Report calls for NASA to ramp up search for alien biosignatures

Astrobiology is the scientific study of study of the origin, evolution, distribution and future of life in the universe. A new report from the National Academies recommends strategies to help NASA expand its search for life elsewhere. Image via NASA.

Late last month, I reported on how the U.S. Congress wants NASA to focus more on searching for alien technosignatures in space. In other words, Congress is encouraging NASA to look for signals from advanced civilizations elsewhere in our galaxy. On October 10, 2018, another congressionally mandated report – this time from the National Academies of Sciences, Engineering and Medicine in Washington, D.C. – urged a related search. The report asked NASA to ramp up its research on alien biosignatures, which are signatures of life in all its various forms, including microbes. It urged NASA to incorporate the science of astrobiology – the study of life in the universe – more fully into all stages of future exploratory missions to the planets of our solar system.

The report is called An Astrobiology Strategy for the Search for Life in the Universe.

From the report:

Astrobiology is the study of the origin, evolution, distribution, and future of life in the universe. It is an inherently interdisciplinary field that encompasses astronomy, biology, geology, heliophysics, and planetary science, including complementary laboratory activities and field studies conducted in a wide range of terrestrial environments. Combining inherent scientific interest and public appeal, the search for life in the solar system and beyond provides a scientific rationale for many current and future activities carried out by the National Aeronautics and Science Administration (NASA) and other national and international agencies and organizations.

Requested by NASA, this study offers a science strategy for astrobiology that outlines key scientific questions, identifies the most promising research in the field, and indicates the extent to which the mission priorities in existing decadal surveys address the search for life’s origin, evolution, distribution, and future in the universe. This report makes recommendations for advancing the research, obtaining the measurements, and realizing NASA’s goal to search for signs of life in the universe.

Could this be a subsurface, liquid-water lake on Mars? The bright horizontal feature in this radar image represents Mars’ icy surface. The south polar layered deposits – layers of ice and dust – are seen to a depth of about a mile (1.5 km). Below is a base layer that in some areas is even brighter than the surface reflections, highlighted in blue. Analysis of the reflected signals suggests liquid water. Subsurface regions like this should be a high priority in the search for life, according to the new report. Image via ESA/NASA/JPL/ASI/Univ. Rome; R. Orosei et al. 2018.

The National Academies will appoint an ad hoc committee to initiate a study of the state of astrobiology as it relates to the search for life in the solar system and exoplanetary systems. The primary objectives of the study will:

– Take account of and build on NASA’s current Astrobiology Strategy 2015;

– Outline key scientific questions and technology challenges in astrobiology, particularly as they pertain to the search for life in the solar system and extrasolar planetary systems;

– Identify the most promising key research goals in the field of the search for signs of life in which progress is likely in the next 20 years;

– Discuss which of the key goals could be addressed by U.S. and international space missions and ground telescopes in operation or in development;

– Discuss how to expand partnerships (interagency, international and public/private) in furthering the study of life’s origin, evolution, distribution, and future in the universe;

– Make recommendations for advancing the research, obtaining the measurements, and realizing NASA’s goal to search for signs of life in the universe.

So what exactly is this report recommending? The National Academies said it wants NASA to expand on how it searches for evidence of life on other planets and moons. Future searches would include both past and present life, by using a more sophisticated catalog and framework to enhance NASA’s ability to detect – and this is significant – both life that might be similar to terrestrial life, and life that may be quite different from life as we know it on Earth.

Until now, NASA has focused on looking for evidence of life that is similar to earthly life, primarily microorganisms that use carbon, nitrogen and water. This led to the follow the water mantra that NASA has used, in particular for its exploration of Mars.

That approach makes sense to some degree, since on Earth, all life we know of requires water.

The new report from the National Academies recommends looking for alien life in two ways – both as we know it (on Earth) and as we don’t. Image via Chart: S. Seager & W. Bains Sci. Adv. 1, e1500047 (2015)/Cone: Ref. 5.

More recently, however, scientists have been considering the possibilities of more exotic forms of life, such as organisms based on methane instead of water. In this view, places like Saturn’s moon Titan – with its liquid methane/ethane lakes and seas – might be more habitable than previously supposed. The report recommends that NASA search for so-called agnostic biosignatures – in other words, for signs of life that aren’t tied to a particular metabolism or molecular blueprint, or other characteristics of life as we currently know it.

The report also recommends a comprehensive framework be established to aid in distinguishing between biosignatures and abiotic (non-living) phenomena, and also to improve understanding of the potential for biosignatures to be preserved (or not) over long planetary time-scales. It suggests the need for in-situ detection of energy-starved or otherwise sparsely distributed life such as chemolithotrophic or rock-eating life. This includes looking for evidence of life below the surface of a planet or moon; the subsurface is now thought to be the best place to look for such evidence on Mars, for example, especially after the discovery of a subsurface lake below the south pole.

This same strategy could, of course, also be applied to moons such as Jupiter’s moon Europa and Saturn’s moon Enceladus, which have subsurface oceans.

The recommendations also extend beyond our own solar system, saying that NASA should also use technologies in near-term direct imaging missions that can suppress the light from stars in order to image exoplanets. For more about this, read my earlier article here at EarthSky: Report calls for direct images of Earth-like exoplanets. These suggestions form a part of the National Academies’ Exoplanet Science Strategy.

Saturn’s moon Titan is another intriguing place to search for “life as we don’t know it.” Could organisms of some kind exist in its subsurface ocean or in the liquid methane/ethane lakes and seas on its surface? Image via Athanasios Karagiotas/Theoni Shalamberidze.

The report also highlights the need for specialized measurements, equipment and analysis required to take full advantage of space missions, including some that exist outside of traditional space science fields, as well as the need for interdisciplinary, non-traditional cooperation and collaboration with organizations outside of NASA.

As also noted, NASA missions have so far mostly been based on geological interests rather than astrobiological. This again has been particularly true with Mars – the Viking missions in the late 1970s to early 1980s were the last ones to focus specifically on looking for evidence of life – the results of which are still hotly debated to this day. Since then, the priority has been to search for evidence of past habitability. Not even past life, rather just the conditions that might have made life possible millions or billions of years ago.

The report stresses that an interdisciplinary approach to astrobiology is necessary toproduce a more complete picture of life on Earth as well as other planets. That approach should integrate the physical, chemical, biological, geologic, planetary and astrophysical sciences into the study of astrobiology to show how the relationship between life and its environment changes – producing a new, more dynamic view of habitability overall. NASA should continue to actively seek new mechanisms to reduce the barriers to these potential collaborations, the report says.

The last time that NASA looked directly for life on Mars, or any other planet or moon, was with the Viking mission in the late 1970s to early 1980s. Image via NASA/JPL.

An online event called An Astrobiology Science Strategy for the Search for Life in the Universe was livestreamed on October 10, 2018, but you can still watch it again here. A prepublication version of the written report is also available here.

Bottom line: NASA needs to expand its search for signs of extraterrestrial life, according to a new congressionally-mandated report from the National Academies of Sciences, Engineering and Medicine. Previous search strategies have mostly been narrowly focused, usually not looking for evidence of life at all. Hopefully these recommendations will bring us closer to discovering the first evidence of alien biology elsewhere in the solar system or beyond.

Source: An Astrobiology Strategy for the Search for Life in the Universe

Via The National Academies of Sciences, Engineering and Medicine

October 18, 2018

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