NASA has selected two finalist concepts for a robotic mission planned to launch in the mid-2020s: a comet sample return mission, Comet Astrobiology Exploration Sample Return (CAESAR), and Dragonfly, a drone-like rotorcraft that would explore potential landing sites on Saturn’s largest moon, Titan. Steve Squyres, James A. Weeks Professor of Physical Sciences in Cornell’s Department of Astronomy, is the principle investigator for CAESAR. 

NASA announced the concepts Dec. 20, following an extensive and competitive peer review process. The concepts were chosen from 12 proposals submitted in April under a New Frontiers program announcement of opportunity.

“This is a giant leap forward in developing our next bold mission of science discovery,” said Thomas Zurbuchen, associate administrator for NASA’s Science Mission Directorate in Washington. “These are tantalizing investigations that seek to answer some of the biggest questions in our solar system today.”

The CAESAR mission seeks to return a sample to earth from the nucleus of 67P/Churyumov-Gerasimenko, a comet that was successfully explored by the European Space Agency’s Rosetta spacecraft, to determine its origin and history. Comets are made up of materials from ancient stars, interstellar clouds, and the birth of our Solar System. The CAESAR sample will reveal how these materials contributed to the early Earth, including the origins of the Earth's oceans, and of life. Led by Squyres, CAESAR would be managed by NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

 “The end date of the flight will really be the beginning,” said Squyres at NASA’s press conference after the announcement. “The science will extend for decades after the sample comes back.”

The CAESAR and Dragonfly missions will receive funding through the end of 2018 to further develop and mature their concepts. NASA plans to select one of these investigations in the spring of 2019 to continue on to subsequent mission phases.  

The selected mission will be the fourth in NASA’s New Frontiers portfolio, a series of principal investigator-led planetary science investigations that fall under a development cost cap of approximately $850 million. Its predecessors are the New Horizons mission to Pluto and a Kuiper Belt object known as 2014 MU69, the Juno mission to Jupiter, and OSIRIS-REx, which will rendezvous with and return a sample of the asteroid Bennu.

The call for concepts was limited to six mission themes: comet surface sample return, lunar south pole-Aitken Basin sample return, ocean worlds (Titan and/or Enceladus), Saturn probe, Trojan asteroid tour and rendezvous, and Venus in situ explorer.

New Frontiers Program investigations address NASA’s planetary science objectives as described in the 2014 NASA Strategic Plan and the 2014 NASA Science Plan. The program is managed by the Planetary Missions Program Office at NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Planetary Science Division in Washington.

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