Destination Moon(s)
It may not generate as much public interest as current plans for crewed landings on Earth's own lunar companion, but the push to send robots to explore moons of the outer solar system may ultimately be the more fateful and noteworthy spaceflight trend of the early 21st century.
For decades, a scientific renaissance of sorts has been simmering for such worlds, many of which despite being so far removed from the sun's radiance seem to harbor vast oceans within their frigid crusts. If there's one lesson to draw from the multibillion-year history of Earth's biosphere, it's that wherever there is liquid water, there can also be life. Perhaps the same holds true for the roofed seas of these far-distant moons. Icy ocean-bearing moons, in fact, could even be the default locales for life in the universe. But to unlock the secrets of these strange new worlds, we must first visit some of them.
NASA's Europa Clipper mission, which launched on Monday to the eponymous moon of Jupiter, is the poster child for this new branch of astrobiological inquiry. Together with another spacecraft, the European Space Agency's JUICE orbiter, in the 2030s it will seek out signs of habitability and perhaps even of life itself on Europa, via sophisticated instruments that will map the moon's surface, study its composition, and even provide piercing glimpses of what lies beneath its icy shell.
What these investigations will actually find, I can only guess, but they're guaranteed to be exciting: Europa is widely considered the most likely place in the solar system for extraterrestrial life to currently exist. Whether that speculation is confirmed or refuted, the implications will be staggering.
—Lee Billings
