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Explorer-Program

Explorer 1 [NASA]

IXPE (SMEX 14) [NASA]

Explorer Name Date S LS Launch Vehicle Mass (kg) Orbit Remarks
1958
Explorer 1 Explorer 1 01.02.1958 CC Juno-1 14 kg 359 km 2542 km, 33.18
Explorer 2 Explorer 2 05.03.1958 F CC Juno-1 14 kg -
Explorer 3 Explorer 3 26.03.1958 CC Juno-1 14 kg 195 km 2810 km, 33.38
Explorer 4 Explorer 4 26.07.1958 CC Juno-1 17 kg 258 km 2233 km, 50.40
Explorer 5 Explorer 5 24.08.1958 F CC Juno-1 17 kg
1959
Explorer (6) S 1 16.07.1959 F CC Juno-2 41 kg -
Explorer 6 S 2 07.08.1959 CC Thor-DM18 Able-3 64 kg 250 km 42327 km, 46.95
Explorer 7 S 1a 13.10.1959 CC Juno-2 41 kg 560 km 1087 km, 50.27
1960
Explorer (8) S 46 23.03.1960 F CC Juno-2 41 kg -
Explorer 8 S 30 03.11.1960 CC Juno-2 41 kg 416 km 2286 km, 49.98
Explorer (9) S 56 04.12.1960 F WI Scout-X1 36 kg -
1961
Explorer 9 S 56a / AD 1 16.02.1961 WI Scout-X1 36 kg 635 km 2581 km, 38.86
Explorer (10) S 45 25.02.1961 F CC Juno-2 34 kg -
Explorer 10 P 14 25.03.1961 CC Delta 35 kg 221 km 181000 km, 33.00
Explorer 11 S 15 27.04.1961 CC Juno-2 43 kg 497 km 1777 km, 28.76
Explorer (12) S 45a 24.05.1961 F CC Juno-2 41 kg -
Explorer (12) S 55 30.06.1961 F WI Scout-X1 85 kg -
Explorer 12 EPE A / S 3 16.08.1961 CC Delta 38 kg 457 km 77170 km, 33.43
Explorer 13 S 55a 25.08.1961 P WI Scout-X1 85 kg 125 km 1164 km, 37.70
Explorer 14 EPE B / S 3a 02.10.1961 CC Delta-A 40 kg 915 km 96959 km, 33.60
1962
Explorer 15 EPE C / S 3b 27.10.1962 CC Delta-A 45 kg 312 km 17619 km, 17.97
Explorer 16 S 55b 16.12.1962 WI Scout-X3 101 kg 759 km 1170 km, 51.99
1963
Explorer 17 AE A / S 6 03.04.1963 CC Delta-B 184 kg 246 km 914 km, 57.61
Explorer 18 IMP A / S 74 (IMP 1) 27.11.1963 CC Delta-C 62 kg 2072 km 194080 km, 35.29
Explorer 19 AD A / S 56b 19.12.1963 Va Scout-X4 7 kg 588 km 2389 km, 78.60
1964
Explorer (20) BE A / S 66 19.03.1964 F CC Delta-B 120 kg -
Explorer 20 IE A / S 48 25.08.1964 Va Scout-X4 44 kg 869 km 1018 km, 79.90
Explorer 21 IMP B (IMP 2) 04.10.1964 CC Delta-C 62 kg 666 km 94526 km, 33.82
Explorer 22 BE B / S 66a 10.10.1964 Va Scout-X4 53 kg 886 km 1079 km, 79.69
Explorer 23 S 55c 06.11.1964 WI Scout-X4 134 kg 464 km 978 km, 51.96
Explorer 24 AD B / S 56c 21.11.1964 Va Scout-X4 9 kg 542 km 2480 km, 81.35 with IE B
Explorer 25 IE B / Injun 4 40 kg 528 km 2492 km, 81.35 with AD B
Explorer 26 EPE D 21.12.1964 CC Delta-C 46 kg 310 km 26202 km, 20.14
1965
Explorer 27 BE C 29.04.1965 WI Scout-X4 60 kg 936 km 1316 km, 41.18
Explorer 28 IMP C (IMP 3) 29.05.1965 CC Delta-C 59 kg 195 km 264252 km, 33.86
Explorer 29 GEOS A 06.11.1965 CC Delta-E 175 kg 1117 km 2273 km, 59.38
Explorer 30 SE A / Solrad 8 / IQSY 19.11.1965 WI Scout-X4 57 kg 693 km 898 km, 59.71
Explorer 31 DME A 29.11.1965 Va Thor-DM21 Agena-B 98 kg 505 km 2983 km, 79.82 with Alouette 2
1966
Explorer 32 AE B 25.05.1966 CC Delta-C1 225 kg 283 km 2718 km, 64.67
Explorer 33 IMP D (AIMP 1) 01.07.1966 CC Delta-E1 79527 km 477380 km, 21.66 lunar orbit planned
1967
Explorer 34 IMP F (IMP 4) 24.05.1967 Va Delta-E1 74 kg 242 km 214382 km, 67.17
Explorer 35 IMP E (AIMP 2) 19.07.1967 CC Delta-E1 lunar orbit
1968
Explorer 36 GEOS B 11.01.1968 Va Delta-E1 209 kg 1084 km 1573 km, 105.79
