SM-65E Atlas

Atlas-E (SM-65E)

Launch of an Atlas-E missile
Function	ICBM Expendable launch system
Manufacturer	Convair
Country of origin	United States
Launch history
Status	Retired
Launch sites	LC-11 & 13 CCAFS OSTF-1, LC-576 & SLC-3, VAFB
Total launches	48
Success(es)	33
Failure(s)	15
First flight	October 11, 1960
Last flight	March 24, 1995
Boosters
No. boosters	1
Powered by	2 LR-89-5
Total thrust	369,802 lbf (1,644.96 kN)
Specific impulse	256 s
Burn time	120 s
Propellant	RP-1/LOX
First stage
Powered by	1 LR-105-5
Maximum thrust	86,844 lbf (386.30 kN)
Specific impulse	316 s
Burn time	309 s
Propellant	RP-1/LOX
[edit on Wikidata]

The SM-65E Atlas, or Atlas-E, was an operational variant of the Atlas missile. It first flew on October 11, 1960, and was deployed as an operational ICBM from September 1961 until April 1966. Following retirement as an ICBM, the Atlas-E, along with the Atlas-F, was refurbished for orbital launches as the Atlas E/F.^[1] The last Atlas E/F launch was conducted on March 24, 1995, using a rocket which had originally been built as an Atlas E.

As fully operational ICBMs, the Atlas E and F, which differed only in guidance systems, had upgraded engines and inertial control instead of the Atlas D's radio ground guidance. The ignition system was also different from the one used on the D-series, which used a "wet" start, meaning that the propellants were injected into the combustion chamber prior to ignition, and a hypergolic igniter on the fully developed version. The Atlas E/F for comparison used pyrotechnic cartridges and a dry start (ignition coming before propellant injection) for an extremely rapid ignition that required no hold-down time on the pad to prevent combustion instability. The booster engines had separate gas generators unlike the Atlas D which had one gas generator for both engines. The launcher system used for the E and F series was also different from the D series, eliminating the hold-down arms in favor of a mechanism that would immediately release the missile as thrust built up.

Atlas-E launches were conducted from Cape Canaveral Air Force Station, at Launch Complexes 11 and 13, and Vandenberg Air Force Base at OSTF-1, LC-576 and SLC-3.^[1]