Editing Explorers Program (section)

=== Small Explorers (SMEX) ===
The Small Explorers class was implemented in 1989 specifically to fund space exploration missions that cost no more than {{US$|120 million}}.<ref name=missions/><ref name="IEEE" /> The missions are managed by the Explorers Project at the [[Goddard Space Flight Center]] (GSFC).<ref name="welcome" />

The first set of three SMEX missions were launched between 1992 and 1998. The second set of two missions were launched in 1998 and 1999. These early missions were managed by the Small Explorers Project Office at Goddard Space Flight Center. In early 1999, that office was closed and with the announcement of opportunity for the third set of SMEX missions NASA converted the program so that each mission was managed by its [[Principal investigator|Principal Investigator]], with oversight by the GSFC Explorers Project.<ref name="welcome" />

NASA funded a competitive study of five candidate heliophysics Small Explorers missions for flight in 2022. The proposals were Mechanisms of Energetic Mass Ejection – eXplorer (MEME-X), Focusing Optics X-ray Solar Imager (FOXSI), Multi-Slit Solar Explorer (MUSE), Tandem Reconnection and Cusp Electrodynamics Reconnaissance Satellites (TRACERS), and Polarimeter to Unify the Corona and Heliosphere (PUNCH).<ref>{{cite web |url=https://www.nasa.gov/press-release/nasa-selects-proposals-to-study-sun-space-environment |title=NASA Selects Proposals to Study Sun, Space Environment |publisher=NASA |first=Dwayne |last=Brown |date=28 July 2017 |access-date=7 December 2017}} {{PD-notice}}</ref><ref>{{cite web |url=https://nspires.nasaprs.com/external/viewrepositorydocument/cmdocumentid=524225/solicitationId=%7BA0C496AC-9B9D-8F7D-A506-B1695BF9BDE8%7D/viewSolicitationDocument=1/2016%20Helio%20SMEX%20AO_amend1_clarify.pdf |title=Announcement of Opportunity: Heliophysics Explorers Program, 2016 Small Explorers (SMEX) |publisher=NASA |date=13 July 2016 |id=NNH16ZDA005O}} {{PD-notice}}</ref><ref>{{cite web |url=https://explorers.larc.nasa.gov/HPSMEX/pdf_files/8_SMEX-AO-2016Helio-CSR-Kickoff-LSP-MENDOZA-HILL.pdf |title=Heliophysics Small Explorers 2016 Announcement of Opportunity: Concept Study Report Kickoff |publisher=NASA{{\}}Launch Services Program |first=Alicia |last=Mendoza-Hill |date=25 August 2017}} {{PD-notice}}</ref> In June 2019 NASA selected TRACERS and PUNCH for flight.<ref>{{cite web |url=https://www.nasa.gov/press-release/nasa-selects-missions-to-study-our-sun-its-effects-on-space-weather |title=NASA Selects Missions to Study Our Sun, Its Effects on Space Weather |publisher=NASA |date=20 June 2019 |url-status=live |archive-url=https://web.archive.org/web/20231031190231/https://www.nasa.gov/news-release/nasa-selects-missions-to-study-our-sun-its-effects-on-space-weather/ |archive-date=31 October 2023}} {{PD-notice}}</ref>

{| class="wikitable"
|+List of SMEX missions <ref name=":0">{{cite web |url=http://space.skyrocket.de/doc_sat/explorer.htm |title=Explorers Program |website=space.skyrocket.de |access-date=8 April 2016}}</ref><ref>{{cite web |url=http://explorers.gsfc.nasa.gov/smex.html |title=Operational Small Explorers (SMEX) Missions |website=Explorers Program |access-date=8 April 2016 |archive-url=https://web.archive.org/web/20160325193350/http://explorers.gsfc.nasa.gov/smex.html |archive-date=25 March 2016 |url-status=dead}} {{PD-notice}}</ref>
|-
! Name
! SMEX<br/>number
! Explorer<br/>number
! Launch (UTC)
! End of<br/>mission
! Status
|-

| [[Solar Anomalous and Magnetospheric Particle Explorer|SAMPEX]]
| SMEX-1
| Explorer-68
| 3 July 1992
| 30 June 2004
| Reentered on 13 November 2012
|-

