Saturn I

From Wikipedia, the free encyclopedia

Saturn I

The first Saturn I was launched October 27, 1961
Fact sheet
Function	Manned LEO launch vehicle
Manufacturer	Chrysler (S-I) Douglas (S-IV) Convair (S-V) - Unflown
Country of origin	USA
Size
Height	55 m (180 ft)
Diameter	6.52 m (21.39 ft)
Mass	509,660 kg (1,123,600 lb)
Stages	2 or 3 (3rd stage never flown)
	Capacity
Payload to LEO	9,000 kg (2 stage)
Payload to TLI	2,200 kg (2 stage)
Launch History
Status	Retired
Launch Sites	LC-37 & LC-34, Cape Canaveral
Total launches	10
Successes	10
Failures	0
Maiden flight	October 27, 1961
Last flight	July 30, 1965
Notable payloads	Apollo CSM (boilerplate) Pegasus
First Stage - S-I
Engines	8 H-1
Thrust	6.7 MN (1,500,000 lbf)
Burn time	~150 seconds
Fuel	RP-1/LOX
Second Stage - S-IV
Engines	6 RL-10
Thrust	400 kN (90,000 lbf)
Burn time	~482 seconds
Fuel	LH2/LOX
Third Stage - S-V (Centaur-C) - unflown
Engines	2 RL-10
Thrust	133 kN (30,000 lbf)
Burn time	~430 seconds
Fuel	LH2/LOX

For the moon of Saturn, see Mimas (moon).

The Saturn I was the United States' first dedicated "space launcher," a rocket designed specifically to launch loads into Earth orbit. Ten Saturn I's were flown by NASA, before it was replaced by the Saturn IB, which included a more powerful upper stage.

[edit] History

The Saturn project was started in April 1957 as a heavy-lift concept designed by Werner von Braun's team at the U.S. Army Ballistic Missile Agency (ABMA). Von Braun proposed using parts of the Redstone and Jupiter missiles, clustering them together to produce a new design with a 1.5-million-pound (6.7 MN) thrust at takeoff. He had earlier referred to Redstone and Jupiter rockets being used as space launchers as the Juno I and Juno II, respectively, and referred to the new design as the Juno V.

The ABMA team considered the Juno V as a general carrier vehicle for research and development of "offensive and defensive space weapons." Specific uses were forecast for each of the military services, including navigation satellites for the Navy; reconnaissance, communications, and meteorological satellites for the Army and Air Force; support for Air Force manned missions; and surface-to-surface logistics supply for the Army at distances up to 6400 kilometers. He also felt the design would make an excellent test-bed for other propulsion systems, notably the new 1.5-million-pound engine on which the Air Force had recently started work in 1955 (which would emerge as the F-1).

Von Braun also proposed using the Juno as the basis of a manned lunar mission as part of Project Horizon. Juno could lift up to 20,000 pounds into low earth orbit, and he proposed launching 15 of them to build a 200,000-lb lunar spacecraft in Earth orbit.

Several configurations were studied, based on various combinations of existing hardware. All of the designs used a common first stage built by surrounding a Jupiter's tanks with eight of those from the Redstone. A thrust plate mounted at the bottom of the tanks carried eight H-1 engines, an adaptation of the engines originally developed for the Navaho missile that had later been used on the Thor and Jupiter missiles as the S-3D. Upper stages based on either the Atlas or Titan I were also studied, with the Titan favored because the Atlas was currently in full production for the US Air Force. They proposed using the existing Titan tooling at 120" diameter, but lengthening it to produce a new 200-foot-long stage. A Centaur would be used as a third stage, which was expected to be ready for operational use in 1963, right when the lower two stages would have completed their testing. The resulting three-stage design was much taller and skinnier than the Saturn design that was eventually built.

In December, ABMA presented the work to ARPA, outlining a "short-cut development program" that would result in the system being fully operational in 1963. The total development cost of $850 million between 1958-1963 also covered 30 research and development flights, some carrying manned and unmanned space payloads. It was not until August that the team was given the go-ahead to start development work, which was followed in September with a contract with Aerojet to start development of the uprated H-1 engines.

