Thor-Burner
Thor-LV2D Burner-1 (Altair-3) with DMSP Block 4A F3 satellite (20 May 1965)
FunctionExpendable launch system
ManufacturerDouglas
Country of originUnited States
Size
Height23m (75 ft)
Diameter2.44m (8 ft)
Mass50,000kg (110,000 lb)
Stages2-3
Launch history
StatusRetired
Launch sitesVandenberg AFB, LC-4300, LE-6, SLC-10W
Total launches26
Success(es)23
Failure(s)3
First flight19 Jan 1965
Last flight19 February 1976

The Thor-Burner was an American expendable launch system, a member of the Thor rocket family.[1][2] It consisted of a Thor missile, with one or two Burner upper stages.[1][2] It was used between 1965 and 1976 to orbit a number of satellites, most commonly Defense Meteorological Satellite Program (DMSP) weather satellites. [3] Twenty-four were launched, of which two failed. It weighed 51,810 kg and was 24 metres tall.

Variants

There are many Thor-Burner variations, according to the type of upper stages used:[4]

Name 1st stage 2nd stage 3rd stage
Thor-LV2D Burner-1 (MG-18) DSV-2S MG-18 -
Thor-LV2D Burner-1 (Altair-3) DSV-2S Altair-3 / FW-4S -
Thor-LV2F Burner-2 DSV-2U Burner-2 / Star-37B -
Thor-LV2F Burner-2 Star-13A DSV-2U Burner-2 / Star-37B Star-13A
Thor-LV2F Burner-2A DSV-2U Burner-2A #1 / Star-37B Burner-2A #2 / Star-26B

Burner-1, MG-18 and Altair

The first two flights used a solid fuel MG-18 as second stage. After than an Altair rocket stage (same as the third stage of some Vanguard launch vehicles) was used, equipped by Boeing with 3-axis control.[5][1]

These combinations were used for six vehicles.[1] The first was launched 1965-01-18 and the sixth 1966-03-30. These were early launches of classified DMSP satellites. Two of these launches failed.[6][1]

Burner-2

The Burner 2 used with the Thor-Burner was the first solid fuel upper-stage vehicle used for general space applications that had full control and guidance capability.[1][7][8][9][10] The first Burner-2 flight was on 1966-09-16.[11][1][7]

On February 19, 1976, the attempted launch of a DMSP satellite from Vandenberg's SLC-10W went awry when SECO occurred 5 seconds early.[12] Although the second stage separated and fired properly, the satellite was left in an unusable orbit from which it decayed only one hour after launch. Investigation into the mishap found that the Thor had been loaded an insufficient amount of RJ-1 (a higher grade of kerosene fuel that offered enhanced performance over standard RP-1) for the mission. The amount of LOX on Thor boosters was always the same on every launch, but the amount of kerosene could vary depending on the engine, as different LR-79 engines had slightly different performance levels, and so factory acceptance data was used to determine the fuel load needed for a particular unit. The particular engine used in Thor 182 had thus been loaded with kerosene according to the data sheet provided by Rocketdyne, however the information contained a typo which led to ground crews loading too little propellant for it. However, the postflight investigation also found that, even if the correct propellant load had been carried, the mission would have still failed because the Thor did not have sufficient performance to loft the DMSP into the required orbit. As the DMSP program evolved, the satellites gradually became heavier and more complex. Program planners, aware of this, selected an LR-79 engine which had particularly high performance, but it still turned out to not be enough for the mission. The failure was thus ultimately attributed to poor mission planning.[13]

Launches

There were twenty six Thor-Burner launches from Vandenberg AFB:[4]

