is a United States space exploration program that provides flight opportunities for physics,
investigations from space. Over 90 space missions have been launched from 1958 to 2011, and it is still active. Starting with
, it has been a NASA program, and they have worked with a variety of other institutions and business, including many international collaborations. Currently, the major subprograms are
. Some additional missions that may be in hibernation or reduced function include
. It began as a U.S. Army proposal to place a scientific satellite into
; however, that proposal was rejected in favor of the U.S. Navy's
. The Explorer program was later reestablished to catch up with the
on October 4, 1957. (
) Explorer 1 was launched January 31, 1958. Besides being the first U.S. satellite, it is known for discovering the
, which continued to use the name for an ongoing series of relatively small space missions, typically an artificial satellite with a science focus. Over the years,
; properties of micrometeoroids raining down on the Earth; much about ultraviolet, cosmic, and X-rays from the solar system and universe beyond;
; and atmospheric physics. These missions have also investigated air density, radio astronomy, geodesy, and gamma ray astronomy. Various space telescopes have made a variety of discoveries, including the first known
, 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.
Explorer categories have included MIDEX, SMEX, UNEX, and others. A subprogram called Missions of Opportunity (MO) has funded instruments on non-NASA missions.
Explorer name numbers can be found in the NSSDC master catalog, typically assigned to each spacecraft in a mission. However, one source says they were not officially assigned after 1975.
Explorer Missions
| # |
Name(s) |
Launch Date |
Mission |
End of Data |
Re-Entry |
| 1 |
Explorer 1 |
January 31, 1958 |
Energetic particle studies, discovered the Van Allen radiation belt The Van Allen radiation belt is a torus of energetic charged particles around Earth, which is held in place by Earth's magnetic field. It is believed that most of the particles that form the belts come from solar wind, and other particles by cosmic rays. It is named after its discoverer, James...
|
May 23, 1958 |
March 31, 1970 |
| 2 |
Explorer 2 Explorer 2 was to be a repeat of the Explorer 1 mission. However, due to a failure in the rocket during launch, the spacecraft did not reach orbit....
|
March 5, 1958 |
Failed to achieve orbit |
– |
– |
| 3 |
Explorer 3 (Gamma 1) Explorer 3 was an artificial satellite of the Earth, nearly identical to the first United States artificial satellite Explorer 1 in its design and mission...
|
March 26, 1958 |
Energetic particle studies |
June 27, 1958 |
June 27, 1958 |
| 4 |
Explorer 4Explorer 4 was a US satellite launched on July 26, 1958. It was instrumented by Dr. James van Allen's group. The Department of Defense's Advanced Research Projects Agency had initially planned two satellites for the purposes of studying the Van Allen radiation belts and the effects of nuclear...
|
July 26, 1958 |
nuclear testOperation Argus was a series of nuclear weapons tests and missile tests secretly conducted during August and September 1958 over the South Atlantic Ocean by the United States's Defense Nuclear Agency, in conjunction with the Explorer 4 space mission. Operation Argus was conducted between the...
studies |
October 5, 1958 |
October 23, 1959 |
| 5 |
Explorer 5 Explorer 5 was a United States satellite with a weight of 17.24 kg.It launched atop a Jupiter-C rocket on August 24, 1958 from Launch Complex 5, but failed when the rocket's booster collided with its second stage after separation, causing the upper stage firing angle to be off.- References :...
|
August 24, 1958 |
Failed to achieve orbit |
– |
– |
| 7x |
Explorer 7x (S 1) |
July 16, 1959 |
Measure earth's radiation balance, destroyed by range safety |
– |
– |
| 6 |
Explorer 6Explorer 6 was a United States satellite launched on August 7, 1959. It was a small, spheroidal satellite designed to study trapped radiation of various energies, galactic cosmic rays, geomagnetism, radio propagation in the upper atmosphere, and the flux of micrometeorites...
(S-2 (Able 3)) |
August 7, 1959 |
Magnetosphere research |
October 6, 1959 |
July 1, 1961 |
| 7 |
Explorer 7Explorer 7 was launched October 13, 1959 at 10:36 a.m. Eastern Time by a Juno II rocket from Cape Canaveral Air Force Station to an orbit of 573 km by 1073 km and inclination of 50.27°. It was designed to measure solar x-ray and Lyman-alpha flux, trapped energetic particles, and heavy...