Explorer 37 SE B / Solrad 9 05.03.1968 WI Scout-B 90 kg 509 km 882 km, 59.42
Explorer 38 RAE A 04.07.1968 Va Delta-J 188 kg 5840 km 5862 km, 120.84
Explorer 39 AD C 08.08.1968 Va Scout-X4 9 kg 684 km 2514 km, 80.69 with IE C
Explorer 40 IE C / Injun 5 71 kg 679 km 2531 km, 80.66 with AD C
1969
Explorer 41 IMP G (IMP 5) 21.06.1969 Va Delta-E1 79 kg 640 km 176219 km, 87.13
1970
Explorer 42 SAS A / Uhuru 12.12.1970 SM Scout-B 163 kg 534 km 573 km, 3.03
1971
Explorer 43 IMP I (IMP 6) 13.03.1971 CC Delta-M6 1569 km 203825 km, 30.20
Explorer 44 SE C / Solrad 10 08.07.1971 WI Scout-B 118 kg 435 km 631 km, 51.05
Explorer 45 SSS A, S-Cubed A 15.11.1971 SM Scout-B 52 kg 234 km 26780 km, 3.56
1972
Explorer 46 MTS A 13.08.1972 WI Scout-D1 90 kg 494 km 810 km, 37.70
Explorer 47 IMP H (IMP 7) 23.09.1972 CC Delta-1604 390 kg 201100 km 235600 km, 17.20
Explorer 48 SAS B 15.11.1972 SM Scout-D1 186 kg 444 km 632 km, 1.90
1973
Explorer 49 RAE B 10.06.1973 CC Delta-1913 1053 km 1064 km, 55.7, lunar orbit lunar orbit
Explorer 50 IMP J (IMP 8) 26.10.1973 CC Delta-1604 81 kg 215092 km 215092 km, 19.70
Explorer 51 AE C 16.12.1973 Va Delta-1900 658 kg 152 km 4074 km, 68.07
1974
Explorer 52 IE D / Injun 6 / Hawkeye 03.06.1974 Va Scout-E1 27 kg 4431 km 122973 km, 88.33
1975
Explorer 53 SAS C 07.05.1975 SM Scout-F1 195 kg 502 km 509 km, 3.00
Explorer 54 AE D 06.10.1975 Va Delta-2910 676 kg 135 km 3569 km, 90.08
Explorer 55 AE E 20.11.1975 CC Delta-2910 721 kg 142 km 2819 km, 19.68
Explorer (56) DAD A 06.12.1975 F Va Scout-F1 40 kg -- with DAD B
Explorer (57) DAD B 9 kg - with DAD A
1976
1977
Explorer 56 ISEE 1 22.10.1977 CC Delta-2914 340 kg 763 km 137531 km, 30.38 with ISEE 2 (not part of Explorer program)
1978
Explorer 57 IUE 26.01.1978 CC Delta-2914 1479 kg
669 kg
30285 km 41296 km, 34.3
Explorer 58 HCMM (AEM 1) 26.04.1978 Va Scout-D1 134 kg 610 km 633 km, 97.6
Explorer 59 ISEE 3 → ICE 12.08.1978 CC Delta-2914 469 kg Sun-Earth Lagrange point L1 halo orbit, later heliocentric
1979
Explorer 60 SAGE (AEM 2) 18.02.1979 WI Scout-D1 149 kg 547 km 659 km, 54.93
Explorer 61 Magsat (AEM 3) 30.10.1979 Va Scout-G1 181 kg 347 km 541 km, 96.7
1980
1981
Explorer 62 DE 1 03.08.1981 P Va Delta-3913 400 kg 558 km 23300 km, 89.92 with DE 2
Explorer 63 DE 2 400 kg 299 km 990 km, 89.99 with DE 1
Explorer 64 SME 06.10.1981 Va Delta-2310 437 kg 481 km 486 km, 97.69 with OSCAR 9
1982
1983
1984
Explorer 65 CCE (AMPTE 1) 16.08.1984 CC Delta-3924 240 kg 1108 km 49675 km, 4.84 with IRM, UKS
1985
1986
1987
1988
1989
Explorer 66 COBE 18.11.1989 Va Delta-5920 2250 kg 872 km 886 km, 99.0
1990
1991
1992
Explorer 67 EUVE 07.06.1992 CC Delta-6920-10 3256 kg 510 km 524 km, 28.4
Explorer 68 SAMPEX (SMEX 1) 03.02.1992 Va Scout-G1 158 kg 514 km 690 km, 81.67
1993
1994
1995
Explorer 69 XTE (RXTE) 30.12.1995 CC Delta-7920-10 3045 kg 564 km 583 km, 22.98
1996
Explorer 70 FAST (SMEX 2) 21.08.1996 Va Pegasus-XL 180 kg 351 km 4164 km, 83.00
1997
Explorer 71 ACE 05.08.1997 CC Delta-7920-8 765 kg Sun-Earth Lagrange point L1 halo orbit
1998
Explorer 72 SNOE (STEDI 1) 26.02.1998 Va Pegasus-XL 132 kg 529 km 581 km, 97.7 with Batsat
Explorer 73 TRACE (SMEX 4) 02.04.1998 Va Pegasus-XL 225 kg 597 km 642 km, 97.80
Explorer 74 SWAS (SMEX 3) 06.12.1998 WI Pegasus-XL 283 kg 638 km 650 km, 69.90
1999
