Proposal for the moon
The South Pole-Aitken Basin on the moon has long been on the wish list of destinations for planetary scientists. The basin, 1,600 miles wide and eight miles deep, is the scar of a cataclysmic impact more than 4 billion years ago, deep enough that parts of the moon’s mantle could have been exposed.
Therefore a spacecraft going there would be able to pick up bits from the inside of a rocky world not easily found elsewhere in the solar system. The proposed MoonRise mission would even bring some dirt and rocks back to Earth for scientists to examine directly.
Proposals to chase comets
The European Space Agency’s Rosetta mission spent a couple of years flying around Comet 67P/Churyumov-Gerasimenko, even putting a small lander down on the surface.
Comet Nucleus Dust and Organics Return, or Condor, proposed by NASA’s Jet Propulsion Laboratory, would return to Comet 67P, scoop up samples and bring them to Earth for closer study.
The Comet Rendezvous, Sample Acquisition, Investigation, and Return, or Corsair, a collaboration between NASA Ames Research Center and the Johns Hopkins University Applied Physics Laboratory, is similar to Condor except it would bring back samples from a different comet: 88P/Howell.
Van Kane, a blogger following planetary science missions, reported in October that there is a third proposal for a cometary sample return, named Caesar, led by Steven W. Squyres of Cornell University, the principal investigator for the Opportunity rover on Mars. But nothing else is known, not even what Caesar stands for.
Proposals for Saturn
To build upon the success and legacy of the Cassini mission to Saturn, which ended this year, five missions have been proposed to return to the ringed planet or its moons.
The Saturn Probe Interior and Atmosphere Explorer, or Sprite, would do essentially what the Cassini spacecraft did in September — drop into Saturn — except Sprite would go much deeper. Measuring the ratio of helium to hydrogen would explain where Saturn formed, an important piece of information for understanding how the solar system came together.
Enceladus, a tiny moon of Saturn, shoots a plume of ice from its south pole, emanating from a subsurface ocean. The Enceladus Life Finder, or Elf, led by Jonathan I. Lunine of Cornell University, would fly through the plumes with instruments that could identify carbon-based molecules and other ingredients to discern if the oceans possess conditions amenable for life.
Another proposal to visit the icy satellite, led by Christopher P. McKay, an astrobiologist at NASA Ames Research Center, is called Enceladus Life Signatures and Habitability, or Elsah, but no details are known.
Two missions have also been proposed to study Titan, which is Saturn’s biggest moon and has seas of hydrocarbons.
Oceanus, led by Christophe Sotin, the chief scientist for solar system exploration at the Jet Propulsion Laboratory, would study Titan from orbit.
Dragonfly, proposed by the Johns Hopkins University Applied Physics Laboratory, is perhaps the most unusual spacecraft concept. It would essentially send a self-flying helicopter to explore Titan, hopping from one intriguing spot to another.