Why a group of scientists think we need another mission to Pluto

In the summer of 2015, a tiny NASA spacecraft called New Horizons zoomed by Pluto, giving us our first ever up-close look at this tiny world at the edge of the Solar System. But many are starting to think that flying by Pluto just once was not enough. A group of scientists argue that we have to go back to the dwarf planet — and this time, we need to put a spacecraft in its orbit.
On Monday, dozens of planetary scientists — including Alan Stern, the principal investigator of the New H