Saturn I (rocket)

Saturn I

The first Saturn I was launched October 27, 1961
Function	Large booster technology Large scientific satellite payloads in LEO Apollo spacecraft development
Manufacturer	Chrysler (S-I) Douglas (S-IV) Convair (S-V) - Unflown
Country of origin	United States
Size
Height	55 m (180 ft)
Diameter	6.52 m (21.39 ft)
Mass	1,124,000 lb (510,000 kg)
Stages	2 or 3 (3rd stage never flown)
Capacity
Payload to LEO	20,000 lb (9,070 kg) (2 stage)
Payload to TLI	4,900 lb (2,220 kg) (2 stage)
Launch history
Status	Retired
Launch sites	LC-37 & LC-34, Cape Canaveral
Total launches	10
Successes	10
Failures	0
First flight	October 27, 1961
Last flight	July 30, 1965
Notable payloads	Boilerplate Apollo CM Pegasus
First stage - S-I
Engines	8 H-1
Thrust	1,500,000 lbf (6.7 MN)
Burn time	~150 seconds
Fuel	RP-1/LOX
Second stage - S-IV
Engines	6 RL10
Thrust	90,000 lbf (400 kN)
Burn time	~482 seconds
Fuel	LH2/LOX
Third stage - S-V (Centaur-C) - unflown
Engines	2 RL10
Thrust	133 kN (30,000 lbf)
Burn time	~430 seconds
Fuel	LH2/LOX

The Saturn I (pronounced "Saturn one") was the United States' first heavy-lift dedicated space launcher, a rocket designed specifically to launch large payloads into low Earth orbit. Most of the rocket's power came from a clustered lower stage consisting of tanks taken from older rocket designs strapped together to make a single large booster, leading critics to jokingly refer to it as "Cluster's Last Stand". However, its design proved sound and very flexible. Its major successes were launching the Pegasus satellites and flight verification of the Apollo Command and Service Module aerodynamics in the launch phase. Originally intended as a near-universal military booster during the 1960s, it served only for a brief period and only with NASA; ten Saturn I rockets were flown before it was replaced by the derivative Saturn IB, which featured a more powerful upper stage and improved instrumentation.

President John F. Kennedy identified the Saturn I, and the SA-5 launch in particular, as being the point where US lift capability would surpass the Soviets, after being behind since Sputnik.

The Saturn project was started as one of a number of proposals to meet a new Department of Defense (DoD) requirement for a heavy-lift vehicle to orbit a new class of communications and "other" satellites. The requirements called for a vehicle capable of putting 9,000 to 18,000 kilograms into orbit, or accelerating 2,700 to 5,400 kg to escape velocity. Existing launchers could place a maximum of about 1,400 kg in orbit, but might be expanded to as much as 4,500 kg with new high-energy upper stages. In any event, these upper stages would not be available until 1961 at the earliest, and would still not meet the DoD requirements for heavy loads.

Wernher von Braun's team at the U.S. Army Ballistic Missile Agency (ABMA) started studying the problem in April 1957. They calculated that a rocket with the required performance would require a lower-stage booster with a thrust of about 1.5 million pound-force (6.7 MN) thrust at takeoff. As it happened, the Air Force had recently started work on just such an engine, eventually emerging as the F-1, but this would not be available in the time frame that the DoD was demanding and would be limited to about 1 million lbf in the short term anyway. Another possibility was a Rocketdyne engine, then known as the E-1, which provided about 360,000 to 380,000 lbf (1,700 kN), four of which would reach the required thrust levels. This approach became the favorite, and in order to quickly provide fuel tankage to supply the engines, a new stage consisting of the tank from a Jupiter wrapped with eight taken from the Redstone would be used along with a thrust plate on the bottom where the engines would be attached.