Atlas rocket

Any of a series of U.S. expendable space launch vehicles.

The Atlas was originally designed as a liquid-fueled ICBM and first tested in an operational version in 1959. Early versions launched most of the Mercury manned missions and, coupled with upper-stage rockets, a number of Ranger, Surveyor, Mariner, and Pioneer probes on lunar and planetary missions. Later generations have become workhorses of the U.S. space program and carry a wide variety of scientific, military, and commercial spacecraft.

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 booster for space vehicles, particularly the U.S. Mercury spacecraft series, designed originally as an intercontinental ballistic missile (ICBM). Atlas is equipped with three engines—two boosters that are jettisoned after about 2 ¹/₂ minutes of operation and a sustainer that operates until orbital velocity is attained. Atlas can lift about 5,800 pounds (2,600 kg) to about a 350-mile (560-kilometre) orbit. Coupled with Agena, the combined Atlas–Agena rocket is used for launching lunar and planetary probes, as well as Earth-orbiting satellites, such as Seasat, where the Agena is also the spacecraft. Atlas–Centaur, or Centaur, combines the first-stage Atlas, which burns kerosene, with a second stage fueled with liquid hydrogen; it was the first rocket to use liquid hydrogen as fuel.

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