Case studies

Omniseal® RACO® Spring-Energized Seal
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Launch Vehicle Large Fuel Tank

    Kha Le
Space Leakage Control Cryogenic


Launch vehicles are most often propelled using fluids with liquid oxygen being the most common oxidizer and fuel being liquid hydrogen or kerosene and most recently liquid methane. All these fluids (except kerosene) are commonly stored at cryogenic temperatures.

Sealing is critical when liquid oxygen or hydrogen are involved since they are easily ignitable. Any small amount of leakage can create a hazardous situation, which can lead to a potential explosion of the whole launch system. Leakage requirements are therefore quite stringent.


With the combination of cryogenic temperatures, large size and strict leakage requirements, at such extremes sealing becomes challenging!


Fluids are stored in very large tanks that are part of launch vehicles, which need to reach GEO (Geostationary Orbit) or further; therefore, the rocket engine needs a significant amount of fuel to be able to fly until its final destination. These large tanks require seals that are equally large in size - typically between 1 and 2 meters or even larger.


Omniseal® RACO® spring-energized seal is a proven solution for this challenging application.

This large diameter seal has been qualified in many NASA space programs for the past 60 years, meeting the precise leakage requirement of this tank application in the range of 10-2/10-3 sccs.

Omniseal RACO Rocket Tank Seal

Big seal, Big benefit!


  • Available in large size

  • High spring force grants excellent leakage performance even at cryogenic temperatures

  • Excellent seal surface finish for cryogenic sealing

  • Product cleanliness in oxygen service per IEST-STDCC1246



  • Omniseal® RACO® Spring-Energized Seal


  • Main/Upper Stage LOX/LH2 Tank Sump


  • High-Performance Polymer Material A01

Precision Part

  • Custom Spring-Energized Manhole Cover Face Seal

Technical Details

  • Media: Liquid Oxygen

  • Temperature: -253°C to 38°C (-423°F to 100°F)

  • Motion: static

  • Pressure: few hundred psi (15 to 20 bar)

  • Counter face: 2195 Aluminium Alloy

Tags: Space Leakage Control Cryogenic