The S-IVB stage (200 series)


The Saturn IB S-IVB (second) stages in storage at the Douglas Aircraft Company's Sacramento Test Operations Facility (SACTO)in Sacramento, California.

credit to NASA

General information

The S-IVB stage was an uprated version of the S-IV. The designation S-IV has its roots in an initial design for a four stage moon rocket. Its first role of the S-IV, was to act as a second stage for the Saturn I booster. This S-IV stage had six cryogenic RL-10 engines with a combined thrust of 37 Tons. At some point NASA settled down on a three stage design of the moon rocket, which became known as the Saturn V. As soon as the requirements for the third stage of the Saturn V stack came into view it became clear that the S-IV with some modification would meet those requirements.

The slightly larger S-IVB had a single cryogenic J-2 engine which would deliver about 100 Ton of thrust, more than twice the thrust of the S-IV with its six RL-10 engines. The S-IVB was produced in two versions: the 200 series which was used as a second stage for the Saturn IB booster and the 500 series which was used as a third stage for the Saturn V booster. This S-IVB 500 would have the important ability to restart the J-2 engine in space to leave the Earth parking orbit into a trajectory to the Moon. (Trans Lunar Injection)


S-IVB stage main parts

From bottom up:
  1. One J-2 engine
  2. A conical shaped thrust structure
  3. The aft skirt
  4. The fuel tank and the liquid oxygen tank with their common bulkhead
  5. The forward skirt
  6. The interstage, a cylindrical shaped connecting ring between the S-IVB and the S-IB stage


Characteristics

  1. Height      : 14.49 meter
    Diameter  : 6.51 meter
    Mass empty stage           : 11.28 Ton
    Mass of propellants        : 106.61 Ton
    Mass of loaded stage      : 117.89 Ton
    Amount of fuel:
    Liquid Oxygen   : 86.88 Ton, 76 569 litres (Mass dens. LOx: 1.137 kg/ltr)
    Liquid Hydrogen : 19.73 Ton, 242 808 litres (Mass dens. LH2: 0.070 kg/ltr).
  2. Typical flight profile
    Ignition at an altitude of 61 km for 7 min and 49 sec., orbit insertion at an altitude of 227 km; downrange distance of 1887 km; velocity: 7 768 m/sec (27 964 km/hr, 26.1 Mach)
  3. J-2 engine:
    J-2 engine thrust : 104 Tons (metric)
    Height of J-2 engine : 3.38 meter
    Diameter of J-2 engine : 2.07 meter
    Mass of J-2 engine : 1.58 Ton
    Combustion pressure inside an J-2 chamber : 53 bar
    Combustion chamber diameter probably around 0.47 meter.
    Fuel consumption rate per J-2 engine : 0.23 Ton/sec.
    Specific Impulse at ground level : 440 sec.
  4. Manufacturer of the J-2 engines: Pratt & Whitney (initially)
    North American Aviation, Rocket dyne Division (eventually)
    Manufacturer of the S-IVB stage: Douglas Airplane Co.

This picture shows the flight path of the SA-205 (Apollo 7) during ascent. The J-2 engine of the S-IVB stage was ignited 2½ minutes after lift-off at an alititude of 61 km. It deliverd thrust for about 8 minutes and was then disposed of at an altitude of 227 km.

Skylab 2 ground track during ascent

This picture shows the ground track of the SA-206 (Skylab 2) during ascent. The S-IVB provided thrust for about 8 minutes and was then separated. The orbit decay of the S-IVB took about 7 days, the stage went down in the middle of the Indian Ocean.

Plan View S-IVB stage Forward section, Looking down

 
The S-IVB 200 stage

From top to bottom: the forward skirt, the combined oxygen & hydrogen tank, the aft skirt, the conical shaped thrust structure and the J-2 engine

Plan View S-IVB stage Aft section, Looking up

 



Site Map |  References |  Change History

Copyright 2005 by   Sander Panhuyzen
Comments and questions are welcome. All pictures and drawings contained on and through these pages are the author's, unless otherwise noted. No unauthorized reproduction without permission.