What is NExSS?

The Nexus for Exoplanet System Science (NExSS) is a research coordination network dedicated to the study of planetary habitability.  The goals of NExSS are to study the diversity of exoplanets; learn about how their history, geology, and climate interact to create conditions for life; and accelerate the discovery and characterization of other potentially life-bearing worlds in the galaxy, using a systems science approach. Researchers in the network aim to understand where habitable niches are most likely to occur – that is, which planets are most likely to be habitable.

NExSS is led by Natalie Batalha of NASA Ames Research Center (ARC), Dawn Gelino of the NASA Exoplanet Science Institute (NExScI), Anthony del Genio of NASA’s Goddard Institute for Space Studies (GISS), and Victoria Meadows of the Virtual Planetary Laboratory (VPL) at the University of Washington. The NExSS network includes team members from universities and research institutes across the US. These teams were selected from proposals submitted across NASA’s Science Mission Directorate.

Why was NExSS created?

NASA’s Kepler mission has revealed that the Milky Way may be home to billions of Earth-sized planets orbiting in the habitable zone of their host stars. Thus, the possibility of finding life beyond Earth looms larger on the horizon.  NExSS aims to play a role in advancing exoplanet science research, broadening opportunities for scientists in the U.S. to engage in this type of interdisciplinary research.

How was NExSS created, and how were the teams for the pilot program selected?

The idea for NExSS was first presented to NASA Deputy Administrator Lori Garver in 2013 as a prospective Agency Grand Challenge. It was not selected at that time. However, the idea was proposed to NASA’s Science Mission Directorate leadership in summer 2014, briefed to the National Research Council’s Committee on Astrobiology and Planetary Sciences (CAPS) at public meetings in December 2014 and March 2015, and presented to the NASA Exoplanets Assessment Group at its January 2015 meeting. All endorsed the idea.

NExSS was launched as a pilot program in 2015 by program officers at NASA HQ. Eighteen inaugural teams were identified that a) were already selected for funding within various NASA R&A programs and b) had research goals complimentary to those of NExSS. All four of NASA’s science divisions – astrophysics, Earth science, heliophysics, and planetary science – routinely issue solicitations for research proposals (Research Opportunities in Space and Earth Sciences, or ROSES). Specific solicitations from which the inaugural teams were drawn included a NASA Astrobiology Institute Cooperative Agreement Notice, Planetary Science and Astrophysics Division components of the Exoplanet Research Program, the Astrophysics Theory and Astrophysics Data Analysis Programs, and the Heliophysics Division’s Living With a Star Program.

The PI of each team serves on a Steering Committee responsible for driving the activities of the network. Membership on the Steering Committee is for the same period of performance as the funded ROSES proposal. No additional research funds are provided for participation in the network.

What are the scientific goals of NExSS?

NExSS teams will help classify the diversity of worlds being discovered, understand the potential habitability of these worlds, and develop tools and technologies needed in the search for life beyond Earth. Scientists are developing ways to identify habitable environments on these worlds and search for biosignatures, or signs of life.  Upcoming NASA missions such as the Transiting Exoplanet Survey Satellite (TESS), the James Webb Space Telescope (JWST), and the Wide-Field Infrared Survey Telescope (WFIRST) will add to the census of exoplanets. Central to the work of NExSS is understanding how biology interacts with the atmosphere, surface, oceans, and interior of a planet, and how these interactions are affected by the host star.


How will new NExSS members be added?

Given the success of the program, membership was refreshed in 2018 in a similar manner as described above for the inaugural teams. Going forward (likely beginning with ROSES 2019), PIs will be able to volunteer to join the NExSS network by responding to a query during the proposal submission process. A move in this direction was made in the 2018 ROSES announcement whereby the NExSS opportunity was described in section C.5 (Exobiology), E.2 (Habitable Worlds), and E.3 (Exoplanet Research).   New members will be added at a cadence that coincides with the program reviews.

NExSS also offers affiliate membership to persons, groups, or organizations whose research interests, goals, and vision are aligned with those of NExSS and would like to actively participate in NExSS-organized activities (e.g. workshops, conferences, virtual seminars, white papers, working groups etc.). Affiliate members receive NExSS emails and invitations and are expected to engage with the NExSS community.