Editing Explorers Program (section)

=== Missions of Opportunity (MO) ===
Missions of Opportunity (MO) are investigations characterized by being part of a non-NASA space mission of any size and having a total NASA cost of under $55 million. These missions are conducted on a no-exchange-of-funds basis with the organization sponsoring the mission. NASA solicits proposals for Missions of Opportunity on SMEX, MIDEX and UNEX investigations.<ref>[https://explorers.gsfc.nasa.gov/missions.html Explorers Missions: Missions of Opportunity (MO)] NASA [[Goddard Space Flight Center]] (GSFC). Accessed on 18 August 2019. {{PD-notice}}</ref>

{| class="wikitable"
|+List of MO<ref name=":1" />
|-
! Name
! Launcher (mission)
! Launch (UTC)
! Status
|-
| [[HETE-2]]
| NASA (Explorer-79)
| 9 October 2000
| Ended in 2008<ref>{{cite web |url=https://heasarc.gsfc.nasa.gov/docs/hete2/hete2.html |title=The HETE-2 Satellite |publisher=NASA |access-date=28 April 2018}} {{PD-notice}}</ref>
|-
| [[INTEGRAL]]
| [[ESA]]<ref>{{cite web |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=2002-048A |title=NASA - NSSDCA - Spacecraft |publisher=NASA |access-date=20 April 2018}} {{PD-notice}}</ref>
| 17 October 2002
| {{success|'''Operational'''}}
|-
| [[Suzaku (satellite)|Suzaku]] (Astro-E2)
| [[JAXA]]<ref>{{cite web |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=2005-025A |title=NASA - NSSDCA - Spacecraft |publisher=NASA |date=21 March 2017 |access-date=20 April 2018}} {{PD-notice}}</ref>
| 10 July 2005
| Ended in 2015
|-
| [[TWINS]]
| [[National Reconnaissance Office|NRO]] ([[USA-184]];<ref>{{cite web |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=2006-027A |title=NASA - NSSDCA - Spacecraft |publisher=NASA |access-date=2018-04-20}} {{PD-notice}}</ref><br/>[[USA-200]]<ref>{{cite web |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=2008-010A |title=NASA - NSSDCA - Spacecraft |publisher=NASA |access-date=2018-04-20}} {{PD-notice}}</ref>)
| TWINS-1: 28 June 2006<br/>TWINS-2: 13 March 2008
| {{success|'''Operational'''}}
|-
| [[CINDI]]
| [[DoD]] ([[C/NOFS]])<ref>{{cite web |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=2008-017A |title=NASA - NSSDCA - Spacecraft |publisher=NASA |date=2017-03-21 |access-date=2018-04-20}} {{PD-notice}}</ref>
| 16 April 2008
| Ended in 2015
|-
| [[Hitomi (satellite)|Hitomi]] (Astro-H)
| [[JAXA]]<ref>{{cite web |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=2016-012A |title=NASA - NSSDCA - Spacecraft |publisher=NASA |date=2017-03-21 |access-date=2018-04-20}} {{PD-notice}}</ref>
| 17 February 2016 
| {{failure|Failed}}
|-
| [[Neutron Star Interior Composition Explorer|NICER]]
| [[ISS]] ([[SpaceX CRS-11|CRS-11]])
| 3 June 2017
| {{success|'''Operational'''}}
|-
| [[Global-scale Observations of the Limb and Disk|GOLD]]
| [[SES (company)|SES]] ([[SES-14]])
| 25 January 2018
| {{success|'''Operational'''}}
|-
| [[X-Ray Imaging and Spectroscopy Mission|XRISM]]
| [[JAXA]]
| 6 September 2023
| {{success|'''Operational'''}}
|-
| [[Atmospheric Waves Experiment|AWE]]
| [[ISS]] ([[SpaceX CRS-29|CRS-29]])
| December 2023
| {{success|'''Operational'''}}
|-
| [[GUSTO (telescope)|GUSTO]]
