Explorers
The mission of the Explorers Program is to provide frequent flight opportunities for world-class scientific investigations from space utilizing innovative, streamlined and efficient management approaches within the heliophysics and astrophysics science areas. This program is managed by the Heliophysics Division and solicits missions for both Heliophysics and Astrophysics. Explorers are opportunities for innovative science and fill the scientific gaps between the larger missions.
The program seeks to enhance public awareness of, and appreciation for, space science and to incorporate educational and public outreach activities as integral parts of space science investigations.
The Explorer program enables the definition, development and implementation of mission concepts through a variety of modes to meet the need of the scientific community and the NASA space science enterprise.
The Explorer Program Office at Goddard Space Flight Center in Greenbelt, MD, provides management of the multiple scientific exploration missions in the Explorer space flight program. The missions are characterized by relatively moderate cost, and by small to medium sized missions that are capable of being built, tested and launched in a short time interval compared to the large observatories.
Missions listed below were competitively selected under the Explorers Program. A mission is assigned to another SMD once the mission launches and throughout the operating phase of the mission.
*Sort missions by clicking the column headers.
| Division | Name | Launch Date | Phase |
|---|---|---|---|
| Heliophysics |
ACE
Advanced Composition Explorer (ACE) observes particles of solar, interplanetary, interstellar, and galactic origins, spanning the energy range from solar wind ions to galactic cosmic ray nuclei. This mission is part of SMD's Explorers Program. This mission is part of SMD's ... | 19970825 August 25, 1997 | 3Operating |
| Heliophysics |
AIM
Aeronomy of Ice in the Mesosphere (AIM) is a mission to determine the causes of the highest altitude clouds in the Earth's atmosphere. The number of clouds in the middle atmosphere (mesosphere) over the Earth's poles has been increasing over ... | 20070425 April 25, 2007 | 3Operating |
| Astrophysics |
Astro-H
Astro-H is a powerful orbiting observatory being developed by the Japan Aerospace Exploration Agency (JAXA) for studying extremely energetic processes in the universe. NASA and the JAXA/Institute of Space and Astronautical Science have teamed up to develop a high resolution ... | 20140215 February 15, 2014 | 2Development |
| Heliophysics |
CINDI/CNOFS
The Coupled Ion-Neutral Dynamics Investigations (CINDI) is a mission to understand the dynamics of the Earth's ionosphere. CINDI will provide two instruments for the Communication/Navigation Outage Forecast System (C/NOFS) satellite, a project of the United States Air Force. This mission ... | 20080416 April 16, 2008 | 3Operating |
| Heliophysics |
FAST
Fast Auroral Snapshot Explorer (FAST) studies the detailed plasma physics of the Earth's auroral regions. Ground support campaigns coordinate satellite measurements with ground observations of the Aurora Borealis, commonly referred to as the Northern Lights. The science instruments on board ... | 19960821 August 21, 1996 | 4Past |
| Astrophysics |
FUSE
Far Ultraviolet Spectroscopic Explorer (FUSE) studied the far ultraviolet portion of the electromagnetic spectrum from high orbit. This range provided an opportunity to answer important questions about many types of astrophysical objects, such as the nuclear regions of active galaxies ... | 19990624 June 24, 1999 | 4Past |
| Astrophysics |
GALEX
Galaxy Evolution Explorer (GALEX) is exploring the origin and evolution of galaxies and the origins of stars and heavy elements, and is also conducting an all-sky ultraviolet survey. This mission is part of SMD's Astrophysics Explorers program. This mission is ... | 20030428 April 28, 2003 | 3Operating |
| Astrophysics |
GEMS
GEMS will use an X-ray telescope to measure the polarization of the X-rays coming from the vicinity of compact objects in the universe: black holes and neutron stars and it will also study the remnants of massive stars which have ... | 20141101 November 2014 | 2Development |
| Heliophysics |
IBEX
IBEX will be the first mission designed to detect the edge of the Solar System. As the solar wind from the sun flows out beyond Pluto, it collides with the material between the stars, forming a shock front. This mission ... | 20081019 October 19, 2008 | 3Operating |
| Heliophysics |
IRIS
The primary goal of the Interface Region Imaging Spectrograph (IRIS) explorer is to understand how the solar atmosphere is energized. The IRIS investigation combines advanced numerical modeling with a high resolution UV imaging spectrograph. | 20121201 December 01, 2012 | 2Development |
| Astrophysics |
NuSTAR
The Nuclear Spectroscopic Telescope Array is a pathfinder mission that will open the high energy X-ray sky for sensitive study for the first time. This mission is part of SMD's Astrophysics Explorers program. | 20120321 TBD | 2Development |
| Heliophysics |
RHESSI
Reuven Ramaty High Energy Solar Spectroscope Imager (RHESSI) studies solar flares in X-rays and gamma-rays. It explores the basic physics of particle acceleration and explosive energy release in these energetic events in the Sun's atmosphere. This is accomplished by imaging ... | 20020205 February 05, 2002 | 3Operating |
| Astrophysics |
RXTE
Rossi X-ray Timing Explorer studied variability over time in the emission of X-ray sources, with moderate spectral resolution. This time behavior is a source of important information about processes and structures in white-dwarf stars, X-ray binaries, neutron stars, pulsars and ... | 19951230 December 30, 1995 | 3Operating |
| Astrophysics |
Suzaku (Astro-E2)
Suzaku (formerly Astro-E2) provides powerful tools to use the Universe as a laboratory for unraveling complex, high-energy processes and the behavior of matter under extreme conditions. This mission is part of SMD's Astrophysics Explorers program. This mission was awarded via ... | 20050710 July 10, 2005 | 3Operating |
| Astrophysics |
Swift
Swift Gamma Ray Burst Explorer is a three-telescope space observatory for studying the position, brightness, and physical properties of gamma ray bursts. Although gamma ray bursts are the largest known explosions in the Universe, outshining the rest of the Universe ... | 20041120 November 20, 2004 | 3Operating |
| Heliophysics |
THEMIS
Time History of Events and Macroscale Interactions during Substorms (THEMIS) is a study of the onset of magnetic storms within the tail of the Earth's magnetosphere. THEMIS will fly five microsatellite probes through different regions of the magnetosphere and observe ... | 20070217 February 17, 2007 | 3Operating |
| Heliophysics |
TRACE
Transition Region and Coronal Explorer (TRACE) observes the effects of the emergence of magnetic flux from deep inside the Sun to the outer corona with high spatial and temporal resolution. This mission is part of SMD's Heliophysics Explorers program. This ... | 19980401 April 01, 1998 | 4Past |
| Heliophysics |
TWINS A & B
TWINS will provide stereo imaging of the Earth's magnetosphere, the region surrounding the planet controlled by its magnetic field and containing the Van Allen radiation belts and other energetic charged particles. This mission is part of SMD's Explorers Program. This ... | 20080313 March 13, 2008 | 3Operating |
| Astrophysics |
WISE
WISE is a NASA-funded scientific research project that will provide a vast storehouse of knowledge about the solar system, the Milky Way, and the Universe. Among the objects WISE will study are asteroids, the coolest and dimmest stars, and the ... | 20091214 December 14, 2009 | 4Past |
| Astrophysics |
WMAP
Wilkinson Microwave Anisotropy Probe (WMAP) produced the earliest “baby picture” of the universe, showing the minute temperature variations within the microwave light produced when the Universe was about 400,000 years old. These data provided a wealth of information about the ... | 20010630 June 30, 2001 | 4Past |