Today, we are on the cusp of amazing discoveries that could tell us more about the possibility of life off the Earth. In fact, astrobiology, which includes the search for life elsewhere, is one of our key priorities at NASA.
The Spirit and Opportunity rovers enabled NASA to discover that Mars had a massive ocean, a thick atmosphere, and a magnetosphere that protected it from the radiation of deep space. In other words, at one time Mars was potentially habitable! The Phoenix lander discovered pure water ice on Mars, and the Curiosity rover found complex organic compounds and methane cycles on Mars. The probability of finding life or past life on another world keeps going up.
Now, the Perseverance rover is en route to Mars on NASA’s first dedicated astrobiology mission. Samples returned from this trip could conclusively determine whether microbial life lived on Mars. Upcoming missions like Dragonfly to Saturn’s moon Titan and the Europa Clipper to study Jupiter’s ocean moon Europa will once again assess the possibilities of life on other worlds. Data from Saturn’s moon Enceladus and other bodies point to many exciting discoveries yet to be made.
NASA’s deep space astrophysics capabilities are also being used for astrobiology. Our telescopes not only peer into other galaxies and discover exoplanets around other stars, they also assess exoplanet atmospheres to find the elements necessary to host life and even look for atmospheric biosignatures. An intriguing discovery recently released by the Royal Astronomical Society about the atmosphere of Venus could also point toward biosignatures.
As we seek to expand our knowledge of our own solar system, four spectacular missions are being considered for up to two Discovery missions to be selected next year. Among them are an astrobiology mission to Neptune’s moon Triton and a geological mission to the most volcanically active planetary body in the solar system, Jupiter’s moon Io. The other two missions being considered have proposed missions to Venus. One is focused on understanding its atmosphere and the other is focused on understanding Venus’ geological history. There is no doubt that NASA’s Science Mission Directorate will have a tough time evaluating and selecting from among these very compelling targets and missions, but I know the process will be fair and unbiased. The U.S. is also partnering with Europe on another proposed Venus mission called EnVision that could be selected to go to our next-door neighbor.
As is normal in science, the more we learn, the more questions we have. This is the virtuous cycle of discovery, including the discovery of potential biosignatures on other worlds. We at NASA are incredibly fortunate to have so many opportunities to pursue and such talented scientists, engineers, and partners capable of pursuing them. Every day gets more exciting for all of us and I can’t wait for the next discovery!