespread in the solar system. The poles of terrestrial planets (e.g. Earth, Mars) and most of the outer-solar-system satellites are covered with ice. Smaller solar system bodies, such as comets and Kuiper Belt Objects (KBOs), contain a significant fraction of water ice and trace amounts of organics. Beneath the ice crust of several moons of Jupiter and Saturn liquid water oceans probably exist.

Laboratory and in-situ analysis of comet dust

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100102122 ◽

1988 ◽

Vol 46 ◽

pp. 8-9

Author(s):

D.E. Brownlee ◽

A.L. Albee

Keyword(s):

Electron Microscopy ◽

Solar System ◽

Laboratory Study ◽

Isotopic Analysis ◽

Building Blocks ◽

Sem Analysis ◽

Early Solar System ◽

Cometary Material ◽

Comet Dust

Comets are primitive, kilometer-sized bodies that formed in the outer regions of the solar system. Composed of ice and dust, comets are generally believed to be relic building blocks of the outer solar system that have been preserved at cryogenic temperatures since the formation of the Sun and planets. The analysis of cometary material is particularly important because the properties of cometary material provide direct information on the processes and environments that formed and influenced solid matter both in the early solar system and in the interstellar environments that preceded it.The first direct analyses of proven comet dust were made during the Soviet and European spacecraft encounters with Comet Halley in 1986. These missions carried time-of-flight mass spectrometers that measured mass spectra of individual micron and smaller particles. The Halley measurements were semi-quantitative but they showed that comet dust is a complex fine-grained mixture of silicates and organic material. A full understanding of comet dust will require detailed morphological, mineralogical, elemental and isotopic analysis at the finest possible scale. Electron microscopy and related microbeam techniques will play key roles in the analysis. The present and future of electron microscopy of comet samples involves laboratory study of micrometeorites collected in the stratosphere, in-situ SEM analysis of particles collected at a comet and laboratory study of samples collected from a comet and returned to the Earth for detailed study.

Harvesting Electromagnetic Energy from Hypervelocity Impacts for Solar System Exploration

2020 XXXIIIrd General Assembly and Scientific Symposium of the International Union of Radio Science ◽

10.23919/ursigass49373.2020.9232364 ◽

2020 ◽

Author(s):

Sean A. Q. Young ◽

Nicolas Lee ◽

Sigrid Close

Keyword(s):

Solar System ◽

Electromagnetic Energy ◽

Hypervelocity Impacts ◽

Solar System Exploration

Low-thrust trajectory and payload analysis for solar system exploration

10.2514/6.1966-497 ◽

1966 ◽

Author(s):

A. FRIEDLANDER ◽

F. NARIN

Keyword(s):

Solar System ◽

Low Thrust ◽

Solar System Exploration