| [[NASA]] ([[high-altitude balloon]])
| 31 December 2023
| Ended on 26 February 2024<ref>{{cite web |last=Littleton |first=Olivia F. |url=https://www.nasa.gov/missions/scientific-balloons/nasa-scientific-balloons-ready-for-flights-over-antarctica/ |title=NASA Scientific Balloons Ready for Flights Over Antarctica |work=[[NASA]] |date=27 February 2024 |access-date=3 August 2024}}</ref>
|-
| [[Sun Radio Interferometer Space Experiment|SunRISE]]
| [[NASA]] ([[Maxar]] satellite)
| 2024
| {{pending|In development<ref>{{cite web |last=Ng |first=Joy |url=https://blogs.nasa.gov/sunspot/2021/09/09/nasas-sunrise-mission-studying-solar-particle-storms-moves-toward-launch/ |title=NASA's SunRISE Mission Studying Solar Particle Storms Moves Toward Launch |work=NASA |date=9 September 2021 |access-date=9 September 2021}} {{PD-notice}}</ref><ref>{{cite press release |last1=Hautaluoma |first1=Grey |last2=Fox |first2=Karen |url=https://www.nasa.gov/press-release/nasa-selects-mission-to-study-causes-of-giant-solar-particle-storms |title=NASA Selects Mission to Study Causes of Giant Solar Particle Storms |publisher=NASA |date=30 March 2020 |access-date=31 March 2020}} {{PD-notice}}</ref>}}
|-
| [[Electrojet Zeeman Imaging Explorer|EZIE]]
| [[NASA]], [[JHUAPL]]
| 2024
| {{pending|In development<ref>{{cite press release |url=https://www.jhuapl.edu/PressRelease/201229-NASA-selects-EZIE-heliophysics |title=Johns Hopkins APL Space Weather Mission Selected by NASA |publisher=JHUAPL |date=29 December 2020 |access-date=30 December 2020}}</ref>}}
|-
| [[Solar-C EUVST]]
| [[JAXA]]
| July 2028
| {{pending|In development<ref>{{cite press release |last1=Hautaluoma |first1=Grey |last2=Frazier |first2=Sarah |url=https://www.nasa.gov/press-release/nasa-approves-heliophysics-missions-to-explore-sun-earth-s-aurora |title=NASA Approves Heliophysics Missions to Explore Sun, Earth's Aurora |publisher=NASA |date=29 December 2020 |access-date=30 December 2020}} {{PD-notice}}</ref><ref>{{cite conference |last=Shimizu |first=Toshifumi |url=https://agu.confex.com/agu/fm23/meetingapp.cgi/Paper/1295860 |title=SH54A-03 The SOLAR-C EUVST mission: Coronal physics advanced by novel EUV spectroscopy |conference=American Geophysical Union (AGU23) |date=15 December 2023 |access-date=26 December 2023}}</ref>}}
|-
| [[Contribution to ARIEL Spectroscopy of Exoplanets|CASE]]
| [[ESA]] ([[Cosmic Vision]] [[ARIEL|M4]])
| 2029
| {{pending|In development<ref>{{cite web |last=Landau |first=Elizabeth |url=https://www.nasa.gov/feature/jpl/nasa-instrument-to-probe-planet-clouds-on-european-mission |title=NASA Instrument to Probe Planet Clouds on European Mission |publisher=NASA |date=8 November 2019 |access-date=12 November 2019}} {{PD-notice}}</ref><ref>{{Cite journal |arxiv=1906.02820 |doi=10.1088/1538-3873/ab2d54 |title=Constraining Exoplanet Metallicities and Aerosols with the Contribution to ARIEL Spectroscopy of Exoplanets (CASE) |journal=Publications of the Astronomical Society of the Pacific |volume=131 |issue=1003 |pages=094401 |year=2019 |last1=Zellem |first1=Robert T. |display-authors=et al. |bibcode=2019PASP..131i4401Z |s2cid=174801052}} {{PD-notice}}</ref>}}
|}