Thor-Burner#Burner-2

There are many Thor-Burner variations, according to the type of upper stages used:{{Cite web |title=Thor with solid-fuel upper stage |url=https://space.skyrocket.de/doc_lau/thor_sd.htm |access-date=2023-11-30 |website=Gunter's Space Page |language=en}}

The first two flights used a solid fuel MG-18 as second stage (Thor-LV2D Burner-1 (MG-18)).

After that an Altair rocket stage (same as the third stage of some Vanguard launch vehicles) was used, equipped by Boeing with 3-axis control (Thor-LV2D Burner-1 (Altair-3)).{{cite web |url=http://www.tbs-satellite.com/tse/online/lanc_thor_solid.html |title=Thor with a solid fuel top stage |publisher=The Satellite Encyclopedia}}

These combinations were used for six vehicles. The first was launched on 1965-01-18 and the sixth on 1966-03-30. These were early launches of classified DMSP satellites. Two of these launches failed.{{cite web |url=http://www.designation-systems.net/dusrm/app3/b-3.html |title=Douglas SLV-2 Thor / Boeing (McDonnell Douglas) SB-3 Delta |publisher=Directory of U.S. Military Rockets and Missiles}}

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.{{Cite web |title=Thor-LV2F Burner-2 |url=https://space.skyrocket.de/doc_lau_det/thor-lv2f_burner-2.htm |access-date=2023-11-29 |website=Gunter's Space Page |language=en}}{{Cite web |title=Thor-LV2F Burner-2 Star-13A |url=https://space.skyrocket.de/doc_lau_det/thor-lv2f_burner-2_star-13a.htm |access-date=2023-11-29 |website=Gunter's Space Page |language=en}}{{Cite web |title=Thor-LV2F Burner-2A |url=https://space.skyrocket.de/doc_lau_det/thor-lv2f_burner-2a.htm |access-date=2023-11-29 |website=Gunter's Space Page |language=en}}{{Cite web |title=Thor Burner 2 |url=http://www.astronautix.com/t/thorburner2.html |access-date=2023-11-29 |website=www.astronautix.com}} The first Burner-2 flight was on 1966-09-16.{{cite web |url=http://www.boeing.com/history/narrative/n058boe.html |title=History - Jets and Moon Rockets: 1957-1970 - The Boeing Company ... Booster Rockets |publisher=Boeing |url-status=dead |archiveurl=https://web.archive.org/web/20120511070230/http://www.boeing.com/history/narrative/n058boe.html |archivedate=2012-05-11 }}

On February 19, 1976, the attempted launch of a DMSP satellite from Vandenberg's SLC-10W went awry when SECO occurred 5 seconds early.{{Cite web |title=Thor Burner 2A |url=http://www.astronautix.com/t/thorburner2a.html |access-date=2023-11-29 |website=www.astronautix.com}} 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.{{Cite web |last=Eleazer |first=Wayne |date=January 19, 2009 |title=The Space Review: Launch failures: Two Thors, one problem |url=http://www.thespacereview.com/article/1287/1}}

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

{{Commons category|Thor-Burner}}{{reflist}}

{{Expendable launch systems}}

{{US launch systems}}

{{Thor and Delta rockets}}

Category:Thor (rocket family)