A nuclear powereddrone could soon explore the skies and surface of Saturn’s moon Titan.
The eight-bladed ‘dragonfly’ drone would fly from one region of Titan to the next, recharging while landed using its own nuclear generator.
It could investigate potentially habitable sites on the moon, which has methane and ethane lakes and rivers.
The Johns Hopkins Applied Physics Laboratory (APL) has submitted a proposal to NASA outlining the drone mission, and later this fall NASA is expected to select a few of the ‘New Frontiers’ mission proposals for further study – but only one will be chosen for flight.
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The eight-bladed ‘dragonfly’ drone would fly from one region of Titan to the next, recharging while landed using its own electric generator
The NASA New Frontiers competition, which selects a new mission every five years, has six themes, including sample-return missions from comets or the moon, an ocean worlds explorer, a probe to Saturn, exploration of the Trojan asteroids and a Venus in-situ explorer.
Dragonfly is one of the candidates, and NASA will narrow down suggestions in November, and make a final selection in July 2019.
The drone concept would take advantage of the rapid advances made in recent years to autonomous aerial systems, which is sometimes referred to as the ‘drone revolution.’
Titan has diverse, carbon-rich chemistry on its surface, which is dominated by water ice and an interior ocean.
It’s one of a few ‘ocean world’s’ in our solar system that has the ingredients for life, and the rich organic material that covers the moon is undergoing chemical processes that might be similar to those on early Earth.
The researchers want to take advantage of Titan’s dense, flight-enabling atmosphere to visit multiple sites by landing on safe terrain, and then moving to more challenging landscapes.
‘This is the kind of experiment we can’t do in the laboratory because of the time scales involved,’ said APL’s Elizabeth Turtle, principal investigator for the Dragonfly mission.
‘Mixing of rich, organic molecules and liquid water on the surface of Titan could have persisted over very long timescales.
‘Dragonfly is designed to study the results of Titan’s experiments in prebiotic chemistry.’
Dragonfly wouldn’t just fly from site to site, it could also drill and take samples, and examine the moon’s surface. Sensors would allow it to track Titan’s atmosphere and weather – which has a methane cycle instead of Earth’s water cycle
The team has already built and flown prototypes of the craft on Earth, which flies using its own autonomous software
At each site, the Dragonfly drone would sample the surface and atmosphere with a suite of instruments that will assess the habitability of Titan’s environment, how far prebiotic chemistry has progressed, and also search for chemical signatures or water and/or hydrocarbon-based life.
These measurements include mass spectrometry to reveal the composition of the surface and atmosphere, gamma-ray spectrometry to measure the composition of the shallow sub-surface, meteorology and geophysics sensors to measure atmospheric conditions such as wind, pressure, temperatures and seismic activity, and a camera suite to characterize the moon’s surface and find landing sites.
The researchers want to take advantage of Titan’s dense, flight-enabling atmosphere to visit multiple sites by landing on safe terrain, and then moving to more challenging landscapes
‘We could take a lander, put it on Titan, take these four measurements at one place, and significantly increase our understanding of Titan and similar moons,’ said the project’s manager Peter Bedini.
‘However, we can multiply the value of the mission if we add aerial mobility, which would enable us to access a variety of geologic settings, maximizing the science return and lowering mission risk by going over or around obstacles.’
Titan’s environment was first discovered by the Cassini-Huygens mission in 2005, when it discovered that Methane rained into lakes and seas.
Over the years, it has revealed chemical environments with the potential to lead to life as it did on Earth.
‘The results are just sitting on the surface,’ said Dr Turtle.
‘If we can get to these different places on the surface of Titan, we can pick up the results of the experiments.
‘They’re just waiting for us,’ she said.
To explore Mars, researchers used rovers.
Each one could travel tens of miles over their lifetime, and as of April 2017 NASA’s Opportunity Rover has travelled more than 27 miles.
But instead, Dr Turtle wants to use drones to travel in Titan’s thick atmosphere, which is four times more dense than Earth’s and would make drone flight easier.
Another feature that makes Titan appealing to explore with drones is its low gravity environment – its gravity is only a tenth as strong as Earth’s.
This means that flight on Titan is easier and the drone could move by a few tens of kilometers in one flight.
This NASA image shows Saturn’s moon, Titan, in ultraviolet and infrared wavelengths. The Cassini spacecraft took the image while on its mission to gather information on Saturn, its rings, atmosphere and moons. The different colors represent various atmospheric content on Titan
A giant of a moon appears before a giant of a planet undergoing seasonal changes in this natural color view of Titan and Saturn from NASA’s Cassini spacecraft. (Photo by: Universal History Archive/UIG via Getty Images)
Other Titan missions suggestions have included balloons and airships, but these always need to remain in the air which uses more power and don’t allow for exploring the ground surface.
But the Dragonfly lander would use use two rotors at each of its four corners to fly from one region of the moon to the next, and recharge using a multimission radioisotope thermoelectric generator (MMRTG) it would carry with it, which converts the heat from decaying radioactive plutonium-238 into electricity.
This could allow the Drangonfly to fly for decades potentially, especially considering Titan’s thick atmosphere would also block out radiation which could harm the drone.
Titan’s dunes are gigantic, reaching, on average, 0.6 to 1.2 miles (1 to 2 kilometers) wide, hundreds of miles (kilometers) long and around 300 feet (100 meters) high
If NASA chooses to fund Dragonfly, it could launch in the mid 2020a and arrive in the 2030s.
While data from Cassini could provide potential landing locations, the drone could also scout them out.
After landing it could map potential sites to explore, or sit tight and wait for researchers to decide where it should go next.
The Cassini aircraft made its 127th and final close approach to Titan on April 21, 2017. On April 26, the spacecraft made the first in a series of 22 dives through the gap between Saturn and its rings as part of its mission’s grand finale. Cassini will end its expedition on September 15, 2017, with a final plunge into the gas giant
But Dragonfly wouldn’t just fly from site to site, it could also drill and take samples, and examine the moon’s surface.
Sensors would allow it to track Titan’s atmosphere and weather – which has a methane cycle instead of Earth’s water cycle.
The moon’s giant sand dunes could be a good potential exploration target as they may consist of a variety of materials from across Titan’s surface.
NASA’s Huygens probe descended onto the mysterious world of Titan 12 years ago. Because Titan is smaller than Earth, its gravity does not hold onto its gaseous envelope as tightly, so the atmosphere extends 370 miles (595km) into space.
Impact craters also might be interesting exploration sites, as they may have melted ice in the crust and put liquid water in contact with organic materials.
The drone, which would cost $1 billion, would arrive during Titan’s northern hemisphere winter, so it would start in the south.
TITAN: EARTH’S ‘TOXIC TWIN’
In the case of Titan these are liquid methane rather than water on Earth.
Regular Earth-water, H2O, would be frozen solid on Titan where the surface temperature is -180°C (-292°F).
Titan is the only place in the solar system known to have rivers, rainfall and seas – and possibly even waterfalls. Two images taken by Cassini of Titan (pictured) on April 18, 2017
With its thick atmosphere and organic-rich chemistry, Titan resembles a frozen version of Earth several billion years ago, before life began pumping oxygen into our atmosphere.
Because Titan is smaller than Earth, its gravity does not hold onto its gaseous envelope as tightly, so the atmosphere extends 370 miles (595km) into space.
With Titan’s low gravity and dense atmosphere, methane raindrops could grow twice as large as Earth’s raindrops.