(S 1A) |
October 13, 1959 |
Energetic particle studies |
August 24, 1961 |
In orbit |
| – |
S 46 |
March 23, 1960 |
Analyze electron and proton radiation energies, failed to achieve orbit |
– |
– |
| 8 |
Explorer 8 Explorer 8 is a U.S. research satellite launched on November 3, 1960. It confirmed the existence of a helium layer in the upper atmosphere....
(S 30) |
November 3, 1960 |
Measured atmospheric composition of the ionosphere |
December 27, 1960 |
In orbit |
| – |
S 56 |
December 4, 1960 |
Atmospheric density measurements, failed to achieve orbit |
– |
– |
| 9 |
S 56A |
February 16, 1961 |
Atmospheric density measurements |
April 9, 1964 |
April 9, 1964 |
| – |
S 45 |
February 24, 1961 |
Ionosphere research, failed to achieve orbit |
– |
– |
| 10 |
Explorer 10 Explorer 10 was an American Earth-orbital satellite that investigated Earth's magnetic fields and nearby plasma...
(P 14) |
March 25, 1961 |
Investigated field magnetic field between the Earth and Moon |
March 25, 1961 |
June 1, 1968 |
| 11 |
Explorer 11 (S 15) |
April 27, 1961 |
Gamma ray astronomy |
November 17, 1961 |
In orbit |
| – |
S 45A |
May 25, 1961 |
Ionosphere research, failed to achieve orbit |
– |
– |
| – |
S 55 (Meteoroid Satellite-A, Micrometeorite Explorer) |
June 30, 1961 |
Micrometeoroid research, failed to achieve orbit |
– |
– |
| 12 |
EPE-A (S 3, Energetic Particle Explorer-A) |
August 16, 1961 |
Energetic particle research |
December 6, 1961 |
September 1, 1963 |
| 13 |
S 55A |
August 25, 1961 |
Micrometeoroid research |
August 28, 1961 |
August 28, 1961 |
| 14 |
EPE-B Explorer 14 is a spin-stabilized, solar-cell-powered spacecraft instrumented to measure cosmic-ray particles, trapped particles, solar wind protons, and magnetospheric and interplanetary magnetic fields. A 16-channel PFM/PM time-division multiplexed telemeter was used. The time required to sample...
(Energetic Particle Explorer-B) |
October 2, 1962 |
Energetic particle research |
August 11, 1963 |
July 1, 1966 |
| 15 |
EPE-C (Energetic Particle Explorer-C) |
October 27, 1962 |
Energetic particle research |
January 30, 1963 |
January 15, 1978 |
| 16 |
S 55B |
December 16, 1962 |
Micrometeoroid research |
July 22, 1963 |
In orbit |
| 17 |
AE-A (Atmosphere Explorer-A) Explorer 17 was a United States satellite, launched at Cape Canaveral from LC-17B on a Delta-B booster, on April 3, 1963, to study the Earth's upper atmosphere. It was the first satellite of five Atmosphere Explorers.- Technical specifications :Explorer 17 was a spin-stabilized sphere 0.95 m in...
|
April 3, 1963 |
Atmospheric research |
July 10, 1963 |
November 24, 1966 |
| 18 |
IMP-A (IMP 1, Interplanetary Monitoring Platform-A) |
November 27, 1963 |
Magnetospheric research |
May 10, 1965 |
December 30, 1965 |
| 19 |
AD-A (Atmospheric Density-A) |
December 19, 1963 |
Atmospheric density measurements |
May 10, 1981 |
May 10, 1981 |
| 20 |
IE-A (S 48, TOPSI, Ionosphere Explorer-A) |
August 25, 1964 |
Ionosphere research |
December 29, 1965 |
In orbit |
| 21 |
IMP-B (IMP 2, Interplanetary Monitoring Platform-B) |
October 4, 1964 |
Magnetospheric research |
October 13, 1965 |
January 30, 1966 |
| 22 |
BE-B (S 66, Beacon Explorer-B) |
October 10, 1964 |
Ionospheric and geodetic research |
February 1970 |
In orbit |
| 23 |
S 55C (Explorer 23) |
November 6, 1964 |
Micrometeoric research |
November 7, 1965 |
June 29, 1983 |
| 24 |
AD-B (Atmospheric Density-B) |
November 21, 1964 |
Atmospheric density measurements |
October 18, 1968 |
October 18, 1968 |
| 25 |
Injun 4 The Injun program was a series of six satellites designed and built by researchers at the University of Iowa. They were intended to observe various radiation and magnetic phenomena in the ionosphere and beyond....
