Editing Mars Climate Orbiter (section)

{{short description|Failed NASA mission to Mars (1998–1999)}}
{{Italic title}}
{{Infobox spaceflight
| name              = ''Mars Climate Orbiter''
| names_list        = Mars Surveyor '98 ''Orbiter''
| image             = Mars Climate Orbiter 2.jpg
| image_caption     = Artist's conception of the ''Mars Climate Orbiter''
| image_size        = 300px
| mission_type      = [[Mars]] orbiter
| operator          = [[NASA]]/[[JPL]]
| website           = [https://science.nasa.gov/mission/mars-climate-orbiter/ science.nasa.gov]
| COSPAR_ID         = 1998-073A
| SATCAT            = 25571
| mission_duration  = {{time interval|11 Dec 1998|23 Sept 1999|show=dhm}}<br>{{small|Mission failure}}

| manufacturer      = [[Lockheed Martin Space Systems|Lockheed Martin]]
| launch_mass       = {{cvt|638|kg|lb}}{{r|launch_prep}}
| power             = 500&nbsp;watts
| launch_date = {{start-date|December 11, 1998, 18:45:51|timezone=yes}}&nbsp;UTC
| launch_rocket     = [[Delta II]] 7425<br>D-264
| launch_site       = [[Cape Canaveral Air Force Station|CCAFS]] [[Cape Canaveral Air Force Station Space Launch Complex 17|SLC-17A]]
| launch_contractor = [[Boeing]]
| last_contact      = {{end-date|23 September 1999 09:06:00|timezone=yes}}&nbsp;UTC<br>{{small|Unintentionally deorbited}}
| disposal_type     = Destroyed
| orbit_epoch       = Planned
| orbit_reference   = [[Areocentric orbit|Areocentric]]
| orbit_periapsis   = 
| orbit_apoapsis    = 
| orbit_inclination = 
| orbit_period      = 
| apsis             = areion

| insignia          = M98patch.png
| insignia_size     = 180px
| insignia_caption  = ''Mars Surveyor 98'' mission logo

| programme         = '''[[Mars Exploration Program]]'''
| previous_mission  = [[Mars Pathfinder]]
| next_mission      = [[Mars Polar Lander|MPL]]
| programme2        = '''[[Mars Surveyor '98]]'''
}}

The '''''Mars Climate Orbiter''''' (formerly the '''Mars Surveyor '98 Orbiter''') was a [[Robotic spacecraft|robotic]] space probe launched by [[NASA]] on December 11, 1998, to study the [[Climate of Mars|Martian climate]], [[Atmosphere of Mars|Martian atmosphere]], and [[Martian surface|surface changes]] and to act as the communications relay in the [[Mars Surveyor '98]] program for [[Mars Polar Lander]]. However, on September 23, 1999, communication with the spacecraft was permanently lost as it went into [[Orbit insertion|orbital insertion]]. The spacecraft encountered Mars on a trajectory that brought it too close to the planet, and it was destroyed in the atmosphere.{{r|MCO_report}} An investigation attributed the failure to a measurement mismatch between two measurement systems: [[International System of Units|SI units]] (metric) by NASA and [[United States customary units|US customary]] units by spacecraft builder [[Lockheed Martin Space|Lockheed Martin]].{{r|cnn_lost}}