Thor DSV-2U

	Launch of the last Thor DSV-2U carrying DMSP-5D1 F5
Function	Expendable launch system
Country of origin	United States
Size
Mass	49500 kg
Stages	3
Capacity
Payload to LEO	500 kg
Launch history
Status	Retired
Launch sites	Vandenberg SLC-10W
Total launches	5
Success(es)	4
Failure(s)	1
First flight	September 11 1976
Last flight	July 15 1980
First stage - Thor DM-19
Engines	LR79-7
Thrust	758.71 kN
Specific impulse	282
Burn time	165
Propellant	LOx/Kerosene
Second stage Star 37XE
Engines	TE-M-714-4
Thrust	45 kN
Burn time	66
Propellant	solid
Third stage - Star-37S-ISS
Engines	TE-M-364-15
Thrust	51.1 kN
Burn time	60
Propellant	solid
	[edit on Wikidata]

The Thor DSV-2U or Thor LV-2F Star-37XE Star-37S-ISS was an American expendable launch system used to launch five DMSP weather satellites between 1976 and 1980.^[1]^[2] It was a member of the Thor family of rockets, and a derivative of the Thor DSV-2.^[1]^[3]

The first stage was a Thor missile in the DM-19 configuration. A Star-37XE was used as the second stage, and the third stage was a Star-37S-ISS.

Thor boosters used an erector system to hoist them up to the pad. While common on Soviet launch vehicles, this method was unusual in the US space program.

Launches

Thor DSV-2U was launched five times between 1976 and 1980 from Space Launch Complex 10W at the Vandenberg Air Force Base.^[1]^[2]

All launches carried DMSP 5D-1 satellites The final launch (Thor 304) occurred on July 14, 1980 and was a failure.

**Thor DSV-2U launches^[1]^[2]**
Serial Number	Launch date	Name	Status
172	11 Sep 1976	DMSP 5D-1/F1	In orbit; aka AMS 1
183	5 Jun 1977	DMSP 5D-1/F2	In orbit; aka AMS 2
143	1 May 1978	DMSP 5D-1/F3	In orbit; aka AMS 3
264	6 Jun 1979	DMSP 5D-1/F4	In orbit; aka AMS 4
304	14 July 1980	DMSP 5D-1/F5	Failed to orbit; aka AMS 5

Thor 304 failure

Thor 304 had been erected on the pad a few weeks before launch, and during this step, a connecting pin in the erector broke and sent the rocket falling back down to ground level. Launch crews examined the Thor for damage, but could not find any outward indication of it. The booster passed routine preflight systems checks and liftoff took place at 6:22 PM PST on July 14, 1980.

Shortly after liftoff, the Thor's telemetry system failed, but weather conditions and visibility were excellent, and the booster could be tracked visually for over two minutes. Telemetry from the DMSP satellite indicated that it was operating properly. SECO took place on time, as did the second stage burn. Third stage burn began, and then after about four seconds, all telemetry abruptly ceased.

The initial assumption was that the third stage exploded, and initial Air Force press releases about the launch stated such. However, radar tracking showed that the third stage motor continued operating as it drove the DMSP into the Pacific Ocean.

The investigation board concluded that connectors in the electrical interface between the second and third stage had been jolted loose by the erector mishap several weeks earlier. After second stage burnout, staging failed to take place due to the misaligned connectors, and the third stage motor thus fired with the spent second stage still attached to it. The force from the third stage motor burning managed to tear the second stage free, but in doing so, it ripped out wiring in the base of the third stage, which shorted out the guidance computer and caused it to direct the stage and spacecraft down into the ocean. Much like the DMSP failure in 1976, the incident was attributed to poor program management.^[4]

References

^ ^a ^b ^c ^d "Thor-LV2F Star-37XE Star-37-S-ISS". Gunter's Space Page. Retrieved 2024-04-12.
^ ^a ^b ^c "Thor DSV-2U". www.astronautix.com. Retrieved 2024-10-11.
^ Wade, Mark (2013-08-17). "Delta". Archived from the original on 2013-08-17. Retrieved 2024-04-12.
^ "The Space Review: Launch failures: Two Thors, one problem".

This rocketry article is a stub. You can help Wikipedia by expanding it.

[:0-1] "Thor-LV2F Star-37XE Star-37-S-ISS". Gunter's Space Page. Retrieved 2024-04-12.

[:1-2] "Thor DSV-2U". www.astronautix.com. Retrieved 2024-10-11.

[3] Wade, Mark (2013-08-17). "Delta". Archived from the original on 2013-08-17. Retrieved 2024-04-12.

[4] "The Space Review: Launch failures: Two Thors, one problem".