(IE-B, Ionosphere Explorer-B) |
November 21, 1964 |
Ionospheric research |
December 1966 |
In orbit |
| 26 |
EPE-D (Energetic Particle Explorer-D) |
December 21, 1964 |
High energy particle observations |
December 27, 1967 |
In orbit |
| 27 |
BE-C (Beacon Explorer-C) |
April 29, 1965 |
Magnetospheric research |
July 20, 1973 |
In orbit |
| 28 |
IMP-C (IMP 3, Interplanetary Monitoring Platform-C) |
May 29, 1965 |
Magnetospheric research |
May 12, 1967 |
July 4, 1968 |
| 29 |
GEOS 1 (GEOS-A) |
November 6, 1965 |
Geodetic earth monitoring |
June 23, 1978 |
In orbit |
| 30 |
SOLRAD 8 (SE-A) |
November 19, 1965 |
Solar radiation monitoring
(Cover for covert ELINT mission) |
November 5, 1967 |
In orbit |
| 31 |
DME A |
November 29, 1965 |
Ionospheric research |
October 1, 1969 |
In orbit |
| 32 |
AE-B (Atmosphere Explorer-B) Explorer 32—also known as Atmosphere Explorer-B —was a satellite launched by the United States to study the Earth's upper atmosphere. It was launched from Cape Canaveral on a Delta-C1 rocket, on 25 May 1966...
|
May 25, 1966 |
Atmospheric research |
March 1967 |
February 22, 1985 |
| 33 |
IMP-D (AIMP 1, Anchored IMP 1, Interplanetary Monitoring Platform-D)Explorer 33 was a spacecraft launched by NASA on July 1, 1966 on a mission of scientific exploration. Originally intended for a lunar orbit, mission controllers worried that the spacecraft's trajectory was too fast to guarantee lunar capture...
|
July 1, 1966 |
Magnetospheric research |
September 21, 1971 |
In orbit |
| 34 |
IMP-F (IMP 4, Interplanetary Monitoring Platform-F) |
May 24, 1967 |
Magnetospheric research |
May 3, 1969 |
May 3, 1969 |
| 35 |
IMP-E (AIMP-E, AIMP 2, Anchored IMP 2, Interplanetary Monitoring Platform-E)Explorer 35 was a spin-stabilized spacecraft instrumented for interplanetary studies, at lunar distances, of the interplanetary plasma, magnetic field, energetic particles, and solar X rays. It was launched into an elliptical lunar orbit. The spin axis direction was nearly perpendicular to the...
|
July 19, 1967 |
Magnetospheric research |
June 24, 1973 |
In Lunar orbit |
| 36 |
GEOS 2 (GEOS-B) |
January 11, 1968 |
Geodetic earth monitoring |
July 1, 1982 |
In orbit |
| 37 |
Solrad 9 (SE B) |
March 5, 1968 |
Solar radiation monitoring
(Cover for covert ELINT mission) |
April 30, 1974 |
November 16, 1990 |
| 38 |
RAE-A (RAE 1, Radio Astronomy Explorer-A) |
July 4, 1968 |
Radio astronomy |
? |
In orbit |
| 39 |
AD-C (Atmospheric Density-C) |
August 8, 1968 |
Atmospheric density measurements |
June 23, 1971 |
June 22, 1981 |
| 40 |
Injun 5 The Injun program was a series of six satellites designed and built by researchers at the University of Iowa. They were intended to observe various radiation and magnetic phenomena in the ionosphere and beyond....
