NASA NASA finalists for New Frontiers: Rosetta's comet or Titan

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NASA selected two finalists for the next round of the New Frontiers program, missions with a cost below $850 million. Both get funding to further refine the proposals, in early 2019 one of them will be selected.

CAESAR wants to go back to 67P/Churyumov-Gerasimenko, previously visited by the Rosetta mission. It is a sample return mission hoping to get about 100 grams back to Earth. The results from Rosetta/Philae will help to design the mission to land on this weirdly shaped comet with a harder than expected surface.

Dragonfly is a much more ambitious project: A helicopter flying in Titan's atmosphere. The atmosphere has a four times higher density and the moon has a 6 times lower gravitational acceleration than Earth, so in principle flight should be easy there. If we ignore that the flight has to be fully autonomous due to the long light speed delay, the cold temperatures, and that there is no way to fix broken parts. Ironically, the fuel of helicopters on Earth, hydrocarbons, is abundant on Titan - but you can't use it as there is no free oxygen. The mission would fly with batteries, recharged by a radioisotope generator between flights. It combines the advantage of surface missions (analyzing samples) with a huge range that normally needs satellite missions.News articles: nytimes, spacepolicyonline

 

[Stavros Kiri]

A helicopter flying in Titan's atmosphere.

That sounds exciting and certainly novel. But both projects are very important. I wouldn't know which one to vote for.