In December, Von Braun presented the design to the newly formed NASA, along with his Horizon proposal for a lunar landing. The Air Force also presented their designs, which included a series of four boosters using common components. The largest of these was much bigger than the Juno, and intended to fly a mission directly to the moon with a single launch, which had been studied in their Lunex Project. NASA selected Von Braun's proposal on January 6th, giving it a vital boost.

At the end of January, NASA outlined their complete development program. This included the Vega and Centaur upper stages, as well as the Juno V and their own Nova boosters. Vega was later cancelled when information on the formerly secret Agena upper stage was released (then known as "Hustler"), and it had performance roughly comparable to NASA's design.

In February 1959, Von Braun had the name changed to Saturn, as "the one after Jupiter." Jupiter had been the basis of the Juno II, and he felt that the new design deserved its own name. Development ramped up quickly. In May the H-1 was being test-fired at ABMA, and construction of the Complex 34 launch sites started at Cape Canaveral in June.

The Air Force was apparently upset by ABMA's continued "wins" with the Saturn, and tried to wrest control of the contract tendering process from ABMA. ARPA eventually sided with the Army, which made matters worse. In December 1959 a change request was received from ARPA to upgrade the upper stage to a much more powerful design using four new 20,000-lbf liquid hydrogen/liquid oxygen powered engines, and an upgraded Centaur using two of the same design. This was ostensibly to allow Saturn to launch Dynasoar, but that reason was somewhat suspect considering Dynasoar had been designed to be launched on the original 120" Titan and didn't seem to need this sort of performance. It later became obvious this was delaying tactic intended to allow the Air Force to quickly plan their own booster that could compete with the Saturn, the "Super Titan".

Ironically, these changes, intended to delay the Saturn, instead proved to "make" the design. Although the new 20,000-lbf engine proposed was never delivered, in order to meet development schedules a cluster of six Centaur engines were placed in the new 160" stage to produce the S-IV of roughly the same performance. When the six engines were later replaced by a single J-2 in the S-IVB, performance improved so much that the Saturn was able to launch the Apollo CSM, proving invaluable during Apollo Project.

In the end, the Department of Defense decided that the Saturn was simply too big and expensive for any military mission. They also thought that big boosters of the Saturn class should be NASA's responsibility because there was no urgent military application for them. The entire ABMA organization was transferred to NASA on July 1, 1960, and the Saturn became part of the Apollo program. The Department of Defense turned to the Titan family of rockets for its heavy-lift needs, in the form of the Titan III and Titan IV. A Titan III has about the same lift capability of a Saturn IB but costs less to manufacture and launch.

The main payload of the Saturn I was the Apollo spacecraft. It was also considered at one time for launch of the X-20 Dyna-Soar spaceplane and later, for launching a Gemini capsule on a proposed lunar mission.

[edit] Data for the Original Saturn I

Parameter	S-I - 1st Stage	S-IV - 2nd Stage	S-V - 3rd Stage
Height (m)	24.48	12.19	9.14
Diameter (m)	6.52	5.49	3.05
Gross mass (kg)	432,681	50,576	15,600
Empty mass (kg)	45,267	5,217	1,996
Engines	Eight - H-1	Six - RL-10	Two - RL-10
Thrust (kN)	7,582	400	133
ISP (seconds)	288	410	425
ISP (kN·s/kg)	2.82	4.02	4.17
Burn duration (s)	150	482	430
Propellant	LOX/RP-1	LOX/LH2	LOX/LH2