(Injun C, IE-C, Ionosphere Explorer-C) |
August 8, 1968 |
Magnetospheric Research |
June 1971 |
In orbit |
| 41 |
IMP-G (IMP 5, Interplanetary Monitoring Platform-G) |
June 21, 1969 |
Magnetospheric research |
December 23, 1972 |
December 23, 1972 |
| 42 |
SAS-A (Small Astronomy Satellite-A, SAS 1) Uhuru was the first satellite launched specifically for the purpose of X-ray astronomy. It was also known as the X-ray Explorer Satellite, SAS-A , SAS 1, or Explorer 42.The observatory was launched on 12 December 1970 into an initial orbit of about 560 km apogee, 520 km...
|
December 12, 1970 |
X-Ray Astronomy |
January 4, 1975 |
April 5, 1979 |
| 43 |
IMP-H (IMP 6, Interplanetary Monitoring Platform-H) |
March 13, 1971 |
Magnetospheric research |
October 2, 1974 |
October 2, 1974 |
| 44 |
Solrad 10 (SE-C, SOLRAD-C) |
July 8, 1971 |
Solar radiation monitoring
(Cover for covert ELINT mission) |
June 30, 1973 |
December 15, 1979 |
| 45 |
SSS-A (S-Cubed A) |
November 15, 1971 |
Magnetospheric research |
September 30, 1974 |
January 10, 1992 |
| 46 |
Meteoroid Technology Satellite (MTS, METEC) |
August 13, 1972 |
Micrometeoroids research |
November 4, 1974 |
November 2, 1979 |
| 47 |
IMP-I (IMP 7, Interplanetary Monitoring Platform-I) |
September 23, 1972 |
Magnetospheric research |
October 31, 1978 |
In orbit |
| 48 |
SAS-B (Small Astronomy Satellite-B, SAS 2) The Small Astronomy Satellite 2, also known also as SAS-2, SAS B or Explorer 48, was a NASA gamma ray telescope. It was launched on 15 November 1972 into low Earth orbit with a periapsis of 443 km and an apoapsis of 632 km...
|
November 15, 1972 |
X-Ray Astronomy |
June 8, 1973 |
August 20, 1980 |
| 49 |
RAE-B (RAE 2, Radio Astronomy Explorer-B) Explorer 49 was a 328 kilogram satellite launched on June 10, 1973 for longwave radio astronomy research. It had four 230-meter long X-shaped antenna elements, which made it one of the largest spacecraft ever built....
|
June 10, 1973 |
Radio astronomy |
April 26, 1977 |
In Lunar orbit |
| 50 |
IMP J (IMP 8, Interplanetary Monitoring Platform-J) |
October 26, 1973 |
Magnetospheric research |
October 7, 2006 |
In orbit |
| 51 |
AE-C (Atmosphere Explorer-C) |
December 16, 1973 |
Atmospheric research |
? |
December 12, 1978 |
| 52 |
Hawkeye 1, Injun 6 (IE-D, Ionosphere Explorer-D)Explorer 52 was a US satellite launched on June 3, 1974 from Vandenberg Air Force Base on a Scout booster.This satellite was also known as:* Hawkeye 1* IE D* Injun 6* Injun F* Neutral Point Explorer* 07325...
|
June 3, 1974 |
Magnetospheric research |
April 28, 1978 |
April 28, 1978 |
| 53 |
SAS-C (Small Astronomy Satellite-C, SAS 3) The Small Astronomy Satellite 3 was a NASA X-ray astronomy space telescope. It functioned from May 7, 1975 to April 1979. It covered the X-ray range with four experiments on board...
|
May 7, 1975 |
X-Ray Astronomy |
April 7, 1979 |
April 9, 1979 |
| 54 |
AE-D (Atmosphere Explorer-D) |
October 6, 1975 |
Atmospheric research |
January 29, 1976 |
March 12, 1976 |
| 55 |
AE-E (Atmosphere Explorer-E) |
November 20, 1975 |
Atmospheric research |
September 25, 1980 |
June 10, 1981 |
| 56 |
ISEE 1 & 2 (International Sun-Earth Explorer-A & B) |
October 22, 1977 |
Magnetospheric research |
September 26, 1987 |
September 26, 1987 |
| 57 |
IUEThe International Ultraviolet Explorer was an astronomical observatory satellite primarily designed to take ultraviolet spectra. The satellite was a collaborative project between NASA, the UK Science Research Council and the European Space Agency...
|
January 26, 1978 |
Ultraviolet astronomy |
September 30, 1996 |
In orbit |
| 58 |
HCMM (AEM-A, Applications Explorer Mission-A, Heat Capacity Mapping Mission The Heat Capacity Mapping Mission was the first Applications Explorer Mission. HCMM provided comprehensive, accurate, high-spatial-resolution thermal surveys of the surface of the Earth....
