A report proposes an assembly of gimbaled valve/nozzle subassemblies for use in injecting either a propellant fluid (e.g., monomethyl hydrazine) or a propellant-simulating fluid (e.g., water) into the combustion chamber of a spacecraft thruster during hot-fire or cold testing, respectively. The proposal is a response to the problem of how to find the angle of impingement of injected fluid that results in the best thruster performance.
This work was done by Marlin Klatte of Caltech for NASA's Jet Propulsion Laboratory.
This invention is owned by NASA, and a patent application has been filed. Inquiries concerning nonexclusive or exclusive license for its commercial development should be addressed to
the Patent Counsel
NASA Resident Office - JPL; (818) 354-5179
Refer to NPO-20520
This Brief includes a Technical Support Package (TSP).
Gimbaled injectors for testing spacecraft thrusters
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Overview
The document presents a technical support package detailing the development of gimbaled injectors for testing spacecraft thrusters, primarily aimed at improving thruster performance during both hot-fire and cold testing. The work, conducted by Marlin F. Klatte at NASA's Jet Propulsion Laboratory (JPL), addresses the limitations of traditional testing methods that utilize fixed-angle injectors. These conventional approaches are often time-consuming and may not yield optimal designs for thruster performance.
The proposed gimbaled injector system allows for real-time adjustment of the angle of fluid injection, which can be either a propellant fluid, such as monomethyl hydrazine, or a propellant-simulating fluid, like water. This flexibility enables engineers to determine the best angle of impingement for the injected fluid more accurately and efficiently. The document highlights that previous methods relied on using simulants to establish optimal impingement angles, which could lead to discrepancies between ignition and steady-state conditions.
The gimbaled injector design incorporates a configuration that includes increased standoff bore holes to accommodate an EDM ball bearing, which is essential for the adjustable mechanism. The bearings are designed to rest on a Teflon seat and are guided by a Teflon ring, ensuring precise movement and stability during testing. The system can be operated manually or automatically, allowing for adjustments to be made before and during hot firing tests.
The motivation behind this innovation stems from the need for more effective testing methods in the Mars Accent Vehicle program, where tests are conducted under various conditions, including low temperatures. By utilizing this new injector design, the goal is to enhance thruster performance, potentially reducing the weight of spacecraft by minimizing the amount of propellant required.
The document also notes that a patent application has been filed for this invention, which is owned by NASA. Inquiries regarding nonexclusive or exclusive licensing for commercial development are directed to the Patent Counsel at NASA's JPL.
Overall, the gimbaled injector represents a significant advancement in spacecraft thruster testing, promising to improve design accuracy and efficiency while potentially leading to lighter spacecraft designs.
