Appendix 3: IGY Satellite Launches
[United States IGY launches in boldface. Satellites and probes other than United States IGY launches have been inserted to complete the 1957-1959 chronological listing.]
| Name (Launch date) |
Experiments | Down | Inclination (Degrees) | Initial Perigee1 (Miles) | Initial Apogee1 (Miles) | |||||
|---|---|---|---|---|---|---|---|---|---|---|
| 1957 | ||||||||||
| Sputnik I2 1957 Alpha (4 Oct 1957) |
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| Sputnik II2 1957 Beta (3 Nov 1957) |
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| 1958 | ||||||||||
| Explorer I 1958 Alpha (31 Jan 1958) |
Cosmic rays Meteoroid erosion Temperatures |
In orbit | 33.3 | 224 | 1573 | |||||
| Explorer II (5 Mar 1958) |
Meteoric dust Meteoroids Temperatures Cosmic rays |
Failed to orbit | ||||||||
| Vanguard I 1958 Beta (17 Mar 1958) |
Temperature | In orbit | 34 | 406 | 2465 | |||||
| Explorer III 1958 Gamma (26 Mar 1958) |
Cosmic rays Meteoroid erosion Temperatures |
28 Jun 1958 | 33.4 | 119 | 1740 | |||||
| Vanguard Test Vehicle 5 (28 Apr 1958) |
Solar x-rays Environmental |
Failed to orbit | ||||||||
| Sputnik III2 1958 Delta (15 May 1958) |
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| Vanguard SLV-1 (27 May 1958) |
Lyman-alpha Environmental |
Failed to orbit | ||||||||
| Vanguard SLV-2 (26 Jun 1958) |
Solar x-rays Environmental | Failed to orbit | ||||||||
| Explorer IV 1958 Epsilon (26 Jul 1958) |
Trapped radiation | 23 Oct 1958 | 50.3 | 163 | 1373 | |||||
| Explorer V (24 Aug 1958) |
Trapped radiation | Failed to orbit | ||||||||
| Vanguard SLV-3 (26 Sept 1958) |
Cloud cover | Failed to orbit | ||||||||
| Pioneer I 1958 Eta 1 (11 Oct 1958) |
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| Explorer VI3 (22 Oct 1958) |
12-ft inflatable sphere | |||||||||
| Pioneer II (at 963 mi, 3d stage failed to ignite) (8 Nov 1958) |
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| Pioneer III 1958 Theta (6 Dec 1958) |
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| Project Score 1958 Zeta (18 Dec 1958) |
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| 1959 | ||||||||||
| Luna 12 1959 Mu 1 (2 Jan 1959) |
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| Vanguard II 1959 Alpha (17 Feb 1959) |
Cloud cover Internal temperature |
In orbit | 32.8 | 346 | 2063 | |||||
| Discoverer I 1959 Beta (28 Feb 1959) |
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| Pioneer IV 1959 Nu 1 (3 Mar 1959) |
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| Discoverer II 1959 Gamma (13 Apr 1959) |
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| Vanguard SLV-5 (13 Apr 1959) |
30-in. inflatable sphere Magnetometer |
Failed to orbit | ||||||||
| Vanguard SLV-6 (22 Jun 1959) |
Earth energy balance | Failed to orbit | ||||||||
| Explorer (16 Jul 1959) |
Failed to orbit | |||||||||
| Explorer VI3 1959 Delta (7 Aug 1959) |
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| Discoverer V 1959 Epsilon (13 Aug 1959) |
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| Explorer (14 Aug 1959) |
Duplicate of Explorer VII | Failed to orbit | ||||||||
| Discoverer VI 1959 Zeta (19 Aug 1959) |
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| Luna II2 1959 Xi 1 (12 Sept 1959) |
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| Vanguard III 1959 Eta (18 Sept 1959) |
Magnetometer Solar x-ray Lyman-alpha Environmental |
In orbit | 33.3 | 317 | 2326 | |||||
| Luna III2 1959 Theta (4 Oct 1959) |
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| Explorer VII 1959 Iota (13 Oct 1959) |
Micrometeoroid Cosmic rays Heavy nuclei Earth energy balance Solar x-ray Lyman-alpha Radio signals Ground studies |
In orbit | 50.3 | 345 | 681 | |||||
| Discoverer VII 1959 Kappa (7 Nov 1959) |
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| Discoverer VIII 1959 Lambda (20 Nov 1959) |
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- Orbit figures are approximate.
- U.S.S.R.
- Two payloads were named Explorer VI: an IGY payload that failed to orbit 22 Oct 1958 and a post-IGY experiment launched successfully 7 Aug 1959.