Space Commerce

Liquid Oxygen Piston Pump Ready for Flight

By Keith Cowing
Press Release
May 24, 2012
Filed under
Liquid Oxygen Piston Pump Ready for Flight

XCOR announced today that it has achieved a key technical milestone with its flight weight rocket piston pump hardware. XCOR engineers have successfully and repeatedly pumped liquid oxygen (LOX) at flow rates required to supply the Lynx suborbital vehicle main engines.
Combined with earlier demonstrated kerosene pumps and fully characterized engines, XCOR is now poised for main propulsion integration into the Lynx flight weight fuselage.

XCOR’s family of rocket piston pumps and engines now includes and is suitable for: kerosene, LOX, liquid hydrogen (LH2), and liquid methane. These piston pumps are a critical component for safe, cost-effective, sustainable, reliable and highly reusable rocket engines for XCOR’s Lynx and other launchers including upper stage liquid hydrogen engines suitable for the Atlas V, Delta IV, and the planned NASA Space Launch System (SLS).

“For propulsion from 50 to 75,000 lbf thrust, XCOR’s proprietary combined thermodynamic cycle for piston pumps is ideal,” said XCOR CEO Jeff Greason. “Unlike a turbo pump used in traditional rocket engines, the development cost of a piston pump is much lower and the useful range of thrust is much higher without modification. Manufacturability is easier, and reliability is considerably higher. The maintenance cycle is closer to that of an automotive engine rather than ‘disassemble and inspect after every flight’ required with conventional turbo fed systems. This technology is integrated into the LOX/kerosene propulsion system on our Lynx suborbital launch vehicle, and will be applied to future main propulsion 30,000 lbf thrust LOX/LH2 engines currently under development.”

“The ability to ensure low cost and easy, repeatable manufacturing of critical pump technology over a 30 to 40 year product lifecycle is a major factor in why we chose this piston pump technology,” said Andrew Nelson, XCOR Chief Operating Officer. “This technology is also tightly coupled with certain design decisions regarding manufacturability of our rocket engine chambers and nozzles. Other rocket engines, nozzles and turbo pumps require time consuming, exotic manufacturing processes, specialty equipment and large cadres of artisan technicians and engineers to assemble and maintain them. XCOR rocket engines, nozzles and piston pumps can be manufactured by a skilled industrial machine shop and may be assembled by a streamlined workforce and tested with mobile equipment, eliminating fixed test hardware, facilities, and personnel. Our customers recognize in our technology the ability to contain the costs of developing, extending and maintaining a propulsion system over several decades.”

“At these thrust classes, the weight is comparable to and potentially lighter than a turbo pump system when the entire propulsion package is taken into account,” said XCOR chief engineer Dan DeLong. “The fuel and oxidizer pump also enables a variety of other innovations, such as our lightweight, highly manufacturable aluminum nozzles. Our pumps are fabricated using readily available automotive manufacturing techniques developed over the past 120 years. This allows us to competitively procure high quality components while avoiding the overhead of maintaining a specialized industrial base. This is our fifth generation piston pump; the first generation was internally funded, DARPA helped on the second. XCOR developed internally the pump that eventually went on the X-Racer which was the first designed and optimized for low manufacturing cost. This latest generation is almost 20 times more powerful than the X-Racer pump, but it’s only twice the weight. After more than ten years work, I think we’re getting good at this.”

“The fielding of the LOX pump is a major milestone for XCOR, the Lynx, our wet lease customers and our engine customers,” said Nelson, “I can’t wait to see it powering our engines later this summer!”

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XCOR Aerospace is a California corporation located in Mojave, California. The company is in the business of developing and producing safe, reliable and reusable rocket powered vehicles, propulsion systems, advanced non-flammable composites and other enabling technologies like rocket piston pumps that enable full reusability. XCOR is working with aerospace prime contractors and government customers on major propulsion systems, and concurrently building the Lynx, a piloted, two-seat, fully reusable, liquid rocket powered vehicle that takes off and lands horizontally. The Lynx-family of vehicles serves three primary missions depending on their specific type including: research & scientific missions, private spaceflight, and micro satellite launch (only on the Lynx Mark III). The Lynx production models (designated Lynx Mark II) are designed to be robust, multi-mission (research / scientific or private spaceflight) commercial vehicles capable of flying to 100+ km in altitude up to four times per day and are being offered globally on a wet lease basis. (

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