TWiT Throwback (Video)

Know How... 148: Rockets, RRoD Fix, and Gasification

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The most powerful engine in the world, fix for the Red Ring of Death, how a Gassifier works, Hobbyking FPV kit, visualize the RF energy around you, and more.

Aerojet Rocketdyne RS-25

You've seen these before, they were known as the "SSME" or "Space Shuttle Main Engine"

  • It's a staged, liquid-fueled cryogenic rocket engine that was conceived of in the 60s, designed in the 70s and first flown in the 80s.
  • The fuel and oxidizer is first dumped into a small combustion chamber and ignited.
  • Those gasses are used to drive turbopumps which pressurize the fuel and oxidizer to be burned in the main combustion chamber
  • The exhaust from the small chamber is then dumped into the HighPressure manifold, adding to the thrust of the engine
  • When we were first developing our rocket engines, we couldn't make a proper 2-stage engine. They kept blowing up. It's actually VERY tricky to exhaust the gases from the primary combustion chamber into the high-pressure manifold
  • So we would just waste that potential thrust
  • We learned how to do it properly from the Russians. It burns a combination of liquid hydrogen and liquid oxygen. - The engine can product 418,000 lbs of thrust at liftoff.

    • Fun Fact: the SRBs on the Space Shuttle generated 2,800,000 lbs of lift (83% of total thrust at liftoff) -- But the SRBs only provide lift for the Shuttle for 2 minutes while the 3 RS-25 engines continued to burn for 8.5 minutes. -- And since solid fuel burns unevenly, it created a "rougher ride" for the Shuttle astronauts than for, say-- the Apollo Astronauts.

    A total of 46 RS-25 engines were made, at a cost of $40 million each. -- They were reusable, so they would be refurbished and requalified after each flight. The exhaust from the RS-25 can reach temperatures of 3,315 degrees Celsius which is enough to BOIL iron... it would definitely destroy the nozzle

    • To prevent that from happening, the fuel (liquid hydrogen) is pumped through a series of small tubes in the nozzle to keep the material below melting.
    • The heated fuel is then released into the combustion chamber where it combines with the oxidizer (liquid O2) and products thrust.

      • This engine, from 50 years ago! will be the future of space travel for the US -- It's the engine for the upcoming "Space Launch System"

      Hosts: Fr. Robert Ballecer, SJ and Bryan Burnett

      Technical Director: Alex Gumpel

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