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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)¹ 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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