The Committee on Astrobiology and Planetary Sciences (CAPS) of the National Academies of Sciences, Engineering, and Medicine was organized in 2012 with the task of supporting scientific progress in astrobiology and planetary science and assisting the federal government in integrating and planning programs in these fields by providing advice on the implementation of decadal survey recommendations. CAPS was empowered by its founding to serve as an independent forum by which astrobiological and planetary sciences can be discussed between the federal government, the scientific community, and other stakeholders in the space science community. In furtherance of this latter goal, CAPS is asked by federal agencies that support astrobiology and planetary science research to gather information and write reports that impact these research communities.
The National Aeronautics and Space Administration (NASA), by its authorizing document, has a statutory obligation to “provide for the widest practicable and appropriate dissemination of information concerning its activities and the results thereof.”1 Regardless of the nature of the discovery of extraterrestrial life, NASA will play a crucial role in its communication both to the general science community and the general public. It is therefore incumbent on NASA to prepare its science and communications apparati for this task.
It was in this context that two of NASA’s Research Coordination Networks (RCN): the Network for Life Detection (NfoLD) and the Nexus for Exoplanet System Science (NExSS),2 hosted the virtual “Standards of Evidence for Life Detection Community Workshop,” held from July 19-22, 2021. A total of 125 community members attended the workshop. The outlined goal of the effort was to discuss the processes needed to increase the scientific confidence in potential biosignature detections and how best to convey the rigorous scientific process and this continuum of confidence to a broader audience.3
The product of this workshop was a document outlining the workshop attendees’ proposed generalized framework for biosignature assessment and a proposed protocol for utilizing the framework in reporting potential discoveries, titled “Community Report from the Biosignatures Standards of Evidence Workshop” (henceforth Community Workshop Report).4 CAPS began its review of the original document that was posted for public comment on October 18, 2021. A finalized draft edited in response
1 National Aeronautics and Space Act of 1958, Section 203(a)(3).
2 The NASA Astrobiology RCNs are a mechanism for community collaboration. Each RCN will have a steering committee comprised of the principal investigators of all teams who have elected to join, both from large teams selected from the Interdisciplinary Consortia for Astrobiology Research (ICAR) solicitation as well as smaller teams from relevant Research Opportunities in Space and Earth Science (ROSES) Research and Analysis (R&A) programs. Additionally, the NASA Astrobiology Program, along with representatives of relevant research elements and Science Mission Directorate Divisions, will identify co-leads and potential members of the RCN and provide funding to support the logistical requirements of the RCN.
3 Network for Life Detection, 2021, “NfoLD Standards of Evidence for Life Detection Community Workshop,” https://www.nfold.org/standards-of-evidence-workshop.
4 Network for Life Detection, 2021, “Community Report from the Biosignatures Standards of Evidence Workshop,” https://www.nfold.org/_files/ugd/c2389f_d081d7f5fcfc455cbe0bb560a900ecb6.pdf.
to input from the community was provided to CAPS for consideration on February 18, 2022. The report is planned for final submission to NASA and to be submitted for publication by mid-2022.
STATEMENT OF TASK
NASA’s Planetary Science Division (PSD) Director Lori Glaze requested that CAPS, in its role as an independent forum, conduct an independent review of the Community Workshop Report and write a report detailing its findings. The statement of task for this activity was as follows:
We request that the Committee on Astrobiology and Planetary Sciences of the National Academies of Sciences, Engineering, and Medicine convene to conduct an independent review of the White Paper on Standards of Evidence for Life Detection and issue a letter report addressing the following questions:
- Does the white paper include a clear and transparent description of the process?
- Does the report accurately reflect the scientific literature? Are there any crucial content areas detrimentally underrepresented in the report?
- Are the assumptions valid and reasonable?
- Are the conclusions valid and supported?
- Are there potential limitations or data gaps that would substantially impact the conclusions?
The committee received this task on August 25, 2021, shortly after the workshop was held. CAPS began to address this task at its virtual 2021 Fall Meeting held on November 10-12, 2021. Meetings to discuss this issue were held between November 10, 2021, and March 23, 2022, both to gather information and community reactions to the report and to discuss issues relevant to the Community Workshop Report’s assumptions, conclusions, and potential limitations.
CAPS, in receiving this charge, considered both the assumptions and the conclusions of the Community Workshop Report. This was done to ensure that this review was both independent and thorough. This report should not be taken as representing a community consensus endorsement nor a repudiation of the Community Workshop Report, but as only the consensus agreement of the 17 CAPS members on the issues raised by the Community Workshop Report.
Information Gathering and Community Input
The committee sought to ensure that this report was informed by as many stakeholders in the relevant communities as possible. To that end, the committee heard from the Community Workshop Science Organizing Committee leaders and members, members of the scientific community, and science journalists and publishers.
The committee also issued a call for public input and established a web form by which input from the community, anonymous or attributed, could be submitted for consideration. The site began accepting input on February 1, 2022, and was publicly announced at the committee’s meeting on February 3, 2022. The link to this web form was distributed via the National Academies to the Space Studies Board’s Planetary Sciences and Astrobiology subscriber list and the email lists of the American Astronomical Society’s Division for Planetary Sciences, the American Geophysical Union’s Planetary Science Newsletter, the Geological Society of America’s Planetary Geology Division, several NASA RCNs, and several NASA Assessment Groups.
The form was closed for submission on February 18, 2022, though late submissions were accepted until February 25, 2022. At the time of closing, 75 independent submissions were received by the committee.
The positions of the input regarding the Community Workshop Report varied from full endorsements to detailed, highly critical opposition of the positions taken along with proposed recommendations. The content of the public input notwithstanding, the polarized nature of the submitted comments indicates (1) the strong opinions held by some members of the community on the proposed assessment framework and the reporting protocol and (2) the lack of community consensus on these issues.
This report’s conclusions were finalized in a committee-wide virtual meeting on April 6, 2022, and the completed draft of this report was reviewed by nine reviewers. The report was then revised in response to reviewer comments and delivered to NASA.
The report is organized as follows. Chapter 2 provides a summary of the committee’s understanding of the context in which the Community Workshop Report was written and the proposals contained therein for the purposes of its review. The committee also briefly discussed its own independent information gathering of community reactions to the report.
Chapter 3 discusses the assessment framework proposed by the Community Workshop Report and its potential impacts on communications. The committee presents findings relevant to several assumptions contained within the Community Workshop Report. The committee considers the use of the proposed common language both within and outside the scientific community, and details potential implications and impacts of the Community Workshop Report’s recommendations.
Chapter 4 focuses on the various ramifications that the Community Workshop Report’s proposals have regarding the scientific process. The committee challenges the assumptions and the conclusions of the proposed ideal verification protocol. Finally, the committee discusses potential consequences not discussed in the Community Workshop Report.