Search for Life

A grand challenge for the U.S. space program

Over the last several months, U.S. voters have had the chance to examine the views of Hillary Clinton and Donald Trump on a wide range of issues. Thanks to the initiative taken by ScienceDebate.org, candidate views on questions dealing with science, innovation and education have now been made available and have given us much to think about.

Nine space-related questions SpaceNews put to the candidates this month yielded mostly noncommittal answers.

There is an unfortunate tendency to frame the coming space debate around what launch vehicle we should be designing, or which celestial body we should  establish as our main, long-term exploration objective. There are strongly held views, and fiercely entrenched positions,  on these issues within the space community. What is lost in this debate is the real scientific potential for the space program, which goes far beyond exploration. What scientific opportunities will present themselves during the next administration?

At this unique point in our human history, our nation can undertake a significant grand challenge — the search for life beyond the confines of the Earth. The discovery of life elsewhere will have at least as profound an impact on our 21st century society as the Apollo moon landings had in the last century. It will create a defining moment, a tipping point, in human history. Success will require cross-disciplinary research from astrophysicists, biologists, engineers, planetary scientists, astronauts, industry leaders and many others. This is a scientific and human-exploration vision that is worthy of a grand challenge for our great nation and its space agency. For the first time in human history, the ability to discover evidence of biological activity on planets circling nearby stars is within reach.

CREDITS: TESS: MASSACHUSETTS INSTITUTE OF TECHNOLOGY/TESS TEAM ARTIST’S CONCEPT; JWST: NORTHROP GRUMMAN ARTIST’S CONCEPT; WFIRST: NASA’S GODDARD SPACE FLIGHT CENTER/CI LAB; EUROPA CLIPPER: NASA/JPL-CALTECH ARTIST’S CONCEPT

CREDITS: TESS: MASSACHUSETTS INSTITUTE OF TECHNOLOGY/TESS TEAM ARTIST’S CONCEPT; JWST: NORTHROP GRUMMAN ARTIST’S CONCEPT; WFIRST: NASA’S GODDARD SPACE FLIGHT CENTER/CI LAB; EUROPA CLIPPER: NASA/JPL-CALTECH ARTIST’S CONCEPT

The fact that the Earth is the only place we know of so far where life has emerged, is only a limitation of our knowledge, the Earth is not “special.” Consequently, the discovery of extraterrestrial life would have a revolutionary impact far beyond its importance for astronomy or biology, since it would affect essentially all areas of thought and belief. In particular, such a discovery would deny any cosmic teleology, or grounds for special origination.  The phenomenon of life will demonstrably become a natural outcome of the laws of physics and chemistry.

In the last two decades, the United States and other advanced nations have embarked on ambitious efforts to search for signs of life, both within and beyond our solar system, employing a combination of spacecraft missions, ground-based astronomical observations and biological studies. Rovers look for evidence of water and microbial activity on the surface of distant Mars. Studies of the moons of Jupiter and Saturn offer intriguing signs of environments that may harbor life in some form. Hubble and other telescopes give us a sense of our place in the universe, and yield tantalizing evidence for other worlds around nearby stars.

We have gained deep insights into the complex interaction of life’s multifaceted expressions with the terrestrial ecosystem. Through examination of life in extreme environments on Earth, we have expanded our understanding of the limits of life and are perhaps getting closer to understanding the conditions in which it may have arisen. In just the last five years, using NASA missions, we have discovered thousands of planets around other stars.

Soon, with the next generation of telescopes now being planned, we will be able to isolate a number of stars that could potentially harbor Earth-like planets in habitable zones using the upcoming NASA Transiting Exoplanet Survey Satellite (TESS) mission, the James Webb Space Telescope (JWST) and the Wide Field Infrared Telescope (WFIRST). However, even these can only tell us where to look. The ultimate challenge is direct detection of “bio-signatures” – features in the planet’s spectrum that would indicate chemistry of geological/biological equilibrium for life as we know it. These signatures include the presence of water, molecular oxygen, ozone, and smaller amounts of carbon dioxide and methane. Astrobiologists are now working with both NASA and National Science Foundation to understand what the bio-signatures of other conceivable forms of life might be.

America’s investment in space and science is an investment in our intellectual leadership, our economic competitiveness and our future. We must maintain our global leadership in space and science, and sustain our reputation as a scientifically literate nation.

Charting the path for human exploration in space is an important matter. But we should not lose sight of the need for leadership in space science. Defining a grand challenge for science is as important as defining a human exploration goal. That grand challenge can be the search for life beyond Earth.

William S. Smith is vice president of ScienceWorks Inc., a consulting firm helping people and organizations succeed in science and engineering research. He is a former president of the Association of Universities for Research in Astronomy.