The

Atlas LV-3B The Atlas LV-3B, Atlas D Mercury Launch Vehicle or Mercury-Atlas Launch Vehicle, was a human-rated expendable launch system used as part of the United States Project Mercury to send astronauts into low Earth orbit. Manufactured by Convair, it wa ...

, Atlas D Mercury Launch Vehicle or Mercury-Atlas Launch Vehicle, was a

human-rated Human-rating certification, also known as man-rating or crew-rating, is the certification of a spacecraft or launch vehicle as capable of safely transporting humans. There is no one particular standard for human-rating a spacecraft or launch veh ...

expendable launch system An expendable launch system (or expendable launch vehicle/ELV) is a launch vehicle that can be launched only once, after which its components are either destroyed during reentry or discarded in space. ELVs typically consist of several rocket sta ...

used as part of the United States

Project Mercury Project Mercury was the first human spaceflight program of the United States, running from 1958 through 1963. An early highlight of the Space Race, its goal was to put a man into Earth orbit and return him safely, ideally before the Soviet Un ...

to send

astronaut An astronaut (from the Ancient Greek (), meaning 'star', and (), meaning 'sailor') is a person trained, equipped, and deployed by a human spaceflight program to serve as a commander or crew member aboard a spacecraft. Although generally r ...

s into

low Earth orbit A low Earth orbit (LEO) is an orbit around Earth with a period of 128 minutes or less (making at least 11.25 orbits per day) and an eccentricity less than 0.25. Most of the artificial objects in outer space are in LEO, with an altitude never mor ...

. Manufactured by American aircraft manufacturing company

Convair Convair, previously Consolidated Vultee, was an American aircraft manufacturing company that later expanded into rockets and spacecraft. The company was formed in 1943 by the merger of Consolidated Aircraft and Vultee Aircraft. In 1953, it ...

, it was derived from the

SM-65D Atlas The SM-65D Atlas, or Atlas D, was the first operational version of the U.S. Atlas missile. Atlas D was first used as an intercontinental ballistic missile (ICBM) to deliver a nuclear weapon payload on a suborbital trajectory. It was later dev ...

missile, and was a member of the Atlas family of rockets. The Atlas D missile was the natural choice for Project Mercury since it was the only launch vehicle in the US arsenal that could put the spacecraft into orbit and also had many flights from which to gather data. But its reliability was far from perfect, and Atlas launches ending in explosions were an all-too common sight at Cape Canaveral. The Atlas had also been originally designed as a weapon system, thus its design and reliability did not need to necessarily be 100% perfect. As such, significant steps had to be taken to human-rate the missile and make it safe and reliable unless NASA wished to spend several years developing a dedicated launch vehicle for crewed programs or else wait for the next-generation

Titan II The Titan II was an intercontinental ballistic missile (ICBM) developed by the Glenn L. Martin Company from the earlier Titan I missile. Titan II was originally designed and used as an ICBM, but was later adapted as a medium-lift space l ...

ICBM to become operational. Atlas' stage-and-a-half configuration was seen as preferable to the two stage Titan in that all engines were ignited at liftoff, making it easier to test for hardware problems during pre-launch checks. Shortly after being chosen for the program in early 1959, the Mercury astronauts were taken to watch the second D-series Atlas test, which exploded a minute into launch. This was the fifth straight complete or partial Atlas failure and the booster was at this point nowhere near reliable enough to carry a nuclear warhead or an uncrewed satellite, let alone a human passenger. Plans to human-rate Atlas were effectively still on the drawing board and Convair estimated that 75% reliability would be achieved by early 1961 and 85% reliability by the end of the year. Despite the Atlas' developmental problems, NASA had the benefit of conducting Project Mercury simultaneously with the Atlas R&D program which gave plenty of test flights to draw data from as well as test modified equipment for Mercury.

Launch outcomes

Launch History

See also

Notes

References