Delta L

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This article is about the rocket, for the firearms issue see Delta L problem
Delta L
Pioneer E Launch GPN-2003-00038.jpg
Delta L before the failed attempt to launch Pioneer E
Function Expendable launch system
Country of origin USA
Launch history
Status Retired
Launch sites Cape Canaveral LC-17A
Vandenberg SLC-2E
Total launches 2
Successes 1
Failures 1
First flight 27 August 1969
Last flight 31 January 1972

The Delta L, Thor-Delta L, or Thrust-Augmented Long Tank Thor-Delta was a US expendable launch system used to launch the Pioneer E and TETR satellites in 1969 (failed) and HEOS satellite in 1972. It was a member of the Delta family of rockets.

The Delta L was a three-stage rocket. The first stage was a Long Tank Thor, a stretched version of the Thor missile, augmented by three Castor-2 solid rocket boosters. The second stage was the Delta E. An FW-1D solid rocket motor was used as the third stage.

The first launch of the Delta L occurred on 27 August 1969, from Launch Complex 17A at the Cape Canaveral Air Force Station. The rocket's hydraulics system malfunctioned, and 383 seconds after launch the Range Safety Officer activated the self-destruct system. Neither the Pioneer E nor the TETR[1] payloads achieved orbit. The second, and final, Delta L launch was from Space Launch Complex 2E at the Vandenberg Air Force Base, on 31 January 1972. It successfully placed the HEOS-2 satellite into a highly elliptical orbit.


  1. ^ Test satellite for NASA's Manned Space Flight Network see:


  • Wade, Mark. "Delta". Encyclopedia Astronautica. Retrieved 2009-02-10. 
  • Krebs, Gunter. "Thor family". Gunter's Space Page. Retrieved 2009-02-10.