Atlas SLV-3 Agena B with OGO 3 on Cape Canaveral LC 12 in 1966
Atlas was the first U.S. intercontinental ballistic missile, but its ICBM service was short-lived. Atlas served longer as an orbital launcher stage. It was best known for powering NASA’s original Mercury orbital missions, but it far more often launched unmanned missions with Agena or Centaur or other upper stages.
Atlas, built by San Diego’s Convair (later General Dynamics) was the “balloon tank” missile. Its stainless steel propellant tank walls were as thin as a dime in some areas and had no internal structural support. Instead, the walls were supported by internal pressure, much like an unopened carbonated beverage can.
Atlas was powered by a unique stage-and-a-half propulsion system that consisted of a jettisonable “booster package” with two powerful Rocketdyne (Y)LR89-NA5(7) engines positioned on each side of a less-powerful, but more fuel efficient and light weight, Rocketdyne (Y)LR-105-NA5(7) sustainer engine. Two small verniers, mounted on opposite sides of the vehicle above the booster package, provided roll control and trajectory tuning. All five engines ignited on the pad.
Numerous Atlas and Atlas-based variants flew during the program’s nearly 50 years duration. A total of 576 launch attempts were made with Rocketdyne-powered Atlases, not including a couple of vehicles destroyed in pre-launch propellant loading accidents.
Also read: ATK Cots Demo Launcher – Space Launch Report
Atlas launched the first U.S. manned orbital flights, the first spacecraft to fly by another planet, the first to orbit another planet, the first to fly past the outer gas giant planets, and the first U.S. spacecraft to impact, land on, and orbit the Moon. Centaur, which flew atop Atlas in 1962 with a first success in 1963, was the world’s first liquid hydrogen-fueled upper stage. Atlas-Agena D was the launch vehicle for numerous Gambit KH-7, a USAF reconnaissance program that was as large or larger than the U.S. Gemini program.
Atlas 2/2A/2AS were the final Rocketdyne powered Atlases, by the end produced by Lockheed Martin in Waterton Canyon, Colorado. AC-164, launched December 2, 2003, was the last heritage Atlas of 284 launched from Vandenberg AFB/Point Arguello since 1959. On May 14, 2004, Lockheed Martin rolled rolled out AC-167, the final Atlas 2AS, shipping it to Cape Canaveral on May 16. On August 31, AC-167 closed out the heritage Atlas program with a successful launch from Space Launch Complex 36A with a National Reconnaissance Office satellite.
Six Atlas 3 launch vehicles finished the balloon tank Atlas era. They dispensed with the stage-and-a-half design, using a “Single Stage Atlas” powered by a single dual chamber RD-180 engine built in Moscow by Energomash. The final Atlas 3 flew on February 5, 2005.
Atlas 5, which used an all-new structurally stable first stage, was for all practical purposes an “Atlas” in name only.
“Baseball Card” type details of most of the flown Atlas variants are provided in the following links, listed in approximate chronological order.
Author :
by Ed Kyle
