Abstract:
The Life Marker Chip (LMC) instrument is an antibody assay-based system which will
attempt to detect molecular signatures of Life in the Martian subsurface as part of the
payload on board the European Space Agency (ESA) ExoMars mission rover, currently
scheduled for launch in 2018. The LMC will have the ability to detect up to 25 different
molecular targets of different origins that are associated with meteoritic in-fall, extinct
or extant Life, prebiotic chemistry and spacecraft contamination. Regolith / crushed
rock samples will be collected for the LMC by the rover and subjected to solvent
extraction to extract organic molecules for analysis by the immunoassays.
One of the key stages in the development of the LMC is the selection of antibodies to be
used in the flight instrument. The challenge lies in the nature of the molecules or classes
of molecules that are LMC targets and the need for antibodies that remain functional in
the extreme conditions during a planetary exploration mission, especially the radiation
environments.
The work described within focuses on two main aspects of the search for LMC-relevant
antibodies; the effect of space radiation on antibody performance [in the form of both
ground-based and Low Earth Orbit (LEO)-set studies] and the development of
―customised‖antibodies against some of the molecules that are being investigated as
potential LMC targets.
The need to study the effects of space radiation on antibodies arose due to lack of any
heritage of their use in interplanetary missions. For all the antibodies in the LMC, the
ability to resist inactivation due to space radiation seen during a Mars mission will be a
prerequisite. The objective of the ground-based radiation studies was to expose a
number of LMC-relevant antibodies to simulated Mars mission radiation in the form of
proton and neutron radiation which are the components of the mission radiation
environment that are expected to have the dominant effect on the operation of the LMC.
Cont/d.
