Encyclopedia Astronautica
Saturn V-25(S)U


American orbital launch vehicle. Boeing study, 1968. 4 156 inch solid propellant boosters; Saturn IC stretched 498 inches with 6.64 million pounds propellant and 5 F-1 engines; S-II standard length with 5 J-2 engines. This vehicle would place Nerva nuclear third stage into low earth orbit, where five such stages would be assembled together with the spacecraft for a manned Mars expedition.

LEO Payload: 248,663 kg (548,208 lb) to a 486 km orbit at 28.00 degrees. Payload: 160,000 kg (350,000 lb) to a translunar trajectory in 1985 dollars. Flyaway Unit Cost $: 174.000 million.

Stage Data - Saturn V-25(S)U

  • Stage 0. 4 x UA 156 inch. Gross Mass: 544,311 kg (1,200,000 lb). Empty Mass: 37,195 kg (82,000 lb). Thrust (vac): 8,924.482 kN (2,006,303 lbf). Isp: 263 sec. Burn time: 157 sec. Isp(sl): 238 sec. Diameter: 3.96 m (12.99 ft). Span: 3.96 m (12.99 ft). Length: 34.00 m (111.00 ft). Propellants: Solid. No Engines: 1. Engine: UA-156. Status: Development 1965.
  • Stage 1. 1 x Saturn MS-IC-25(S). Gross Mass: 3,223,800 kg (7,107,200 lb). Empty Mass: 211,900 kg (467,100 lb). Thrust (vac): 45,925.500 kN (10,324,463 lbf). Isp: 304 sec. Burn time: 192 sec. Isp(sl): 265 sec. Diameter: 10.06 m (33.00 ft). Span: 19.00 m (62.00 ft). Length: 54.70 m (179.40 ft). Propellants: Lox/Kerosene. No Engines: 5. Engine: F-1A. Status: Study Boeing 1967. Comments: S-IC with 41.5 foot stretch, 6,640,0000 lbs propellant, uprated F-1 engines.
  • Stage 2. 1 x Saturn MS-II-4(S)B. Gross Mass: 494,100 kg (1,089,300 lb). Empty Mass: 42,300 kg (93,200 lb). Thrust (vac): 5,169.000 kN (1,162,037 lbf). Isp: 421 sec. Burn time: 355 sec. Isp(sl): 200 sec. Diameter: 10.06 m (33.00 ft). Span: 10.06 m (33.00 ft). Length: 24.84 m (81.49 ft). Propellants: Lox/LH2. No Engines: 5. Engine: J-2. Status: Study Boeing 1967. Comments: Standard S-II but with structural strength increased from 86% to 502% depending on station, resulting in 8.6% increase in empty weight.
  • Stage 3. 1 x Saturn S-N V-25(S)U. Gross Mass: 245,760 kg (541,800 lb). Empty Mass: 71,190 kg (156,940 lb). Thrust (vac): 889.325 kN (199,928 lbf). Isp: 825 sec. Burn time: 1,500 sec. Diameter: 10.06 m (33.00 ft). Span: 10.06 m (33.00 ft). Length: 48.17 m (158.03 ft). Propellants: Nuclear/LH2. No Engines: 1. Engine: Nerva. Status: Study 1969. Comments: Version of Nerva studied by Boeing for manned Mars expedition.

Status: Study 1968.
Gross mass: 6,439,300 kg (14,196,200 lb).
Payload: 248,663 kg (548,208 lb).
Height: 153.00 m (501.00 ft).
Diameter: 10.06 m (33.00 ft).
Thrust: 72,338.40 kN (16,262,319 lbf).
Apogee: 486 km (301 mi).

More... - Chronology...


Associated Countries
Associated Engines
  • F-1A Rocketdyne Lox/Kerosene rocket engine. 9189.6 kN. Study 1968. Designed for booster applications. Gas generator, pump-fed. Isp=310s. More...
  • Nerva DoE nuclear/lh2 rocket engine. 266 kN. Study 1968. Early version of Nerva engine proposed for use in Saturn and RIFT configurations in 1961. Isp=800s. More...
  • UA-156 CSD solid rocket engine. 8924.3 kN. Tested 1968. Isp=263s. Proposed as strap-on booster for Saturn INT-27, Saturn V-25(S)B, Saturn V-25(S)U. More...

See also
  • Saturn The Saturn launch vehicle was the penultimate expression of the Peenemuende Rocket Team's designs for manned exploration of the moon and Mars. Numerous designs and variants were studied, but in the end only three models - the Saturn I, IB, and V - were built in the 1960's, and then only used to support NASA's Apollo moon landing program. More...
  • Saturn V America's booster for the Apollo manned lunar landing. The design was frozen before a landing mode was selected; the Saturn V could be used for either Earth-Orbit-Rendezvous or Lunar-Orbit-Rendezvous methods. The vehicle ended up with the same payload capability as the 'too large' Nova. The basic diameter was dictated by the ceiling height at the Michoud factory selected for first stage manufacture. Despite the study of innumerable variants, production was ended after only 12 were built and America spent the next fifty years in a pointless slow-motion withdrawal from manned space exploration. More...

Associated Manufacturers and Agencies
  • Von Braun American manufacturer of rockets and spacecraft. Von Braun, USA. More...

Associated Stages
  • Saturn S-N V-25(S)U Nuclear/LH2 propellant rocket stage. Loaded/empty mass 245,760/71,190 kg. Thrust 889.33 kN. Vacuum specific impulse 825 seconds. Version of Nerva studied by Boeing for manned Mars expedition. More...
  • Saturn MS-IC-25(S) Lox/Kerosene propellant rocket stage. Loaded/empty mass 3,223,800/211,900 kg. Thrust 45,925.50 kN. Vacuum specific impulse 304 seconds. S-IC with 41.5 foot stretch, 6,640,0000 lbs propellant, uprated F-1 engines. More...
  • Saturn MS-II-4(S)B Lox/LH2 propellant rocket stage. Loaded/empty mass 494,100/42,300 kg. Thrust 5,169.00 kN. Vacuum specific impulse 421 seconds. Standard S-II but with structural strength increased from 86% to 502% depending on station, resulting in 8.6% increase in empty weight. More...
  • UA 156 inch Solid propellant rocket stage. Loaded/empty mass 544,311/37,195 kg. Thrust 8,924.48 kN. Vacuum specific impulse 263 seconds. More...

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