Small Explorer program
The first set of three SMEX missions were launched between 1992-07-03 and 1998-12-05. The second set of two missions were launched 1998-04-02 and 1999-03-05. These missions were managed by the Small Explorer Project Office at NASA's Goddard Space Flight Center (GSFC). In the Spring of 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, with oversight by the GSFC Explorers Project.
Three SMEX missions are currently funded for their primary missions: Nuclear Spectroscopic Telescope Array (NuSTAR), Aeronomy of Ice in the Mesosphere (AIM) and Interstellar Boundary Explorer (IBEX). AIM was launched in 2007, IBEX in 2008, and NuSTAR launched in June 2012. Interface Region Imaging Spectrograph (IRIS) was launched in 2013.
Extended-phase or completed missions
- Fast Auroral Snapshot Explorer (FAST)
- Solar Anomalous and Magnetospheric Particle Explorer (SAMPEX)
- Submillimeter Wave Astronomy Satellite (SWAS)
- Transition Region and Coronal Explorer (TRACE)
- Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI)
- Galaxy Evolution Explorer (GALEX)
On 2008-05-29 NASA announced selection of six candidate mission proposals for further evaluation as part of SMEX. These include:
- Coronal Physics Explorer (CPEX),
- Gravity and Extreme Magnetism SMEX (GEMS),
- Interface Region Imaging Spectrograph (IRIS), (Launched in 2013)
- Joint Astrophysics Nascent Universe Satellite (JANUS),
- Neutral Ion Coupling Explorer (NICE),
- Transiting Exoplanet Survey Satellite (TESS). (Planned for Launch)
NASA announced on June 19, 2009 that the two winning proposals were GEMS and IRIS. GEMS did not pass a confirmation review conducted on 2012-05-10, which effectively cancelled the project. The project team intends to appeal the cancellation.
- Wide Field Infrared Explorer (WIRE)
- "Explorer Missions". NASA.
- SAMPEX: NASA's first small explorer satellite (1998) - IEEE
- "SMEX home page (kept for historical purposes only)". NASA.
- "NASA Selects Small Explorer Investigations for Concept Studies". NASA.
- "Orbital To Build New Space Science Satellite To Study X-Ray Polarization". SpaceMart.com. 2009-07-09. Retrieved 2009-07-09.
- "Neutral Ion Coupling Explorer Homepage". UCB.
- "NASA Awards Two Small Explorer Development Contracts". NASA. 2009-06-19.
- "NASA To Cancel GEMS X-Ray Telescope". Space News. 4 June 2012.