) |
April 26, 1978 |
Thermal mapping of the earth |
September 30, 1980 |
December 22, 1981 |
| 59 |
ISEE 3 (International Sun-Earth Explorer-C, ICEThe International Cometary Explorer spacecraft was originally known as International Sun/Earth Explorer 3 satellite, launched August 12, 1978. It was part of the ISEE international cooperative program between NASA and ESRO/ESA to study the interaction between the Earth's magnetic field and the...
) |
August 12, 1978 |
Magnetospheric research |
Hibernation |
In heliocentric orbit A heliocentric orbit is an orbit around the Sun. All planets, comets, and asteroids in our Solar System are in such orbits, as are many artificial probes and pieces of debris. The moons of planets in the Solar System, by contrast, are not in heliocentric orbits as they orbit their respective planet...
|
| 60 |
SAGE (AEM-B, Applications Explorer Mission-B, Stratospheric Aerosol and Gas Experiment) |
February 18, 1979 |
Stratospheric aerosol and ozone data |
January 7, 1982 |
April 11, 1989 |
| 61 |
MAGSAT Magsat spacecraft was launched in the fall of 1979 and ended in the spring of 1980. The mission was to map the Earth's magnetic field, the satellite has two magnetometers...
(AEM-C, Applications Explorer Mission-C, Magnetic Field Satellite) |
October 30, 1979 |
Mapped the near surface magnetic field of the Earth |
May 6, 1980 |
June 11, 1980 |
| 62 |
DE 1Dynamics Explorer was a NASA mission, launched on August 3, 1981 and terminated on February 28, 1991. It consisted of two unmanned satellites, DE-1 and DE-2, whose purpose was to investigate the interractions between plasmas in the magnetosphere and those in the ionosphere...
(DE-A, Dynamics Explorer-A) |
August 3, 1981 |
Magnetospheric research |
February 28, 1991 |
In orbit |
| 63 |
DE 2Dynamics Explorer was a NASA mission, launched on August 3, 1981 and terminated on February 28, 1991. It consisted of two unmanned satellites, DE-1 and DE-2, whose purpose was to investigate the interractions between plasmas in the magnetosphere and those in the ionosphere...
(DE-B, Dynamics Explorer-B) |
August 3, 1981 |
Magnetospheric research |
1983 |
February 19, 1983 |
| 64 |
SME The Solar Mesosphere Explorer was an United States unmanned spacecraft to investigate the processes that create and destroy ozone in Earth's upper atmosphere. The mesosphere is a layer of the atmosphere extending from the top of the stratosphere to an altitude of about...
(Solar Mesosphere Explorer) |
October 6, 1981 |
Atmospheric research |
April 4, 1989 |
March 5, 1991 |
| 65 |
AMTPE/CCE (Active Magnetospheric Particle Tracer Explorers/Charge Composition Explorer) |
August 16, 1984 |
Magnetospheric research |
July 12, 1989 |
In orbit |
| 66 |
COBEThe COsmic Background Explorer , also referred to as Explorer 66, was a satellite dedicated to cosmology. Its goals were to investigate the cosmic microwave background radiation of the universe and provide measurements that would help shape our understanding of the cosmos.This work provided...
|
November 18, 1989 |
Microwave astronomy |
December 23, 1993 |
In orbit |
| 67 |
EUVEThe Extreme Ultraviolet Explorer was a space telescope for ultraviolet astronomy, launched on June 7, 1992. With instruments for UV radiation between wavelengths of 7 and 76 nm, the EUVE was the first satellite mission especially for the short-wave ultraviolet range...
|
June 7, 1992 |
Ultraviolet astronomy |
January 30, 2002 |
January 30, 2002 |
| 68 |
SAMPEX The Solar Anomalous and Magnetospheric Particle Explorer satellite was launched in July 1992 into a low earth orbit at an altitude of 520 by 670 km and 82 degrees inclination. The satellite, which has far exceeded its expected three-year lifetime, has primarily operated in a three-axis...
