View source for Pluto Kuiper Express

{{Short description|Cancelled NASA flyby mission to Pluto}}
{{Use mdy dates|date=August 2015}}
{{italic title}}
{{Infobox spaceflight
| name                  = ''Pluto Kuiper Express''
| image                 = Pluto express.jpg
| image_caption         = Artist's impression of ''Pluto Kuiper Express'' encountering the [[Pluto]]–[[Charon (moon)|Charon]] system
| image_size            = 300px
| names_list            = ''Pluto Fast Flyby'' (1992–1995)<br>''Pluto Kuiper Express'' (1995–2000)

| mission_type          = [[Pluto]] flyby
| operator              = [[NASA]]
| mission_duration      = Cancelled

| manufacturer          = 
| launch_mass           = {{cvt|220|kg|lb}}{{r|nssdc}}
| payload_mass          = {{cvt|7|kg|lb}}{{r|nssdc}}
| power                 = 228&nbsp;watts

| launch_date           = December 2004
| launch_rocket         = [[Delta II]] or [[Space Shuttle]]

| trans_bandwidth       = 5-Mbit/s

| interplanetary        = 
  {{Infobox spaceflight/IP
   |type            = flyby
   |object          = [[Jupiter]]
   |arrival_date    = April–June 2006{{r|nssdc}}
  }}
  {{Infobox spaceflight/IP
   |type            = flyby
   |object          = [[Pluto]]
   |arrival_date    = December 2012{{r|nssdc}}
   |distance        = {{cvt|15000|km|mi}}
  }}
}}

'''''Pluto Kuiper Express''''' was an interplanetary [[space probe]] that was proposed by [[Jet Propulsion Laboratory]] (JPL) scientists and engineers and under development by [[NASA]]. The spacecraft was intended to be launched to study [[Pluto]] and its moon [[Charon (moon)|Charon]], along with one or more other [[Kuiper Belt|Kuiper belt]] objects (KBOs). The proposal was the third of its kind, after the ''Pluto 350'' and a proposal to send a [[Mariner Mark II]] spacecraft to Pluto.

Originally conceived as ''Pluto Fast Flyby'', and later briefly named ''Pluto Express'', the mission was inspired by a 1991 [[United States Postal Service]] stamp that branded Pluto as "Not Yet Explored". The project brought on JPL engineers and students from the [[California Institute of Technology]] and, later, [[Alan Stern]] and other scientists from the Pluto 350 project. While the project was initiated in 1992, the project's development phase was lengthy, spending nearly a decade in the proposal and funding stage. During planning, the mission was changed to include a Kuiper belt object flyby and re-christened the ''Pluto Kuiper Express'', after the discovery of numerous such objects beyond [[Neptune]] in the mid-to-late 1990s. NASA ultimately decided to cancel the mission in 2000, however, citing the project's expanding budget as the ultimate reason for the cancellation.{{r|NYT-20010213}}

After the mission's cancellation, most of the ''Pluto Fast Flyby'' team, including Stern, went on to develop ''[[New Horizons]]'', a mission nearly identical to ''Pluto Kuiper Express'', for NASA's [[New Frontiers program]]. The spacecraft was successfully launched in January 2006, after a financial standoff with NASA and additional delays, and went on to perform the first ever flyby of the Pluto–Charon system in July 2015.

== 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}}

==References==
{{Reflist|refs=

<ref name="Carroll_1993">{{Cite magazine
| author1= M. Carroll
| title= Space Exploration: Quick trip to Pluto
| url= https://books.google.com/books?id=S812DHiH7dUC&pg=PA27
| date= June 1993
| magazine= [[Popular Science]]
| volume= 242
| issue= 6
| page= 27
| issn= 0161-7370 }}
</ref>

<ref name="Evans_2015">{{cite web
| author1= B. Evans
| title= Three Weeks to Pluto: A World of Tiny Moons and Missed Mission Opportunities (Part 2)
| url= https://www.americaspace.com/2015/06/21/three-weeks-to-pluto-a-world-of-tiny-moons-and-missed-mission-opportunities-part-2/
| website= AmericaSpace
| date= 21 June 2015
| access-date= 1 August 2015 }}
</ref>

