NASA has shortlisted two new robotic space missions to explore the outer Solar System, with both returning to familiar targets.
One, called Dragonfly, would fly a drone around Saturn’s largest moon Titan, which was explored by the Cassini-Huygens mission.
The other would take us back to Comet 67P Churyumov-Gerasimenko, the celestial wanderer studied for two years by Europe’s Rosetta spacecraft.
Dragonfly’s drone, officially described as a dual-quadcopter lander, wiould be able to fly to several locations across Titan, hundreds of kilometers apart.
Titan is unique because it is the only moon to have a dense atmosphere like the Earth, with weather and rain.
It is also remarkable for having Earthlike features, including seas, lakes and rivers. But they are filled with liquid methane rather than water.
Titan’s inhospitable atmosphere is an orange petrochemical smog. But scientists believe the remote moon could be like Earth was three billion years ago, before oxygen was introduced into our then poisonous atmosphere.
In January 2005, Cassini’s piggyback probe Huygens landed on Titan, which is 5,151 km (3,200 miles) in diameter, and bigger than our own Moon. It took photos of an amazing alien landscape as it parachuted through Titan’s atmosphere, plus rocks in the lake bed where it touched down.
The Dragonfly mission, which would launch in the mid 2020s, will analyse material on Titan’s surface to investigate its organic chemistry and habitability.
Other experiments would monitor atmospheric and surface conditions, and image landforms to investigate geological processes, and perform seismic studies.
Related: Is there life on Titan?
Amanda Hendrix, a Senior Scientist at the Planetary Science Institute in Tucson, Arizona, said, “I am very excited about the Dragonfly concept. Titan is such a fascinating and Earth-like world, with its thick atmosphere, weather and surface liquids.
“I like that Dragonfly takes advantage of the Titan environment, namely the low gravity and thick atmosphere, to explore multiple sites across the diverse world. The Huygens probe gave us a first tantalizing glimpse of the surface of Titan, and I’m eager to see more.”
The second concept mission to be shortlisted is called CAESAR (Comet Astrobiology Exploration Sample Return), and it would also laucnh in the mid 2020s.
CAESAR would fly back to Comet 67P Churyumov-Gerasimenko to collect a 110g (3.5 oz) sample from its surface and fly it back to Earth, parachuting it to the ground for scientists to study in their laboratories.
The comet, a leftover fragment from the formation of the Solar System, is known to be packed with water ice and organic materials. Some astronomers believe that the ingredients for life could have been brought to Earth by comets.
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