A short post to highlight the presence of an atomic force microscopy instrument onboard a high speed spacecraft that orbited a comet that yielded science data reported in a journal. The spacecraft, Rosetta, sampled comet dust particles from comet 67P/Churyumov-Gerasimenko and analysed it first with a Comet Secondary Ion Mass Analyzer (COSIMA), followed by an atomic force microscope in the MicroImaging Dust Analysis System (MIDAS), in what is a tour de force for using atomic force microscopy in challenging analysis environment.1
Based on recording the movement of a cantilever with a sharp tip that scans across a surface, atomic force microscopy is a high precision instrumented technique requiring special ballast for removing vibration induced artefacts from surface imaging. Capable of mapping the topography (i.e., elevation changes, and thus surface structure) of the sampled surface such as that of a microparticle in dust, atomic force microscopy could yield insights into the structure of the material. But, atomic force microscopy’s application utility on spacecraft is very limited and, up to now, impossible, due to the high speed at which a spacecraft moves and the vibration induced. Thus, it is an incredible feat of engineering to incorporate an atomic force microscope into an instrument package onboard a spacecraft orbiting a comet for at source analysis of collected comet dust particles without a sample return step such as that in the Apollo missions to the Moon.
Just to add on, if the sharp tip at the end of the cantilever is coupled with specific type of molecules such as hydrophilic molecules, it is possible to determine the spatial distribution of chemical functionalities (such as polar or hydrophobic surface) on the comet dust particle; thereby, yielding yet more information on the possible deliver of organic molecules to Earth through impact during the formative years of the planet in the Late Bombardment Period. Known as chemical force microscopy, the technique could add new knowledge to the compendium collected by rovers and spacecraft concerning the presence of organic molecules on Mars and comets; specifically, providing a layer of chemical information on top of spatial and topographic knowledge of analysed microparticles.
- Kolokolova, L. Planetary science: Cometary dust under the microscope. Nature 537, 37–38 (2016).