<ref name="Lawren_1995">{{cite magazine 
| author1= B. Lawren
| title= Ninth rock from the Sun: Researchers want to send spacecraft to Pluto before it's too late
| url= http://nest.machinecode.org/intricate/omni_magazine/Omni%20v17%20%238%20Fall%201995.html
| magazine= [[Omni (magazine)|Omni]]
| volume= 17
| issue= 8
| issn= 0149-8711
| date= 1995
| access-date= 1 August 2015
| archive-date= 7 March 2015 
| archive-url= https://web.archive.org/web/20150307064610/http://nest.machinecode.org/intricate/omni_magazine/Omni%20v17%20%238%20Fall%201995.html 
| url-status= dead }}
</ref>

<ref name="nssdc">{{Cite web
| author1= E. Grayzeck
| title= Pluto Kuiper Express
| url= https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=PLUTOKE
| website= nssdc.gsfc.nasa.gov
| publisher= [[NASA]]
| date= 26 August 2014
| access-date= 4 June 2015
| id= PLUTOKE }}
</ref>

<ref name="NYT-20000923">{{cite news
| title= NASA Halts Work on Mission to Pluto
| url= https://www.nytimes.com/2000/09/23/science/23PLUTO.html
| work= [[The New York Times]]
| date= 23 September 2000
| access-date= 18 July 2015
| url-access= registration }}
</ref>

<ref name="NYT-20010213">{{cite news
| author1= K. Chang
| title= It May Be Now or Never for a Mission to Pluto
| url= https://www.nytimes.com/2001/02/13/science/it-may-be-now-or-never-for-a-mission-to-pluto.html
| work= [[The New York Times]]
| date= 13 February 2001
| access-date= 18 July 2015
| url-access= registration }}
</ref>

<ref name="Savage_2000">{{Cite press release
| author1= D. Savage
| title= NASA seeks proposals for Pluto mission; plans to restructure outer planet program
| url= https://www3.nasa.gov/home/hqnews/2000/00-201.txt
| publisher= [[NASA]]
| date= 20 December 2000
| access-date= 18 July 2015 }}
</ref>

<ref name="Wheeler_1995">{{Cite magazine
| author1= M. Wheeler
| title= Destination: Pluto
| url= https://books.google.com/books?id=NmYEAAAAMBAJ&pg=PA62
| magazine= [[Popular Mechanics]]
| date= July 1995
| volume= 172
| issue= 7 
| pages= 64–66
| issn= 0032-4558 }}
</ref>

<ref name="Wilford_1992">{{Cite news
| author1= J. N. Wilford 
| title= NASA plans quick visit to edge of solar system
| url= https://news.google.com/newspapers?id=cEFWAAAAIBAJ&pg=3702%2C3367124
| work= [[The Gainesville Sun]]
| agency= [[The New York Times]]
| page= 9A
| date= 11 September 1992
| access-date= 1 August 2015 }}
</ref>

}}

== External links ==
* [http://pluto.jhuapl.edu/ ''New Horizons'': NASA's Pluto–Kuiper Belt Mission], The Johns Hopkins University Applied Physics Laboratory
* [https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=PLUTOKE ''Pluto Kuiper Express''], NASA-National Space Science Data Center
* {{Cite web |last=Cheng |first=Kenneth |date=18 July 2015 |title=The Long, Strange Trip to Pluto, and How NASA Nearly Missed It |url=https://www.nytimes.com/2015/07/19/us/the-long-strange-trip-to-pluto-and-how-nasa-nearly-missed-it.html |url-access=registration |website=[[The New York Times]]}}

{{Pluto|state=expanded}}
{{New Horizons}}

[[Category:Proposed NASA space probes]]
[[Category:Missions to Pluto]]
[[Category:Cancelled spacecraft]]