When reading the Discover Magazine article How New Horizons Survived the 40-Year-Glitch and Made it to Pluto while writing this question I saw "...the new NASA administrator tried to kill New Horizons in favor of a high-tech fission-powered mission." (see below for the context):
What was the high-tech fission-powered mission? Does it have a name - and is it described somewhere?
The missions had such hopeful names: Pluto 350, Pluto Fast Flyby, Pluto Express. Finally, Stern came up with the winning concept, New Horizons. His final proposal was due one week after 9/11, while the offices of the Johns Hopkins University Applied Physics Lab (which operates the mission) were still shut. Stern completed the proposal and NASA approved it.
The following year, the new NASA administrator tried to kill New Horizons in favor of a high-tech fission-powered mission. He failed, and New Horizons survived. One benefit of its long, difficult competition is that Stern and the mission engineers came up with a relatively inexpensive, flyweight spacecraft. New Horizons weighs about half as much as Voyager 1, and in real dollars costs roughly one-third as much. Placing a lightweight probe atop a large Atlas V rocket yielded the fastest object ever launched when New Horizons took off in 2006...