Editing Pluto Kuiper Express (section)

== History ==
[[File:Pluto Fast Flyby.jpg|thumb|Artist's impression of ''Pluto Fast Flyby'' at [[Pluto]] and [[Charon (moon)|Charon]].]]
[[File:Pluto Fast Flyby Remake.png|thumb|Artist's impression of ''Pluto Fast Flyby'' at [[Pluto]].]]
[[File:20150626 pluto-ff.jpg|thumb|Artist's vision of ''Pluto Fast Flyby'' approaching [[Pluto]]'s mottled surface. A tenuous, transient atmosphere is visible as blue haze beyond the bright limb while Pluto's companion [[Charon (moon)|Charon]] looms in the distance.]]
As proposed by [[Jet Propulsion Laboratory]] (JPL) in 1992, the Pluto Fast Flyby mission was to be two craft weighing {{cvt|150|kg|lb}} each. The voyage from Earth to Pluto was to take seven or eight years, with a launch as early as 1998. The two craft would be timed to view different sides of Pluto. The budget for the mission was said to be no more than $400-million, with NASA administrator [[Daniel Goldin]] wholeheartedly supporting the proposal.{{r|Wilford_1992|Carroll_1993}}

By 1995, the proposed mission was known as Pluto Express, and pre-project manager [[Robert Staehle]] of JPL suggested a budget "in the neighborhood of $300 million". At this point the mission was still to have been twin spacecraft, and it was hoped it could be launched in 1998.{{r|Lawren_1995}} NASA tried to negotiate with Russia for use of [[Proton (rocket family)|Proton]] rockets to launch the spacecraft, in exchange for carrying Russian "Drop Zond" probes to Pluto.{{r|Wheeler_1995}} Another idea, emanating from the [[Max Planck Institute]], would have had Germany contribute funding for the launch, in exchange for Pluto Express carrying a German probe to be dropped at [[Io (moon)|Io]] during the Jupiter gravity assist.{{r|Evans_2015}}

The timing of the mission was important, as it would have passed Pluto shortly before its [[atmosphere]] froze, which it was thought to do for a considerable part of its orbit. The mission's main objectives would have been to map Pluto's surface and examine the double system's geology and geomorphology, as well as determining the composition of [[Atmosphere of Pluto|Pluto's atmosphere]]. This last task would have been considerably more difficult after the start of atmospheric freezing. Scientific equipment on board would have included [[visible light]] imaging systems, [[infrared]] and [[ultraviolet]] [[spectrometer]]s, and an ultrastable oscillator (USO) for use in a [[radio occultation]] experiment.

The spacecraft was to have been a simple hexagonal prism-shaped structure weighing some {{cvt|220|kg|lb}}, powered by [[radioisotope thermal generator]]s (RTGs) similar to those used on the ''[[Galileo project|Galileo]]'' and ''[[Cassini–Huygens|Cassini]]'' missions. On-board control and data collection would have been maintained by a 1.5 MIPS [[RISC]]-based computer system capable of processing data at 5&nbsp;Mbit/s. This would have allowed for the transmission of over one gigabyte of data over a one-year period. Communications would have been via a fixed {{cvt|1.47|m|ft}} [[high-gain antenna]], directionally corrected using a wide-field star tracker. Early in the mission's planning there was suggestion of combining efforts with the Russian space agency and including [[Zond program|Zond]] probes to study the Plutonian atmosphere. This plan was later abandoned.

The Pluto Express was predicted to be launched in 2001, but it was not ready until late 2004. The spacecraft was to have been launched via either a [[Delta rocket]] or the [[Space Shuttle]], most likely in December 2004. Had that happened, the only option would have been to use a Delta rocket, as the Shuttle fleet was grounded after the [[Space Shuttle Columbia disaster|''Columbia'' disaster]]. The course would have been initially via [[Jupiter]], whose [[gravity well]] would have been used to increase the probe's velocity via a [[gravity assist]]. The closest approach distance to Pluto would have been about {{cvt|15000|km|mi}} at 17–18 km/s, so as to allow for {{cvt|1.0|km|mi}} resolution mapping. After passing Pluto, the spacecraft would have used its imaging camera to search for [[Kuiper Belt objects]].{{r|nssdc}}

In September 2000 NASA ceased work on the Pluto-Kuiper Express mission,{{r|Savage_2000}} although the agency said it was being "rethought and replanned", not scrapped. The mission's cost at that time was said by a NASA spokesperson to be an unaffordable $500 million (compared to an original budget of $350 million in 1999).{{r|NYT-20000923}}