In-situ-analysis of ice particles in the solar system: application, methods, instrument developement

• Applicant: Professor Dr. Frank Postberg
• Subject Area: Mineralogy, Petrology and Geochemistry
• Term: from 2014 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 248701662

The better part of condensed matter in the outer solar system (beginning roughly at the asteroid belt) consists of water ice. Current findings on the composition of icy surfaces and particles are almost exclusively based on absorption-spectroscopy, particularly in the infrared range. However, in this way, compounds that are embedded in a water ice matrix can only be investigated to a certain degree. This applies in particular to anorganic components, which are often only slightly active or even inactive in the infrared range. Many organic compounds are also difficult to identify, much less to quantify, by absorption-spectroscopy.The comprehensive goal of the requested funds, conjoint with a Heisenberg Fellowship, is the chemical characterisation of icy bodies in the solar system by means of a new method. This is done through in situ mass spectrometry of ice particles in space, which collide with the appropriate detectors at high speed. If the particles' origins are known, the composition and geochemistry of the mother body can also be characterised. This approach, the capabilities of which have been impressively shown through Cassini's Cosmic Dust Analyser (CDA), is particularly well suited to icy materials and complements absorption-spectroscopy. Within the framework of the proposed research programme, the in situ mass spectrometry shall be applied and further developed. For that purpose, data from current space missions (Cassini, Rosetta) will be analysed and future missions will be prepared for an optimal science return. This is supported by a series of lab experiments with icy analogue materials. In sub-project 1, the previous work with Cassini-CDA data will be expanded to a qualitatively new level. The target is a comprehensive, systematic description of the composition of icy materials in the Saturnian system. From this, comprehensive insights into the composition of Saturn's ring system and its cryo-volcanic active icy moon Enceladus can be derived. Enceladus ice fountains, which emerge through warm cracks in the moon's icy crust, are fed by liquid water and may provide valuable information about the moon's astrobiological potential. A core resource for the interpretation of CDA mass spectra will be the use of the analogue experiments as described in sub-project 2. These devices simulate high-speed impacts of ice particles onto the detector plate and are extremely helpful in the interpretation of space data. However, this method applies not only to CDA spectra, but also to the data of other current or future space missions, e.g. Rosetta. Existing national and international cooperations and investments will be used and further expanded

• DFG Programme: Research Grants
• Participating Persons: Professor Dr. Bernd Abel; Privatdozent Dr.-Ing. Ralf Srama; Professor Dr. Mario Trieloff