Explorer 75 WIRE (SMEX 5) 05.03.1999 Va Pegasus-XL 275 kg 539 km 592 km, 97.53 Mission failure
Explorer 76 TERRIERS (STEDI 2) 18.05.1999 Va Pegasus-XL HAPS 121 kg 540 km 553 km, 97.7 with MUBLCOM
Explorer 77 FUSE (MIDEX 0) 24.06.1999 CC Delta-7320-10C 1360 kg 753 km 770 km, 24.98
2000
Explorer 78 IMAGE (MIDEX 1) 25.03.2000 Va Delta-7326 494 kg 1000 km 45922 km, 90
Explorer 79 (MoO) HETE 2 09.10.2000 Kw Pegasus-H 124 kg 598 km 641 km, 1.9
2001
Explorer 80 MAP (WMAP, MIDEX 2) 30.06.2001 CC Delta-7425-10C 800 kg Sun-Earth Lagrange point L2 halo orbit
2002
Explorer 81 HESSI (RHESSI, SMEX 6) 05.02.2002 CC Pegasus-XL 293 kg 587 km 600 km, 38
(Int) INTEGRAL 17.10.2002 Ba Proton-K Blok-DM-2 4100 kg 10.000 km 153.000 km, 51.6 Participation on INTEGRAL
2003
Explorer 82 CHIPSat (UNEX 1) 13.01.2003 Va Delta-7320-10C 60 kg 586 km 594 km, 94.0 with ICESAT
Explorer 83 GALEX (SMEX 7) 28.04.2003 CC Pegasus-XL 312 kg 690 km 702 km, 29
2004
Explorer 84 Swift (MIDEX 3, Neil Gehrels Swift Observatory) 20.11.2004 CC Delta-7320-10C 1331 kg 600 km 600 km, 19
2005
(MoO) Astro E2 10.07.2005 Ka M-5 (2) 1700 kg 570 km 570 km, 31.3 Instrument on Astro E2
2006
(MoO) TWINS A 28.06.2006 Va Delta-4M+(4,2) 1111 km 37594, 62.4 Payload on Trumpet 4
2007
Explorer 85 THEMIS P1 (MIDEX 5A) → ARTEMIS P1 17.02.2007 CC Delta-7925-10C 100 kg 1.6 Re 34.0 Re, 3.9; later lunar orbit with THEMIS P2, P3, P4, P5
Explorer 86 THEMIS P2 (MIDEX 5B) → ARTEMIS P2 100 kg 1.2 Re x 19.9 Re, 9.8; later lunar orbit with THEMIS P1, P3, P4, P5
Explorer 87 THEMIS P3 (MIDEX 5C) 100 kg 1.6 Re 11.6 Re, 7 with THEMIS P1, P2, P4, P5
Explorer 88 THEMIS P4 (MIDEX 5D) 100 kg 1.6 Re 11.6 Re, 7 with THEMIS P1, P2, P3, P5
Explorer 89 THEMIS P5 (MIDEX 5E) 100 kg 1.3 Re 13.1 Re, 12 with THEMIS P1, P2, P3, P4
Explorer 90 AIM (SMEX 9) 25.04.2007 Va Pegasus-XL 200 kg 585 km 600 km, 97.79
2008
(MoO) TWINS B 13.03.2008 Va Atlas-5(411) 1112 km 37580 km, 63.6 Payload on Trumpet 5
(MoO) CINDI 16.04.2008 Kw Pegasus-XL 395 kg 400 km 850 km, 13 Instruments on C/NOFS
Explorer 91 IBEX (SMEX 10) 19.10.2008 Kw Pegasus-XL [Star-27] 105 kg 12260 km 304347 km, 21.38
2009
Explorer 92 WISE (MIDEX 6) (ex NGSS) → NEOWISE 14.12.2009 Va Delta-7320-10C 532 kg 526 km 530 km, 97.50
2010
2011
2012
Explorer 93 NuSTAR (SMEX 11) 13.06.2012 Kw Pegasus-XL 360 kg 525 km 525 km, 6
2013
Explorer 94 IRIS (SMEX 12) 28.06.2013 Va Pegasus-XL 236 kg 621 km 662 km, 97.90
2014
2015
2016
(MoO) NeXT 07.02.2016 Ta H-2A-202 2700 kg 565 km 580 km, 31.01 Instrument on Astro H
2017
(MoO) NICER 03.05.2017 CC Falcon-9 v1.2 372 kg 400 km 400 km, 51.6 Instrument on ISS
2018
(MoO) GOLD 25.01.2018 Ko Ariane-5ECA 4423 kg 35783 km 35792 km, 0.02 Instrument on SES 14
Explorer 95 TESS (MIDEX 7) 18.04.2018 CC Falcon-9 v1.2 365 kg 17 Re 59 Re
2019
Explorer 96 ICON (MIDEX 8) 11.10.2019 CC Pegasus-XL 288 kg 575 km 575 km, 27
2020
2021
Explorer 97 IXPE (SMEX 14) 09.12.2021 CCK Falcon-9 v1.2 (Block 5) 330 kg 588 km 603 km, 0.2
2022
2023
(Int) Euclid 01.07.2023 CC Falcon-9 v1.2 (Block 5) 2160 kg Sun-Earth Lagrange point L2 halo orbit Participation in Euclid
(MoO) Resolve 06.09.2023 Ta H-2A-202 2700 kg 567 km 580 km, 31.00 Instrument on XRISM
(MoO) AWE 10.11.2023 CC Falcon-9 v1.2 (Block 5) 400 km 400 km, 51.6 Instrument on ISS



