Program: Explorer

USA


American scientific program operated by the US Army.

Over the years, NASA has launched a series of "Explorer" spacecraft carrying a wide variety of scientific investigations. The list below identifies the 74 successful and 4 unsuccessful missions as on March 2000. The list identifies the international ID for each spacecraft, its common name (different than "Explorer N" for most), its launch date. On March 2000, Explorers 50 (IMP 8), 67-74 and 77-78 (EUVE, SAMPEX, RXTE, FAST, ACE, SNOE, TRACE, SWAS, FUSE, and IMAGE) are still operating.

A long-lived series of long-lived spacecraft

NASA's Explorer spacecraft series is not simply the longest running series of spacecraft, it has produced highly-durable (i.e., well-engineered) spacecraft as well. Of the 73 successful Explorer missions depicted, fully five of them had had missions which lasted 10 or more years, the longest of which (IMP 8) has been operational for over 26 years now and still produces valuable information about the solar wind. NASA's IUE spacecraft operated for 19 years and produced copious amounts of data for the astronomical community. The ISEE 3/ICE spacecraft operated for 14 years. As of March of 2000, of the ten operational Explorer missions, SNOE and TRACE have operated for about two year, ACE two and a half years, FAST for about three and a half, RXTE for over four, EUVE and SAMPEX for nearly eight, and IMP 8 for more than 26. SWAS has been operational for slightly more than one year, having been launched in early December 1998. The latest two additions are FUSE (June 1999) and IMAGE (March 2000).


Listing of Explorer missions:

  Satellite Name      NSSDC ID   Identification           Launch date (M/D/Y)