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v t e Orbital launch systems
List of orbital launch systems Comparison of orbital launch systems
Current	Angara 1.2 A5 Ariane 6 Atlas V Ceres 1 1S Chollima-1 Electron Falcon 9 Block 5 Falcon Heavy Firefly Alpha Gravity-1 GSLV H-IIA H3 Hyperbola-1 Jielong 1 3 KAIROS^† Kaituozhe 2 Kinetica 1 Kuaizhou 1 1A 11 Long March 2C 2D 2F 3A 3B/E 3C 4B 4C 5 5B 6 6A 7 7A 8 11 11H LVM3 Minotaur I IV V C Nuri OS-M1^† Pegasus XL Proton-M PSLV Qaem 100 Qased RS1^† Shavit 2 Simorgh SLS Block 1 Soyuz-2 2.1a / STA 2.1b / STB 2-1v SSLV Starship Tianlong-2 Unha Vega C Vulcan Centaur Zhuque 2
In development	Antares 330 Bloostar Cyclone-4M Deca Epsilon S Eris Gravity-2 Hyperbola-2 Irtysh Kuaizhou 21 31 Long March 9 10 12 Miura 5 MLV Neutron New Glenn New Line 1 NGLV Nova OS-M 2 4 Orbex Prime Pallas-1 Red Dwarf SLS Block 1B Block 2 Soyuz-7 Terran R Tianlong-3 VLM Vega E Zero Zhuque 3 Zuljanah
Retired	Antares 110 120 130^† 230 230+ Ariane 1 2 3 4 5 ASLV Athena I II Atlas B D E/F G H I II III LV-3B SLV-3 Able^† Agena Centaur Black Arrow Conestoga^† Delta A B C D E G J L M N 0100 1000 2000 3000 4000 5000 II III IV IV Heavy Diamant Dnepr Energia Epsilon Europa I^† II^† Falcon 1 Falcon 9 v1.0 v1.1 v1.2 "Full Thrust" Feng Bao 1 GSLV Mk I H-I H-II H-IIB Juno I Juno II Kaituozhe-1 Kosmos original 1 2/2I 3 3M Lambda 4S LauncherOne Long March 1 1D^† 2A 2E 3 3B 4A Mu 4S 3C 3H 3S 3SII V N1^† N-I N-II Naro-1 Paektusan^† Pilot-2^† R-7 Luna Molniya M L Polyot Soyuz original FG L M U U2 Soyuz/Vostok Sputnik Voskhod Vostok L K 2 2M R-29 Shtil' Volna^† Rocket 3 Safir 1 1A 1B Saturn I IB V Scout X-1 Blue Scout II^† X-2^† X-2M X-3 X-3M X-4 X-2B^† B A B-1 D-1 A-1 E-1 F-1 G-1 Shavit original 1 SLV Space Shuttle SPARK^† Sparta SS-520 Start-1 Terran 1^† Thor Able Ablestar 1 2 Agena A B D Burner 1 2 Delta DSV-2U Thorad-Agena SLV-2G SLV-2H Titan II GLV IIIA IIIB IIIC IIID IIIE 34D 23G CT-3 IV Tsyklon R-36-O original 2 3 Universal Rocket UR-500 Proton Proton-K Rokot Strela Vanguard Vega original VLS-1^† Zenit 2 2M 2FG 3SL 3SLB 3F Zhuque 1^†
Classes	Sounding rocket Small-lift launch vehicle Medium-lift launch vehicle Heavy-lift launch vehicle Super heavy-lift launch vehicle
This Template lists historical, current, and future space rockets that at least once attempted (but not necessarily succeeded in) an orbital launch or that are planned to attempt such a launch in the future Symbol ^† indicates past or current rockets that attempted orbital launches but never succeeded (never did or has yet to perform a successful orbital launch)

v t e Orbital launch systems developed in the United States
Active	Atlas V**^†† Electron Falcon 9 Block 5 Falcon Heavy Firefly Alpha Minotaur I IV V C Pegasus XL RS1^† SLS Block 1 Vulcan Centaur
In development	Antares 330 Daytona I MLV New Glenn Neutron Nova Red Dwarf SLS Block 1B Block 2 Starship Terran R
Retired	Antares 110/120/130/230/230+^††† Athena I II Atlas B D E/F G H I II III LV-3B SLV-3 Able Agena Centaur Conestoga Delta A B C D E G J L M N 0100 1000 2000 3000 4000 5000 II III IV IV Heavy Falcon 1 Falcon 9 v1.0 v1.1 v1.2 "Full Thrust" H-I* Juno I Juno II LauncherOne N-I* N-II* Pilot Rocket 3 Saturn I IB V Scout Space Shuttle SPARK Sparta Terran 1 Thor Able Ablestar Agena Burner Delta DSV-2U Thorad-Agena Titan II GLV IIIA IIIB IIIC IIID IIIE 34D 23G CT-3 IV Vanguard
* - Japanese projects using US rockets or stages ** - uses Russian engines ^† - never succeeded ^†† - no new orders accepted ^††† - used Ukrainian first stage