Illustration of the seven planets orbiting the TRAPPIST-1 ultra-cool low mass star. Planets e, f, and g orbit in the suspected habitable zone (green) based on the spectral type and modeling of the system. Note: the size of the planets is greatly exaggerated compared to their orbital
radii and that the radial dimension of the TRAPPIST-1 system has been enlarged by a factor of 25. In
other words, the entire TRAPPIST-1 system would fit well inside the orbit of Mercury.

A new report issued today has recommended that NASA should support research on a broader range of biosignatures and environments, and incorporate the field of astrobiology into all stages of future exploratory missions.

“An Astrobiology Strategy for the Search for Life in the Universe” is a Congressionally mandated report from the National Academies of Sciences, Engineering, and Medicine.

Europan environments that may harbor life or preserve biosignature. A variety of geologic and geophysical processes, including ocean currents governed by tides, rotation, and heat exchange, are required to drive water from the subsurface to the surface and govern how any exchange operates.
SOURCE: Kevin Hand, Jet Propulsion Laboratory, “On the Habitability of Ocean Worlds,” presentation
to the Workshop on Searching for Life across Space and Time, December 5, 2016.



Novel biosignatures

The blue-ribbon committee found that the lines of evidence now used to look for current and past life on Earth and beyond, called biosignatures, needs expansion.

Also, recommended is investigating novel “agnostic” biosignatures – signs of life that are not tied to a particular metabolism or molecular “blueprint,” or other characteristics of life as we currently know it.

Chemical evidence consistent with serpentinization and water-rock interactions on Enceladus and known hydrothermal activity make Enceladus a key target for astrobiology exploration.
Sampling the moon’s plumes would help to establish if life exists there now.
Southwest Research Institute


Diversity of life

The report explains that NASA should focus on research and exploration of possible life below the surface of a planet in light of recent advances that have demonstrated the breadth and diversity of life below Earth’s surface, the nature of fluids beneath the surface of Mars, and the likelihood of life-sustaining geological processes in planets and moons with subsurface oceans.

A renewed focus on how to seek signs of subsurface life will inform astrobiology investigations of other rocky planets or moons, ocean or icy worlds, and beyond to exoplanets.

Life detection technologies

The report emphasizes the need for NASA to ramp up efforts in developing mission-ready life detection technologies to advance the search for life. Highlighted is implementing technologies in near-term ground- and space-based direct imaging missions that can suppress the light from stars.

Flagged in the NASA-sponsored report is, so far, planning, implementation, and operations of planetary exploration missions with astrobiological objectives have tended to be more strongly defined by geological perspectives than by astrobiology-focused strategies.

Artist rendition of CubeSats at Europa. These twin CubeSats are currently in a feasibility
study to be included with the NASA Europa Clipper mission.

Private-sector space missions

Within its nearly 200 pages, the report notes that the burgeoning space economy and possibility of private-sector robotic and human missions to Mars pose challenges to compliance with articles VI and IX of the Outer Space Treaty.

“These challenges are complicated by the absence of a regulatory body in the U.S. with authority to authorize and supervise private-sector activities beyond low-Earth orbit,” the report states.

Planetary protection issues

The recent transfer of NASA’s Office of Planetary Protection (OPP) from the Science Mission Directorate to the Office of Safety and Mission Assurance is generally regarded as a positive change, the report adds.

“However, the move has had some negative consequences,” the report observes. The disestablishment of the Planetary Protection Subcommittee of the NASA Advisory Council has deprived the OPP of its primary internal source of independent scientific and technical advice. “Further, the long-term future of the Planetary Protection research and analysis program, long underfunded and offered only intermittently in recent years, remains unclear.”

The report — “An Astrobiology Strategy for the Search for Life in the Universe” – is available at:

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