Explorer  1           58-001A    Explorer 1                02/01/58 US          
Explorer  2             -        Explorer 2, Failed        03/05/58 US          
Explorer  3           58-003A    Explorer 3                03/26/58 US          
Explorer  4           58-005A    Explorer 4,1958 Epsilon,  07/26/58 US          
Explorer  5             -        Explorer 5, Failed        08/24/58 ARPA        
Explorer  6           59-004A    Explorer 6                08/07/59 USAF-NASA   
Explorer  7           59-009A    Explorer 7                10/13/59 NASA        
Explorer  8           60-014A    Explorer 8                11/03/60 NASA-GSFC   
Explorer  9           61-004A    Explorer 9,Balloon        02/16/61 NASA-LARC   
Explorer 10           61-010A    P 14                      03/25/61 NASA-GSFC   
Explorer 11           61-013A    S 15                      04/27/61 NASA-GSFC   
Explorer 12           61-020A    EPE-A                     08/16/61 NASA-GSFC   
Explorer 13           61-022A    S 55A                     08/25/61 NASA-LARC   
Explorer 14           62-051A    EPE-B                     10/02/62 NASA-GSFC   
Explorer 15           62-059A    EPE-C                     10/27/62 NASA-GSFC   
Explorer 16           62-070A    S 55B                     12/16/62 NASA-LARC   
Explorer 17           63-009A    AE-A                      04/03/63 NASA-GSFC   
Explorer 18           63-046A    IMP-A                     11/27/63 NASA-GSFC   
Explorer 19           63-053A    AD-A                      12/19/63 NASA-LARC   
Explorer 20           64-051A    IE-A                      08/25/64 NASA-NBS    
Explorer 21           64-060A    IMP-B                     10/04/64 NASA-GSFC   
Explorer 22           64-064A    BE-B                      10/10/64 NASA-APL    
Explorer 23           64-074A    S 55C                     11/06/64 NASA-LARC   
Explorer 24           64-076A    AD-B                      11/21/64 NASA-LARC   
Explorer 25           64-076B    Injun 4                   11/21/64 SUI-GSFC    
Explorer 26           64-086A    EPE-D                     12/21/64 NASA-GSFC   
Explorer 27           65-032A    BE-C                      04/29/65 NASA-APL    
Explorer 28           65-042A    IMP-C                     05/29/65 NASA-GSFC   
Explorer 29           65-089A    GEOS 1                    11/06/65 NASA-OSSA   
Explorer 30           65-093A    SOLRAD 8                  11/19/65 NASA-NRL    
Explorer 31           65-098B    DME-A                     11/29/65 NASA-APL    
Explorer 32           66-044A    AE-B                      05/25/66 NASA-GSFC   
Explorer 33           66-058A    IMP-D                     07/01/66 NASA-GSFC   
Explorer 34           67-051A    IMP-F                     05/24/67 NASA-GSFC   
Explorer 35           67-070A    IMP-E                     07/19/67 NASA-GSFC   
Explorer 36           68-002A    GEOS 2                    01/11/68 NASA-APL    
Explorer 37           68-017A    SOLRAD 9                  03/05/68 USN         
Explorer 38           68-055A    RAE-A                     07/04/68 NASA-GSFC   
Explorer 39           68-066A    AD-C                      08/08/68 NASA-LARC   
Explorer 40           68-066B    Injun 5                   08/08/68 SUI         
Explorer 41           69-053A    IMP-G                     06/21/69 NASA-GSFC   
Explorer 42           70-107A    Uhuru                     12/12/70 NASA-GSFC   
Explorer 43           71-019A    IMP-I                     03/13/71 NASA-GSFC   
Explorer 44           71-058A    SOLRAD 10                 07/08/71 USN-NASA    
Explorer 45           71-096A    S-Cubed A                 11/15/71 NASA-GSFC   
Explorer 46           72-061A    Meteoroid Technology Sat  08/13/72 NASA-LARC   
Explorer 47           72-073A    IMP-H                     09/23/72 NASA-GSFC   
Explorer 48           72-091A    SAS-B                     11/15/72 NASA-GSFC   
Explorer 49           73-039A    RAE-B                     06/10/73 NASA-GSFC   
Explorer 50           73-078A    IMP-J                     10/26/73 NASA-GSFC   
Explorer 51           73-101A    AE-C                      12/16/73 NASA-GSFC   
Explorer 52           74-040A    Hawkeye 1                 06/03/74 NASA-LARC   
Explorer 53           75-037A    SAS-C                     05/07/75 NASA-GSFC   
Explorer 54           75-096A    AE-D                      10/06/75 NASA-GSFC   
Explorer 55           75-107A    AE-E                      11/20/75 NASA-GSFC   
Explorer 56           77-102A    ISEE 1                    10/22/77 NASA-GSFC   
Explorer 57           78-012A    IUE                       01/26/78 NASA-ESA    
Explorer 58           78-041A    HCMM                      04/26/78 NASA-OA     
Explorer 59           78-079A    ISEE 3                    08/12/78 NASA-GSFC   
Explorer 60           79-013A    SAGE                      02/18/79 NASA-OA     
Explorer 61           79-094A    Magsat                    10/30/79 NASA-GSFC   
Explorer 62           81-070A    Dynamics Explorer 1       08/03/81 NASA-GSFC   
Explorer 63           81-070B    Dynamics Explorer 2       08/03/81 NASA-GSFC   
Explorer 64           81-100A    SME                       10/06/81 NASA-OSS    
Explorer 65           84-088A    AMPTCCE                 08/16/84 NASA-GSFC   
Explorer 66           89-089A    Cosmic Background Explor  11/18/89 NASA-GSFC   
Explorer 67           92-031A    EUVE                      06/07/92 NASA        
Explorer 68           92-038A    SAMPEX                    07/03/92 NASA-GSFC   
Explorer 69           95-074A    X-Ray Timing Explorer     12/30/95 NASA-GSFC   
Explorer 70           96-049A    FAST                      08/21/96 NASA-GSFC   
Explorer 71           97-045A    Advanced Composition Exp. 08/25/97 NASA-OSS    
Explorer 72           98-012A    SNOE                      02/26/98 US          
Explorer 73           98-020A    TRACE                     04/02/98 NASA-GSFC   
Explorer 74           98-071A    SWAS                      12/06/98 NASA-GSFC   
Explorer 75           99-011A    WIRE, Failed              03/05/99 NASA-GSFC   
Explorer 76           99-026A    TERRIERS, Failed          05/18/99 BOSTON U    
Explorer 77           99-035A    FUSE                      06/23/99 JHU-ANU     
Explorer 78           00-017A    IMAGE                     03/25/00 NASA-GSFC   
 