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| 2 July 1996
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|-

| [[Fast Auroral Snapshot Explorer|FAST]]
| SMEX-2
| Explorer-70
| 21 August 1996
| 4 May 2009
| 
|-

| [[Submillimeter Wave Astronomy Satellite|SWAS]]
| SMEX-3
| Explorer-74
| 6 December 1998
| 21 July 2004
| 
|-

| [[TRACE]]
| SMEX-4
| Explorer-73
| 2 April 1998
| 21 June 2010
| 
|-

| [[Wide Field Infrared Explorer|WIRE]]
| SMEX-5
| Explorer-75
| 5 March 1999
| {{n/a}}
| Spacecraft equipment failure; reentered on 10 May 2011
|-

| [[Reuven Ramaty High Energy Solar Spectroscopic Imager|RHESSI]]
| SMEX-6
| Explorer-81
| 5 February 2002
| April 2018
| Deorbited on 20 April 2023
|-

| [[GALEX]]
| SMEX-7
| Explorer-83
| 28 April 2003
| May 2012
| Decommissioned on 28 June 2013
|-

| SPIDR
| SMEX-8
| {{center|—}}
| ''Scheduled for 2005''
| {{n/a}}
| Cancelled in 2003 due to poor instrument sensitivity <ref>{{cite web |url=http://www.spacetoday.net/Summary/1695 |title=NASA cancels space science mission |website=spacetoday.net |date=4 June 2003 |access-date=28 April 2018 |url-status=live |archive-url=https://web.archive.org/web/20190427111301/http://www.spacetoday.net/Summary/1695 |archive-date=27 April 2019}}</ref>
|-

| [[Aeronomy of Ice in the Mesosphere]] (AIM)
| SMEX-9
| Explorer-90
| 25 April 2007
| 19 August 2024
| Reentered on 19 August 2024
|-

| [[Interstellar Boundary Explorer|IBEX]]
| SMEX-10
| Explorer-91
| 19 October 2008
| 
| {{success|'''Operational'''}}
|-

| [[NuSTAR]]
| SMEX-11
| Explorer-93
| 13 June 2012
| 
| {{success|'''Operational'''}}
|-

| [[Interface Region Imaging Spectrograph|IRIS]]
| {{nowrap|SMEX-12}}
| {{nowrap|Explorer-94}}
| 28 June 2013
| 
| {{success|'''Operational'''}}
|-

| [[Gravity and Extreme Magnetism|GEMS]]
| SMEX-13
| {{center|—}}
| ''Scheduled for 2014''
| {{n/a}}
| Cancelled in 2012 due to expected cost overruns<ref>{{cite web |last1=Berger |first1=Brian |first2=Dan |last2=Leone |agency=Space News |url=https://www.space.com/16041-gems-spacecraft-nasa-cancellation.html |title=GEMS Spacecraft Team Appeals NASA Cancellation Decision |publisher=Space.com |date=7 June 2012 |access-date=28 April 2018}}</ref>
|-

| [[Imaging X-ray Polarimetry Explorer]] (IXPE)
| SMEX-14
| {{nowrap|Explorer-97}}
| 9 December 2021
| 
| {{success|'''Operational'''}}
|-

| [[Polarimeter to Unify the Corona and Heliosphere|PUNCH]]
| SMEX-15
| 
| 12 March 2025<ref name="nasa-lspedu">{{cite web |url=https://public.ksc.nasa.gov/lspeducation/upcoming-missions/ |title=Upcoming Missions |work=[[NASA Launch Services Program]] |date=1 July 2024 |access-date=3 August 2024}}</ref>
| 
| {{pending|Launched}}<ref name="nasa-20220803">{{cite web |last=Oxford |first=Clarence |url=https://www.spacedaily.com/reports/NASAs_PUNCH_Mission_Commences_Study_of_Solar_Wind_999.html |title=NASA's PUNCH Mission Commences Study of Solar Wind |date=13 March 2025 |access-date=19 March 2025 |work=Space Daily}} {{PD-notice}}</ref>
|-

| [[Tandem Reconnection and Cusp Electrodynamics Reconnaissance Satellites|TRACERS]]
| SMEX-16
| 
| April 2025<ref>{{cite web |last=Foust |first=Jeff |url=https://spacenews.com/nasa-selects-spacex-for-rideshare-launch-of-smallsat-mission/ |title=NASA selects SpaceX for rideshare launch of smallsat mission |work=SpaceNews |date=30 September 2023 |access-date=1 October 2023 |url-status=live |archive-url=https://archive.today/20231219234720/https://spacenews.com/nasa-selects-spacex-for-rideshare-launch-of-smallsat-mission/ |archive-date=19 December 2023}}</ref>
| 
| {{pending|In development}}
|-

| [[Compton Spectrometer and Imager|COSI]]
| SMEX-17
| 
| August 2027<ref>{{cite press release |url=https://www.nasa.gov/news-release/nasa-awards-launch-services-contract-for-space-telescope-mission/ |title=NASA Awards Launch Services Contract for Space Telescope Mission |work=NASA |date=2 July 2024 |access-date=3 July 2024}} {{PD-notice}}</ref>
| 
| {{pending|In development}}
|}

<gallery>
File:SAMPEX 3.jpg|SAMPEX
File:RHESSI.jpg|RHESSI
File:IBEX spacecraft.jpg|IBEX
File:IXPE-artist-rendition.jpg|IXPE
</gallery>