In the ERC-funded project, Prof. Frank Postberg and his team will study mainly the icy moons Enceladus (Saturn) and Europa (Jupiter). Those locations probably have the highest astrobiological potential in our solar system. Putative hydrothermal activity on the floor of those oceans may offer favourable conditions for life to emerge. Data from the Cassini-Huygens probe will be analyzed using innovative laboratory-based methods to determine the geochemical properties of Enceladus. The researchers hope to draw conclusions on how hospitable a mighty ocean under an ice shield in the moon's interior might be.
One of the most important findings of the Cassini Mission was the discovery that Saturn's small ice moon Enceladus is cryo-volcanically active with a plume from high velocity jets of water vapour and ice particles that emerge from warm fractures in the surface. The analysis of these grains with the mass spectrometer of the Cosmic Dust Analyzer (CDA) provides the unique opportunity to gather information about subsurface processes below the moon's icy crust. Excitingly, the compositional analysis of grains emitted from Enceladus showed that they emerge from liquid water close to the icy surface that has been in contact with the moon's rocky core at much greater depth (Postberg et al., Nature 2009, Nature 2011). Moreover, silica nano-grains embedded in the ice particles indicated that there is ongoing hydrothermal activity with temperatures of 90°C or more (Hsu, Postberg, Sekine et al., Nature 2015).
We are currently focusing in analyzing the organic material emitted by Enceladus in order constrain the astrobiological potential of this subsurface water world. CDA spectra of icy material emitted by Enceladus subsurface ocean exhibit an abundance of organic material. Due to lack of suitable methodology, less than 5% of all E ring spectra have been yet evaluated. In 2017, we started a refined, systematic CDA spectra evaluation of the entire CDA E ring dataset of over 200.000 ice grain spectra. A newly developed code will automatically recognize ice grain spectra with high abundance of inorganic and organic material. Analogue experiments with our laser assisted mass spectrometer we aim on identification and quantification of the abundant, but currently ambiguous, signatures and relate them to high-mass organic parent molecules.
In May 2015, the NASA announced a flagship mission to explore the habitability of the Jovian ice moon Europa that harbours a huge subsurface ocean. One of the 10 instruments is a Surface Dust Mass Analyzer (SUDA), which will carry out key measurements to characterize the composition of the icy moons surface as well as its subsurface ocean. Surface ejecta, generated by the ambient micro-meteoroid bombardment that erodes the surface, are naturally present on all atmosphereless moons like Europa - they are enshrouded in clouds of ballistic dust particles. In situ mass spectrometric analysis of these grains impacting onto SUDA reveals their composition as characteristic samples of Europa's surfaces at each flyby. The particles can be traced back to their point of origin, linking them to surface features and allows compositional mapping with in situ techniques.
Recent observations with the Hubble space telescope indicated plume activity on Europa. This would allow the Europa Clipper to direct sample fresh material emerging from the sub-surface in a similar way as Cassini-Huygens did at Enceladus. SUDA is lead by LASP at the University of Colorado in Boulder and supported by our research group in Berlin. The spacecraft is scheduled for a launch in 2022 arriving at Jupiter a few years later. As Co-Investigator the head of our group, Prof. Frank Postberg, is in charge of the spectral analysis of Europa’s surface and subsurface material. In the near future, he will start to establish an extensive spectrum-library of analogue materials with a laser-assisted mass spectrometer.
FINANCIAL SUPPORT • PROJECT FUNDING
• Project ID: 724908
• Funded by the European Union as European Research Council (ERC) Consolidator Grant
• Term: Feb 01, 2017 - Jan 31, 2022