 

Explorer Name Date S LS Launch Vehicle Mass (kg) Remarks
1 Explorer 1 01.02.1958    CC Juno-1 14   
2 Explorer 2 05.03.1958 F CC Juno-1 14   
3 Explorer 3 26.03.1958    CC Juno-1 14   
4 Explorer 4 26.07.1958    CC Juno-1 17   
5 Explorer 5 24.08.1958 F CC Juno-1 17   
(6) S 1 16.07.1959 F CC Juno-2 41   
6 S 2 07.08.1959    CC Thor-DM18 Able-3 64   
7 S 1a 13.10.1959    CC Juno-2 41   
- S 46 23.03.1960 F CC Juno-2 41   
8 S 30 03.11.1960    CC Juno-2 41   
(9) S 56 04.12.1960 F WI Scout-X1 36   
9 S 56a / AD 1 16.02.1961    WI Scout-X1 36   
- S 45 24.02.1961 F CC Juno-2 34   
10 P 14 25.03.1961    CC Delta-DM19 35   
11 S 15 24.04.1961    CC Juno-2 43   
(12) S 45a 24.05.1961 F CC Juno-2 41   
(12) S 55 30.06.1961 F WI Scout-X1 85   
12 EPE A / S 3 16.08.1961    CC Delta-DM19 38   
13 S 55a 25.08.1961 P WI Scout-X1 85   
14 EPE B / S 3a 02.10.1961    CC Delta-A 40   
15 EPE C / S 3b 27.10.1962    CC Delta-A 45   
16 S 55b 16.12.1962    WI Scout-X3 101   
17 AE A / S 6 03.04.1963    CC Delta-B 184   
18 IMP A / S 74 (IMP 1) 27.11.1963    CC Delta-C 62   
19 AD A / S 56b 19.12.1963    Va Scout-X4 7   
(20) BE A / S 66 19.03.1964 F CC Delta-B 120   
20 IE A / S 48 25.08.1964    Va Scout-X4 44   
21 IMP B (IMP 2) 04.10.1964    CC Delta-C 62   
22 BE B / S 66a 10.10.1964    Va Scout-X4 53   
23 S 55c 06.11.1964    WI Scout-X4 134   
24 AD B / S 56c 21.11.1964    Va Scout-X4 9 with IE B
25 IE B / Injun 4 40 with AD B
26 EPE D 21.12.1964    CC Delta-C 46   
27 BE C 29.04.1965    WI Scout-X4 60   
28 IMP C (IMP 3) 29.05.1965    CC Delta-C 59   
29 GEOS A 06.11.1965    CC Delta-E 175   
30 SE A / Solrad 8 / IQSY 19.11.1965    WI Scout-X4 57   
31 DME A 29.11.1965    Va Thor-DM21 Agena-B 98 with Alouette 2
32 AE B 25.05.1966    CC Delta-C1 225   
33 IMP D (AIMP 1) 01.07.1966    CC Delta-E1      
34 IMP F (IMP 4) 24.05.1967    Va Delta-E1 75   
35 IMP E (AIMP 2) 19.07.1967    CC Delta-E1      
36 GEOS B 11.01.1968    Va Delta-E1 209   
37 SE B / Solrad 9 05.03.1968    WI Scout-B 90   
38 RAE A 04.07.1968    Va Delta-J 188   
39 AD C 08.08.1968    Va Scout-X4 9 with IE C
40 IE C / Injun 5 71 with AD C
41 IMP G (IMP 5) 21.06.1969    Va Delta-E1 79   
42 SAS A / Uhuru 12.12.1970    SM Scout-B 163   
43 IMP H (IMP 6) 13.03.1971    CC Delta-M6      
44 SE C / Solrad 10 08.07.1971    WI Scout-B 118   
45 SSS A, S-Cubed A 15.11.1971    SM Scout-B 52   
46 MTS A 13.08.1972    WI Scout-D1 90   
47 IMP I (IMP 7) 23.09.1972    CC Delta-1604 390   
48 SAS B 15.11.1972    SM Scout-D1 186   
