SpaceX's Falcon Heavy rocket will launch NASA probe to Saturn's largest moon

NASA has announced that a SpaceX Falcon Heavy rocket will launch NASA's Dragonfly, a car-sized octocopter drone that will explore Saturn's moon Titan, the most unusual moon in our solar system.

Dragonfly is scheduled to launch in 2028 and will need one of the most powerful rockets in the world to carry it to Titan because the robotic probe itself is big.

Measuring 3.85 metres long and just as wide, the 875-kilogram, car-sized probe sports eight rotors that will enable it to fly through the thick atmosphere of Saturn's largest moon, landing at times to sample the surface.

Titan is the only moon in the solar system with an atmosphere about 1.5 times as dense at its surface as the air on Earth.

The moon also has low gravity, only one-seventh of our planet, which together will make it easy for such a large vehicle to fly above the alien landscape during it's mission, set to last a little over three years. That duration might be conservative as many vehicles sent to other planets far outlive their expected lifetimes.

Our first observations of Titan from space came when the Pioneer 11 spacecraft passed within 355,600 kilometres of the moon in 1979, revealing an orange cloud-shrouded globe with temperatures likely too cold for all known forms of life. 

Humanity got a second, much closer look at Saturn's largest moon from a distance of 6,492 kilometres with the Voyager 1 spacecraft in 1980, when a scientist described it as a primitive Earth in deep freeze because the organic chemicals on its surface are similar to those thought to have existed on our planet before life evolved.

Titan's surface was obscured by its hazy brown clouds in those early observations. However, later observations by the Hubble space telescope, the Cassini mission — which carried instruments that could peer through the clouds — and an amazing touchdown on the surface by the European Huygens probe, revealed a truly alien world. 

In some ways, Titan seems remarkably Earth-like, with a mostly nitrogen atmosphere, clouds, rain, rivers, lakes and seas. It's the only known world beyond Earth with liquids on its surface. But unlike Earth, the ingredients are in a different order.

The rain and the liquid that flows in its rivers and fill its lakes are methane and ethane, which are the main ingredients in natural gas. This is because of the ultra cold temperatures at the surface of –179 C. 

At those temperatures, water is frozen as hard as rock. And in fact, it's ice that forms Titan's hard surface, while a liquid water ocean resides beneath that icy crust. So Titan is referred to as an ocean world similar to Jupiter's moon Europa and Saturn's moon Enceladus.

The Dragonfly probe is equipped with a suite of instruments and a drill to sample and analyze the chemistry of the surface, searching for the building blocks of life and, who knows, maybe signs of current or extinct life.

Perhaps it should include a fishing rod so it could land beside one of the methane lakes and toss in a line with a lure to see if anything bites.

The probe will take six years to reach Titan and is expected to spend another three years exploring it during this $4.7 billion mission. Although, the spacecraft is nuclear-powered so it has the capacity to run much longer. 

Dragonfly will be largely on its own due to the tremendous distance between Earth and Titan where a radio signal takes about an hour and a half each way. The vehicle has cameras for navigation and a light detection and ranging (LIDAR) system to map the surface in 3D to choose safe places to land. 

This is a mission of pure discovery, where surprises are expected to be the norm. It's the robots who are the first to go where no one has gone before, and Titan is indeed a strange new world.