[edit] Saturn I - Block II launch events

Event	Time (s)	Altitude (km)	Range (km)
Ignition command	-3.02	.	.
Commit	0.04	.	.
First motion	0.17	.	.
Liftoff	0.40	.	.
Guidance computer release	0.43	.	.
Begin roll maneuver	8.40	.	.
End roll maneuver	13.40	.	.
Begin tilt	15.40	.	.
Mach one	55.24	7.18	.
Max Q	73.00	13.53	.
S-IV LH2 prestart	107.00	.	.
Freeze tilt	134.40	.	.
S-IV LOX prestart	138.47	.	.
Inboard engine cutoff	140.24	78.35	67.31
Outboard engine cutoff	146.24	88.08	79.54
Ullage rocket ignition	146.56	.	.
S-I / S-IV separation	146.64	.	.
Retro rocket ignition	146.71	.	.
S-IV ignition	148.34	.	.
Jettison ullage / LES	158.64	.	.
Switch platforms (ST-90S to ST0124)	160.64	.	.
Resume tilt	164.24	.	.
Stop tilt	623.93	.	.
S-IV cutoff	625.93	509.64	1856.39
Orbit insertion	635.93	.	.

[edit] S-I stage

The S-I is an eight-engine first-stage rocket booster. It is composed of nine propellant containers, eight fins, a thrust structure assembly, eight H-1 rocket engines, and many other components. The propellant containers consist of eight Redstone tanks, four holding LOX, painted white, and four holding RP-1, painted black. They are clustered around a central Jupiter rocket tank, which contains LOX. The four outboard engines can gimbal, meaning they can be steered to properly guide the rocket. This requires a few more engine components.

Here are the specifications:

Height: 24.48 m
Diameter: 6.52 m
Engines: 8 H-1
Thrust: 1,600,000 lbf (7.1 MN)
Fuel: RP-1 (Refined kerosene) 41,000 US gal (155 m³)
Oxidizer: liquid oxygen (LOX) 66,000 US gal (250 m³)
Burn time: 2.5 min
Burnout altitude: 42 miles (68 km)

[edit] H-1 engine

The H-1 engine is a 200,000-lbf (890 kN) thrust LOX/RP-1 engine, used alone in the first stages of some Delta rockets and the Jupiter rocket. It is derived from the Navaho missile, and was simplified and improved for S-IB use. It is used in clusters on all S-IB rocket stages. Later it would be uprated to 205,000 lbf (912 kN) of thrust. The H-1 preceded the F-1 engine, which was used on the Saturn V rocket. Here are the basic data:

Fuel: RP-1 (refined kerosene)
Oxidizer: liquid oxygen (LOX)
Height: 8.5 ft (2.6 m)
Width: 5.5 ft (1.7 m)
Thrust: 200,000 lbf (890 kN)
Uprated thrust: 205,000 lbf (912 kN)
Fuel flowrate: 2092 US gal/min (132 L/s)
Oxidizer flowrate: 3330 US gal/min (210 L/s)
Oxidizer to fuel ratio: 2.23:1
Type: bipropellant standard
Nominal chamber pressure: 633 psia (4.4 MPa)
Inboard weight: 1780 lb (810 kg)
Outboard weight: 2020 lb (920 kg)
Expansion area ratio: 8:1
Specific impulse(Isp): 263 seconds (2.6 kN·s/kg)

[edit] S-IV stage

Main article: S-IVB

The S-IV stage is a large Lox/LH2-fueled rocket stage. It is powered by six RL-10 engines, which can gimbal. This stage has a "common bulkhead," meaning that one propellant tank is directly connected to the other, as if conjoined twins. This saves about ten tons of weight. Here are the S-IV specs:

Height: 12.19 m
Diameter: 5.49 m
Engines: 6 RL-10
Thrust: 400 kN
Fuel: liquid hydrogen (LH2)
Oxidizer: liquid oxygen (LOX)
Burn time: approx. 410 s
Burnout altitude (for Saturn I): up to 450 km

[edit] RL-10 engine

The RL-10 engine is a 66.70 kN thrust LOX/LH2 engine, used in the upper stages of some Atlas rockets and the Titan rocket. It is used in clusters on all S-IV and Centaur stages.

