National Aeronautics and Space Administration

Medium Class Explorers (MID EX)

• Advanced Composition Explorer (ACE)
• Ionospheric Connection Explorer (ICON)
• Neil Gehrels Swift Observatory (Swift)
• Transiting Exoplanet Survey Satellite (TESS)
• Time History of Events and Macroscale Interactions During Substorms (THEMIS)
• Near-Earth Object Wide Field Infrared Survey Explorer (NEOWISE previoulsy WISE)

Small Explorers (SMEX)

• Aeronomy of Ice in the Mesosphere (AIM)
• Interstellar Boundary Explorer (IBEX)
• Interface Region Imaging Spectrograph (IRIS)
• Nuclear Spectroscopic Telescope Array (NuSTAR)

Missions of Opportunity (MO)

• Global-scale Observations of the Limb and Disk (GOLD)
• Neutron star Interior Composition Explorer (NICER)
• Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS)

Living With a Star Missions

• Parker Solar Probe (PSP)
• Solar Dynamics Observatory (SDO)
• Space Environment Testbeds 1 (SET-1)
• Solar Orbiter

Solar Terrestrial Probes Missions

• Hinode (Solar-B)
• Magnetospheric Multiscale (MMS)
• Solar TErrestrial RElations Observatory (STEREO)
• Thermosphere Ionosphere Mesosphere Energetics and Dynamics Mission (TIMED)

Past Missions

Explorers Missions

Medium Class Explorers (MID EX)

• Far Ultraviolet Spectroscopic Explorer (FUSE)
• Imager for Magnetopause-to-Aurora Global Exploration (IMAGE)
• Interplanetary Monitoring Platform-8 (IMP-8)
• Rossi X-ray Timing Explorer (RXTE previously XTE)
• Wilkinson Microwave Anisotropy Probe (WMAP previously MAP)

Small Explorers (SMEX)

• Fast Auroral Snapshot Explorer (FAST)
• Galaxy Evolution Explorer (GALEX)
• Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI previously HESSI)
• Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX)
• Submillimeter Wave Astronomy Satellite (SWAS)
• Transition Region And Coronal Explorer (TRACE)

University Class Explorers (UNEX)/STEDI

• Cosmic Hot Interstellar Plasma Spectrometer (CHIPS)
• Student Nitric Oxide Explorer (SNOE)

Missions of Opportunity (MO)

• Coupled Ion Neutral Dynamic Investigation (CINDI/CNOFS)
• High Energy Transient Explorer 2 (HETE-2)
• SUZAKU (ASTRO-E2)

Living With a Star Missions

• Van Allen Probes (RBSP)