Atlas LV-3B

Atlas LV-3B

An Atlas D LV-3B launching Mercury-Atlas 6
Function	Manned expendable launch system
Manufacturer	Convair
Country of origin	United States
Size
Height	28.7 metres (94.3 ft)
Diameter	3.0 metres (10.0 ft) width over boost fairing 4.9 metres (16 ft)
Mass	120,000 kilograms (260,000 lb)
Stages	1½
Capacity
Payload to LEO	1,360 kilograms (3,000 lb)
Launch history
Status	Retired
Launch sites	CCAFS LC-14
Total launches	9
Successes	7
Failures	2
First flight	29 July 1960
Last flight	15 May 1963
Boosters
No. boosters	1
Engines	2
Thrust	1,300 kilonewtons (300,000 lbf)
Burn time	134 seconds
Fuel	RP-1/LOX
First stage
Diameter	3.0 metres (10.0 ft)
Engines	1
Thrust	300 kilonewtons (67,000 lbf)
Burn time	5 minutes
Fuel	RP-1/LOX

The Atlas LV-3B, Atlas D Mercury Launch Vehicle or Mercury-Atlas Launch Vehicle, was a man-rated expendable launch system used as part of the United States Project Mercury to send astronauts into low Earth orbit. It was derived from the SM-65D Atlas 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 a large number of flights to gather data from. In addition, the Atlas's stage-and-a-half design with all engines firing at liftoff and no upper stages made it easier to verify and test that all systems were operating correctly prior to launch. But its reliability was far from perfect and Atlas launches ending in explosions were an all-too common sight at Cape Canaveral. Thus, significant steps had to be taken to man-rate the missile and make it safe and reliable unless NASA wished to spend several years developing a dedicated launch vehicle for manned programs or else wait for the next-generation Titan II ICBM to become operational.

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 unmanned satellite, let alone a human passenger. Plans to man-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.

Aside from the modifications described below, Convair set aside a separate assembly line dedicated to Mercury-Atlas vehicles which was staffed by personnel who received special orientation and training on the importance of the manned space program and the need for as high quality workmanship as possible. Components used in the Mercury-Atlas vehicles were given thorough testing to ensure proper manufacturing quality and operating condition, in addition components and subsystems with excessive operating hours, out-of-specification performance, and questionable inspection records would be rejected. All components approved for the Mercury program were earmarked and stored separately from hardware intended for other Atlas programs and special handling procedures were done to protect them from damage.