49 RAE B 10.06.1973    CC Delta-1913      
50 IMP J (IMP 8) 26.10.1973    CC Delta-1604 81   
51 AE C 16.12.1973    Va Delta-1900 658   
52 IE D / Injun 6 / Hawkeye 03.06.1974    Va Scout-E1 27   
53 SAS C 04.05.1975    SM Scout-F1 195   
54 AE D 06.10.1975    Va Delta-2910 676   
55 AE E 20.11.1975    CC Delta-2910 721   
(56) DAD A 05.12.1975 F Va Scout-F1 40 with DAD B
(57) DAD B 9 with DAD A
56 ISEE 1 22.10.1977    CC Delta-2914    with ISEE 2
57 IUE 26.01.1978    CC Delta-2914 1479 / 669   
58 HCMM (AEM 1) 26.04.1978    Va Scout-D1 134   
59 ISEE 3 -> ICE 12.08.1978    CC Delta-2914 469   
60 SAGE (AEM 2) 18.02.1979    WI Scout-D1 147   
61 Magsat (AEM 3) 30.10.1979    Va Scout-G1 181   
62 DE 1 03.08.1981 P Va Delta-3913 400 with DE 2
63 DE 2 400 with DE 1
64 SME 06.10.1981    Va Delta-2310 437 with Oscar 9
65 CCE (AMPTE 1) 16.08.1984    CC Delta-3924 240 with IRM, UKS
66 COBE 18.11.1989    Va Delta-5920 2250   
67 EUVE 07.06.1992    CC Delta-6920-10 3256   
68 SAMPEX (SMEX 1) 04.02.1992    Va Scout-G1 158   
69 XTE (RXTE) 30.12.1995    CC Delta-7920-10 3045   
70 FAST (SMEX 2) 21.08.1996    Va Pegasus-XL 180   
71 ACE 05.08.1997    CC Delta-7920-8 765   
72 SNOE (STEDI 1) 25.02.1998    Va Pegasus-XL 132 with Batsat
73 TRACE (SMEX 4) 01.04.1998    Va Pegasus-XL 225   
74 SWAS (SMEX 3) 05.12.1998    WI Pegasus-XL 283   
75 WIRE (SMEX 5) 04.03.1999    Va Pegasus-XL 275   
76 TERRIERS (STEDI 2) 18.05.1999    Va Pegasus-XL HAPS 121 with MUBLCOM
77 FUSE (MIDEX 0) 24.06.1999    CC Delta-7320-10C 1360   
78 IMAGE (MIDEX 1) 25.03.2000    Va Delta-7326 494   
79 MAP (WMAP, MIDEX 2) 30.06.2001    CC Delta-7425-10C 800   
80 HESSI (RHESSI, SMEX 6) 05.02.2002    CC Pegasus-XL 293   
81 CHIPSat (UNEX 1) 13.01.2003    Va Delta-7320-10C 60 with ICESAT
82 GALEX (SMEX 7) 28.04.2003    CC Pegasus-XL 312   
83 Swift (MIDEX 3) 20.11.2004    CC Delta-7320-10C 1331   
 85 THEMIS 1 (MIDEX 5A) 17.02.2007    CC Delta-7425-10C 100 with THEMIS 2, 3, 4, 5
 86 THEMIS 2 (MIDEX 5B) 100 with THEMIS 1, 3, 4, 5
 87 THEMIS 3 (MIDEX 5C) 100 with THEMIS 1, 2, 4, 5
 88 THEMIS 4 (MIDEX 5D) 100 with THEMIS 1, 2, 3, 5
 89 THEMIS 5 (MIDEX 5E) 100 with THEMIS 1, 2, 3, 4
 90 AIM (SMEX 9) 25.04.2007    Va Pegasus-XL      
 91 IBEX (SMEX 10) 19.10.2008    Kw Pegasus-XL      
 92 WISE (MIDEX 6) 14.12.2009   S Va, SLC-2W Delta-7320-10C   661   
 95 TESS (MIDEX 7) 18.04.2018   S CC, SLC-40 Falcon-9 v1.2      
 96 ICON (Midex 8) 11.10.2019   S L-1011, RW13/31 Pegasus-XL      



