ExoPAG Findings

Whereas the Astro2020 Decadal Survey recommended that NASA develop an exo-Earth direct imaging mission (recently dubbed the Habitable Worlds Observatory, HWO) and whereas whole-disk observations of the only known habitable world (Earth) at direct imaging-relevant wavelengths, timescales, and phase angles are extremely rare, so that the reflected-light spectral data for Earth adopted in the Decadal Survey are reliant on model predictions.

We find that the community of exoplanet scientists engaged in the development of HWO would benefit from novel whole-disk observations of solar system worlds, especially Earth. Data from spacecraft provide the only opportunity to make whole-disk observations of Earth and other solar system worlds without contamination from Earth’s atmosphere. Thus, these observations are crucial analogs for the exoplanet data that would be produced by HWO. Whole-disk observations from spacecraft provide a key opportunity to (1) understand how reflected light observations of planets depend on wavelength, phase, and time and (2) validate the data and tools currently in-use for planning HWO. For Earth, (1) published whole-disk spectroscopy is wholly lacking at some visible wavelengths critical to HWO observations, (2) weather-induced brightness variability at HWO-relevant illumination phases has not been well-sampled at timescales beyond a single rotation, and (3) spectral observations at lower-illumination phases beyond quadrature, where models predict important scattering effects related to exoplanet ocean and cloud remote sensing, are extremely limited. As a near-term example, whole-disk observations of Earth from NASA PSD’s OSIRIS-APEX mission could yield reflected-light spectroscopic data at wavelengths, phase angles, and timescales that heretofore have not been recorded for our planet and that are directly relevant to the science definition of an APD exo-Earth direct imaging mission.

[23 Yes, 0 No, 0 Abstention]

Whereas the Decadal Survey on Astronomy and Astrophysics 2020 emphasizes exoplanet research and has identified as a priority science area the search for habitable worlds, and whereas the exoplanet research community has significantly grown over the past years and attracted many young scientists.

We find that the proposal success rate in the Exoplanet Research Program falls well below the success rate of other comparable programs which can potentially hurt the retention and training of young scientists, US leadership in exoplanet science, and the efficiency with which NASA can achieve its strategic goals.

[35 Yes, 0 No, 1 Abstention]

"Whereas exoplanet science is inherently interdisciplinary, requiring expertise in heliophysics, earth science, planetary science, and astrophysics, among other disciplines, as well as deep and broad knowledge in theory, computation, observation, experiment, statistics, and instrument development, and whereas interdisciplinary research can require longer timeframes and greater resources to take full advantage of such diverse expertise within a collaboration, and whereas existing opportunities of scale that permit longer periods of performance to support interdisciplinary research teams are restricted to areas that specifically address the goals of the astrobiology program,

We find that longer term programs of scale (e.g. five year periods of performance and up to several million USD awards) would enable NASA to rapidly and efficiently address linked sets of the Exoplanet Exploration Program Science Gaps, for example 01-03, 02, 04-06, and 07-08-10, which contribute significantly to achieving NASA’s strategic goals, provided that such new opportunities did not come at the expense of existing programs which are also extremely valuable to help NASA achieve its strategic goals."

[41 Yes, 7 No, 2 Abstention]

Whereas candidate missions plan to observe a limited number of nearby target stars, and whereas each mission has different criteria for selecting targets, and whereas a comprehensive catalog of the physical and environmental properties of all nearby stars and their planetary systems could make future surveys more efficient (e.g. understanding the multiplicity or composition of potential targets given apparent correlations between these properties and exoplanet demographics), perhaps more cost effective, and probably lower risk,

We find that assembling such a catalog can potentially save significant NASA resources, and would help candidate missions address ExoPAG Science Gaps 06, 07, and 10, which contribute significantly to achieving NASA’s strategic goals.

[61 Yes, 0 No, 1 Abstention]

Whereas ExoPAG is inherently an interdisciplinary research community whose expertise and interests are relevant to some programs covered by the Earth Science, Heliophysics, Planetary Science, and Astrophysics Divisions, and whereas some programs administered by NASA, such as XRP, draw resources from multiple divisions, and whereas new initiatives, such as the Lunar Development and Analysis Program, could benefit from input from communities such as ExoPAG,

We find that multiple audiences would benefit from exposure to reports and findings generated by the ExoPAG to help shape their research programs, and that ExoPAG could benefit from receiving relevant reports and findings from other Program Analysis Groups.

[58 Yes, 0 No, 2 Abstentions]

Whereas the Exoplanet Research Program (XRP) has been one of NASA’s most successful R&A programs in addressing critical elements of NASA’s strategic goals specifically related to exoplanet science, and whereas the research community is growing and dynamic having the highest rate of new NASA R&A PIs of any other program, and whereas the success rate has dropped to the lowest rate of any other R&A program (with the exception of the FINNEST fellowships), and whereas the funding mechanisms, as well as the scope of the calls, are expected to evolve in the coming year as other divisions participate,

We find that close monitoring of the program, scrutiny of success rates and programmatic balance, along with feedback from and communication with the community might help avoid unintended consequences during this evolution.

[58 Yes, 0 No, 5 Abstentions]