A new high-performance, long-life gyroscope that serves as a balancing "inner ear" for spacecraft has been licensed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., to the Hughes Space and Communications Company, El Segundo, Calif.
Spacecraft require gyroscopes to maintain orientation in flight. Gyroscopes determine changes in angular direction, traditionally by virtue of a rapidly spinning, heavy mass. Spinning mass gyroscopes, originally the gyroscopes of choice for space applications, require lubrication and eventually wear out. By contrast, the newly developed JPL/Hughes microgyro does not have any specific life-limiting features. The resulting long life of more than 15 years is a significant plus for space applications.
Jointly developed by JPL and Hughes, this new gyroscope is lighter, cheaper, higher-performing and less complex than its conventional counterparts while uniquely designed for continuous space operation. Its dimensions are 4 by 4 millimeters (0.16 by 0.16 inches)), smaller than a shirt button, and its weight is less than one gram just under 0.03 ounces.
"This agreement typifies the type of cooperation between the space program and industry that provides benefits back to American business," said Merle McKenzie, manager of JPL's Commercial Technology and Regional Economic Development Program.
Other gyroscopes designed for use in space use solid-state technology -- that is, without any moving parts -- provide the required long lifetime, but these instruments are very expensive, power-hungry and bulky, weighing up to 20 pounds or more.
Current gyroscopes on a chip, only useful for some terrestrial applications, can measure rotation at just over the speed of the minute hand on a watch, but no slower, whereas the newly licensed microgyro can measure rotation 30 times slower than the hour hand. In the world of gyroscopes for space, measurement of extremely slow rotation is highly desirable -- the slower the better -- because the slowest of rotations can take a spacecraft significantly off target over an extended period.
Unlike its microgyro counterparts, the JPL/Hughes instrument features superior performance in both space and terrestrial environments, making it a versatile, dual-use technology.
Like its current microgyro counterparts, the JPL/Hughes version relies on measurement of vibrations. "The heart of the instrument is a cloverleaf design that is tied down and vibrates at a very high speed," said JPL's Dr. Tony Tang, engineering lead for the development of the instrument. "We look for changes in the vibration of a light piece of micro-machined silicon that has no moving parts." The exclusive use of silicon helps to reduce costs, since this durable material is now routinely used for computer chips and it is thus more easily fabricated than other materials.
The new microgyroscope, including its control electronics, was created out of a technology cooperation agreement between Hughes and JPL beginning in 1997. Hughes recently acquired exclusive rights from the California Institute of Technology to develop the microgyro for commercial space applications. Caltech has the right to elect title to inventions developed at JPL under its contract with NASA to manage JPL.
Further details about JPL's technology transfer activities are available at http://techtrans.jpl.nasa.gov/tu.html .
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