Editing TRACE (section)

{{Short description|NASA satellite of the Explorer program}}
{{other uses|Trace (disambiguation){{!}}Trace}}
{{Use American English|date=November 2021}}
{{Use dmy dates|date=November 2021}}
{{Infobox spaceflight
| name              = Transition Region and Coronal Explorer
| names_list        = Explorer-73<br/>SMEX-4<br/>TRACE
| image             = 506998main TRACE artist rendition.jpg
| image_caption     = 
| image_size        = 

| mission_type      = [[Heliophysics]]
| operator          = [[NASA]]{{\}}[[Goddard Space Flight Center|GSFC]]
| COSPAR_ID         = 1998-020A
| SATCAT            = 25280
| website           = [https://sdowww.lmsal.com/TRACE/ TRACE]
| mission_duration  = 1 year (planned)<br/>{{Age in years, months and days|1998|04|02|2010|06|21}} (achieved)<ref name="lmsal-final">{{cite web |url=http://trace.lmsal.com/POD/TRACEpod.html |title=TRACE science mission terminated |publisher=Lockheed Martin Solar and Astrophysics Lab |date=June 21, 2010 |access-date=September 13, 2015 |archive-date=7 February 2016 |archive-url=https://web.archive.org/web/20160207100712/http://trace.lmsal.com/POD/TRACEpod.html |url-status=dead}}</ref>

| spacecraft        = Explorer LXXIII
| spacecraft_type   = Transition Region and Coronal Explorer
| spacecraft_bus    = TRACE
| manufacturer      = [[Goddard Space Flight Center]]
| launch_mass       = {{cvt|250|kg}}
| dimensions        = {{cvt|1.9|xx|1.1|m}}
| power             = 220 [[watt]]s

| launch_date       = 2 April 1998, 02:42:39 [[Coordinated Universal Time|UTC]]
| launch_rocket     = [[Pegasus (rocket)|Pegasus XL]] (F21)
| launch_site       = [[Vandenberg Space Force Base|Vandenberg]], ''[[Stargazer (aircraft)|Stargazer]]''
| launch_contractor = [[Orbital Sciences Corporation]]

| entered_service   = 20 April 1998
| deactivated       = 21 June 2010, 23:56 UTC
| last_contact      = 21 June 2010
| decay_date        =

| orbit_reference   = [[Geocentric orbit]]<ref name="Trajectory">{{cite web |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/displayTrajectory.action?id=1998-020A |title=Trajectory: TRACE (1998-020A) 
|publisher=NASA |date=28 October 2021 |access-date=29 November 2021}} {{PD-notice}}</ref>
| orbit_regime      = [[Sun-synchronous orbit]]
| orbit_periapsis   = {{cvt|520.0|km}}
| orbit_apoapsis    = {{cvt|547.2|km}}
| orbit_inclination = 97.84°
| orbit_period      = 95.48 minutes
| apsis             = gee

| instruments       = TRACE Imaging Telescope

| insignia          = TRACE logo.png
| insignia_caption  = TRACE  mission patch
| insignia_size     = 200px

| programme         = '''[[Explorers Program|SMEX program]]'''
| previous_mission  = [[Fast Auroral Snapshot Explorer]] (Explorer 70) (SMEX-2)
| next_mission      = [[Submillimeter Wave Astronomy Satellite]] (Explorer 74) (SMEX-3)

| programme2        = '''[[Explorer program]]'''
| previous_mission2 = [[Student Nitric Oxide Explorer]] (Explorer 72)
| next_mission2     = [[Submillimeter Wave Astronomy Satellite]] (Explorer 74)
}}

'''Transition Region and Coronal Explorer''' ('''TRACE''', or '''Explorer 73''', '''SMEX-4''') was a [[NASA]] [[heliophysics]] and [[solar observatory]] designed to investigate the connections between fine-scale magnetic fields and the associated plasma structures on the Sun by providing high-resolution images and observation of the [[Sun|solar]] [[photosphere]], the transition region, and the [[solar corona]]. A main focus of the TRACE instrument is the fine structure of [[coronal loop]]s low in the solar atmosphere. TRACE is the third spacecraft in the [[Small Explorer program]], launched on 2 April 1998, and obtained its last science image on 21 June 2010, at 23:56 [[Coordinated Universal Time|UTC]].<ref>{{cite web |url=http://trace.lmsal.com/ |title=Transition Region and Coronal Explorer |publisher=Lockheed Martin Solar and Astrophysics Lab}}</ref>