Date Serial Variant Site Payload
19.01.1965 224 Thor-LV2D Burner-1 (MG-18) 4300-B6 DSAP-1 F10 (Stage 2 failed to separate from satellite)
18.03.1965 306 Thor-LV2D Burner-1 (MG-18) 4300-B6 DSAP-1 F11
20.05.1965 282 Thor-LV2D Burner-1 (Altair-3) 4300-B6 DSAP-3 F1
10.09.1965 213 Thor-LV2D Burner-1 (Altair-3) 4300-B6 DSAP-2 F1
06.01.1966 251 Thor-LV2D Burner-1 (Altair-3) 4300-B6 DSAP-2 F2 (Stage 2 failed)
31.03.1966 147 Thor-LV2D Burner-1 (Altair-3) 4300-B6 DSAP-2 F3
16.09.1966 167 Thor-LV2F Burner-2 4300-B6 DSAP-4A F1
08.02.1967 169 Thor-LV2F Burner-2 4300-B6 DSAP-4A F2
29.06.1967 171 Thor-LV2F Burner-2 Star-13A LE-6 Aurora (P67-1) / SECOR 9 (EGRS 9)
23.08.1967 266 Thor-LV2F Burner-2 LE-6 DSAP-4A F3
11.10.1967 268 Thor-LV2F Burner-2 LE-6 DSAP-4A F4
23.05.1968 277 Thor-LV2F Burner-2 SLC-10W DSAP-4B F1
23.10.1968 173 Thor-LV2F Burner-2 SLC-10W DSAP-4B F2
23.07.1969 279 Thor-LV2F Burner-2 SLC-10W DSAP-4B F3
11.02.1970 287 Thor-LV2F Burner-2 SLC-10W DSAP-5A F1
03.09.1970 288 Thor-LV2F Burner-2 SLC-10W DSAP-5A F2
17.02.1971 249 Thor-LV2F Burner-2 SLC-10W DSAP-5A F3 / NRL-PL 170A / NRL-PL 170B / NRL-PL 170C (S70-4)
08.06.1971 210 Thor-LV2F Burner-2 SLC-10W SESP 1 (P70-1)
14.10.1971 159 Thor-LV2F Burner-2A SLC-10W DSAP-5B F1
24.03.1972 153 Thor-LV2F Burner-2A SLC-10W DSAP-5B F2
09.11.1972 294 Thor-LV2F Burner-2A SLC-10W DSAP-5B F3
17.08.1973 291 Thor-LV2F Burner-2A SLC-10W DSAP-5B F4
16.03.1974 207 Thor-LV2F Burner-2A SLC-10W DMSP-5B F5
09.08.1974 275 Thor-LV2F Burner-2A SLC-10W DMSP-5C F1
24.05.1975 197 Thor-LV2F Burner-2A SLC-10W DMSP-5C F2
19.02.1976 182 Thor-LV2F Burner-2A SLC-10W DMSP-5C F3 (Thor failed, wrong orbit attained)

References

Wikimedia Commons has media related to Thor-Burner.
  1. 1 2 3 4 5 6 7 "Thor with solid-fuel upper stage". Gunter's Space Page. Retrieved 2023-11-29.
  2. 1 2 "Thor Burner". www.astronautix.com. Retrieved 2023-11-29.
  3. ↑ "Thor Burner 1". www.astronautix.com. Retrieved 2023-11-29.
  4. 1 2 "Thor with solid-fuel upper stage". Gunter's Space Page. Retrieved 2023-11-30.
  5. ↑ "Thor with a solid fuel top stage". The Satellite Encyclopedia.
  6. ↑ "Douglas SLV-2 Thor / Boeing (McDonnell Douglas) SB-3 Delta". Directory of U.S. Military Rockets and Missiles.
  7. 1 2 "Thor-LV2F Burner-2". Gunter's Space Page. Retrieved 2023-11-29.
  8. ↑ "Thor-LV2F Burner-2 Star-13A". Gunter's Space Page. Retrieved 2023-11-29.
  9. ↑ "Thor-LV2F Burner-2A". Gunter's Space Page. Retrieved 2023-11-29.
  10. ↑ "Thor Burner 2". www.astronautix.com. Retrieved 2023-11-29.
  11. ↑ "History - Jets and Moon Rockets: 1957-1970 - The Boeing Company ... Booster Rockets". Boeing. Archived from the original on 2012-05-11.
  12. ↑ "Thor Burner 2A". www.astronautix.com. Retrieved 2023-11-29.
  13. ↑ "The Space Review: Launch failures: Two Thors, one problem".


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