WASHINGTON — NASA announced the latest mission in its New Frontiers program, called Dragonfly, will explore Saturn’s largest moon, Titan. It’s the only moon in our solar system that has an atmosphere.
Before it ended in 2017, the Cassini mission flew by Titan while studying Saturn. The data provided by the Hyugens probe, which was part of the Cassini mission, suggested that Titan was the perfect candidate for further exploration.
“It’s the first drone lander and it can fly over 100 miles through Titan’s thick atmosphere,” said NASA Administrator Jim Bridenstine in a statement. “Titan is most comparable to early Earth. Dragonfly’s instruments will help evaluate organic chemistry and the chemical signatures of past or present life. We will launch Dragonfly to explore the frontiers of human knowledge for the benefit of all humanity.”
The New Frontiers program has also included the Juno mission to Jupiter, the New Horizons probe that visited Pluto in 2015 and distant Kuiper Belt Object Ultima Thule on January 1.
The ultimate goal is for Dragonfly to visit an impact crater, where they believe that important ingredients for life mixed together when something hit Titan in the past, possibly tens of thousands of years ago.
It’s a Mars rover-sized drone, reaching about ten feet long.
Titan is similar chemically to Earth before life evolved, the agency said. They want to explore sand dunes on Titan to determine if they’re made of the same complex organic material discovered in the atmosphere.
“It’s the science that motivates us to do this exciting and difficult mission,” said Thomas Zurbuchen, NASA’s associate administrator for Science at the agency’s Headquarters in Washington.
“Titan has the key ingredients for life,” said Lori Glaze, director of NASA’s Planetary Science Division. “It has complex organic molecules and the energy required for life. We will have the opportunity to observe processes similar to what happened on early Earth when life formed and potentially conditions that could harbor life today. We can look for biosignatures.”
Once Dragonfly lands, it will spend two and a half years flying around Titan. It only has propellers, with skids to land, but no wheels to allow it to roam over the surface.
It will launch in 2026, but won’t reach Titan until the 2034 because Saturn is so far from us. Dragonfly will also explore Titan’s atmosphere, surface properties, subsurface ocean and liquid on the surface.
Titan isn’t exactly known for being hospitable. Larger than both our own moon and the planet Mercury, Titan is unique in our solar system. It is the only moon with clouds and a dense atmosphere of nitrogen and methane, which gives it a fuzzy orange appearance. Its atmospheric pressure is 60% greater than Earth’s, meaning it exerts the kind of pressure you feel at the bottom of a swimming pool, according to NASA. And the surface of Titan is minus 290 degrees Fahrenheit.
So it would make sense that the potential for life on Titan would have to look a little different than our planet. But Titan’s atmosphere may not be much different than that of primordial Earth’s — and life found a way here. It may not be like the alien life in science fiction, but in 2017 researchers confirmed the presence of something that may lead to life on Titan, according to a study published Friday in the journal Science Advances.
Vinyl cyanide is a complex organic molecule capable of forming cell membrane-like spheres. While it may sound toxic, this chemical would be right at home on Titan, where significant quantities of it have been detected through data from the Atacama Large Millimeter Array (ALMA), a group of radio telescopes in Chile.
Titan also has Earth-like liquid bodies on its surface, but the rivers, lakes and seas are made of liquid ethane and methane, which form clouds and cause liquid gas to rain from the sky.
The surface temperature is so cold that the rivers and lakes were carved out by methane, the way rocks and lava helped to form features and channels on Earth.
These methane pools on the surface are the kind of environment that could help vinyl cyanide molecules link together to form cell-like membranes, not unlike the basis for organisms on Earth. “The presence of vinyl cyanide in an environment with liquid methane suggests the intriguing possibility of chemical processes that are analogous to those important for life on Earth,” said Maureen Palmer, lead study author and researcher at NASA’s Goddard Space Flight Center.
The ALMA data confirmed what previous studies and simulations, like one from Cornell University in 2015, had predicted about the potential presence of this molecule on Titan. “Researchers definitively discovered the molecule, vinyl cyanide. That is our best candidate for a ‘protocell’ that might be stable and flexible in liquid methane,” said Jonathan Lunine, a Cornell professor who participated in the 2015 study. “This is a step forward in understanding whether Titan’s methane seas might host an exotic form of life.”
Titan is also believed to have an internal liquid water ocean, like those on Europa, one of Jupiter’s moons, and Enceladus, another of Saturn’s moons. Earlier this year, NASA announced that Europa and Enceladus’ oceans have some or most of the ingredients necessary for life as we know it.
But how does Titan compare? First of all, it’s bigger than Europa and Enceladus. It’s also entirely unique in its possession of a dense atmosphere, which has obscured the observations that researchers have tried to make of Titan. And Titan doesn’t have confirmed active geysers on its surface like those other moons.
Given its complex chemistry, it’s safe to say that Titan isn’t hospitable to humans. But it is attractive to researchers. “Saturn’s moon, Enceladus, is the place to search for life like us, life that depends on — and exists in — liquid water,” Lunine said. “Titan, on the other hand, is the place to go to seek the outer limits of life — can some exotic type of life begin and evolve in a truly alien environment, that of liquid methane?”