Saturn INT-21

Saturn INT-21

Function	Launch vehicle
Manufacturer	Boeing (S-IC) North American (S-II)
Country of origin	United States
Size
Height	80 m (262 ft (without payload))
Diameter	10 m (33 ft)
Mass	2,916,000 kg (6,429,000 lb)
Stages	2
Capacity
Payload to LEO	75,000 kg (165,000 lb)
Launch history
Status	Retired
Launch sites	LC-39A, Kennedy Space Center
Total launches	0
Notable payloads	Skylab
First stage - S-IC
Engines	5 Rocketdyne F-1
Thrust	34.02 MN (7,648,000 lbf)
Burn time	150 seconds
Fuel	RP-1/LOX
Second stage - S-II
Engines	5 Rocketdyne J-2
Thrust	5 MN (1,000,000 lbf)
Burn time	360 seconds
Fuel	LH2/LOX

The Saturn INT-21 was a study for an American orbital launch vehicle of the 1970s. It was derived from the Saturn V rocket used for the Apollo program, using its first and second stages, but lacking the third stage. The guidance unit would be moved from the top of the third stage to the top of the second stage. The INT-21 was never flown.

A related variant was launched once, from the Kennedy Space Center, Florida carrying the Skylab space station into orbit, at 17:30 GMT, on May 14, 1973. As Skylab was built from an S-IVB stage, there was no need to move the guidance unit. This version was intended to be used for other flights in the Apollo Applications Program, and would have also been used to launch other American space stations, including Skylab B.

See also

The Saturn INT-21 would have been similar to the Saturn V which launched the Skylab space station, on May 14, 1973

• Comparison of orbital launch systems
• Apollo program
• Saturn I
• Saturn IB
• Saturn V
• Skylab
• Apollo Applications Program
• S-IC
• S-II
• Saturn I SA-1

External links

• Saturn INT-21 in Encyclopedia Astronautica
• Skylab, US Centennial of Flight Commission