Under Study:
 

Explorer Name Date Suc LS Launch Vehicle Mass (kg) Remarks
DUO (SMEX 10/11) 1 or 2 to be selected in Nov. 2004    CC Taurus-2110 *   
JMEX (SMEX 10/11)    CC Pegasus-XL *   
NEXUS (SMEX 10/11)    Pegasus-XL *   
NuSTAR (SMEX 10/11)    Kw Pegasus-XL *   



Cancelled or status unclear:
 

Explorer Name Date Suc LS Launch Vehicle Mass (kg) Remarks
   Owl 1 cancelled 1966 ?    Va Scout-A 70  
   Owl 2 cancelled 1966 ?    Va Scout-A 70  
   CATSAT (STEDI 3) cancelled    Va Delta-7320-10C 109 with ICESAT
   IMEX (UNEX 2) cancelled    CC Titan-402B IUS    with DSP 22
   FAME (MIDEX 4) cancelled    CC Delta-7425-10C      
   SPIDR (SMEX 8) cancelled    Va Pegasus-XL [Star-26C]      

* = Launch vehicle baselined



Sub programs:

AD (Air Density)
ADE (Atmospheric Density Explorer)
AE (Atmosphere Explorer)
DME (Direct Measurement Explorer)
EPE (Energetic Particules Explorer)
GEOS (Geodetic Earth Orbiting Satellite)
IE (Ionosphere Explorer)
IMP (Interplanetary Monitoring Probes)
 History of NASA's Delta-class Explorers
 ---------------------------------------
                                          Launch    End of ops  Current orbit
 Int'l Sun-Earth Explorer 1    ISEE-1  1977 Oct 22  1987 Sep 26 Reentered 1987
 Int'l Ultraviolet Explorer    IUE     1978 Jan 26  1996 Sep 30 29474 x 42211 x 38
 Int'l Sun-Earth Explorer 3    ISEE-3  1978 Aug 12  1997 May  5 Solar orbit 
 Dynamics Explorer 1           DE-1    1981 Aug  3  1991 Feb 28   581 x 23192 x 88
 Dynamics Explorer 2           DE-2    1981 Aug  3  1983 Feb 19 Reentered 1983
 Solar Mesosphere Explorer     SME     1981 Oct  6  1986 Dec    Reentered 1991
 Charge Composition Explorer AMPTE-CCE 1984 Aug 16  1989 Jan     1102 x 49679 x  3
 Cosmic Background Explorer    COBE    1989 Nov 18  1997 May  1   873 x   887 x 99
 Extreme Ultraviolet Explorer  EUVE    1992 Jun  7  2001 Feb  2   424 x   433 x 28
 X-ray Timing Explorer         RXTE    1995 Dec 30  Operational   540 x   555 x 23
 Advanced Composition Explorer ACE     1997 Aug 25  Operational Earth-Sun L1
 Far UV Spectroscopic Explorer FUSE    1999 Jun 24  Operational   751 x   766 x 25

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Ref.: #7(SR446), #14, #15, #27, #89 - update: 22.01.20 Home