NASA’s real challenge will be sending a drone to Saturn’s moon Titan. Their mission Dragonfly to search for life on Titan as well as to study how life begins on planet Earth.
The next step in exploring our solar system is to fly on other worlds. To show the technology, the Mars Helicopter will piggyback on NASA’s Mars 2020 rover mission. But this is just the beginning. The real challenge will be the 2026 Dragonfly mission, sending a drone to the biggest moon of Saturn, Titan–as NASA has just announced.
It requires air or, more usually, an atmosphere for a craft to become airborne. Only a couple of objects fit that bill in our solar system. Titan boasts a thicker atmosphere than Earth, which has long engulfed this world in mystery. Studies have shown that Titan can host primitive life forms and is the perfect location to study how life on our own planet might have arisen.
Titan is behind Jupiter’s Ganymede and is the second largest moon in the solar system. In fact, the 5,149 km diameter of Titan is greater than the 4,880 km diameter of the planet Mercury. Its environment is mostly nitrogen (96%), close to Earth’s atmosphere (80% nitrogen, the rest oxygen and less than 1% of other trace gases).
From 2004 to 2017, the Cassini spacecraft orbited Saturn and was the first to use radar and other instruments during multiple flybys to peer under the clouds of Titan.
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In 2005, the Huygens probe touched the surface of Titan. It disclosed that Titan is the only world in our solar system other than Earth with a hydrological cycle that is presently active— complete with rain, rivers, and lakes, some over 100 meters deep. The only difference is that the clouds don’t rain water.
Because Saturn and its moons are about ten times far from the sun than the Earth, temperatures are so low (-179° C on average) that water is in the form of frozen solid and acts like rocks on earth.
The lakes on Titan are filled with the liquid form of methane gas. In the atmosphere of Titan other complex organic (meaning carbon-based) molecules form and fall like snow. Then, this snow is rearranged by the wind into dunes.
In 2034, the Dragonfly mission will land safely in one of these dune fields called Shangri-La. From there, to investigate the nature of organic material, it will fly to different locations.
The significant aspect of the mission is to shed light on the processes leading to the origin of life on Earth. We understand that macromolecules like DNA and proteins have been created from simpler organic molecules like amino acids. But in this process, we haven’t pinned down the precise intermediate steps— something we can observe on Titan.
With all these building blocks around, there is speculation as to whether life could exist on Titan, for instance in the form of microorganisms. Life at the very fundamental stage is believed to require at least three components: liquid water, a source of carbon, and a source of energy.
Although Titan has plenty of carbon around, the cold temperatures hold water as ice and also restrict the available energy. However, liquid water may exist under the frozen ground. We also know that water plumes erupting from the neighboring moon Enceladus rain down to the upper atmosphere of Titan, offering a main source of oxygen.
Also Read: Secrets of Jupiter’s Moon
There are many types of microorganism that can live on Earth under extreme circumstances known as extremophiles. But even among these, basic functions of life take hold at temperatures below -20°C. So, we would need to extend the envelope of appropriate conditions we know from Earth quite far for life to occur on Titan.
But then again, Earth’s life is the only example we know of to date, and in our imagination, we may be restricted. Even if it only looks like a distant option, the Dragonfly mission will correctly evaluate Titan’s habitability and look for indications of previous or present signs of potential life.
The Selk impact crater with a diameter of 80kms is one of the flight destinations to address both how life originated on Earth and whether it presently exists in the crater. Here, the impact that created it on the geological time scale in relatively recent times melted water ice and provided heat energy to allow such reactions to occur.
Flying a drone on Titan promises to be a wonderful experience that takes us back in time as well!