Editing CONTOUR (section)

{{Short description|Failed NASA cometary flyby mission (2002)}}
{{DISPLAYTITLE: ''CONTOUR''}}
{{Infobox spaceflight
| name                  = ''CONTOUR''
| names_list            = Comet Nucleus Tour
| image                 = Contour comet.jpg
| image_caption         = Artist impression of ''CONTOUR'' approaching a comet.
| image_alt             = The ''CONTOUR'' spacecraft approaches the coma of a comet, while another comet is visible in the background.
| image_size            = 300px

| mission_type          = [[Comet|Cometary]] flyby
| operator              = [[NASA]] / [[Applied Physics Laboratory|APL]]
| COSPAR_ID             = 2002-034A
| SATCAT                = 27457
| website               = [https://science.nasa.gov/mission/contour/ science.nasa.gov]
| mission_duration      = {{time interval|3 Jul 2002|15 Aug 2002|sep=,}}

| manufacturer          = [[Applied Physics Laboratory]]
| launch_mass           = {{cvt|398|kg|lb}}
| dimensions            = {{cvt|2.1|xx|1.8|xx|1.8|m|ft}}
| power                 = 670&nbsp;watts

| launch_date           = 3 July 2002, 06:47:41 [[Coordinated Universal Time|UTC]]
| launch_rocket         = [[Delta II]] 7425–9.5<br>D-292
| launch_site           = [[Cape Canaveral Space Force Station|Cape Canaveral]] [[Cape Canaveral Air Force Station Space Launch Complex 17|SLC-17]]
| launch_contractor     = [[Boeing]]

| disposal_type         = Destroyed
| last_contact          = 15 August 2002

| instruments_list       = <!-- start collapsible list of instruments -->
 {{Infobox spaceflight/Instruments
  |acronym1  = CIDA  | name1  = Comet Impact Dust Analyzer
  |acronym2  = CRISP | name2  = CONTOUR Remote Imager/Spectrograph
  |acronym3  = CAI   | name3  = CONTOUR Aft Imager
  |acronym4  = NGIMS | name4  = Neutral Gas Ion Mass Spectrometer
 }}

| programme             = '''[[Discovery Program]]'''
| previous_mission      = [[Genesis (spacecraft)|Genesis]]
| next_mission          = [[MESSENGER]]
}}

The '''Comet Nucleus Tour''' ('''CONTOUR''') was a [[NASA]] [[Discovery Program|''Discovery''-class]] space probe that failed shortly after its July 2002 launch. It was the only Discovery mission to fail.

The two comets scheduled to be visited were [[Comet Encke|Encke]] and [[Schwassmann-Wachmann-3]], and the third target was [[6P/d'Arrest|d'Arrest]]. It was hoped that a new comet would have been discovered in the [[inner Solar System]] between 2006 and 2008, in which case the spacecraft trajectory would have been changed if possible to rendezvous with the new comet. Scientific objectives included imaging the nuclei at resolutions of up to {{convert|4|m|ft|sp=us}}, performing spectral mapping of the nuclei at resolutions of up to {{convert|100|m|ft|sp=us}}, and obtaining detailed [[compositional data]] on gas and dust in the near-nucleus environment, with the goal of improving knowledge of the characteristics of comet nuclei.

After the [[solid rocket motor]] intended to inject the spacecraft into [[solar orbit]] was ignited on August 15, 2002, contact with the probe could not be re-established. Ground-based telescopes later found three objects along the course of the satellite, leading to the speculation that it had disintegrated. Attempts to contact the probe were ended on December 20, 2002. The probe thus accomplished none of its primary scientific objectives, but did prove some spaceflight technologies, such as the APL-developed non-coherent [[Doppler tracking]] spacecraft navigation technique, which was later used on the [[New Horizons]] spacecraft.<ref name=DeBoy_2004/>