RL60 was an American cryogenic upper stage engine that was under development by Pratt & Whitney. It was a potential replacement for the RL-10.

RL60 Next Generation Rocket Engine Picture

Pratt & Whitney is applying its unmatched 40 years of expander cycle, cryogenic upper-stage engine experience to the development of the RL60. This new high-performance offering is designed to produce 60,000 pounds of thrust and meet the evolving needs of expendable launch requirements or human-rated missions.

RL60 will provide more than double the thrust of the company’s venerable RL10 engine for increased performance and launch capability. The RL60’s expander cycle gives the engine greater range of operation, including multiple firings in space. The engine also offers flexibility as it can operate anywhere within a range of 50,000 to 65,000 pounds of thrust.

RL-60 expander cycle engine will be approximately the same size as the RL-10, allowing for direct substitution with minimal vehicle modifications.

The RL60 demonstration phase is now underway with component testing completed. Demonstrator engine testing is planned for mid 2003.


Thrust: 50,000 to 65,000 lb

Weight: 1,100 lb

Specific impulse: 465 sec

Cycle: Full expander

Propellants: LH2/LOX

Mixture ratio: 4.5 to 6.2

NPSP LH2/LOX: <2.0 psi

Restarts: Multiple

RL60 Next Generation Rocket Engine Picture


Modern Engineering for Design of Liquid-Propellant Rocket Engines (Progress in Astronautics and Aeronautics, Vol 147
from Amazon.com, Amazon.co.uk, Amazon.ca

Rocket Propulsion Elements, 7th Edition by George P. Sutton (Author), Oscar Biblarz (Author)

Rocket Exhaust Plume Phenomenology by Frederick S. Simmons
from Amazon.com, Amazon.co.uk, Amazon.ca

Amateur Rocket Motor Construction: A Complete Guide To The Construction Of Homemade Solid Fuel Rocket Motors
from Amazon.com, Amazon.co.ukAmazon.ca

RL60 Links

  • RL60 Pratt & Whitney: Information and picture source (19 August 2007) – link no longer available.
  • RL-60: by astronautix.com

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