Planned:
 

Explorer Name Date S LS Launch Vehicle Mass (kg) Orbit Remarks
2024
(MoO) EZIE 1 xx.xx.2024 ? ?
(MoO) EZIE 2
(MoO) EZIE 3
(MoO) SunRISE 1 xx.xx.2024 CC Vulcan Centaur VCxx
(MoO) SunRISE 2
(MoO) SunRISE 3
(MoO) SunRISE 4
(MoO) SunRISE 5
(MoO) SunRISE 6
2025
SPHEREx (MIDEX 9) xx.04.2025 Va Falcon-9 v1.2 (Block 5) ~200
PUNCH-NFI (SMEX 15) 40 kg
PUNCH-WFI 1 (SMEX 15) 40 kg
PUNCH-WFI 2 (SMEX 15) 40 kg
PUNCH-WFI 3 (SMEX 15) 40 kg
TRACERS A (SMEX 16A) xx.xx.2025 ? Falcon-9 v1.2 (Block 5)
TRACERS B (SMEX 16B)
COSI (SMEX 17) xx.xx.2025 ? ?
2026
(MoO) EUVST 2026 Ka Epsilon-S Instrument on Solar C
2027
MUSE (MIDEX 10) xx.xx.2027 ? ?
2028
HelioSwarm Hub (MIDEX 11A) xx.xx.202x ? ?
HelioSwarm Node 1 (MIDEX 11B)
HelioSwarm Node 2 (MIDEX 11C)
HelioSwarm Node 3 (MIDEX 11D)
HelioSwarm Node 4 (MIDEX 11E)
HelioSwarm Node 5 (MIDEX 11F)
HelioSwarm Node 6 (MIDEX 11G)
HelioSwarm Node 7 (MIDEX 11H)
HelioSwarm Node 8 (MIDEX 11I)
2029
(MoO) CASE 2029 Ko Ariane-62 (baselined) Instrument on ARIEL
2030
UVEX (MIDEX 12) xx.xx.2030 ? ?
TBD



Cancelled or status unclear:
 

Explorer Name Date S LS Launch Vehicle Mass (kg) Orbit Remarks
Owl 1 cancelled 1966 ? Va Scout-A 70 kg
Owl 2 cancelled 1966 ? Va Scout-A 70 kg
MSS A cancelled 197x ? WI Scout-B ? 36 kg
CATSAT (STEDI 3) cancelled Va Delta-7320-10C 109 kg with ICESAT
IMEX (UNEX 2) cancelled CC Titan-402B IUS 159 kg with DSP 22
FAME (MIDEX 4) cancelled CC Delta-7425-10C
SPIDR (SMEX 8) cancelled 2003 Va Pegasus-XL [Star-26C]
GEMS (SMEX 13) cancelled 2012 CC Pegasus-XL * 267 kg

* = Launch vehicle baselined

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