Saturn II

Saturn II

Saturn II proposals: INT-17, INT-18, INT-19.
Function	Orbital launch vehicle
Manufacturer	North American (S-II) Douglas (S-IVB)
Country of origin	United States
Size
Height	167 feet (51 m)
Diameter	33 feet (10 m)
Mass	1,112,000 to 4,178,200 pounds (504,400 to 1,895,200 kg)
Stages	2
Capacity
Payload to LEO (100 nmi (185 km), 28° inclination)	47,000 to 146,400 pounds (21,300 to 66,400 kg)
Associated rockets
Family	Saturn
Derivatives	INT-17 INT-18 INT-19
Launch history
Status	Study 1966
Launch sites	Kennedy Space Center Launch Complex 39,
Total launches	0
Boosters (INT-18) – UA1207
No. boosters	2 or 4
Motor	1
Thrust	1,600,000 lbf (7,100 kN) SL
Total thrust	3,200,000 lbf (14,000 kN) or 6,400,000 lbf (28,000 kN) SL
Specific impulse	272 seconds SL
Burn time	120 seconds
Fuel	APCP
First stage (INT-17) – S-II–INT-17
Length	81.49 feet (24.84 m)
Diameter	33.0 feet (10.1 m)
Empty mass	105,000 pounds (48,000 kg)
Gross mass	1,091,000 pounds (495,000 kg)
Engines	7 HG-3-SL
Thrust	1,334,000 lbf (5,930 kN) SL
Specific impulse	275 seconds (2.70 km/s) SL 450 seconds (4.4 km/s) vac
Burn time	200 seconds
Fuel	LH2/LOX
First stage (INT-18) – S-II
Length	81.49 feet (24.84 m)
Diameter	33.0 feet (10.1 m)
Empty mass	86,090 pounds (39,050 kg)
Gross mass	1,082,000 pounds (491,000 kg)
Engines	5 Rocketdyne J-2
Thrust	551,700 lbf (2,454 kN) SL 1,161,300 lbf (5,166 kN) vac
Specific impulse	200 seconds (2.0 km/s) SL 421 seconds (4.13 km/s) vac
Burn time	390 seconds
Fuel	LH2/LOX
Second stage – S-IVB-200
Length	58.3 feet (17.8 m)
Diameter	21.68 feet (6.61 m)
Empty mass	28,400 pounds (12,900 kg)
Gross mass	261,900 pounds (118,800 kg)
Engines	1 Rocketdyne J-2
Thrust	231,900 lbf (1,032 kN) vac
Specific impulse	421 seconds (4.13 km/s) vac
Burn time	475 seconds
Fuel	LH2/LOX

The Saturn II was a series of American expendable launch vehicles, studied by North American Aviation under NASA contract in 1966, derived from the Saturn V rocket used for the Apollo lunar program. The intent of the study was to eliminate production of the Saturn IB, and create a lower-cost heavy launch vehicle based on Saturn V hardware. North American studied three versions with the S-IC first stage removed: the INT-17, a two-stage vehicle with a low Earth orbit payload capability of 47,000 pounds (21,000 kg); the INT-18, which added Titan UA1204 or UA1207 strap-on solid rocket boosters, with payloads ranging from 47,000 pounds (21,000 kg) to 146,400 pounds (66,400 kg); and the INT-19, using solid boosters derived from the Minuteman missile first stage.

For this study, the Boeing company also investigated configurations designated INT-20 and INT-21 which employed its S-IC first stage, and eliminated either North American's S-II second stage, or the Douglas S-IVB third stage. Budget constraints led to cancellation of the study and exclusive use of the Space Shuttle for orbital payloads.

There was a large payload gap between the Saturn IB's 46,000-pound (21,000 kg) low Earth orbit capacity and the Saturn V's 310,000-pound (140,000 kg) capability. In the mid-1960s NASA's Marshall Space Flight Center (MSFC) initiated several studies to extend the capabilities of the Saturn family. NASA specified a LEO of 100 nautical miles (185 km), 28° inclination for payload calculations, and the studies examined a number of Modified Launch Vehicle (MLV) configurations based on the Saturn IB and Saturn V launch vehicles as well as Intermediate Payload (INT) launch vehicles based on modified Saturn V stages (MS-IC, MS-II, and MS-IVB). Martin Marietta (builder of Atlas and Titan rockets), Boeing (builder of S-IC first stages), and North American Aviation (builder of the S-II second stage) were three of the companies that provided responses.