|
July 3, 1992 |
Magnetospheric research |
June 30, 2004 |
In orbit |
| 69 |
RXTEThe Rossi X-ray Timing Explorer is a satellite that observes the time structure of astronomical X-ray sources. The RXTE has three instruments—the Proportional Counter Array, the High-Energy X-ray Timing Experiment , and one instrument called the All Sky Monitor...
|
December 30, 1995 |
X-ray astronomy |
Operational
|
In orbit |
| 70 |
FAST The Fast Auroral Snapshot Explorer was launched from Vandenberg Air Force Base on board a Pegasus XL rocket on August 21, 1996. One in the series of NASA's Small Explorer spacecraft, FAST was designed to observe and measure the plasma physics of the auroral phenomena which occur around both poles...
|
August 21, 1996 |
Auroral phenomena |
operational? |
In orbit |
| 71 |
ACEAdvanced Composition Explorer is a NASA space exploration mission being conducted as part of the Explorer program to study matter in situ, comprising energetic particles from the solar wind, the interplanetary medium, and other sources. Real-time data from ACE is used by the Space Weather...
|
August 25, 1997 |
Solar/interplanetary/interstellar particle research |
Operational |
In L1 orbit In orbital mechanics, a Lissajous orbit, , named after Jules Antoine Lissajous, is a quasi-periodic orbital trajectory that an object can follow around a Lagrangian point of a three-body system without requiring any propulsion. Lyapunov orbits around a libration point are curved paths that lie...
|
| 72 |
SNOE |
February 26, 1998 |
Atmospheric research |
December 13, 2003 |
December 13, 2003 |
| 73 |
TRACETRACE was a NASA space telescope designed to investigate the connections between fine-scale magnetic fields and the associated plasma structures on the Sun by providing high resolution images and observation of the solar photosphere and transition region to the corona...
|
April 2, 1998 |
Solar observatory |
June 21, 2010 (Hibernation) |
In orbit |
| 74 |
SWAS The Submillimeter Wave Astronomy Satellite was an astronomical observatory launched on December 5, 1998 as part of the Small Explorer program within NASA...
|
December 6, 1998 |
Submillimeter astronomy |
July 2004 hibernationAugust 2005 after Deep Impact sub-mission |
In orbit |
| 75 |
WIRE The Wide Field Infrared Explorer was a satellite launched on 5 March 1999 on the Pegasus XL rocket into a polar orbit between 409 km and 426 km above the Earth's surface...
|
March 5, 1999 |
Infrared astronomy, primary mission failed due to loss of coolant |
No Survey, limited secondary mission |
May 10, 2011 |
| 76 |
TERRIERS |
May 18, 1999 |
Atmospheric research, satellite failed shortly after achieving orbit |
May 18, 1999 |
In orbit |
| 77 |
FUSEThe Far Ultraviolet Spectroscopic Explorer is a space-based telescope operated by the Johns Hopkins University Applied Physics Laboratory. FUSE was launched on a Delta II rocket on June 24, 1999, as a part of NASA's Origins program...
|
June 23, 1999 |
Ultraviolet astronomy |
October 18, 2007 |
In orbit |
| 78 |
IMAGEIMAGE , or Explorer 78, was a NASA MIDEX mission that studied the global response of the Earth's magnetosphere to changes in the solar wind...
|
March 25, 2000 |
Magnetospheric research |
December 18, 2005 |
Contact lost |
| 79 |
HETE-2 The High Energy Transient Explorer was an American astronomical satellite with international participation . The prime objective of HETE was to carry out the first multiwavelength study of gamma-ray bursts with UV, X-ray, and gamma-ray instruments mounted on a single, compact spacecraft...
|
October 9, 2000 |
UV, X-Ray, and gamma ray astronomy |
Operational |
In orbit |
| 80 |
WMAP |
June 30, 2001 |
Microwave astronomy |
October 2010 |
In L2 orbit In orbital mechanics, a Lissajous orbit, , named after Jules Antoine Lissajous, is a quasi-periodic orbital trajectory that an object can follow around a Lagrangian point of a three-body system without requiring any propulsion. Lyapunov orbits around a libration point are curved paths that lie...
|
| 81 |
RHESSI |
February 5, 2002 |
X-ray and gamma ray solar flare imaging |
Operational |
In orbit |
| 82 |
CHIPSatCHIPSat is a now-decommissioned, but still-orbiting, microsatellite. It was launched on January 12, 2003 from Vandenberg Air Force Base aboard a Delta II with the larger ICESat, and had an intended mission duration of one year...
