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:
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.
- 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?
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.