Jonathan Lunine at the University of Arizona has just posted his intent to develop a proposal for a Titan Aerial Explorer. From his announcement, "The mission to be proposed includes a balloon with the capability for ground-penetrating radar, radio science and multi-spectral imaging and spectroscopy, aerosol analyses, and possibly other instruments. The goal is to explore the processes that are at work on the surface on and near-surface of Titan with sufficient resolution and wavelength capability to quantify Titan’s methane hydrologic cycle." The proposal would be submitted for the European Space Agency's next Medium class science mission for launch around 2022.
Editorial Thoughts: I would like to see one or more Titan in-situ missions fly in the 2020's. Titan's thick atmosphere and low gravity makes it an easy world (once you spend many years flying there) to land on, float above, or fly around. Lunine's mission potentially would face several challenges such as power (ESA currently does not have plutonium power sources, which as I understand it would be necessary both for power and to heat the gases for the balloon) and bringing the balloon technology up to flight readiness (the Titan Flagship mission's balloon reportedly was judged to require further technology development before flight). However, Dr. Lunine has a solid resume, so he must have ideas on how to address these problems.