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Solar System Debris Disk - S2D2

Proposal for Science Themes of ESA's L2 and L3 Missions

Understanding the conditions for planet formation is the primary theme of ESA's Cosmic Vision plan. Planets and left-over small solar system bodies are witnesses and samples of the processing in different regions of the protoplanetary disk. Small bodies fill the whole solar system from the surface of the sun, to the fringes of the solar system, and to the neighboring stellar system. This is covered by the second theme of Cosmic Vision. Associated with the small bodies is a Debris Disk of dust and meteoroids that are constantly generated from the disintegration of their parent bodies due to a wide range of processes.


In recent years the solar system is no longer the only planetary system available to study. An ever-growing number of extra-solar planetary systems is being been discovered. Either the planets are seen directly, or the effects of the planet on their central star or on their environment are observed. Planets form in a protoplanetary disk from collapsing interstellar material which is mixed and heated and, finally, condensed and agglomerated into planetesimals that accreted into planets. Material not consumed in planets remains in a wide disk of planetesimals around the central star. 
Debris disks have been identified around a significant fraction of main-sequence stars using the mid or far infrared excess in the spectral energy distribution of the stars. Debris disks are optically thin and mostly gas-free disks of 1 µm to 100 µm-sized dust grains. Such short-lived grains are continually replenished through mutual collisions in a ring of unseen km-sized and bigger planetesimals. 
Most of the concepts required to explain extra-solar debris disks have been developed from observations of our own solar system debris disk. However, the detailed processes (the combination of planetary scattering and collisional shattering) and the resulting large-scale structure of this disk remain obscure. Indeed, our own solar system has inner and outer debris disks that are directly analogous to those in exoplanetary systems. Moreover, the best current models of the interplanetary dust environment are not in agreement.
Unlike extra-solar debris disks, knowledge of the solar system debris disk comes mostly from direct observations of the parent bodies. The sizes of these parent bodies range from Near Earth Asteroids with sizes of a few 10 m, to km-sized comet nuclei, to over 1000 km-sized Trans-Neptunian Objects. The inner zodiacal dust cloud has been probed by remote sensing instruments at visible and infrared wavelengths, micro crater counts, in situ dust analyzers, meteor observations and recent sample return missions. Nevertheless, the dynamical and compositional interrelations between dust, interplanetary meteoroids, and their parent objects are still largely unknown. No similar observations exist for the outer debris cloud.
An additional scientifically important population of dust is interstellar dust passing through the solar system. These grains are the present day version of the raw material that was collected in the protoplanetary disk, heated, mixed, and reassembled in planetesimals and planets.
To develop our understanding of exoplanetary systems, we thus need to study our own system. This requires two complementary missions
  • S2: for the first time, we will have a 'bird's eye view' of our inner debris disk in the infrared to examine the extent and fine structure of the 'warm' zodical cloud, and finally we may observe the 'cold' outer Trans-Neptunian disk.
  • D2: an in-situ observations and sample return mission to probe the orbital and compositional connection between the dust in the inner interplanetary debris disk and its source bodies, mapping the sky in dust. This mission will provide a direct comparison of the composition of interstellar raw material with the more processed material from comets and asteroids.  

The dynamical and compositional interrelations between dust, interplanetary meteoroids and their parent objects are still largely unknown. The outer debris cloud of our own solar system has not been observed in the infrared so far, and exodisks harbor unobserved planets or planetesimals, while their debris disks show clear features. By studying the interaction (compositionally and dynamically) between dust and these parent bodies, we learn about the exodisks as well as about our own solar system. To date, no compositional and density “map” exists of the debris disk of the Sun and the existing meteoroid models do not provide reliable answers for meteoroid fluxes further away from the Sun as 1 AU.

If we want to understand exoplanetary systems, we must start at "home". S2D2 will shed light on all these questions by mapping our solar system in dust, using the unique combination of in-situ dust measurements, analyses of returned samples, and a bird’s eye view for infrared observations of our outer “home” debris disk and beyond. This will provide links between interplanetary meteoroids and their parent objects, teaching us about hidden planetesimals in exodisk debris clouds and much more. The wealth of science return of a mission like S2 and D2 is large: S2D2 therefore covers nearly all topics of the first and second cosmic vision themes, providing valuable information for astronomy, exoplanet sciences, solar system formation, planetary sciences, astrobiology and make human interplanetary spaceflight safer by better understanding the meteoroid environment.

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Science Goals

  • Determine the extent and fine structure of the solar system debris disk 
  • Establish the dynamical and compositional relationships between micrometeoroids and their parent bodies
  • Characterize similarities and differences of micron to mm-sized meteoroids flux 
  • Determine compositional differences between interstellar, comet, and asteroid dust
  • Link samples returned and analyzed to meteor streams and parent objects

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PD Dr.-Ing. Ralf Srama
Institute for Space Systems
University of Stuttgart
Pfaffenwaldring 29
70569 Stuttgart
Tel. +49 711 6856 2511
( )

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Full Proposal

A pdf version of the proposal is available here.  

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Supporting Team

Jessica Agarwal
Gonzalo Aniano
Jean-Charles Augereau
Raul Baragiola
Jürgen Blum
Mark Booth
Charles Bowers
Christelle Briois
Geoffrey Bryden
Vincenzo della Corte
William Danchi
Stanley F Dermott
Christopher B. Dreyer
Francesca Esposito
Katherina Fiege
Amara Graps
Eberhard Grün
Gerrit Hausmann
Georg Herdrich
Jon K. Hillier
Peter Hoppe
Jonathan Horner
Mihaly Horanyi
Regan E. Howard
Stavro Ivanovski
Annette Jäckel
Anthony P. Jones
Nozair Khawaja
Thomas Kehoe
Emil Khalisi
Hiroshi Kimura
Masanori Kobayashi
Ludmilla Kolokolova
Alexander Krivov
Harald Krüger
Rene Laufer
Melissa Lane
Jeremie Lasue
Julia C. Lee
Mark Leese
Yanwei Li
Kay Liseau
Rene Liseau
Franz Lura
Jonathan Marshall
Nicole Meyer-Vernet
Amaya Moro-Martin
Patrick Michel
Georg Moragas-Klostermeyer
Andreas Morlok
Harald Mutschke
Christoph Nöldeke
Pavol Pastor
Manish Patel
Emanuele Perinati
Andre Poppe
Frank Postberg
René Reviol
Jens Rodmann
Alessandra Rotundi
Frank Schäfer
Jürgen Schmidt
Hiroki Senshu
P Shallma
Irakli Simonia
Jonathan Slavin
Rachel Soja
Ralf Srama
Christopher C. Stark
Christiaan Sterken
Thomas Stephan
Veerle Sterken
Zoltan Sternovsky
Roland Thissen
Mario Trieloff
Josep Maria Trigo
Sebastian Wolf
Oleg Vaisberg
Jeremie Vaubaillon
Padma Yanamandra-Fisher

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You have the possiblity to express your support and interest to this mission proposal by filling out the following form. Press the button "SUBMIT" and the form content is copied into an e-mail to the address "".

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