On Wednesday, NASA announced its selection of two robotic mission concepts as the top finalists for a launch to be held in the mid-2020s: an exploration of Saturn’s moon Titan and a trip to a comet to retrieve compound samples for lab testing. While the missions are radically different in what they’ll investigate, both underscore a larger pivot in NASA’s allocation of time, resources, and manpower toward extraterrestrial worlds in the hopes of one day finding a planet or moon capable of hosting life—or already hosting, yes, aliens.
The mission to Titan, called Dragonfly, would send a dronelike spacecraft out to the moon to study the world’s chemistry and potential habitability. Titan is thought to possess a subsurface liquid ocean that could be a breeding ground for biological life. Along with Titan’s dense atmosphere, its conditions are extremely encouraging for scientists hoping to stumble on signs of extraterrestrial life within our solar system.
The other mission, the Comet Astrobiology Exploration Sample Return, or CAESAR, would expand on the European Space Agency’s Rosetta mission to assess the comet 67P/Churyumov-Gerasimenko. CAESAR would take a step forward and study the comet’s origin and history in hopes of learning more about how comets could be the delivery boys of materials essential to the evolution and support of life, such as water and other organic compounds.
NASA will select one mission sometime in spring 2019 for continued development, ostensibly for launch sometime in the next decade. But more importantly, the selection of these two missions, over 12 others, is key evidence that NASA is pivoting its science missions toward astrobiology. This is a purposeful pivot that makes sense given recent history.
In just a few years, for example, NASA will launch its Mars 2020 rover to the red planet with the explicit goal of investigating whether Mars was once habitable and home to extraterrestrial organisms. The Juno spacecraft currently orbiting Jupiter is surveying the planet’s atmosphere to learn whether gas giants are a sort of chemical lab for materials essential to life. Some agency experts are making the case for why other ocean worlds orbiting Jupiter and Saturn, like Enceladus or Europa, are worthy destinations for the search for alien life, too.
Outside the solar system, scientists already suspect nearly every star in the galaxy possesses a planet. Rough estimates suggest the vast majority of those aren’t gaseous giants like Saturn or Jupiter but rocky like Earth. Many of them, we’re learning as we tally up our exoplanet discoveries, sit in regions around their stars where they might be capable of possessing an atmosphere and liquid surface water—meaning life could make a home there. Of the 3,504 exoplanets scientists have found and confirmed, 53 are thought to be potentially habitable. And when you remember space is literally infinite, it seems bonkers to bet against the possibility life exists somewhere.
Additionally, the more we learn about life here on Earth, the more it seems possible that even in harsh environmental conditions, alien life could still evolve and learn to survive. The ability of tardigrades to survive the vacuum of space itself feels like proof of that.
There’s more reason to believe the astrobiology push is a permanent fixture of NASA’s vision for its future. Just this week, New Scientist reported on NASA’s ongoing efforts to develop plans for a robotic mission into interstellar space by 2069 (the 100-year anniversary of Apollo 11). The plan is to send a spacecraft to investigate the nearest exoplanet to Earth, Proxima b, located just 4.24 light-years away. Although those plans are far in the future and will require a massive upgrade in space propulsion technology, it’s clear the agency wants to be at the forefront of what is possibly the most exciting scientific endeavor of the century. (Russian billionaire Yuri Milner is already throwing $100 million to that goal in the form of his Breakthrough Starshot project, which aims to send ultralight nanocraft to explore the same region that’s home to Proxima b.)
This year, Congress told NASA to “search for life’s origin, evolution, distribution, and future in the universe.” It seems the agency is taking that directive to heart and pivoting to astrobiology.