The FAA’s 2011 U.S. Commercial Space Transportation Developments and Concepts: Vehicles, Technologies, and Spaceports report highlights a pair of significant advancements by XCOR Aerospace in 2010. They involve significant progress on a new type of piston pump engine that could make turbopumps obsolete. XCOR also completed a series of crucial wind tunnel tests on its Lynx suborbital vehicle.
Both achievements are worth a closer look. Excerpts from the report follow with my notes in italics.
High Performance Cryogenic Piston Pumps
In June 2010, XCOR and ULA announced the first successful demonstration of XCORâ€™s cryogenic piston pump. The pneumatically powered test device is designed to pump liquid hydrogen. Unlike traditional turbopumps, which rely on rotating machinery, XCORâ€™s rocket engine pumps use one or more pistons to accelerate propellant into the combustion chamber. XCORâ€™s piston pumps have demonstrated longer life and lower costs than turbo machinery and have been validated with liquid oxygen and nitrogen. In addition, catastrophic failure of a piston pump is far less destructive to adjacent hardware than failure of a turbopump.
Under a fixed-price contract with ULA, XCOR developed a technology demonstrator, based on previous designs, to extend cryogenic pump applications to liquid hydrogen. Through a rapid development and test phase, XCOR demonstrated liquid-hydrogen pump technology and will continue to mature the technology with ULA. In addition to nine different rocket engines in its product line, XCORâ€™s cryogenic pump technology may enable in-space propellant transfer and other cryogenic fluid management applications.
Editor’s Note: XCOR is pursuing the Holy Grail of rocket technology: engines that can be reused dozens or even hundreds of times without needing to be overhauled. In short, propulsion systems that are similar to modern jet aircraft in reliability, operations and maintenance.
This approach is key to the company’s gas-and-go Lynx space plane, which is designed to fly, refuel, and soar back into the heavens. If the company succeeds with suborbital flights and can uprate this technology for orbital operations, then the cost of reaching space could go down significantly.
The company’s technology could be key to in-orbit refueling, which is a key capability that NASA wants to add to its toolbox. That puts XCOR in the running for R&D contracts for this crucial technology. And it will have a vehicle on which it could test such technologies in space.
Lynx Aerodynamic Validation
Lynx will use a lightweight but strong all-composite airframe. A thermal protection system will cover the nose cap and leading edges of the wings to protect these vulnerable areas from the heat of reentry.
On September 20, 2010, XCOR announced the successful completion of supersonic wind tunnel testing of a precision-scale model of the Lynx suborbital spacecraft. Tests at NASAâ€™s Marshall Space Flight Center confirmed that the Lynx can maintain stable flight throughout the projected flight profile. These tests also provided data to refine the design. Previous sub-sonic tests highlighted design flaws that required minor changes to spacecraft body for stability. These changes were evaluated in Marshallâ€™s wind tunnel, and the results indicate the stability issues were corrected. XCOR plans a final set of wind tunnel tests before vehicle assembly.
XCOR successfully tested the Lynx scale model as part of a Cooperative Research and Development Agreement between the company, NASA, and the Air Force Research Laboratoryâ€™s (AFRL) Air Vehicles Directorate.
Editor’s Note: These tests gave XCOR great confidence in its Lynx design, which is paving the way for eventual test flights of the Lynx Mark I prototype. The U.S. Air Force helped to pay for the tests, which shows the military’s interest in XCOR’s technology. It will be interesting to see if the USAF becomes a customer of XCOR, either flying experiments and personnel or buying its own vehicles.