Basic data:

Fuel: LH-2 (liquid hydrogen)
Oxidizer: liquid oxygen (LOX)
Height: 68 in (1.7 m)
Width: 39 in (1.0 m)
Thrust: 15,000 lbf (67 kN)
Isp: 433 seconds (4.25 kN·s/kg)
Burn Time: 482 s
Nominal chamber pressure: 24.0 bar (2.4 MPa)
Dry weight: 298 lb (135 kg)
Expansion area ratio: 40:1

[edit] Saturn I Instrument Unit

The Instrument Unit is a ring shaped structure fitted to the top of the Block II Saturn I second stage (S-IV). The Instrument Unit was used on SA-5 through SA-10. Equipment used in the Saturn I Instrument Unit was used to test design concepts for next generation Saturn V Instrument Unit. A few Saturn I Instrument Unit components are the same as used on the Saturn IB. An inertial platform and control computer are similar in design and operation to those used in the Saturn IB.

The Instrument Unit is manufactured by Marshall Space Flight Center. Within it are the ST-90 and ST-124 guidance platforms, control, and telemetry systems. It controls ascent through the atmosphere, compensating for any winds or loss of thrust during the ascent.

The IU has an optical window so that a ground based theodolite can be used for alignment. The theodolite alignment was needed for a launch to proceed.

The guidance computer used in the early Saturn I rocket was adapted from the computer developed for the Titan II by IBM.

[edit] Instrument Unit specifications

Diameter: 154 in (3.9 m)
Height: 91 in (2.3 m)
Weight: 6,105 lb (2,769 kg)

[edit] Saturn I launches

[edit] Saturn I vehicles and launches

Serial number	Mission	Launch date	Notes
SA-1	SA-1	October 27, 1961	First test flight. Block I. Suborbital. Range 398 km, Apogee 136.5 km. Apogee Mass 115,700 lb (52,500 kg).
SA-2	SA-2	April 25, 1962	Second test flight. Block I. Suborbital. 86,000 kg water released at apogee of 145 km.
SA-3	SA-3	November 16, 1962	Third test flight. Block I. Suborbital. 86,000 kg water released at apogee of 167 km.
SA-4	SA-4	March 28, 1963	Fourth test flight. Block I. Suborbital. Dummy SIV 2nd stage. Apogee 129 km, range 400 km.
SA-5	SA-5	January 29, 1964	First live S-IV 2nd stage. Orbit 760 by 264 km. Mass 38,700 lb (17,550 kg). Decayed 30 April 1966.
SA-6	A-101	May 28, 1964	First Apollo boilerplate launch. Block II. Orbit 204 by 179 km. Mass 38,900 lb (17,650 kg). Apollo BP Decayed 1 June 1964.
SA-7	A-102	September 18, 1964	Second Apollo boilerplate launch. Block II. Orbit 203 by 178 km. Mass 36,800 lb (16,700 kg). Apollo BP-15 Decayed 22 September 1964.
SA-9	A-103	February 16, 1965	First Pegasus Micrometeoroid Satellite. Orbit 523 by 430 km. Mass 3,200 lb (1,450 kg). Pegasus 1 Decayed 17 September 1978. Apollo BP-26 Decayed 10 July 1985.
SA-8	A-104	May 25, 1965	Second Pegasus Micrometeoroid Satellite. Orbit 594 by 467 km. Mass 3,200 lb (1,450 kg). Pegasus 2 Decayed 3 November 1979. Apollo BP-16 Decayed 8 July 1989.
SA-10	A-105	July 30, 1965	Third Pegasus Micrometeoroid Satellite. Orbit 567 by 535 km. Mass 3,200 lb (1,450 kg). Pegasus 3 Decayed 4 August 1969. Apollo BP-9A Decayed 22 November 1975.

[edit] References

• Bilstein, Roger E. (1980). Stages to Saturn: A Technological History of the Apollo/Saturn Launch Vehicles. NASA SP-4206. ISBN 0-16-048909-1.
  • Available for reading on-line: http://history.nasa.gov/SP-4206/sp4206.htm
  • and in softcover through the U.S. Government Printing Office: http://history.nasa.gov/gpo/order.html
• Saturn launch vehicles (PDF)