SSP seminar

Exospheric Sampling of Mercury's Surface Composition

Stefano A. Livi (Southwest Research Institute)

Monday 25th February 2008, 12:00
Pratt conference room, 60 Garden Street

ESA's BepiColombo mission to the planet Mercury includes a comprehensive set of advanced instruments. Strofio, one of the instruments on the SERENA neutral and ionizing particle suite on the Mercury Planet Orbit (MPO), is a high mass resolution, time-of-flight system for low energy neutral particles.

Key questions addressed by Strofio are:

  • What are the composition, isotopic abundance, spatial distribution, and temporal variability of the neutral particles in Mercury's exosphere?
  • How do the surface, exosphere, and magnetosphere interact?
  • What is the chemical composition of Mercury's surface?
Strofio takes advantage of the direct coupling between the neutral atoms in the exosphere and their source regions in the outer layers of the regolith to answer fundamental questions about Mercury, its highly variable exosphere and its small but dynamic magnetosphere.

The design of the Strofio sensor is driven by the attempt to achieve both isotopic resolving capability (goal is a cross talk of 10-5 or better between two adjacent masses at the 50% level) and temporal resolution (a full-range spectrum can be collected in as short as 100 ms) within very limited resources (goal is 2 kg, 4W, 1,000 cm3). Laboratory tests on an available prototype show that these goals are within reasonable reach. This instrument is currently being developed as an integral part of the Serena/BepiColombo project, but could be readily adapted to a number of future missions, including missions to study planetary atmospheres and exospheres, cometary missions, and fast flybys.


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