|
January 13, 2003 |
Ultraviolet spectroscopy and astronomy |
April 11, 2008 |
In orbit |
| 83 |
GALEXThe Galaxy Evolution Explorer is an orbiting ultraviolet space telescope launched on April 28, 2003. A Pegasus rocket placed the craft into a nearly circular orbit at an altitude of and an inclination to the Earth's equator of 29 degrees....
|
April 28, 2003 |
Ultraviolet astronomy |
Operational |
In orbit |
| 84 |
SWIFTThe Swift Gamma-Ray Burst Mission consists of a robotic spacecraft called Swift, which was launched into orbit on 20 November 2004, 17:16:00 UTC on a Delta II 7320-10C expendable launch vehicle. Swift is managed by the NASA Goddard Space Flight Center, and was developed by an international...
|
November 20, 2004 |
Gamma ray astronomy |
Operational |
In orbit |
| 85 |
THEMISThe Time History of Events and Macroscale Interactions during Substorms mission was originally a constellation of five NASA satellites to study energy releases from Earth's magnetosphere known as substorms, magnetic phenomena that intensify auroras near Earth's poles...
A |
February 17, 2007 |
Magnetospheric research |
Operational |
In orbit |
| 86 |
THEMISThe Time History of Events and Macroscale Interactions during Substorms mission was originally a constellation of five NASA satellites to study energy releases from Earth's magnetosphere known as substorms, magnetic phenomena that intensify auroras near Earth's poles...
B (ARTEMIS P1) |
February 17, 2007 |
Magnetospheric research |
Operational |
In orbit |
| 87 |
THEMISThe Time History of Events and Macroscale Interactions during Substorms mission was originally a constellation of five NASA satellites to study energy releases from Earth's magnetosphere known as substorms, magnetic phenomena that intensify auroras near Earth's poles...
C (ARTEMIS P2) |
February 17, 2007 |
Magnetospheric research |
Operational |
In orbit |
| 88 |
THEMISThe Time History of Events and Macroscale Interactions during Substorms mission was originally a constellation of five NASA satellites to study energy releases from Earth's magnetosphere known as substorms, magnetic phenomena that intensify auroras near Earth's poles...
D |
February 17, 2007 |
Magnetospheric research |
Operational |
In orbit |
| 89 |
THEMISThe Time History of Events and Macroscale Interactions during Substorms mission was originally a constellation of five NASA satellites to study energy releases from Earth's magnetosphere known as substorms, magnetic phenomena that intensify auroras near Earth's poles...
E |
February 17, 2007 |
Magnetospheric research |
Operational |
In orbit |
| 90 |
AIMThe Aeronomy of Ice in the Mesosphere is a satellite to conduct a 26-month study of noctilucent clouds . It is the ninetieth Explorer program mission and is part of the NASA-funded Small Explorer program...
|
April 25, 2007 |
Noctilucent cloud observation |
Operational |
In orbit |
| 91 |
IBEXInterstellar Boundary Explorer is a NASA satellite that will make the first map of the boundary between the Solar System and interstellar space. The mission is part of NASA's Small Explorer program. The IBEX satellite was launched with a Pegasus-XL rocket on October 19, 2008, at 17:47:23 UTC...
|
October 19, 2008 |
Mapping the boundary between the Solar System and interstellar space. |
Operational |
In orbit |
| 92 |
WISEWide-field Infrared Survey Explorer is a NASA infrared-wavelength astronomical space telescope launched on December 14, 2009, and decommissioned/hibernated on February 17, 2011 when its transmitter was turned off...
|
December 14, 2009 |
Infrared astronomy |
February 17, 2011 Hibernation |
In orbit |
Explorer missions in the NSSDC master catalog listing.
This does not include Missions of Opportunity (MO), but does include some spacecraft with launch failures or were cancelled.
Many more missions are proposed, but not selected. For example in 2011, the overall explorer program received 22 full missions solicitations, 20 Missions of Opportunity, and 8 USPI.
Another type of program called missions of opportunity (MO), which adds small missions to other spacecraft, such as an additional instrument. Examples of this include