Piston pumps for rocket engines

03/26/13 09:11:00    

By Michael Mealling

Yesterday XCOR Aerospace announced the successful 65 second burn of a flight weight piston pump fed rocket engine

For those not in the business this is a very significant milestone for chemical propulsion systems. This test showed that a piston based pump can pump cryogenic and non-cryogenic liquids at high enough flow rate and pressure to run a typical biprop engine. Until now rocket engins have either been fed from pressurized tanks (making them much heavier than necessary) or from turbopumps that run at such high speeds and pressures that most are built to be on the hairy edge of self destruction. Turbine pumps are not designed so much as evolved. They are usually the most expensive and bug prone pieces of a rocket engine.

What XCOR did was remove the turbo pump and replace it with something someone from any high school shop class would recognize. It looks like most other pumps we use in industry, using pistons to drive the fluids instead of centrifugal force. But what they wouldn't recognize is how to make the same design pump both kerosene and liquid oxygen. Most of the seals and tubes you would put on a regular pump would simply burst into flame in the presence of liquid oxygen and even a tiny bit of friction. Most of the time a design built for cryogenic temperatures is very different from things that run near normal temperatures. That is a very significant piece of engineering.

Great job guys!