  The search of life in the Universe is a fundamental problem of astrobiology
and a major priority for NASA. A key area of major progress since the NASA
Astrobiology Strategy 2015 (NAS15) has been a shift from the exoplanet
discovery phase to a phase of characterization and modeling of the physics and
chemistry of exoplanetary atmospheres, and the development of observational
strategies for the search for life in the Universe by combining expertise from
four NASA science disciplines including heliophysics, astrophysics, planetary
science and Earth science. The NASA Nexus for Exoplanetary System Science
(NExSS) has provided an efficient environment for such interdisciplinary
studies. Solar flares, coronal mass ejections and solar energetic particles
produce disturbances in interplanetary space collectively referred to as space
weather, which interacts with the Earth upper atmosphere and causes dramatic
impact on space and ground-based technological systems. Exoplanets within close
in habitable zones around M dwarfs and other active stars are exposed to
extreme ionizing radiation fluxes, thus making exoplanetary space weather (ESW)
effects a crucial factor of habitability. In this paper, we describe the recent
developments and provide recommendations in this interdisciplinary effort with
the focus on the impacts of ESW on habitability, and the prospects for future
progress in searching for signs of life in the Universe as the outcome of the
NExSS workshop held in Nov 29 - Dec 2, 2016, New Orleans, LA. This is one of
five Life Beyond the Solar System white papers submitted by NExSS to the
National Academy of Sciences in support of the Astrobiology Science Strategy
for the Search for Life in the Universe.
